Appendix D - Glossary

2,3-Diphosphoglycerate: A compound in red blood cells that affects oxygen binding to and release from hemoglobin.

Ablation: Destruction of part or all of an organ or structure.

Acanthosis nigricans: Dark patches of skin with a thick, velvety texture; increased thickness and hyperpigmentation of the outer cell layers of the skin; typically observed at areas of flexure. Most commonly found in those who are overweight, have darker skin, and/or have diabetes or prediabetic conditions.

Acaricide: A chemical that kills mites and ticks.

Acetylcholine: Neurotransmitter at synapses in the ganglia of the visceral motor system and a variety of sites within the central nervous system.

Achalasia: Disorder in which the esophageal sphincter is impaired, preventing normal swallowing and often causing reflux of contents and a feeling that something is caught in the throat.

Achlorhydria: Absence of free hydrochloric acid in the stomach.

Acinar cells: The cells in the pancreas responsible for the synthesis, secretion, and storage of certain digestive enzymes.

Action potential: A rapid change in the polarity of the voltage of a cell membrane from negative to positive and back to negative; a wave of electrical discharge that travels across a cell membrane.

Acute coronary syndromes: Ischemic chest discomfort at rest most often accompanied by ST-segment elevation, ST-segment depression, or T-wave inversion on the 12-lead electrocardiogram; caused by plaque rupture and partial or complete occlusion of the coronary artery by thrombus. Acute coronary syndromes include myocardial infarction and unstable angina.

Acute interstitial nephritis: An acute inflammation of the kidney, often due to drugs; patients commonly present with fever, rash, and peripheral eosinophilia.

Acute rheumatic fever: Post-streptococcal immune sequelae occurring 2 to 3 weeks following inadequately treated throat infection with group A Streptococcus.

Addiction: A primary, chronic, neurobiologic disease with genetic, psychosocial, and environmental factors influencing its development and manifestations. Characterized by behaviors such as impaired control over substance use, compulsive use, continued use despite harm, and craving.

Adenoma: A nonmalignant tumor of the epithelial tissue that is characterized by glandular structures.

Adenomatous polyposis coli: A gene associated with familial adenomatous polyposis, an inherited disorder characterized by the development of myriad polyps in the colon, often occurring in adolescents and young adults ages 15 to 25.

Adjuvant chemotherapy: Treatment given after primary surgical treatment and designed to eliminate any remaining cancer cells that are undetectable, with the goal of improving survival.

Adjuvant therapy: Treatment that follows a definitive local therapy, usually surgery, to eradicate undetectable tumor cells and follows the primary modality with the intent of reducing the risk of disease relapse and prolonging survival. The ultimate goal is to cure patients who would not otherwise be cured by the primary modality alone.

Adrenalectomy: Surgical removal of an adrenal gland.

Adverse drug reaction: As defined by the American Society of Health-System Pharmacists, any unexpected, unintended, undesired, or excessive response to a medication that requires discontinuing the medication; changing the medication; modifying the dose (except for minor dosage adjustments); necessitates admission to the hospital; prolongs stay in a healthcare facility; necessitates supportive treatment; significantly complicates diagnosis; negatively affects prognosis; or results in temporary or permanent harm, disability, or death.

Aeroallergen: An airborne substance that causes an allergic response.

Afterload: The force against which a ventricle contracts that is contributed to by the vascular resistance, especially of the arteries, and by the physical characteristics (mass and viscosity) of the blood.

Ageism: Discrimination against aged persons.

Agoraphobia: Intense fear about situations (at least two different types) that escape would be difficult or help would be unavailable.

Air embolus: An obstruction in a small blood vessel caused by air that is introduced into a blood vessel and carried through the circulation until it lodges in a smaller vessel.

Akathisia: An extrapyramidal movement disorder presenting as a subjective sense of restlessness and difficulty in staying still (motor restlessness). Motor or subjective feelings of restlessness, often characterized by the urge to move limbs and inability to sit still.

Akinesia: Lack of movement.

Allodynia: Pain that results from a stimulus that does not normally cause pain.

Allogeneic: A transplant taking cells from one person and donating them to another.

Allograft: Tissue or organ transplanted from a donor of the same species but different genetic makeup; recipient’s immune system must be suppressed to prevent rejection of the graft.

Allograft survival: After the transplant procedure, when the transplanted organ continues to have some degree of function, from excellent to poor.

Allorecognition: Recognition of the foreign antigens present on a transplanted organ or the donor’s antigen presenting cells.

Alopecia: Hair loss.

α₂ autoreceptors: These adrenergic type receptors are located on norepinephrine neurons and respond to norepinephrine. These receptors function as a negative feedback loop such that stimulation inhibits the release of norepinephrine and thus blockade would result in release.

α₂ heteroreceptors: These adrenergic type receptors are located on serotonin neurons and respond to serotonin. These receptors function as a negative feedback loop such that stimulation inhibits the release of serotonin and thus blockade would result in release.

Ambulatory esophageal reflux monitoring: A telemetry capsule containing a tiny camera is swallowed, or a transnasal catheter is inserted to determine how often reflux is occurring as well as the incidence of abnormal esophageal acid exposure. The telemetry capsule provides about 48 hours of data, whereas the transnasal catheter provides about 24 hours of data.

Amenorrhea: Abnormal cessation or absence of menses; absence or discontinuation of regular menstrual periods.

Amotivation: Apathy, loss of effectiveness, and diminished capacity or willingness to carry out complex, long-term plans, endure frustration, concentrate for long periods, follow routines, or successfully master new material.

Ampulla of Vater: Dilation of the duodenal wall at the opening of the fused pancreatic and common bile ducts.

Amylin: A 37-amino acid polypeptide hormone secreted from the β-cells of the pancreas in response to nutrients. Mechanisms of action include slowing gastric emptying, suppressing postmeal glucagon secretion, and suppressing appetite.

Amyloid: Any of a group of chemically diverse proteins that are composed of linear nonbranching aggregated fibrils.

Analgosedation: A practice of utilizing analgesics first to treat pain and sedation.

Anaphylactic/anaphylaxis: Immediate, severe, potentially fatal hypersensitivity reaction induced by an antigen.

Anaphylactoid: An anaphylactic-like reaction, similar in signs and symptoms but not mediated by IgE. The drug causing this reaction produces direct release of inflammatory mediators by a pharmacological effect.

Anastomosis: A surgical connection between two structures that are not normally connected, often between two blood vessels; connection of two hollow organs to restore continuity after resection.

Androgen deprivation therapy: Agents such as LHRH agonists, GnRH antagonist, and antiandrogens that are used to suppress testosterone levels to that consistent with medical castration (testosterone levels < 50 ng/mL).

Anergy: A reduction or lack of an immune response to a specific antigen.

Aneurysm: A blood-filled bulge which forms in the wall of a weakened blood vessel; if ruptured, it may result in bleeding, shock, and/or other negative health outcome including mortality.

Angioedema: Swelling similar to urticaria (hives), but the swelling occurs beneath the skin instead of on the surface; characterized by deep swelling around the eyes and lips and sometimes of the hands and feet. If it proceeds rapidly, it can lead to airway obstruction and suffocation, and should therefore be treated as a medical emergency.

Angiogenesis: The formation of new blood vessels. Increased blood flow to deliver nutrients is required for tumor growth.

Angiography: Examination of blood vessels using X-rays after injection of a radiopaque substance.

Anosmia: Loss of smell.

Anovulatory cycle: A menstrual cycle where ovaries fail to produce, mature or release an egg.

Anterior circulation: Blood supply to the anterior section of the brain supplied by the internal carotid arteries, anterior cerebral artery, and middle cerebral artery.

Anterograde amnesia: Inability to remember new information; may be caused by neurodegenerative disorders or medications such as benzodiazepines.

Anticitrullinated protein antibodies: Antibodies directed against cyclic citrullinated peptide, a circular peptide (a ring of amino acids) containing the amino acid citrulline.

Anticoagulant: Any substance that inhibits, suppresses, or delays the formation of blood clots. These substances occur naturally and regulate the clotting cascade. Several anticoagulants have been identified in a variety of animal tissues and have been commercially developed for medicinal use.

Antinuclear antibodies: Autoantibodies that interact with components of cellular nuclei and DNA often presenting in connective tissues disorders.

Antiphospholipid syndrome: The association of thrombosis and/or pregnancy morbidity with antiphospholipid antibodies.

Antiprotease: A substance that inhibits the enzymatic activity of a protease.

Aortic dissection: A serious condition in which there is a tear in the wall of the aorta.

Aortic stenosis: A condition in which the aortic valve becomes thickened or calcified leading to a narrowing of the aortic valve opening and restriction of blood flow from the left ventricle.

Aphakic: The absence of a lens in the eye.

Aphasia: Impairment of language affecting the ability to speak and to understand speech; the loss of a previously held ability to speak or understand spoken or written language due to disease or injury of the brain.

Aphthous ulcer: A small superficial area of ulceration within the gastrointestinal mucosa, typically found in the oral cavity.

Aplasia cutis: A congenital defect consisting of circumscribed absence of skin involving usually the scalp and has been attributed to certain medications such as methimazole.

Apoptosis: Programmed cell death as signaled by the nuclei in normally functioning cells when age or state of cell health and condition dictates.

Arcuate scotoma: An arc-shaped area of blindness in the visual field.

Arteriovenous malformation: A tangle of blood vessels, usually in the brain, that results in abnormal connections between arteries and veins; if ruptured, it may result in hemorrhage.

Arthrocentesis: Puncture and aspiration of a joint. Certain drugs can be injected into the joint space for a local effect.

Ascites: Accumulation of fluid within the peritoneal cavity.

Asterixis: A flapping tremor of the arms and hands seen in patients with end-stage liver disease.

Astringent: A substance that causes tissues to constrict, resulting in a drying effect of the skin.

Atelectasis: Decreased or absent air in a partial or entire lung, with resulting loss of lung volume.

Atherosclerosis: Accumulation of lipids, inflammatory cells, and cellular debris in the subendothelial space of the arterial wall.

Atherosclerotic cardiovascular disease: Disease in which plaque builds up in vessels.

Atopic march: Describes the development of allergic diseases (eg, atopic dermatitis, allergic rhinitis, asthma) that often start at a young age.

Atopy: A genetic predisposition to develop allergic diseases.

Atresia: Congenital absence of a normal opening or normally patent lumen.

Atrial depolarization: Change in the membrane potential of an atrial myocyte, resulting in loss of polarization. Under normal conditions, depolarization of atrial myocytes is followed by atrial contraction.

Atrophic urethritis: Thinning and inflammation of the vaginal walls secondary to decline in estrogen, experienced by almost 50% of postmenopausal women.

Atypical femoral fracture: Stress fracture occurring in the long straight portion of the femur.

Augmentation: A complication in which symptoms worsen from dopaminergic therapy in restless legs syndrome.

Aura: Visual, but sometimes sensory, motor, or verbal disturbance usually occurring before a migraine or seizure.

Auspitz sign: Pinpoint bleeding that occurs when a psoriasis scale or lesion is peeled off of the skin.

Autologous: A transplant using one’s own stem cells.

Avolition: Loss of motivation.

Azoospermic: Having no living spermatozoa in the semen, or failure of spermatogenesis.

Barium enema: A diagnostic test using an X-ray to view the lower gastrointestinal tract (colon and rectum) after rectal administration of barium sulfate, a chalky liquid contrast medium.

Barrett esophagus: A change of the normal squamous epithelium of the distal esophagus to a metaplastic, columnar-lined epithelium, usually caused by prolonged exposure of the esophageal mucosa to gastric acid. The condition is associated with an increased risk of developing esophageal cancer.

Basal Ganglia: Cluster of nerve cells deep in the brain that coordinate normal movement.

Bence-Jones proteins: Light-chained immunoglobulins found in the urine.

β-hydroxybutyric acid: A ketone body that is elevated in ketosis is synthesized in the liver from acetyl-coenzyme A and can be used as an energy source by the brain when blood glucose is low.

B₂ microglobulin: A low molecular weight protein that may be elevated in multiple myeloma.

Bilateral learning: Learning relationship where two people can simultaneously learn from each other.

Bilateral salpingo-oophorectomy: Surgical excision (removal) of both ovaries and the fallopian tubes.

Bile acids: The organic acids in bile, the yellowish-brown or green fluid secreted by the liver and discharged into the duodenum where it aids in the emulsification of fats, increases peristalsis, and retards putrefaction.

Biliary sludge: A deposit of tiny stones or crystals made up of cholesterol, calcium bilirubinate, and other calcium salts. The cholesterol and calcium bilirubinate crystals in biliary sludge can lead to gallstone formation.

Biopsy: The removal of cells or tissue for examination.

Bladder hypotonicity: Low elastic tension of the bladder.

Blast: An immature cell.

Blood urea nitrogen (BUN): A waste product in the blood produced from the breakdown of dietary proteins. The kidneys filter blood to remove urea and maintain homeostasis; a decline in kidney function results in an increase in BUN.

Body habitus: Body physique or build; describes the physical characteristics of the individual.

