MEDizzy - A 27-year-old white woman comes to the physician because of

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ADRENAL DISORDERS

A 27-year-old white woman comes to the physician because of a six-month history of progressive weakness and fatigue, and occasional mild abdominal pain. She also has noticed that her skin has become more tan, especially at the elbows, knees, and knuckles, despite the fact that she is not usually in the sun. Laboratory tests show decreased serum levels of sodium, bicarbonate, chloride, and glucose and increased levels of potassium. Which of the following is the most likely diagnosis?

ExplanationThe correct answer is A. This patient has Addison disease (also known as primary adrenocortical deficiency), which is adrenal insufficiency (remember the “GFR” of the adrenal gland: Glomerulosa is the outer layer, which makes mineralocorticoids, namely aldosterone; Fasciculata is the middle layer, which makes glucocorticoids such as cortisol; and Reticularis is the inner layer, which makes sex steroids such as estrogens and androgens). Decreased levels of aldosterone lead to hypotension, increased levels of potassium, and decreased levels of sodium, chloride, and bicarbonate. Decreased levels of cortisol lead to decreased glucose levels. Decreased cortisol also leads to increased levels of ACTH (as the pituitary attempts to increase stimulation of the adrenal gland), causing hyperpigmentation (from a precursor hormone to ACTH that stimulates melanocytes), especially at physical pressure points such as the elbows, knees, and knuckles. Answer B is incorrect. Conn syndrome is defined as a chronic excess of aldosterone secretion from an aldosterone-secreting adenoma in one adrenal gland. Unlike patients with Addison disease, people with Conn syndrome would have, among other findings, hypertension, increased serum sodium, decreased serum potassium, low serum renin, and increased serum aldosterone. Answer C is incorrect. Cushing syndrome is a name for any condition that causes an excess of glucocorticoids, such as cortisol. Early signs include hypertension and weight gain, which progress to truncal obesity, moon facies, and a “buffalo hump” from accumulation of fat in the posterior neck and back. Answer D is incorrect. A pheochromocytoma is neoplasm of the chromaffin cells (neural crest derivatives that synthesize and release mostly catecholamines). Most cases present with hypertension, headache, tremor, sweating, and a sense of apprehension. The hypertension may occur in isolated bursts or chronically and may be associated with palpitations.