Chapter 45. Adrenal Gland Disorders
Which of the following is true regarding the HPA axis?
A. CRH is secreted by the hypothalamus to stimulate ACTH secretion from the anterior pituitary.
B. The adrenal cortex stimulates the anterior pituitary to secrete cortisol.
C. Cortisol exerts positive feedback on the hypothalamus to increase secretion of CRH.
D. The adrenal medulla produces testosterone and estrogen under the control of the pituitary.
Option A: Correct. Adrenal hormone production is controlled by the hypothalamus and pituitary. CRH is secreted by the hypothalamus and stimulates secretion of ACTH from the anterior pituitary, which in turn stimulates the adrenal cortex to produce cortisol.
Option B: Incorrect. ACTH from the anterior pituitary stimulates the adrenal cortex to produce cortisol.
Option C: Incorrect. When sufficient or excessive cortisol levels are reached, a negative feedback is exerted on the secretion of CRH and ACTH, thereby decreasing overall cortisol production. This is a negative feedback mechanism.
Option D: Incorrect. The control of adrenal androgen synthesis follows a similar negative feedback mechanism to that of cortisol.
Which of the following is the most common etiology of primary adrenal insufficiency?
B. Chronic glucocorticoid administration at supraphysiologic dose
Option A: Correct. Autoimune processes account for 70%–90% of all cases of primary adrenal insufficiency.
Option B: Incorrect. Chronic glucocorticoid administration at supraphysiologic doses is considered a drug-induced etiology which is the most common cause of secondary and tertiary adrenal insufficiency.
Option C: Incorrect. Infectious or granulomatous diseases such as cytomegalovirus, fungal infections, HIV, sarcoidosis, and tuberculosis can cause primary adrenal insufficiency but are not the most common etiology.
Option D: Incorrect. Megestrol acetate has glucocorticoid-like activity and, therefore, is considered a drug-induced etiology which is the most common cause of secondary and tertiary adrenal insufficiency.
The clinical presentation of primary adrenal insufficiency differs from that of secondary or tertiary adrenal insufficiency in the following way(s):
A. Hyperpigmentation is more commonly seen in secondary and tertiary adrenal insufficiency.
B. Hyperkalemia is more commonly seen in primary adrenal insufficiency.
C. Increased aldosterone concentration is most often seen in ...