Body mass index: A calculation utilized to correct weight changes for height and is a direct calculation regardless of gender. It is the result of the weight in kilograms divided by the height in meters squared. If nonmetric measurements are used, it is the result of the weight in pounds multiplied by 703 and then that quantity divided by the product of height in inches squared.

Borborygmus: Rumbling or gurgling noises in the abdomen caused by movement of gas and fluid in the intestines.

Bouchard nodes: Hard, bony enlargement of the proximal interphalangeal (middle) joint of a finger or toe.

Boutonniere deformity: Joint deformity associated with rheumatoid arthritis that presents as flexion of the proximal interphalangeal (PIP) joints with hyperextension of the distal interphalangeal (DIP) joints.

Brachial plexus: Collection of nerves that arises from the spine at the base of the neck from nerves that supply parts of the shoulder, arm, forearm, and hand.

Brachytherapy: A form of radiotherapy where a sealed radiation source is placed inside or next to the area requiring treatment.

Bradycardia: Slower than normal heart rate.

Breakpoint: In antimicrobial therapy, the concentration of the antimicrobial agent that can be achieved in serum after a normal or standard dose of that agent.

Bronchiectasis: Chronic dilation of bronchi or bronchioles as a result of inflammatory disease or obstruction associated with heavy sputum.

Bronchoscopy: A specialized procedure that inserts a lighted instrument (bronscope) through the nose or mouth and into the lungs to exam the lungs.

Bullectomy: Surgical removal of one or more bullae (air spaces in the lung measuring > 1 cm in diameter in the distended state).

Burst suppression: Electroencephalography pattern characterized by electrical brain activity alternating with periods of no activity.

Calcitonin: A hormone produced by the parafollicular cells of the thyroid gland; involved in helping regulate levels of calcium and phosphate in the blood.

Calculi: The plural of calculus; stones (eg, kidney stones).

Campylobacter: Gram-negative bacillus often associated with traveler’s diarrhea.

Capillary leak: Loss of intravascular volume into the interstitial space within the body.

Carcinogenesis: Production or origin of cancer.

Carcinoma: A cancerous tumor of the epithelial tissue of an organ; a malignant growth that arises from epithelium, found in skin or the lining of body organs. Carcinomas tend to infiltrate into adjacent tissue and spread to distant organs.

Carcinomatosis: Condition of having widespread dissemination of carcinoma (cancer) in the body.

Cardiac cachexia: Physical wasting with loss of weight and muscle mass caused by cardiac disease; a wasting syndrome that causes weakness and a loss of weight, fat, and muscle.

Cardiac index: Cardiac output normalized for body surface area (cardiac index = cardiac output/body surface area).

Cardiac output: The volume of blood ejected from the left side of the heart per unit of time: Cardiac output (L/min) = Stroke volume (L) × heart rate (beats/min).

Cardiac remodeling: Genome expression resulting in molecular, cellular, and interstitial changes and manifested clinically as changes in size, shape, and function of the heart resulting from cardiac load or injury.

Cardiomyopathy: Diseases of the heart muscle in which the heart muscle becomes enlarged, thick, or rigid.

Carotid bruit: Abnormal sound heard when auscultating a carotid artery caused by turbulent blood flow, usually due to the presence of atherosclerotic plaques.

Carotids: The two main arteries in the neck.

Castration-resistant prostate cancer: Prostate cancer that continues to progress despite suppression of typical hormonal growth signals (ie, despite androgen deprivation that achieves castration levels of testosterone).

Castration-sensitive prostate cancer: Prostate cancer that is controlled by typical hormonal growth signals (ie, despite androgen deprivation that achieves castration levels of testosterone). Also often referred to as castration-naive prostate cancer.

Cataplexy: Weakness or loss of skeletal muscle tone in the jaw, legs, or arms that is elicited by emotion (eg, anger, surprise, laughter, or sadness).

Causalgia: Persistent burning pain, allodynia, and hyperpathia following a traumatic nerve lesion.

Central pain: Pain that results from a lesion or dysfunction in the central nervous system.

Cervical adenopathy: Enlargement of cervical lymph nodes in the neck.

Cervicitis: Inflammation of the cervix.

Chemokines: Any of a group of cytokines produced by various cells that stimulate chemotaxis in white blood cells.

Chemokine receptor: Transmembrane or G-protein coupled receptors that upon binding of a chemokine, initiates an intracellular immune signaling cascade.

Chemoprevention: The use of drugs, vitamins, or other agents to reduce the risk of or delay the development or recurrence of cancer; clinical application of pharmacologic agents to reduce the risk of developing certain malignancies.

Chemoprophylaxis: Use of a medication (or chemical agent) to prevent disease.

Chemoreceptor trigger zone: A location in the area postrema of the fourth ventricle of the brain. It is exposed to cerebrospinal fluid and blood and is easily stimulated by circulating toxins to induce nausea and vomiting.

Chemosis: Edema of the bulbar conjunctiva.

Cheyne-Stokes respiration: Pattern of breathing with gradual increase in depth (and sometimes in rate) to a maximum, followed by a decrease resulting in apnea; the cycles ordinarily are 30 seconds to 2 minutes in duration, with 5 to 30 seconds of apnea.

Chikungunya: Mosquito-borne disease with a clinical syndrome of systemic fevers and arthritis.

Chimeric: An individual, organ, or substance composed of substances with different genetic origins.

Chloasma: Melasma characterized by irregularly shaped brown patches on the face and other areas of the skin, often seen during pregnancy or associated with the use of oral contraceptives.

Chlorpromazine equivalents: Approximate dose equivalent of a first-generation antipsychotic to 100 mg of chlorpromazine (relative potency).

Cholangitis: Inflammation of the bile duct system.

Cholecystitis: Inflammation of the gall bladder.

Cholelithiasis: Formation of stones in the gallbladder (gallstones).

Cholestasis: Reduced or lack of flow of bile, or obstruction of bile flow.

Cholesteatoma: A mass of keratinized epithelial cells and cholesterol resembling a tumor that forms in the middle ear or mastoid region.

Chorea: A type of dyskinesia with rhythmic dance-like movement. The increase in motor activity may be associated with fidgetiness, twitching, or flinging movements.

Chronotropic: Pertaining to the heart rate.

Chvostek’s sign: Elicited by tapping on the proximal distribution of the facial nerve (adjacent to the ear). This will produce a brief spasm of the upper lip, eye, nose, or face in hypocalcemic patients.

Chylothorax: The presence of lymphatic fluid (chyle) in the pleural cavity.

Circadian rhythm: Natural, internal biological process that regulates the sleep–wake cycle every 24 hours.

Cirrhosis: Hepatic fibrosis and regenerative nodules that have destroyed the architecture of the liver, scarring the liver tissues. Progressive scarring of the liver results in nonfunctional hepatocytes.

Clonal expansion: An immunologic response in which lymphocytes stimulated by antigen proliferate and amplify the population of relevant T-cells.

Closed comedo: A plugged hair follicle of sebum, keratinocytes, and bacteria that remains beneath the surface of the skin. Also referred to as a “whitehead.”

Clotting cascade: A series of enzymatic reactions by clotting factors leading to formation of a blood clot. The clotting cascade is initiated by several thrombogenic substances. Each reaction in the cascade is triggered by the preceding one, and the effect is amplified by positive feedback loops.

Clotting factor: Plasma proteins found in the blood that are essential to the formation of blood clots. Clotting factors circulate in inactive forms but are activated by their predecessor in the clotting cascade or a thrombogenic substance. Each clotting factor is designated by a Roman numeral (eg, factor VII) and by the letter “a” when activated (eg, factor VIIa).

Clubbing: Proliferation of soft tissues, especially in the nail bed, which results in thickening and widening of fingers and toes.

Coalescence: Fusion of smaller lipid emulsion particles forming larger particles, resulting in destabilization of the emulsion.

Cognitive deficits: An impairment in the mental process that affects the way a person interacts with their environment.

Colonocyte: Cell lining the colonic surface.

Colonoscopy: Visual examination of the colon using a lighted, lens-equipped, flexible tube (colonoscope) inserted into the rectum.

Comedolytic: An agent that can break up or destroy a comedo.

Comorbidities: Multiple disease states occurring concurrently in one patient.

Complete response: The disappearance of all signs of cancer in response to treatment.

Complex regimen: Taking medications three or more times per day, or 12 or more doses per day.

Concreteness: Inability to think in abstract terms; may be a primary developmental defect or secondary to organic mental disorder or schizophrenia.

Congenital adrenal hyperplasia: A rare inherited condition resulting from a deficiency in cortisol and aldosterone synthesis with resulting excess androgen production; clinical presentation depends on the variant of the condition but typically manifests as abnormalities in sexual development and/or adrenal insufficiency.

Conjunctivitis: Inflammation of the conjunctiva.

Conjunctival injection: Erythema of the conjunctiva.

Conjunctivitis medicamentosa: A drug-induced form of allergic conjunctivitis resulting from overuse of topical ocular vasoconstrictors.

Consolidation therapy: Treatment given after cancer has disappeared following the initial therapy; used to kill any cancer cells that may be left in the body.

Continuous positive airway pressure (CPAP): Main therapy for obstructive sleep apnea by producing a positive pressure column in the upper airway using room air.

Cor pulmonale: Right-sided heart failure caused by lung disease.

Corneal arcus: Accumulation of lipid on the cornea.

Coronary artery bypass graft surgery: Surgical intervention to improve coronary blood flow by removing a vein from the leg and attaching one end to the aorta and the other end to the coronary artery distal to the atherosclerotic plaque. Alternatively, an artery from the inside of the chest wall may be used to bypass the coronary occlusion.

Cosyntropin: A synthetic version of adrenocorticotropic hormone.

Counterirritant: A substance that elicits a superficial inflammatory response with the objective of reducing inflammation in deeper, adjacent structures.

C-peptide: Peptide made when proinsulin is split into insulin and C-peptide. They split before proinsulin is released from endocytic vesicles within the pancreas, one C-peptide for each insulin molecule. C-peptide is the abbreviation for “connecting peptide.” It is used to determine if a patient has type 1 or type 2 diabetes mellitus.

Creaming: Aggregation of lipid emulsion particles that then migrate to the surface of the emulsion, can be reversed with mild agitation.

Creatinine: A waste product in the blood produced from the breakdown of protein by-products generated by muscle in the body or ingested in the diet. The kidneys filter blood to remove creatinine and maintain homeostasis; a decline in kidney function results in an increase in creatinine.

Crepitus: A grating sound or sensation typically produced by friction between bone-on-cartilage or bone-on-bone contact.

Critical care medicine: A medical practice that deals with life-threatening disease states or syndromes.

Cross-allergenicity: Sensitivity to one drug with activity to a different drug with a similar chemical structure.

Cross-cultural: Engagement involving persons from different cultures.

Crypt abscess: Neutrophilic infiltration of the intestinal glands (crypts of Lieberkühn); a characteristic finding in patients with ulcerative colitis.

Cutis laxa: Hypereflacidity of the skin with loss of elasticity.

Cyanosis: A dark blue or purple discoloration of the skin and mucous membranes due to deficient oxygenation of the blood.

Cyclooxygenase: An enzyme that catalyzes the conversion of arachidonic acid to prostaglandins and consists of two isoforms, generally abbreviated COX-1 and COX-2.

Cystocele: Herniation (abnormal protrusion) of the urinary bladder into the vagina.

Cysts: Nodules that harden into larger, pus-filled lesions.

Cytokines: Regulatory proteins, such as interleukins and lymphokines, that are released by cells of the immune system and act as intercellular mediators in the generation of an immune response.

Cytomegalovirus (CMV) disease: The term used when patients who are already infected with CMV present with the classically associated symptoms that resemble a viral infection and may include fever, malaise, arthralgias, and others.

Cytomegalovirus (CMV) infection: The term used when a patient has anti-CMV antibodies in the blood, when CMV antigens are detected in infected cells, or when the virus is isolated from a culture.

D test: Double-disk diffusion microbiological testing that indicates the presence or absence of macrolide-induced resistance to clindamycin.

Delayed peak response: The effects of a dose of medication take longer than expected to initiate.

Deliriogenic: To cause or promote increases in delirium.

Delirium: Transient brain syndrome presenting as disordered attention, cognition, psychomotor behavior, and perception.

Delirium tremens: Symptom of alcohol withdrawal characterized by hallucinations, delirium, severe agitation, fever, elevations of blood pressure and heart rate, and possible cardiac arrhythmias.

Dendritic cells: Immune regulating cells found in body tissues that serve as antigen-presenting cells.

Dengue: Mosquito-borne disease causing systemic fevers and hematologic abnormalities.

Dennie-Morgan line: A line or fold below the lower eyelids; associated with atopy.

Dermatophyte: Any microscopic fungus that grows on the skin, scalp, and nails.

Desquamation: Peeling or shedding of the epidermis (superficial layer of the skin) in scales or flakes.

