+
For instructor materials including Power Points, Answers to Clinical Encounter Questions, please contact userservices@mhprofessional.com.
++
LEARNING OBJECTIVES
Upon completion of the chapter, the reader will be able to:
Discuss the pathophysiology of central nervous system (CNS) infections and the impact on antimicrobial treatment regimens (including antimicrobial dosing and CNS penetration).
Describe the signs, symptoms, and clinical presentation of CNS infections.
List the most common pathogens causing CNS infections and identify risk factors for infection with each pathogen.
State the goals of therapy for CNS infections.
Outline the initial management strategies for CNS infections.
Design appropriate empirical antimicrobial regimens for patients suspected of having CNS infections (taking age, vaccine history, and other patient-specific information into account) caused by each of the following pathogens, and analyze the impact of antimicrobial resistance on both empirical and definitive therapy: Neisseria meningitidis meningitis, Haemophilus influenzae meningitis, Listeria monocytogenes meningitis, group B Streptococcus meningitis, gram-negative bacillary meningitis, postneurosurgical infection, CNS shunt infection, herpes simplex encephalitis.
Modify empirical antimicrobial regimens based on laboratory data and other diagnostic criteria.
Discuss the management of close contacts of patients diagnosed with CNS infections.
Identify candidates for vaccines and other prophylactic therapies to prevent CNS infections.
Describe the role of adjunctive agents (eg, dexamethasone) in the management of CNS infections.
++
The term central nervous system (CNS) infections describes a variety of infections involving the brain and spinal cord and associated tissues, fluids, and membranes, including meningitis, encephalitis, brain abscess, cerebrospinal fluid (CSF) shunt infections, and postoperative infections. 
CNS infections, such as meningitis, are considered neurologic emergencies that require prompt recognition, diagnosis, and management to prevent death and residual neurologic deficits. Improperly treated, CNS infections are associated with high rates of morbidity and mortality. Despite advances in care, the overall mortality of bacterial meningitis in the United States remains at approximately 15%, and at least 10% to 30% of survivors are afflicted with neurologic impairment, including hearing loss, hemiparesis, and learning disabilities.1,2 Antimicrobial therapy and preventive vaccines have revolutionized management and improved outcomes of bacterial meningitis and other CNS infections dramatically.
+++
EPIDEMIOLOGY AND ETIOLOGY
++
CNS infections are uncommon and declining in incidence, with a rate of 0.8 per 100,000 persons between 1997 and 2010.3 However, the severity of these infections demands prompt medical intervention and treatment. CNS infections can be caused by bacteria, fungi, mycobacteria, viruses, parasites, and spirochetes.
++
Bacterial meningitis is the most common cause of CNS infections. While vaccination has reduced the incidence of disease by many common pathogens, Streptococcus pneumoniae (pneumococcus) was the most common pathogen for bacterial meningitis (0.306 cases per 100,000), followed by Neisseria meningitidis (meningococcus, 0.123 cases per 100,000).3 Staphylococcal species and gram-negative bacteria account for 0.114 and 0.127 cases per 100,000 persons, respectively in the United States.3 Group B Streptococcus (GBS) and Listeria monocytogenes remain important causes, ...