Diabetes insipidus: Polyuria due to the failure of renal tubules to reabsorb water in response to antidiuretic hormone; an uncommon disorder that occurs when the kidneys pass an abnormally large volume of urine (3−20 quarts/day versus the typical 1−2 quarts/day) that is dilute and odorless (“insipid”). It is unrelated to diabetes mellitus, although both conditions cause frequent urination and constant thirst. Individuals with diabetes insipidus have normal blood glucose levels; however, their kidneys cannot balance fluid in the body.

Diabetic ketoacidosis: Reversible but life-threatening short-term complication primarily seen in patients with type 1 diabetes caused by the relative or absolute lack of insulin that results in marked ketosis and acidosis.

Dialysate: The physiologic solution used during dialysis to remove excess fluids and waste products from the blood.

Dialysis: The process of removing fluid and waste products from the blood across a semipermeable membrane to maintain fluid, electrolyte and acid–base balance in patients with kidney failure.

Diaphoresis: Sweating or profuse perspiration, generally as a symptom of a disease or an adverse drug effect.

Diarthrodial joint: A freely moveable joint (eg, knee, shoulder). Contrast with amphiarthrodial joint (a slightly movable joint; eg, vertebral joint) and synarthrodial joint (an unmovable joint; eg, fibrous joint).

Dientamoeba fragilis: Parasitic trichomonad associated with diarrheal illness in travelers.

Diffuse alveolar hemorrhage: Bleeding into the alveolar space of the lungs, resulting in hemoptysis, anemia, and diffuse alveolar infiltrates; a rare but life-threatening manifestation of systemic lupus erythematosus.

Dilated cardiomyopathy: Ability of the heart to pump blood is decreased because the left ventricle is enlarged and weakened.

Diphasic dyskinesia: Motor fluctuations occurring while plasma levodopa concentrations are rising and when they are falling. In each dosing interval, the patient may experience improvement, dyskinesia and improvement (IDI) or dyskinesia, improvement, dyskinesia (DID).

Direct current cardioversion: The process of administering a synchronized electrical shock to the chest, the purpose of which is to simultaneously depolarize all of the myocardial cells, resulting in restoration of normal sinus rhythm.

Disease progression: In cancer, at least a 20% increase in the sum of the longest diameter of target lesions from baseline, including new lesions discovered during treatment.

Disease-free survival: Period of time from the end of treatment that the patient survives without signs or symptoms of the disease.

Disseminated erythrosquamous papules: Widespread or whole body red, scaly psoriatic lesions.

DNA mismatch repair (dMMR) genes: Genes that control an intrinsic intracellular mechanism that corrects nucleotide insertion errors made during DNA replication, by excising the mismatched base pairs that escaped correction by the proofreading activities of DNA polymerases and replacing the mismatched bases with the correct ones.

Dose density: A chemotherapy treatment plan in which drugs are given with less time between treatments than in a standard chemotherapy treatment plan.

Dravet syndrome: Previously termed severe myoclonic epilepsy of infancy. Epilepsy syndrome that begins in infancy or early childhood with features of focal or generalized seizures that start before 15 months of age.

Ductus arteriosus: Shunt connecting the pulmonary artery to the aortic arch that allows blood from the right ventricle to bypass fetal lungs.

Duodenal enterocyte: Cells lining the duodenum, which is the first of three parts of the small intestine.

Dysarthria: Speech disorder due to weakness or incoordination of speech muscles; speech is slow, weak, and imprecise.

Dysesthesia: An unpleasant abnormal sensation.

Dyskinesia: Abnormal involuntary movements, which include dystonia, chorea, and akathisia.

Dyslipidemia: Elevation of the total cholesterol, low-density lipoprotein cholesterol or triglyceride concentrations, or a decrease in high-density lipoprotein cholesterol concentration in the blood.

Dysmenorrhea: Menstrual-associated crampy pelvic pain occurring with or just prior to menses. “Primary” dysmenorrhea implies pain in the setting of normal pelvic anatomy, while “secondary” dysmenorrhea is secondary to underlying pelvic pathology.

Dyspareunia: Pain during or after sexual intercourse.

Dyspepsia: Upper abdominal symptoms that may include pain or discomfort, bloating, feeling of fullness despite little food intake, unusual fullness after meals, nausea, loss of appetite, heartburn, regurgitation of food or acid, and belching.

Dysphagia: Painful or difficult swallowing, accompanied by a sensation of food being stuck in passage.

Dysphonia: Impairment of the voice or difficulty speaking.

Dyspnea: Difficult or labored breathing.

Dystonia: Disorder presenting with involuntary muscle contractions. Dystonias can also present as slow repetitive movements or abnormal postures. This is a type of dyskinesia. The movement is slow and twisting. It may be associated with painful muscle contractions or spasms.

Ebstein anomaly: Rare heart defect where the tricuspid valve is not formed properly in utero and blood leaks back into the right atrium; congenital heart defect in which the opening of the tricuspid valve is displaced toward the apex of the right ventricle. The severity can greatly vary from person to person.

Eburnation: A condition in which bone or cartilage becomes hardened and denser.

Ecchymosis: Passage of blood from ruptured blood vessels into subcutaneous tissue causing purple discoloration of the skin.

Eclampsia: Seizures associated with high blood pressure in a pregnant woman.

Ectopic pregnancy: Presence of a fertilized ovum outside of the uterine cavity.

Effector cells: Cells that become active in response to initiation of the immune response.

Electroconvulsive therapy (ECT): Administration of electric current to the brain through electrodes placed on the head in order to induce seizure activity in the brain, used in the treatment of certain mental disorders; ECT is a form of neurostimulation therapy in which patients are administered a controlled dose of electricity to induce a short, controlled seizure. Patients are unconscious and administered neuromuscular blockers to minimize movement.

Electroencephalography: The recording of brain waves via electrodes placed on the scalp or cortex.

Embolism: The sudden blockage of a vessel caused by a blood clot or foreign material which has been brought to the site by the flow of blood.

Embolization: Process by which a blood clot or foreign material dislodges from its site of origin, flows in the blood, and blocks a distant vessel.

Endometritis: Inflammation of the endometrium.

Endoscopy: A diagnostic tool used to examine the inside of hollow organs using a lighted, flexible instrument called an endoscope; refers to procedures such as gastroscopy, duodenoscopy, colonoscopy, and sigmoidoscopy.

Endothelial cell: A single layer of cells surrounding the lumen of arteries.

Endovascular: Procedures involving insertion of a catheter containing medications or instruments into a blood vessel for the treatment of vascular disease.

End-stage liver disease: Liver failure that is usually accompanied by complications such as ascites or hepatic encephalopathy.

Entamoeba histolytica: Most common cause of amoebic diarrhea in travelers.

Enteric fever/typhoid fever: Name of clinical syndrome associated with Salmonella typhi.

Enterotoxigenic E. coli: Gram-negative bacillus most commonly associated with traveler’s diarrhea.

Enthesitis: Inflammation of the sites where tendons, ligaments, or fascia attach to bone.

Enuresis: Involuntary discharge of urine.

Eosinophilic asthma: Subgroup of asthma with elevated sputum and blood eosinophils, thickening of the basement membrane zone, and corticosteroid responsiveness. Criteria that have been used for medications to treat eosinophilic asthma include blood eosinophil count ≥ 150 cells/μL (0.150 × 109/L), > 300 cells/μL (0.3 × 109/L), or 400 cells/μL (0.4 × 109/L) in the past year, sputum eosinophil count ≥ 3% (0.03), and exhaled nitric oxide concentration ≥ 50 ppb.

Epilepsy: A neurological disorder characterized by recurring motor, sensory, or psychic malfunction with or without loss of consciousness or convulsive seizures.

Epistaxis: Nasal hemorrhage with blood drainage through the nostrils; a nosebleed.

Erosive esophagitis: A severe form of gastroesophageal reflux disease in which the mucous membrane lining the esophagus is inflamed with areas of erosion resulting from abnormal reflux of gastric acid.

Erythrodermic psoriasis: Generalized erythema covering nearly the entire body surface area. Fever and malaise are common and while quite rare, can be severe and even fatal; it is usually associated with a worsening of other forms of psoriasis.

Erythematous: Flushing of the skin caused by dilation of capillaries. Erythema is often a sign of inflammation and infection.

Erythropoiesis stimulating agents: Agents developed by recombinant DNA technology that have the same biological activity as endogenous erythropoietin to stimulate erythropoiesis (red blood cell production) in the bone marrow.

Erythropoietin: A hormone primarily produced by the progenitor cells of the kidney that stimulates red blood cell production in the bone marrow. Lack of this hormone leads to anemia.

Esophageal manometry: Measurement of pressures and muscle contractions in the esophagus.

Esophageal stricture: Abnormal narrowing of the esophageal lumen.

Esophageal varices: Dilated blood vessels in the esophagus.

Essential fatty acid deficiency: Deficiency of linoleic acid, linolenic acid, and/or arachidonic acid, characterized by hair loss, thinning of skin, and skin desquamation. Long-chain fatty acids include trienes (containing 3 double-bonds [e.g., 5,8, 11-eicosatrienoic acid (or Mead acid), trienoic acids]) and tetraenes (containing 4 double-bonds [e.g., arachidonic acid]). Biochemical evidence of essential fatty acid deficiency includes a triene:tetraene greater than 0.2 and low linoleic or arachidonic acid plasma concentrations.

Essential medicines list: Medicines that satisfy the priority healthcare needs of the population that are selected and placed on a list by a group convened by the World Health Organization.

Euthymia: Normal or stable mood state.

Exanthem: Eruption of the skin.

Excess body weight: Calculated as the difference between actual and ideal body weight.

Excoriation: Recurrent skin picking resulting in lesions.

Exfoliative dermatitis: Severe inflammation and peeling of the entire skin surface due to a reaction to certain drugs.

Exploratory laparotomy: Surgical incision into the abdominal cavity, performed to examine the abdominal organs and cavity in search of an abnormality and diagnosis.

Extensive colitis: Inflammation that involves the majority of the colon in patients with inflammatory bowel disease.

External beam: An external source of radiation is pointed at a particular part of the body.

Extraction ratio: Fraction of the drug entering the liver in the blood that is irreversibly removed.

Extrapyramidal symptoms: Adverse effects of medications such as phenothiazine antipsychotics; types include dystonia (involuntary muscle contractions), tardive dyskinesia (repetitive, involuntary movements), parkinsonian symptoms (akinesia and tremors), and akathisia (motor restlessness or anxiety).

Extravasation: Movement of fluid from inside a blood vessel into the surrounding tissues.

Federal poverty level: A measure of income issued every year by the US Department of Health and Human Services; used to determine eligibility for certain government assistance programs and benefits.

Felty syndrome: An extra-articular manifestation of rheumatoid arthritis associated with splenomegaly and neutropenia.

Ferritin: A protein in the body that binds to iron; most of the iron stored in the body is bound to ferritin.

Festination: Walking with short, rapid, shuffling steps.

Fibrin: An insoluble protein that is one of the principal ingredients of a blood clot. Fibrin strands bind to one another to form a fibrin mesh. The fibrin mesh often traps platelets and other blood cells.

Fibrinolysis: A normal ongoing process that dissolves fibrin and results in the removal of small blood clots; hydrolysis of fibrin.

Fibroadenoma: A benign neoplasm which commonly occurs in breast tissue and is derived from glandular epithelium.

Fibrosis: Development of fibrous connective tissue in response to injury or damage.

Fluorescence in situ hybridization (FISH): A laboratory technique used to look at genes or chromosomes in cells and tissues. Pieces of DNA that contain a fluorescent dye are made in the laboratory and added to cells or tissues on a glass slide. When these pieces of DNA bind to specific genes or areas of chromosomes on the slide, they light up when viewed under a microscope with a special light.

Fistula: Abnormal connection between two internal organs (eg, arteriovenous fistula is a connection between an artery and a vein), or between an internal organ and the exterior or skin (e.g., enterocutaneous fistula is a connection between the intestine and the skin).

Fistulogram: X-ray photograph (or radiograph) taken after injection of a contrast material or radiopaque material (material that will not allow passage of x-rays and will be visible in an x-ray photograph, or radiograph).

Flexural psoriasis: Characterized by lesions found in skin folds that tend to be erythematous plaques which are often found in the axillary, genital, perineal, intergluteal, and inframammary regions. While shiny, smooth, and deep red in color, there may be skin fissures and the absence of the silvery scales.

Flight of ideas: A nearly continuous flow of rapid speech and thought that jumps from topic to topic, usually loosely connected.

Floppy iris or small pupil syndrome: A triad of pupillary constriction, iris prolapse, and billowing, which can complicate cataract surgery.

Flow cytometry: A method of measuring the number of cells in a sample, the percentage of live cells in a sample, and certain characteristics of cells, such as size, shape, and the presence of tumor markers on the cell surface. The cells are stained with a light-sensitive dye, placed in a fluid, and passed in a stream before a laser or other type of light. The measurements are based on how the light-sensitive dye reacts to the light.

Foam cell: Lipid-laden white blood cell.

Focal seizures: Seizures that start in a small area of the brain. They may stay localized or spread to involve larger areas or the entire brain.

Forced expiratory volume in the first second (FEV₁): The volume of air that a patient can forcibly exhale in the first second of forced exhalation after taking a maximal breath.

Forced vital capacity: The maximum volume of air that can be forcibly exhaled after taking a maximal breath.

Fraction of exhaled nitric oxide (FeNO): A noninvasive test that, when elevated, is an indicator of inflammation in the airways and likely responsiveness to inhaled corticosteroids.

Frailty: Excess demand imposed on reduced capacity; a common biological syndrome in the elderly.

Frank-Starling mechanism: Increase in stroke volume in response to an increase in volume of blood filling the heart (ie, end-diastolic volume) when all other factors remain constant.

Freezing: In Parkinson disease, a sudden but temporary inability to move.

French (scale): A scale used to measure the external diameter of a feeding tube.

Frequency (urinary): Eight or more micturitions in 24 hours.

Gallstone (cholelithiasis): A solid formation in the gallbladder or bile duct composed of cholesterol and bile salts.

Gamma knife: A type of radiation therapy that targets cancer cells within the head and brain with high precision. The treatment delivers intense radiation doses to the target area while sparing surrounding tissue.

γ-Aminobutyric acid (GABA): An inhibitory neurotransmitter.

Gastric bypass: A surgical procedure for weight loss that elicits its effectiveness through malabsorption and gastric volume limitation. The procedure involves full partitioning of the proximal gastric segment into a jejunal loop.

Gastritis: Inflammation of the stomach lining.

Gastroparesis: A form of autonomic neuropathy involving nerves of the stomach. It may include nausea, vomiting, feeling full, bloating and lack of appetite, and may cause wide fluctuations in blood sugars due to insulin action and nutrient delivery not occurring at the same time.

Gastrostomy: Operative placement of a new opening into the stomach, usually associated with feeding tube placement.

Generalized seizures: A seizure where the entire cerebral cortex is involved from the onset of the seizure.

Geniculate nucleus: The portion of the brain that processes visual information from the optic nerve and relays it to the cerebral cortex.

Geriatric syndrome: Age-specific presentations or differential diagnoses, including visual and hearing impairment, malnutrition and weight loss, urinary incontinence, gait impairment and falls, osteoporosis, dementia, delirium, sleep problems, and pressure ulcers; commonly seen conditions in elder patients.

Giardia: Protozoal gastrointestinal disease acquired by ingesting contaminated water.

Gleason score: System of histological grading used in prostate cancer. Individual scores range from 2 to 5. The two highest scores from each sample are combined for a total score (up to 10). Higher scores indicate higher-grade and more aggressive tumor.

Glomerular filtration rate: The volume of plasma that is filtered by the glomerulus per unit of time, usually expressed as mL/min or mL/min/1.73 m² (and in some areas in SI units of mL/s or mL/s/m²), which adjusts the value for body surface area. This is the primary index used to describe overall renal function.

Glomerulonephritis: A general term for an inflammatory disease that affects the glomerulus of the kidney and is immunologically mediated. Glomerular lesions that are characterized by the inflammation of the capillary loops of the glomerulus. These lesions are generally caused by immunologic, vascular, or idiopathic diseases and lead to high blood pressure and possible loss of kidney function.

Glucagon: Hormone involved in carbohydrate metabolism produced by the pancreas and released when glucose levels in the blood are low. When blood glucose levels decrease, the liver converts stored glycogen into glucose, which is released into the bloodstream. The action of glucagon is opposite of insulin.

Gluconeogenesis: Formation of glucose from precursors other than carbohydrates especially by the liver and kidney using amino acids from proteins, glycerol from fats, or lactate produced by muscle during anaerobic glycolysis.

Glucose 6 phosphate dehydrogenase (G6PD) deficiency: A generally asymptomatic genetic condition known to cause life-threatening hemolysis when patients are prescribed certain medications or triggers; enzymatic deficiency that may result in hemolytic anemia when exposed to substrate that is metabolized by G6PD.

Glucosuria: Presence of glucose in the urine.

Glutamate: An excitatory amino acid found in the central nervous system.

Glycogenolysis: The process by which glycogen is broken down to glucose in body tissues.

Glycoprotein: A protein containing an attached carbohydrate chain.

Goiter: An enlargement of the thyroid gland, causing a swelling in the front part of the neck.

Gonioscopy: Examination of the anterior-chamber angle. A gonioprism or Goldman lens is used to perform gonioscopic evaluation.

Grandiosity: Exaggerated sense of self-importance, ideas, plans, or abilities.

Gut-associated lymphoid tissue: Lymphoid tissue, including Peyer patches, found in the gut that are important for providing localized immunity to pathogens.

Guttate psoriasis: Characterized a heavy or light sprinkling of teardrop-like, salmon-pink papules covered with a fine scale. These lesions are found primarily on the trunk and proximal extremities.

Gynecomastia: Excessive development of breasts in males.

Harm reduction: Interventions aimed at reducing the negative health or social consequences associated with substance use.

Hashimoto Disease: Condition in which the immune system attacks the thyroid gland; may result in hypothyroidism. Symptoms may include fatigue, weight gain, pale or puffy face, feeling cold, joint and muscle pain, constipation, dry and thinning hair, heavy menstrual flow or irregular periods, depression, a slowed heart rate, and problems getting pregnant and maintaining pregnancy. Occurs more commonly in women than in men.

Health literacy: Degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions.

Heavy menstrual bleeding: Prolonged menstrual bleeding lasting more than 7 days or cyclic, heavy menstrual bleeding (> 80 mL per cycle).

Heberden nodes: Hard, bony enlargement of the distal interphalangeal (terminal) joint of a finger or toe.

Hematemesis: Vomiting of blood.

Hematochezia: Passage of stool that is bright red or maroon, usually because of bleeding from the lower gastrointestinal tract.

Hematoma: A localized swelling in an organ or soft tissue that is filled with clotted or partially clotted blood resulting from a break in a blood vessel wall.

Hemiparesis: A slight paralysis or weakness on one side of the body.

Hemisensory deficit: Loss of sensation on one side of the body.

Hemithorax: A single side of the trunk between the neck and the abdomen in which the heart and lungs are situated.

Hemolytic anemia: Low hemoglobin resulting from hemolysis of red blood cells.

Hemoptysis: The expectoration of blood or blood-tinged sputum from the larynx, trachea, bronchi, or lungs.

Heparin-induced thrombocytopenia: A clinical syndrome of IgG antibody production against the heparin-platelet factor 4 complex occurring in approximately 1% to 5% of patients exposed to either heparin or low-molecular-weight heparin. Results in excess production of thrombin, platelet aggregation, and thrombocytopenia (due to platelet clumping), often leading to venous and arterial thrombosis, amputation of extremities, and death.

Hepatic encephalopathy: Confusion and disorientation experienced by patients with advanced liver disease due to the accumulation of ammonia in the bloodstream.

Hepatic steatosis: Accumulation of fat in the liver.

Hepatocellular carcinoma: Cancer of the liver.

Hepatorenal syndrome: Acute kidney injury occurring in individuals with disease of the liver or biliary tract due to decreased renal blood flow and conditions that damage both organs.

Hepatotoxicity: Toxicity to the liver causing damage to liver cells.

HER2 positive: Tumor positivity is defined by IHC (3+ when > 10% of the cells harbor complete membrane staining) and FISH (if the number of HER2 gene copies is ≥ 6, or the HER2/chromosome 17 ratio is ≥ 2).

Herniation: Abnormal protrusion of an organ through a defect or natural opening; for example, protrusion of the brain through the cranial wall.

Hesitancy (urinary): A decrease in the force of the stream of urine (usually the result of an obstruction or stricture between the bladder and the external urethral orifice).

Heterotopic: Placing a transplanted organ into an abnormal anatomic location.

Heterozygous: Having different alleles at a gene locus.

Hiatal hernia: Protrusion of a portion of the stomach through the esophageal hiatus of the diaphragm.

Hirsutism: Excessive body and facial hair, especially in a female.

Homeostenosis: Impaired capability to withstand stressors and decreased ability to maintain physiological and psychosocial homeostasis; a state commonly found in elderly.

Homozygous: Having identical alleles at a gene locus.

Hormone receptor positive: Expression of estrogen and/or progesterone receptors in breast cancer cells.

Hot flashes: A feeling of warmth that is commonly accompanied by skin flushing and mild-to-severe perspiration.

Human leukocyte antigens (HLA): Groups of genes found on the major histocompatibility complex that contain cell-surface antigen presenting proteins. The body uses HLA to distinguish between self cells and non–self cells.

Humoral: A substance that acts as a result of contact with targets for activity through blood or body fluids.

Hydrocephalus: A condition marked by accumulation of cerebral spinal fluid in the brain resulting in increased pressure inside the skull.

Hydronephrosis: Swelling of the renal pelvis and calyces of the kidney due to a back-up of urine due to obstruction.

Hyperalgesia: An exaggerated intensity of pain sensation.

Hypercalcemia: Excessive amount of calcium in the blood.

Hypercalciuria: Excessive amount of calcium in the urine.

Hypercapnia: Excessive carbon dioxide in the bloodstream, typically caused by inadequate respiration.

Hypercoagulable state: A disorder or state of excessive or frequent thrombus formation; also known as thrombophilia.

Hyperemesis gravidarum: A rare disorder of severe and persistent nausea and vomiting during pregnancy that can result in dehydration, malnutrition, weight loss, and hospitalization.

Hyperopia: Farsightedness.

Hyperglycemic hyperosmolar nonketotic syndrome: Severe increase in serum glucose concentration without the production of ketones, leading to an increase in serum osmolality and symptoms such as increased thirst, increased urination, weakness, fatigue, confusion, and in severe cases, convulsions and/or coma.

Hyperpigmentation: A common darkening of the skin, which occurs when an excess of melanin forms deposits in the skin.

Hypertrichosis: Excessive growth of hair.

Hypogammaglobulinemia: Low production of gamma globulins, resulting in reduced antibodies.

Hypogonadism: A medical condition resulting from or characterized by abnormally decreased functional activity of the gonads, with retardation of growth and sexual development. Associated with testosterone deficiency resulting from either testicular or pituitary/hypothalamic diseases.

Hypomania: Characterized by a persistently elevated, expansive, or irritable mood with related symptoms of increased goal-directed activity or energy including inflated self-esteem, decreased need for sleep, excessive talkativeness, racing thoughts, distractibility, and a propensity to be involved in high-risk activities with the symptoms lasting 4 to 6 days and does not require hospitalization or significant functional impairment.

Hypomimia: Lack of facial expression. Often termed masked face.

Hypophonia: Decreased voice volume.

Hypopituitarism: A clinical disorder characterized by complete or partial deficiency in pituitary hormone production.

Hyposmia: Reduced ability to smell.

Hypoxemia: Deficiency of oxygen in the blood.

Hypoxia: Deficiency of oxygen in body tissues.

Hysterectomy: Surgical removal of the uterus.

Immunoassay: A laboratory technique that uses the binding of antibodies to detect the presence or quantity of a certain substrate or antigen.

Immunoglobulin G index: The ratio of immunoglobulin G to protein in the serum or cerebrospinal fluid.

Immunophenotyping: A process used to identify cells, based on the types of antigens or markers on the surface of the cell. This process is used to diagnose specific types of leukemia and lymphoma by comparing the cancer cells to normal cells of the immune system.

Immunotherapy: A type of biological therapy that uses substances to stimulate or suppress the immune system to help the body fight cancer, infection, and other diseases.

Implantable cardioverter-defibrillator: A device implanted into the heart transvenously with a generator implanted subcutaneously in the pectoral area that provides internal electrical cardioversion of ventricular tachycardia or defibrillation of ventricular fibrillation.

Impulse control disorders: Urges and behaviors that are excessive and/or harmful to the individual or others; may include behaviors such as gambling, compulsive shopping or sexual behavior.

Incretin effect: A greater insulin stimulatory effect after an oral glucose load than that caused by an intravenous glucose infusion. The majority of the effect is thought to be due to glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1). Patients with type 2 diabetes have a significant reduction of the incretin effect, implying these patients either have decreased concentration of incretin hormones, or a resistance to their effects. GLP-1 concentrations are reduced in patients with type 2 diabetes in response to a meal, while GIP concentrations are either normal or increased, suggesting a resistance to actions of GIP, thus making GLP-1 a more logical target for therapeutic intervention.

Induction: The first treatment given for a disease; often part of a standard set of treatments, such as surgery followed by chemotherapy and radiation.

Induction therapy: The first series of a treatment regimen typically designed to put a person into remission.

Infantile spasms (West syndrome): A seizure syndrome in infants younger than 1 year of age. It is characterized by a specific electroencephalogram pattern and spasms or jitters.

Initiation: In carcinogenesis, a cancer-causing substance encounters a normal cell to produce genetic damage, resulting in a mutated cell.

Inotropic: Relating to or influencing the force of muscular contractions.

In-stent restenosis: Complex process following stent implantation resulting in smooth muscle cell proliferation within an implanted stent, renarrowing of the arterial lumen, and recurrent ischemia.

Insulin resistance: Decreased response to insulin found before or early in the diagnosis of type 2 diabetes mellitus.

International normalized ratio (INR): Ratio of the patient’s clotting time to the clinical laboratory’s mean reference value, normalized by raising it to the international sensitivity index (ISI) power to account for differences in thromboplastin reagents. Therefore: INR = (patient’s prothrombin time/laboratory’s mean normal prothrombin time)^ISI.

Intra-articular: Administered to or occurring in the space within joints.

Intraperitoneal: Within the peritoneal cavity.

Intravesicular: Situated or occurring in the bladder.

Intussusception: The enfolding of one segment of the intestine within another.

Iontophoresis: Introduction of a medication into tissue through use of an electric current.

Ipsilateral: Occurring on the same side.

Irritant (venous): A drug that causes a burning sensation in the vein during intravenous administration; sometimes referred to as chemical phlebitis.

Ischemic penumbra: Ischemic, but still viable cerebral tissue. Typically, a rim of mild to moderately ischemic tissue in between normally perfused tissue and the area of evolving infarction; may remain viable for several hours.

Japanese encephalitis: A viral mosquito-borne disease endemic to Southeast Asia.

Jejunal entercocyte: Cells lining the jejunum, a section of the small intestine connecting the duodenum to the ileum.

Jejunostomy: Operative placement of a new opening into the jejunum, usually associated with feeding tube placement.

Juvenile myoclonic epilepsy: An epilepsy syndrome that typically occurs during teenage years and consists of generalized tonic-seizures and myoclonic jerks. Absence seizures may also occur with this syndrome.

Keratinization: The sloughing of epithelial cells in the hair follicle.

Keratinocytes: Predominant cell type in the outermost layer of the skin.

Keratitis: Infection of the cornea.

Keratoconjunctivitis sicca: An eye disease caused by eye dryness, which results from either decreased tear production or increased tear film evaporation. Also known as dry eye syndrome.

Kernicterus: A type of encephalopathy (brain disease or damage) as a result of high levels of bilirubin in the blood reaching the central nervous system.

Ketosis: Abnormal increase of ketone bodies present in conditions of reduced or disturbed carbohydrate metabolism.

Korotkoff sounds: The noise heard over an artery by auscultation when pressure over the artery is reduced below the systolic arterial pressure.

Kyphosis: Abnormal curvature of the spine resulting in protrusion of the upper back.

Lactose intolerance: The inability to digest lactose, a sugar found in milk products, resulting in diarrhea, bloating, and gas after ingestion.

Lagophthalmos: Poor closure of the upper eyelid.

Lamina cribrosa: Series of perforated sheets of connective tissue that the optic nerve passes through as it exits the eye.

Laminectomy: A type of surgery in which a surgeon removes part or all of the vertebral bone.

Laparoscopic: Abdominal exploration or surgery employing a type of endoscope called laparoscope.

Laparoscopic adjustable gastric banding: A surgical procedure for weight loss that elicits its effectiveness through gastric volume limitation; involves inserting a silicone band lined with an inflatable donut-shaped balloon around the neck of the stomach to be filled with isotonic liquid.

Laparotomy: Surgical opening of the abdominal cavity.

Laryngoscopy: Endoscopy of the larynx.

Left shift: An increase in the number of immature neutrophils. These immature cells may also be referred to as band neutrophils. Mature neutrophils may be referred to as segs.

Lennox–Gastaut syndrome: An epilepsy syndrome that often appears early in life that consists of a distinct electroencephalogram pattern, mild-to-severe developmental delay, and multiple seizure types.

Lesch-Nyhan syndrome: A rare inherited gene mutation that results in accumulation of abnormally high uric acid levels.

Leukocytoclastic vasculitis: Acute cutaneous vasculitis characterized by purpura (especially of the legs) and histologically by exudation of neutrophils and sometimes fibrin around dermal venules, with extravasation of red blood cells.

Leukocytosis: A condition in which the number of white blood cells circulating in the blood is increased.

Leukopenia: A condition where the number of circulating white blood cells are abnormally low due to decreased production of new cells, possibly in conjunction with medication toxicities.

Lewy bodies: Abnormal deposits of a protein called alpha-synuclein inside some nerve cells. They occur in a variety of locations, and their structure and composition vary depending on location.

Lhermitte sign: Tingling or shock-like sensation passing down the arms or trunk when the neck is flexed.

Libido: Sexual drive or desire.

Lichenification: Thickened, leathery, and hyperpigmented skin as a result of recurrent rubbing.

Ligament of Treitz: Landmark in the proximal portion of the jejunum beyond which it is preferred that postpyloric feedings be delivered for minimization of aspiration.

Linea nigra: Dark vertical line that appears on the abdomen during pregnancy.

Linear accelerator: A medical device that customizes high energy X-rays or electrons to conform to a tumor’s shape and destroy cancer cells while sparing surrounding normal tissue.

Lipophilic: Having affinity for fatty substances.

Livedo reticularis: Purple mottling of the skin.

Low trauma fracture: A fracture resulting from a fall from standing height or less amount of trauma.

Lower esophageal sphincter: A manometrically defined zone of the distal esophagus with an elevated basal resting pressure that prevents the reflux of gastric material from the stomach. It relaxes on swallowing to permit the free passage of food into the stomach.

Lymphadenopathy: Enlargement greater than 1 cm of one or more lymph nodes.

Lymphatic: The network of vessels carrying tissue fluids.

Lymphoproliferative: Of or related to the growth of lymphoid tissue.

Macrocytosis: Enlargement of red blood cells with near-constant hemoglobin concentration.

Macrophage: A type of white blood cell that recognizes, surrounds, and ingests foreign particles and infectious microorganisms.

Maintenance therapy: The second phase of a treatment regimen, occurring after induction; typically designed to maintain remission.

Major malformation A defect that has either cosmetic or functional significance.

Maltodextrin: Easily digestible partially hydrolyzed starch.

Mania: Persistently elevated, expansive, or irritable mood with related symptoms of increased goal-directed activity or energy including inflated self-esteem, decreased need for sleep, excessive talkativeness, racing thoughts, distractibility, and a propensity to be involved in high-risk activities with the symptoms lasting at least a week or requiring hospitalization.

Mastalgia: Tenderness of the breast.

Mastodynia: Pain in the breast.

Maternal mortality ratio: The number of maternal deaths during a given time period per 100,000 live births during the same time period; highlights the risk of maternal deaths relative to the number of live births.

Matrix metalloproteinases: Any of a group of enzymes, normally located in the extracellular space of tissue, that function to break down proteins (eg, collagen) and require zinc or calcium atoms as cofactors for enzymatic activity. Responsible for the degradation of connective tissue.

Meatal stenosis: Narrowing in the opening of the urethra.

Meconium: First intestinal discharge (“stool”) of a newborn infant, usually green in color and consisting of epithelial cells, mucus, and bile.

Mediastinal: Part of the chest that lies between the sternum and the spinal column, and between the lungs. This area contains the heart, large blood vessels, trachea, thymus gland, esophagus, and connective tissues.

Mediastinoscopy: A procedure that inserts a lighted instrument (mediastinoscope) used to examine the mediastinum.

Medication-assisted treatment: Use of medications with counseling and other behavioral therapies for the treatment of substance use disorders.

Melasma: Patchy skin pigmentation, often seen during pregnancy.

Melena: Abnormally dark black, tarry feces containing blood (usually from gastrointestinal bleeding).

Meningococcal: A term used to describe a disease caused by Neisseria meningitidis bacteria.

Menopause: Marked by final menstrual period due to loss of follicular activity and confirmed by 12 months of amenorrhea.

Mesial temporal lobe epilepsy: Involves medial or internal structures of the temporal lob and accounts for almost 80% of all temporal lobe seizures.

Mesocortical: A neural pathway that connects the ventral tegmentum to the cortex, particularly the frontal lobes. It is one of the major dopamine pathways in the brain.

Mesolimbic: One of the four major dopamine pathways in the brain, connecting the ventral tegmental area to the nucleus accumbens.

Mesothelioma: A benign or malignant tumor affecting the lining of the chest or abdomen. Commonly caused by exposure to asbestos fibers.

Metabolic Acidosis: A condition in the blood and tissues that is a consequence of an accumulation of lactic acid resulting from tissue hypoxia and anaerobic metabolism; may also be caused by a decrease in the concentration of alkaline compounds (typically bicarbonate).

Metabolic syndrome: Constellation of cardiovascular risk factors related to hypertension, abdominal obesity, dyslipidemia, and insulin resistance diagnosed by the presence of at least three of the following criteria: increased waist circumference, elevated triglyceride concentrations, decreased high density lipoprotein (HDL) cholesterol or active treatment to raise HDL cholesterol, elevated blood pressure or active treatment with antihypertensive therapy, or elevated fasting glucose or active treatment for diabetes.

Metastasis: Cancer that has spread from the original site of the tumor.

Methemoglobinemia: Condition caused by elevated levels of methemoglobin in red blood cells, resulting in enhanced oxygen affinity in heme sites and reduced oxygen delivery to tissues; leads to hypoxia, cyanosis, shortness of breath, mental status changes, and dizziness. In severe cases, it can lead to seizures, coma, or death.

Michaelis–Menten: Another term for zero-order pharmacokinetics. Drugs that follow zero-order pharmacokinetics reach saturation of metabolism within the usual dose ranges. This results in large changes in concentrations with small changes in doses.

Microalbuminuria: Urinary excretion of small but abnormal amounts of albumin. Confirmed spot urine albumin to creatinine ratio of 30 to 300 mg/g (3.4−34 mg/mmol creatinine) is consistent with microalbuminuria. Considered an early sign of chronic kidney disease.

Microcytosis: A condition in which the erythrocytes are smaller than normal.

Micrognathia: Abnormal smallness of the jaws.

Micrographia: Small handwriting, often seen in patients with Parkinson disease.

Microsatellite instability (MSI): The condition of genetic hypermutability that results from impaired DNA mismatch repair (MMR). The presence of MSI represents phenotypic evidence that MMR is not functioning normally.

Microvascular: Pertaining to the smaller vessels of the circulatory system such as capillaries, venules, and arterioles.

Microvascular pulmonary emboli: An obstruction in the small blood vessels in the lung caused by material (eg, blood clot, fat, air, foreign body) that is carried through the circulation until it lodges in another small vessel.

Micturition: Act of passing urine.

Minor malformation: Defect that has neither cosmetic nor functional significance.

Miosis: Pupil constriction.

Moebius syndrome: Rare congenital neurological disorder that is characterized by facial paralysis and affects eye movement.

Monoamine neurotransmitter: Serotonin, norepinephrine, and dopamine.

Monocyte: A large, phagocytic white blood cell that can further differentiate into macrophages or dendritic cells.

Monoparesis: Slight or incomplete paralysis affecting a single extremity or part of one.

Monosodium urate: A crystallized form of uric acid that can deposit in joints leading to an inflammatory reaction and signs and symptoms of gout.

Morphine equivalents: Dose of an opiate equivalency as it relates to morphine.

Mucositis: A complication of some cancer therapies in which the lining of the digestive system becomes inflamed. Often seen as sores in the mouth.

Multiparity: Condition of having given birth to multiple children.

Muscularis mucosa: The thin layer of smooth muscle found in most parts of the gastrointestinal tract.

Myalgia: Muscle aches or pains not necessarily associated with creatine kinase elevations.

Mydriasis: Pupil dilation.

Myelin: A protein and phospholipid sheath that surrounds the axons of certain neurons. Myelinated nerves conduct impulses more rapidly than nonmyelinated nerves.

Myelodysplastic syndrome: A type of cancer in which the bone marrow does not make enough healthy blood cells (white blood cells, red blood cells, and platelets) and there are abnormal cells in the blood and/or bone marrow.

Myelopathy: A neurologic deficit related to the spinal cord.

Myelosuppression: Reduction in white blood cells, red blood cells, or platelets.

Myocardial infarction: Myocardial cell death secondary to prolonged or severe local lack of oxygen supply (ischemia) to the myocardium; formation of an infarct, an area of tissue death, due to a local lack of oxygen.

Myoglobinuria: Presence of myoglobin in urine.

Myonecrosis: Necrotic damage to muscle tissue.

Myopathy: Unexplained muscle pain or weakness with creatine kinase elevations greater than 10 times the upper limit of normal.

Myringotomy: A surgical incision made in the tympanic membrane to relieve pressure and drain fluid from the middle ear.

Myxedema: Hypothyroidism characterized by a relatively hard edema of subcutaneous tissue, with increased content of proteoglycans in the fluid; characterized by somnolence, slow mentation, dryness and loss of hair, increased fluid in body cavities such as the pericardial sac, subnormal temperature, hoarseness, muscle weakness, and slow return of a muscle to the neutral position after a tendon jerk.

Nail psoriasis: Characterized by pitting, onycholysis, hyperkeratosis, and an oil-drop sign.

Nasal scotoma: Area of blindness in the nasal portion of peripheral vision.

Nasolacrimal occlusion: Closure of the tear duct to decrease systemic absorption of a drug.

Natriuresis: Excretion of sodium in the urine.

Necrotizing enterocolitis: Medical condition seen in premature infants, where portions of the bowel undergo necrosis.

Nelson syndrome: A condition characterized by the aggressive growth of a pituitary tumor and hyperpigmentation of the skin.

Neoadjuvant chemotherapy: Chemotherapy given before surgical resection to decrease tumor burden and make cancer more amenable to surgical resection.

Nephrolithiasis: A condition marked by the presence of renal calculi (stones) in the kidney or urinary system.

Nephron: The working unit of the kidney that filters blood to remove fluid, toxins and drugs. Each kidney contains approximately 1 million nephrons.

Nephrostomy: Narrow-gauge pigtail drain inserted into the renal pelvis for the purpose of draining urine.

Neuritic plaques: Extracellular deposits of amyloid beta with concentration markedly increased in the hippocampus, amygdala, and cerebral cortex. The plaque is thought to be formed through a cascade involving the formation of abnormally folded amyloid beta from amyloid precursor protein.

Neurofibrillary tangles: Aggregates of hyperphosphorylated tau protein, which can disrupt cellular function and lead to cellular degeneration and death.

Neuropathic pain: Pain resulting from a lesion or dysfunction of the nervous system.

Neuropathy: An abnormal and usually degenerative state of the nervous system or nerves. Damage to the small and large nerves due to glycation end products, lack of blood and nutrients to the nerves, or chemical imbalances.

Neurotransmitter: Chemical intermediary that carries messages between nerve cells.

Neutralizing antibodies: Antibodies that develop in response to a therapeutic agent that decreases the efficacy of the agent.

Nigrostriatal: One of the four main dopamine pathways in the brain, running from the substantia nigra to the caudate and putamen.

Nociception: Encoding and processing of noxious stimuli to the nervous system.

Nociceptors: Receptors for pain caused by injury from physical stimuli (mechanical, electrical, or thermal) or chemical stimuli (toxins); located in the skin, muscles, or in the walls of the viscera.

Nocturia: Excessive urination that occurs during sleep, causing patients to awaken overnight.

Nodule: An abnormal small swelling or aggregation of cells in the body.

Nonpolyposis: Absence of polyps.

Nonrapid eye movement sleep: The dreamless phases of sleep.

Non–ST-segment elevation myocardial infarction: A type of myocardial infarction that is limited to the subendocardial myocardium and is smaller and less extensive than an ST-segment elevation myocardial infarction.

Noradrenergic: Involving the transmission of norepinephrine.

Nulliparity: Condition of not having given birth to a child.

Nystagmus: Rapid, involuntary movements of the eyes.

Obtunded: Decreased level of consciousness.

Odynophagia: Pain on swallowing food and fluids, which is often due to esophageal disease.

Off time: In the context of Parkinson disease, the time when a Parkinson disease patient has poor control of their symptoms.

Off-label use: Use of a medication outside the scope of its approved, labeled use.

Oiling out: Continued coalescence of lipid emulsion particles, resulting in irreversible separation of the emulsion (also called “breaking” or “cracking” of the emulsion).

Oligoclonal immunoglobulin G bands: Small discrete bands in the gamma globulin region of fluid electrophoresis.

Oligohydramnios: Decreased amniotic fluid.

Oliguria: Reduced urine output; usually defined as less than 400 mL in 24 hours or less than 0.5 mL/kg/hour.

Omentumectomy: Excision of the double fold of peritoneum attached to the stomach and connecting it with abdominal viscera (omentum).

On time: In the context of Parkinson disease, the time when the Parkinson disease patient has good control of their symptoms.

Oncogene: A gene that is a mutated form of a gene involved in normal cell growth.

Open comedo: A plugged hair follicle of sebum, keratinocytes, and bacteria that protrudes from the surface of the skin and appears black or brown in color. Also referred to as a “blackhead.”

Opportunity cost: The benefits foregone by selecting one alternative over another, for example, spending on healthcare reduces disposable income that may have been used on savings or investment.

Opsonization: The process by which an antigen is altered so as to become more readily and more efficiently engulfed by phagocytes.

Optic neuritis: Usually monocular central visual acuity loss and ocular/periorbital pain caused by demyelination of the optic nerve.

Oral glucose tolerance test: A test to measure the body’s response to glucose; may be used to screen for type 2 diabetes and gestational diabetes.

Orchiectomy: Surgical removal of the testes.

Organification: Binding of iodine to tyrosine residues of thyroglobulin.

Orthopnea: Difficulty in breathing that occurs when lying down and is relieved upon changing to an upright position.

Orthostasis: Characterized by a drop in blood pressure when standing up from sitting or lying down, often causing lightheadedness and dizziness.

Orthostatic hypotension/orthostasis: Significant blood pressure reduction upon standing due to the impairment of autonomic reflexes or depletion of intravascular volume.

Orthotopic: Placing a transplanted organ into the normal anatomic location.

Osmolality: A measure of the number of osmotically active particles per unit solution, independent of the weight or nature of the particle.

Osmolar gap: The difference between the measured serum osmolality and the calculated serum osmolality.

Osteoblasts: Cells that secrete the matrix for bone formation.

Osteoclasts: Cells involved in bone resorption.

Osteodystrophy: Defective bone growth, usually attributed to kidney disease or alterations in calcium and phosphorus metabolism.

Osteomalacia: Softening of the bones.

Osteonecrosis: Death of bone tissue.

Osteopenia: Reduced bone density or mass.

Osteophytes: Bony outgrowths (also called bone spurs) into the joint space.

Osteoporosis: Disease of the bones characterized by a loss of bone tissue, resulting in brittle, weak bones that are susceptible to fracture (porous bones).

Ostomy: Surgical operation where part of the abdominal wall is opened and part of the intestine is connected to the opening for intestinal draining (eg, colostomy, ileostomy).

Otalgia: Ear pain or earache.

Overall objective response rate: The proportion of patients with a complete response or partial response to anticancer treatment over a defined time period.

Ovulation: Periodic ripening and rupture of mature follicle and the discharge of ovum from the cortex of the ovary.

Palliative care: Pharmacological and nonpharmacological therapy intended to improve quality of life.

Palpable cord: Presence of an induration (cord) that is palpable, sometimes nodular, along the course of/or within an affected vein. Persistence of this cord when the extremity is raised suggests the presence of thrombus.

Pancreatitis: Inflammation of the pancreas.

Pancreatic pseudocyst: A cyst-like space not lined by epithelium and contained within the pancreas.

Panhypopituitarism: A clinical disorder characterized by complete deficiency in pituitary hormone production.

Pannus: Inflamed synovial tissue that invades and destroys articular structures.

Papilledema: Swelling of the optic disk/nerve due to increased intracranial pressure.

Papules: Solid, elevated lesion less than 0.5 cm in diameter.

Paracentesis: Removal of ascitic fluid from the peritoneal space.

Paracentral scotoma: Blind spots near the center of the visual field.

Parasomnias: Abnormal sleep behaviors such as sleep terrors and sleepwalking.

Parenchyma: The functional tissue of an organ as distinguished from connective and supporting tissue.

Parenteral nutrition: Delivery of nutrients via the intravenous route.

Paresthesia: An abnormal touch sensation, such as burning or prickling, that occurs without an outside stimulus.

Partial response: A decrease in the size of a tumor, or in the extent of cancer in the body, in response to treatment.

Paternalistic medicine: A philosophy of medicine that promotes the physicians’ wishes above any other member of the healthcare team or patients.

Peak expiratory flow: The maximum flow rate of air leaving the lungs upon forced exhalation. Individualized best measurements are established for each patient using a handheld peak flow meter.

Pelvic inflammatory disease: Inflammation of the endometrium, uterine tubes, and pelvic peritoneum; often due to a sexually transmitted infection.

Percutaneous coronary intervention: A minimally invasive procedure whereby access to the coronary arteries is obtained through either the femoral or radial artery up the aorta to the coronary ostia. Contrast media is used to visualize the coronary artery stenosis using a coronary angiogram. A guidewire is used to cross the stenosis and a small balloon is inflated to compress the atherosclerotic plaque and restore coronary artery blood flow. A stent is often deployed at the site to prevent acute closure and restenosis of the coronary artery. Newer stents are coated with antiproliferative drugs, such as paclitaxel, sirolimus, zotarolimus, or everolimus, which further reduce the risk of restenosis of the coronary artery.

Percutaneous endoscopic gastrostomy: Gastric feeding tube placed via endoscopic technique.

Percutaneous endoscopic jejunostomy: Jejunal feeding tube placed via endoscopic technique.

Pericarditis: Inflammation of the pericardium, the sac-like tissue that surrounds the heart.

Perihilar: The area surrounding the region where the bronchi, arteries, veins, and nerves enter and exit the lungs.

Perimenopause: Transitional period prior to menopause.

Perimetry: Measurement of the visual field.

Peripheral artery disease: Atherosclerosis of the peripheral arteries.

Peripheral vascular resistance: The sum of resistance to blood flow by systemic blood vessels.

Phagocytosis: The process of engulfing and ingesting an antigen by phagocytes.

Pharmacodynamics: Biochemical, physiologic, and molecular effects of drugs on the body.

Pharmacogenomics: The study of inherited genetic variations that dictate different drug responses. Pharmacogenomics explores the ways such variations can be used to predict responses to investigational products and plays an increasingly important role in drug discovery.

Pharmacokinetics: The movement of drug into, through, and out of the body.

Phenotype: The visible or observable properties of an organism that are produced by the interaction of the genotype and the environment.

Pheochromocytoma: A tumor arising from chromaffin cells, most commonly found in the adrenal medulla. The tumor causes the adrenal medulla to hypersecrete epinephrine and norepinephrine resulting in hypertension and other signs and symptoms of excessive sympathetic nervous system activity. The tumor is usually benign but may occasionally be cancerous.

Phlebitis: Inflammation of a blood vessel (e.g., vein).

Phobia: Excessive or unreasonable fear to a specific object (eg, people, animals) or situation (eg, flying), which are avoided or experienced with significant distress.

Photobiomodulation: Use of red or near-infrared light to stimulate healing, relieve pain and inflammation, and prevent tissue from dying.

Photochemotherapy: The use of psoralens in addition to ultraviolet rays for patients with a significant amount of body surface area affected (>10%).

Photodynamic therapy: Treatment with drugs that become active when exposed to light.

Photophobia: Intolerance to bright light.

Phototherapy: The use of ultraviolet rays for patients with a significant amount of body surface area affected (>10%).

Physical dependence: A state of adaptation that is manifested by a drug-class specific withdrawal syndrome that can be produced by abrupt cessation, rapid dose reduction, decreasing blood level of the drug, and/or administration of an antagonist.

Pilosebaceous unit: A hair follicle and the surrounding sebaceous glands.

Pica: An abnormal desire to eat substances (such as chalk or ashes) not normally eaten.

Plaque psoriasis: The most common form of psoriasis; manifests as well-defined, sharply demarcated, erythematous plaques typically covered with silvery scales. These plaques are irregular, round to oval in shape, and are almost always found on the scalp, trunk, buttocks, and limbs.

Plasma cell: Antibody-producing cells.

Plasmodium falciparum: The most common cause of clinical malaria globally and the cause of the most fatalities associated with malaria.

Plasmodium vivax: The most common cause of clinical malaria in the Americas. It is the species most commonly associated with a delayed onset of relapse after treatment.

Pleurisy: Chest pain upon inspiration occurring due to inflammation of the lining of the lungs.

Pleuritis: Inflammation of the lining (pleura) around the lungs.

Pneumatic otoscopy: A diagnostic technique involving visualization of the tympanic membrane for transparency, position, and color, and its response to positive and negative air pressure to assess mobility.

Pneumococcal: A term used to describe a disease caused by Streptococcus pneumoniae bacteria.

Pneumothorax: A condition that occurs when air leaks into the space between chest wall and lung. The air pocket exerts pressure against the lung causing it, or a portion of it, to “collapse”; often referred to as a collapsed lung.

Podagra: Gout of the foot, especially the first metatarsophalangeal joint.

Podocyte: Cells that make up the epithelial lining of Bowman’s capsule of the kidneys that surround the capillaries in the glomerulus. These cells are responsible for filtering blood in the glomerulus.

Polycystic ovary syndrome: Condition in which women have many small cysts on their ovaries that can lead to hormone imbalances and irregular periods.

Polycythemia: An abnormal increase in the number of erythrocytes in the blood.

Polycythemia vera: A hematologic cancer that is slow-growing in which the bone marrow produces excess red blood cells.

Polydipsia: Excessive thirst.

Polymerase chain reaction: A laboratory method used to make many copies of a specific DNA sequence.

Polymorphism: Occurrence in more than one form such as variance of genes.

Polyphagia: Eating excessively large amounts of food at a meal.

Polypharmacy: Taking multiple medications concurrently.

Polyps: Any growth or mass protruding from a mucous membrane.

Polysomnography: Specific type of sleep study that records brain waves, oxygen levels, heart rate, breathing, and eye and leg movements.

Polyuria: Excessive excretion of urine resulting in profuse micturition.

Posterior circulation: Blood supply to the posterior section of the brain through the vertebral, basilar, and posterior cerebral arteries (ie, brainstem, cerebellum, occipital lobe).

Post-intensive care syndrome: The disability noted after discharge from the intensive care unit and critical illness. Impairments which have been described include, but are not limited to, issues with cognition, mental health disabilities, and recurring physical ailments, specifically neuromuscular weakness.

Prader–Willi syndrome: A genetic disorder characterized by short stature, mental retardation, low muscle tone, abnormally small hands and feet, hypogonadism, and excessive eating leading to extreme obesity.

Prebiotic: Substance that can be used to nourish beneficial microbes in the gut.

Prediabetes: An asymptomatic but abnormal state that precedes the development of clinically evident diabetes.

Preload: The stretched condition of the heart muscle at the end of diastole just before contraction; volume in the left ventricle at the end of diastole estimated by the pulmonary artery occlusion pressure (also known as the pulmonary artery wedge pressure or pulmonary capillary wedge pressure).

Priapism: A prolonged, painful erection lasting more than 4 hours. Considered a medical emergency.

Primary amenorrhea: Absence of menses by age 15 in the presence of normal secondary sexual development or within 5 years of thelarche (if occurs before age 10).

Probiotic: Microorganisms administered to achieve a health benefit.

Proctitis: Inflammation confined to the rectum in patients with inflammatory bowel disease.

Proctosigmoiditis: Inflammation involving the sigmoid colon and rectum in patients with inflammatory bowel disease.

Progenitor: A primitive cell.

Prognostic factors: Biological or clinical markers associated with survival independent of therapy.

Progression-free survival: The length of time during and after the treatment of a disease, such as cancer, that a patient lives with the disease but it does not get worse. In a clinical trial, measuring the progression-free survival is one way to see how well a new treatment works.

Progressive multifocal leukoencephalopathy: A neurological disorder characterized by the destruction of myelin-producing cells.

Prolapse: The dropping, falling, sinking, or sliding of an organ from its normal position or location in the body.

Promotion: The stage of carcinogenesis in which existing tumors are stimulated to grow and survive.

Proptosis: Forward displacement of the eyeball.

Prostaglandin: Any of a large group of biologically active, carbon-20, unsaturated fatty acids that are produced by the metabolism of arachidonic acid through the cyclooxygenase pathway.

Prostate-specific antigen (PSA): Protein produced by columnar secretory cells in the prostate that plays a role in the liquefaction of seminal fluid. Serum PSA levels greater than 10 ng/mL are associated with prostate cancer.

Prostatectomy: Surgical removal of the prostate gland and tissues surrounding it.

Prostatism: A syndrome associated with outlet obstruction at the bladder neck and most commonly caused by benign prostatic hyperplasia.

Protease: Any of numerous enzymes that catalyze the breakdown of proteins.

Proteasome: A large protein complex that helps destroy other cellular proteins when they are no longer needed.

Protectant: An agent that forms an occlusive barrier between the skin and surrounding moisture.

Proteinuria: The presence of measurable amounts of protein in the urine, which is often indicative of structural glomerular or tubular damage in the kidney.

Proteoglycan: Any one of a class of glycoproteins of high molecular weight that are found in the extracellular matrix of connective tissue. They are made up mostly of carbohydrate consisting of various polysaccharide side chains linked to a protein and resemble polysaccharides rather than proteins with regard to their properties.

Proteosome: An enzyme complex that degrades intracellular proteins.

Prothrombin time: A measure of coagulation representing the amount of time required to form a blood clot after the addition of thromboplastin to the blood sample; also known as Quick test.

Prothrombotic state: A state of high coagulation of the blood.

Proto-oncogene: A gene involved in normal cell growth. Mutations (changes) in a proto-oncogene may cause it to become an oncogene, which can cause the growth of cancer cells.

Pruritus: Localized or generalized itching due to irritation of sensory nerve endings.

Pseudophakic: The presence of a lens after cataract extraction.

Pseudopolyp: An area of hypertrophied gastrointestinal mucosa that resembles a polyp and contains nonmalignant cells.

Psoralens: Compounds that act as photosensitizing compounds.

Psoriatic arthritis: Inflammatory arthropathy associated with psoriasis. This condition is characterized by stiffness, pain, swelling, and tenderness around the joints and ligaments.

Pulmonary artery catheter: An invasive device used to measure hemodynamic parameters directly, including cardiac output and pulmonary artery occlusion pressure; calculated parameters include stroke volume and systemic vascular resistance.

Pulmonary artery occlusion pressure: A hemodynamic measurement obtained via catheter placed into the pulmonary artery used to evaluate patient volume status within the left ventricle.

Pulmonary embolus: An obstruction of the pulmonary artery or one of its branches by material that originated elsewhere in the body. The embolic material is often either a thrombus, air, tumor, or adipose tissue.

Pulmonary hypertension: An elevation in the pulmonary arterial pressure that can lead to right ventricular failure and heart failure symptoms.

Pulse oximetry: A noninvasive method of measuring arterial oxygen saturation. A pulse oximeter is a small device placed on a finger or earlobe that reads reflected light from capillary blood and estimates oxygen saturation.

Pulsus paradoxus: A large fall in systolic blood pressure and pulse volume during inspiration or an abnormal variation in pulse volume during respiration in which the pulse becomes weaker with inspiration and stronger with expiration.

Punding: Stereotyped behavior with repetitive movement or actions. An adverse reaction to dopaminergic therapy.

Purkinje fibers: Specialized myocardial fibers that conduct impulses from the atrioventricular node to the ventricles.

Purpura: A small hemorrhage of the skin, mucous membrane, or serosal surface.

Purulent: Containing, consisting of, or being pus.

Pustular psoriasis: A type of psoriasis associated with collection of neutrophils great enough to be seen clinically; may be generalized or localized. Often characterized by widespread sterile pustules and erythema.

Pustules: Vesicles filled with purulent fluid less than 0.5 cm in diameter.

Quality indicators: A list of indicators used by long-term care facility administrators and government overseers to identify potential problems in patient care.

Quality of life: An individual’s sense of well-being and ability to carry out activities of daily living.

Quiescence: Dormant disease.

Radon: A chemically inert, radioactive gaseous element produced by the decay of radium, which is a risk factor for developing lung cancer.

Rapid cycling: Four or more mood episodes (major depressive, manic, or hypomanic) within 1 year.

Rapid eye movement sleep: Phase of sleep in which the eyes move rapidly, there is low muscle tone, and dreaming may occur.

Rapid sequence intubation: An airway procedure that aims to reduce the incidence of complications when placing an endotracheal tube. During the procedure, agents are utilized to induce an amnestic state while also causing muscle relaxation to allow for easier passage of the tube to the lungs.

Raynaud Disease: Decrease in blood flow to fingers or toes due to spasming of blood vessels; occurs in response to cold temperatures or stress; results in numbness, pain, and color changes of affected digits.

Rectal prolapse: Externally visible sinking of the rectum through the anal sphincter.

Recurrence: The development of a new episode after a patient has achieved remission of a condition or disease for a sustained period of time.

Reentry: Circular movement of electrical impulses, a mechanism of many arrhythmias.

Regurgitation: The effortless and nonprojectile passage of refluxed gastric contents into the pharynx or mouth.

Relapse: Return of symptoms prior to achieving remission or shortly after achieving remission. The relapse is typically considered a return of the original symptoms rather than a new episode as in recurrence.

Remission: A near absence of symptoms or return to baseline between episodes. Patient has no or minimal symptoms of disease. In the case of cancer in partial remission, some but not all signs and symptoms of cancer have disappeared. In complete remission, all signs and symptoms of cancer have disappeared, although cancer still may be in the body.

Renin–angiotensin–aldosterone system: The hormonal system controlled mainly by the kidneys and adrenal glands, which regulates blood pressure, blood volume, and electrolyte balance.

Resistance-associated substitution: Resistance to a drug resulting in decreased antiviral activity caused by an amino acid change in the viral protein.

Resistant: A disease state or medical condition, such as cancer or infection, that does not respond to treatment.

Respiratory disturbance index: Measure reported on polysomnography that reports respiratory events during sleep.

Response inhibition: Ability to stay on task.

Reticulocytes: Immature blood cells that mature into erythrocytes.

Retinopathy: Occurs when the microvasculature nerve layer that provides blood and nutrients to the retina is damaged and can cause blindness.

Retrograde ejaculation: Semen flows to the bladder instead of the urethra.

Retrograde pyelography: Injection of a radiocontrast agent into the ureters to visualize the ureter and kidney with fluoroscopy or radiography.

Retrovirus: An RNA virus that uses an enzyme, reverse transcriptase, to turn the RNA into DNA in order to become part of the host cell’s DNA (eg, Human Immunodeficiency Virus).

Rhabdomyolysis: Muscle symptoms with marked elevation in creatine kinase at 40 times the upper limit of normal which results in myoglobinuria and acute renal failure.

Rheumatic fever: A rare, acute immune-mediated disease that occurs mainly in children and young adults that is characterized by fever, arthritis, and inflammation of the pericardium and heart valves; it is associated with untreated or undertreated group A streptococcal disease.

Rheumatic heart disease: Valvular heart disease resulting from acute rheumatic fever.

Rheumatoid factors: Antibodies reactive with the Fc region of IgG.

Rhonchi: Abnormal, rumbling sounds heard on auscultation of an obstructed airway; more prominent during expiration and may clear somewhat on coughing.

Rickettsia: Intracellular bacteria often associated with tick bites and causing a nonspecific febrile syndrome.

Rotational thromboelastometry: A type of viscoelastic testing that measures clot formation to breakdown.

Rubefacient: A substance that produces redness of the skin.

Salicylism: A toxic syndrome caused by excessive doses of acetylsalicylic acid (aspirin), salicylic acid, or any other salicylate product. Signs and symptoms may include severe headache, nausea, vomiting, tinnitus (ringing in the ears), confusion, increased pulse, and increased respiratory rate.

Salmonella: Gram-negative enteric rod known to cause gastroenteritis.

Scleritis: Inflammation of the outer layer of the eyeball (sclera).

Scoliosis: Abnormal lateral (sideways) curvature of the spine.

Scotoma: A spot in the visual field in which vision is absent or deficient.

Sebaceous gland: Gland that produces sebum.

Sebum: Substance produced by the sebaceous gland that is composed of lipids.

Secondary amenorrhea: Absence of menses for three cycles or 6 months in a previously menstruating woman.

Seizure: A sudden electrical disturbance of the cerebral cortex, when a population of neurons fires rapidly and repetitively for seconds to minutes and electrical discharges are excessively rapid, rhythmic, and synchronous.

Sensitive: A disease state or medical condition that responds to treatment.

Sentinel lymph node: The first lymph node to which cancer is likely to spread from the primary tumor.

Sequential compression devices: A nonpharmacologic method of preventing venous thromboembolism.

Seropositive: Showing a positive reaction to a test on blood serum for a disease.

Severe myoclonic epilepsy of infancy: See Dravet syndrome.

Shigella: Gram-negative enteric bacteria causing a syndrome of explosive infectious diarrhea.

Sialorrhea: Drooling.

Sigmoidoscopy: Visual inspection of the sigmoid colon and rectum with a flexible tube called a sigmoidoscope.

Sleep apnea: Temporary stoppage of breathing during sleep; can be caused by narrowing of the airways resulting from swelling of soft tissue.

Sleep latency: Amount of time it takes to fall asleep.

Sleeve gastrectomy: A surgical treatment for weight loss that involves constructing a small gastric “sleeve” but cutting vertically and removing up to 90% of the stomach.

Slit-lamp biomicroscope: An instrument that allows for the microscopic examination of the cornea, anterior-chamber lens, and posterior chamber.

Spasticity: Feelings of stiffness and involuntary muscle contractions or sudden movements.

Sphincter of Oddi: Muscle where common bile duct empties into small intestine.

Spirometry: Measurement by means of a spirometer of the air entering and leaving the lungs.

Splanchnic: Relating to the viscera or internal organs.

Spondylolysis: A stress fracture in the lumbar spine through the pars interarticularis, a thin bone joining two vertebrae.

Stable disease: Cancer that has either insufficient increase to be defined as progressive disease or shrinkage to be defined as a response.

Steatohepatitis: A severe form of liver disease caused by fat deposition in the liver, characterized by hepatic inflammation that may rapidly progress to liver fibrosis and cirrhosis.

Steatorrhea: Passage of fat in large amounts in the feces, due to the failure to digest and absorb it.

Steatosis: Infiltration of liver cells with fat.

Stenting: Placement of a stent (a metal or plastic tube) to allow blood flow through an artery.

Stent retriever: Thrombectomy device used to trap a thrombus between the arterial wall and stent to allow rapid restoration of blood flow. The stent is pulled back to remove the thrombus.

Stevens-Johnson syndrome: A severe expression of erythema multiforme (also known as erythema multiforme major); typically involves the skin and the mucous membranes, with the potential for severe morbidity and even death.

Stimulant: Medication that increases functional activity in the body.

Stomatitis: Inflammation of mucous membranes in the mouth.

Stricture: An abnormal narrowing of a body passage, especially a tube or a canal.

Stridor: High-pitched, whistling sound.

Stroke volume: The amount of blood ejected from the heart during systole.

Strongyloides: Parasitic nematode generally causing gastrointestinal syndromes, although it does have the ability to cause disseminated disease.

ST-segment elevation myocardial infarction: A type of myocardial infarction that typically results in an injury that transects the thickness of the myocardial wall.

Subchondral: Situated beneath and supporting cartilage.

Substance use disorder: Recurrent use of a substance and the pathological pattern of behaviors that result from substance use, including significant impairment in health, disability, or failure to meet obligations at home, work, or school.

Substantia nigra: The area in the brainstem with highly pigmented cells that make dopamine.

Suspending agent: An additive used in the compounding of oral liquid medications to suspend drug particles throughout a liquid and enables resuspension of particles by agitation (e.g., shaking well).

Swan neck deformity: Joint deformity associated with rheumatoid arthritis that presents as flexion of the distal interphalangeal (DIP) joints with hyperextension of the proximal interphalangeal (PIP) joints.

Sympathomimetic: An agent that mimics the activity of a naturally occurring agonist, like epinephrine, to activate the sympathetic nervous system. Examples include ephedrine, pseudoephedrine, and phenylephrine.

Synechia: Adhesions or abnormal attachment of the iris to another structure. Peripheral anterior synechia refers to occurrence of synechia with the trabecular meshwork.

Synovitis: Inflammation of the synovial membrane, often in combination with pain and swelling of the affected joint.

Synovium: The membrane lining the internal surfaces of joints.

Systemic inflammatory response syndrome: A complex pathophysiologic response to an insult such as infection, trauma, burns, pancreatitis, and/or other injuries.

T-lymphocyte: A type of white blood cell that originates in the bone marrow and matures in the thymus and serves an essential role in the adaptive immune system.

T2-weighted magnetic resonance imaging: A setting of the magnetic resonance imaging machine that shows water and similar fluids such as cerebrospinal fluid as a bright signal.

Tachycardia: An abnormally rapid heart rate.

Tachyphylaxis: The continued or repeated exposure to a drug that may lead to a diminished pharmacological response over time.

Tachypnea: Faster than normal respiratory rate.

Tachypneic: Rapid breathing indicated by a rate of greater than 20 breaths/min.

Tangentiality: Abandoning one’s ideational objective in pursuit of thoughts peripheral to the original goal. Used to describe a thought and speech pattern wherein the individual never gets to the point or answers the question.

Tardive dyskinesia: A chronic disorder of the nervous system characterized by involuntary jerky or writing movements of the face, tongue, jaws, trunk, and limbs, usually developing as a late side effect of prolonged treatment with antipsychotic drugs.

Targeted therapy: A type of treatment that uses drugs or other substances to identify and attack specific types of cancer cells with less harm to normal cells.

Tendinosis: Tendon degeneration without accompanying inflammation.

Tenesmus: Difficulty with bowel evacuation despite the urgency to defecate.

Teratogenic: Causing malformation in a fetus.

Terminal secretions: The noise produced by the oscillatory movements of secretions in the upper airways in association with the inspiratory and expiratory phases of respiration. It is also known as “death rattle.”

Tetany: A condition characterized by spasms of the hands and feet, cramps, spasm of the voice box (larynx), and overactive neurological reflexes usually due to low blood calcium.

Thelarche: Onset of breast development.

Thought blocking: Speech is halted, often in midsentence, and then picked up later, usually at another point in the thought process.

Thrombin: An enzyme formed from prothrombin which converts fibrinogen to fibrin and also activates platelets. It is the principal driving force in the clotting cascade.

Thrombocytopenia: A condition whereby the number of circulating platelets are abnormally low due to decreased production of new cells, possibly secondary to medication toxicities.

Thrombocytosis: Increased number of platelets in the blood.

Thromboelastography: A type of viscoelastic testing that measures clot formation to breakdown.

Thrombogenesis: Process of forming a blood clot.

Thrombolysis: Process of enzymatically dissolving or breaking apart a blood clot.

Thrombolytic: An enzyme that dissolves or breaks apart blood clots.

Thrombophlebitis: Inflammation of a blood vessel (eg, vein) associated with the stimulations of clotting and formation of a thrombus (or blood clot).

Thromboplastin: A substance that triggers the coagulation cascade. Tissue factor is a naturally occurring thromboplastin and is used in the prothrombin time test.

Thrombosis: A condition in which blood changes from a liquid to a solid state and produces a blood clot.

Thrombotic thrombocytopenic purpura: Condition characterized by formation of small clots within the circulation resulting in the consumption of platelets and a low platelet count.

Thrombus: Blood clot attached to the vessel wall and consisting of platelets, fibrin, and clotting factors; may partially or completely occlude the lumen of a blood vessel compromising blood flow and oxygen delivery to distal tissue.

Thyroglobulin: A thyroid hormone-containing protein, usually stored in the colloid within thyroid follicles.

Thyroid peroxidase: Enzyme that catalyzes the organification and coupling steps of thyroid hormone synthesis.

Thyroiditis: Inflammation of the thyroid gland.

Thyrotoxicosis: A syndrome caused by elevated levels of thyroid hormone; often caused by hyperthyroidism, a condition in which the thyroid gland produces excessive levels of thyroid hormone.

Tocolytic: Medication used to stop premature labor.

Tonometry: Method by which the cornea is indented or flattened to measure intraocular pressure.

Tophi: Collections of monosodium urate crystals that develop in tissues and generally appear as firm nodules under the skin.

Topoisomerase-I: Enzymes that cut one of the two strands of double-stranded DNA, relax the strand, and reanneal the strand.

Torsade de pointes: Very rapid ventricular tachycardia characterized by a gradually changing QRS complex in the electrocardiogram; may change into ventricular fibrillation.

Total abdominal hysterectomy and bilateral salpingo-oophorectomy: Surgical removal of the uterus, fallopian tubes, and ovaries which results in immediate menopause.

Total fertility rate: The average number of children a woman would have if she survives all her childbearing (or reproductive) years, which are typically considered to be between 15 and 49.

Toxic epidermal necrolysis: A life-threatening skin disorder characterized by blistering and peeling of the top layer of skin.

Transcranial magnetic stimulation (TMS): A form of neurostimulation therapy that involves the use of a magnet placed over the head. TMS is thought to induce the release of monoamine neurotransmitters.

Transesophageal echocardiogram: Procedure used to generate an image of the heart via sound waves, via a probe introduced into the esophagus (rather than the traditional transthoracic view) in order to obtain a better image of the left atrium.

Transferrin saturation: The ratio of serum iron and total iron-binding capacity, multiplied by 100.

Transformation/conversion: The change that a normal cell undergoes to become malignant.

Transmural: Existing or occurring across the entire wall of an organ or blood vessel.

Transsphenoidal pituitary microsurgery: Surgery through the nasal cavity to access the pituitary gland through the sphenoid bone.

Traveler’s diarrhea: An acute infectious diarrhea that afflicts travelers during or immediately upon return and is due to ingestion of contaminated food or beverages resulting in diarrhea and other gastrointestinal symptoms.

Trigeminal neuralgia: Sudden, severe facial pain described as sharp shooting pain or electric shock in the jaw, teeth or gums.

Triple-negative breast cancer: Characterized by the absence of the three receptors used to guide treatment; this subtype is associated with the poorest prognosis.

Trismus: Limited jaw range of motion (also known as “lockjaw”).

Trophic feeding: Very low-rate feedings designed to keep the gut stimulated.

Troponins T or I: Proteins found predominately in the myocardium. Troponin I and T are released into the blood from the myocytes at the time of myocardial cell necrosis secondary to infarction. These biochemical markers become elevated and are used in the diagnosis of myocardial infarction.

Trousseau’s sign: Elicited by inflating a blood pressure cuff on the patient’s upper arm, whereby hypocalcemic patients will experience tetany of the wrist and hand as evidenced by thumb adduction, wrist flexion, and metacarpophalangeal joint flexion.

Trypsin: A proteolytic enzyme formed in the small intestine from trypsinogen by the action of enteropeptidase, which once activated hydrolyzes peptides, amides, and esters.

Tuberoeruptive xanthomas: Small yellow-red raised papules usually presenting on the elbows, knees, back, and buttocks.

Tuberoinfundibular: One of the four main dopamine pathways in the brain, projecting from the arcuate and periventricular nuclei of the hypothalamus to the infundibular region of the hypothalamus.

Tubulointerstitial: Involving the tubules or interstitial tissue of the kidneys.

Tumor lysis syndrome: A syndrome resulting from cytotoxic therapy, occurring generally in aggressive, rapidly proliferating lymphoproliferative disorders; characterized by combinations of hyperuricemia, lactic acidosis, hyperkalemia, hyperphosphatemia, and hypocalcemia.

Tumor suppressor gene: A gene that suppresses growth of cancer cells.

Tympanocentesis: Puncture of the tympanic membrane with a needle to aspirate middle ear fluid.

Tympanostomy tube: Small plastic or metal tube surgically inserted in the eardrum to keep the middle ear aerated and improve hearing in patients with chronic middle ear effusion.

Uhthoff phenomenon: Acute worsening of multiple sclerosis symptoms on exposure to heat because high body temperatures may exceed the capacitance of the demyelinated nerve and conduction may fail.

Unknown-onset seizures: Seizures where the onset (ie, focal or generalized) cannot be determined.

Unstable angina: Pathogenically similar to non–ST-segment myocardial infarction but without muscle damage, therefore troponins are not elevated.

Uremia: A condition that results from accumulation of metabolic waste products and endogenous toxins in the body resulting from impaired kidney function; symptoms include nausea, vomiting, weakness, loss of appetite and mental confusion.

Urethral stricture: Narrowing of the urethra.

Urgency (urinary): A compelling need to urinate that is difficult to defer.

Uricosuric: Pertaining to, characterized by, or promoting renal excretion of uric acid.

Urticaria: Itchy, raised, swollen areas on the skin, also known as hives.

Uterine tachysystole: Uterine hyperstimulation with frequent contractions, hypertonus and non-reassuring fetal heart rate pattern.

Uveitis: Inflammation of the uvea. Uveal structures include the iris, the ciliary body, and the choroid.

Valsalva maneuver: A technique that forces respiratory expiration against a closed glottis.

Valvular heart disease: Damage or defects in one or more of the heart valves, disrupting blood flow into and out of the heart. The most common valves affected are the aortic and mitral valves. Valvular stenosis is a narrowing of the valve opening restricting the forward flow of blood. Valvular regurgitation or insufficiency occurs when there is inadequate closure of the valve leaflets leading to blood “leaking” backward.

Vasculitis: Inflammation of the walls of blood vessels.

Vasomotor symptoms: Menopausal symptoms that include both hot flashes (flushes) and night sweats for which women most commonly seek therapy.

Vasopressors: Medications that cause constriction of blood vessels, increase in vascular resistance, and increase in blood pressure.

Ventilation: Movement of air between the environment and the lungs.

Ventilation/perfusion ratio (V_A/Q): A comparison of the proportion of lung tissue being ventilated by inhaled air to the rate of oxygenation of pulmonary blood.

Ventricular depolarization: Change in the membrane potential of a ventricular myocyte, resulting in loss of polarization. Under normal conditions, depolarization of ventricular myocytes is followed by ventricular contraction.

Vertigo: Sensation of spinning or feeling out of balance.

Vesicants: Chemotherapy drugs that cause significant tissue damage if extravasation occurs.

Viral hemorrhagic fevers: Highly virulent viral diseases causing significant hematologic abnormalities and a high mortality rate. Ebola would be the most well-known.

Virilization: Production or acquisition of virilism, which is masculine characteristics.

Viscoelastic testing: Point-of-care testing devices utilizing thromboelastography principles to evaluate clot formation and dissolution.

Volvulus: Twisting of the intestine causing obstruction and possible necrosis.

Vulvovaginal atrophy: Thinning of vaginal tissue due to a lack of estrogen stimulation.

Wernicke syndrome: Neurologic condition caused by thiamine deficiency and characterized by mental confusion, ataxia, and ophthalmoplegia.

West Nile encephalitis: Mosquito-borne disease causing a clinical syndrome of viral encephalitis.

Wheeze: A high-pitched whistling sound caused by air moving through narrowed airways; usually heard at the end of expiration but may be heard during inspiration and expiration in acute severe asthma.

White coat hypertension: A persistently elevated average office blood pressure of greater than 140/90 mm Hg and an average awake ambulatory reading of less than 135/85 mm Hg.

Wilson Disease: A disorder of copper metabolism, characterized by cirrhosis of the liver and neurological manifestations.

Xanthomas: Firm raised nodules composed of lipid-containing histocytes.

Xerostomia: Unusual dryness of the mouth.

ZAP-70 expression: An intracellular tyrosine kinase found in CLL B-cells.

Zika virus: Mosquito-borne disease associated with fetal neurologic developmental anomalies when acquired by pregnant women.

Zymogen: An inactive protein precursor of an enzyme that is converted into an active form.