A 37-year-old woman comes to the office due to a two-month history of abdominal pain, salt craving, and weight loss. She also has dizziness on standing. The patient has no chronic medical conditions and takes no medications. She does not use tobacco, alcohol, or illicit drugs. Her mother and sister have hypothyroidism. Blood pressure is 100/70 mm Hg supine and 80/50 mm Hg standing. Laboratory results are as follows: Which of the following changes in circulating hormone levels are expected in this patient?

Question

A 37-year-old woman comes to the office due to a two-month history of abdominal pain, salt craving, and weight loss. She also has dizziness on standing. The patient has no chronic medical conditions and takes no medications. She does not use tobacco, alcohol, or illicit drugs. Her mother and sister have hypothyroidism. Blood pressure is 100/70 mm Hg supine and 80/50 mm Hg standing. Laboratory results are as follows:

Which of the following changes in circulating hormone levels are expected in this patient?

Quizplus · Accepted Answer

This patient has multiple signs and symptoms of primary adrenal insufficiency (PAI) (also known as Addison disease), including abdominal pain, weight loss, salt craving, orthostasis (dizziness on standing), and electrolyte disturbance. PAI usually results from autoimmune destruction of the bilateral adrenal cortex and is more likely to occur in patients with a personal or family history of autoimmune disease (eg, Hashimoto thyroiditis). Because all 3 layers of the adrenal cortex are affected, clinical manifestations result from a reduction in circulating mineralocorticoids, glucocorticoids, and androgens. Reduced aldosterone, the principal mineralocorticoid in the body, leads to markedly decreased sodium absorption by the renal collecting tubule principal cells with consequent retention of potassium (leading to hyperkalemia). The decrease in total body sodium results in hypovolemia and hypotension that may lead to renal insufficiency. The hypovolemia provides nonosmotic stimulus for antidiuretic hormone (ADH) secretion, which stimulates water retention and leads to hyponatremia. Cortisol, the main glucocorticoid in the body, normally inhibits ADH secretion; therefore, reduced cortisol further contributes to hyponatremia. Cortisol is also necessary for the synthesis of epinephrine in the adrenal medulla; the consequent reduction in circulating epinephrine leads to a compensatory increase in norepinephrine to increase vascular tone in an effort to maintain blood pressure. (Choice B) Increased ADH and normal levels of cortisol, aldosterone, and norepinephrine occur in the syndrome of inappropriate ADH secretion (SIADH). SIADH presents with hyponatremia, but it does not explain this patient's hyperkalemia, salt craving, and orthostatic symptoms. (Choices C, D, and E) Elevations in aldosterone, ADH, and norepinephrine occur in conditions that decrease effective arterial blood volume and renal perfusion (eg, heart failure, cirrhosis, dehydration). Cortisol levels are often elevated in dehydration and heart failure; total cortisol is low in cirrhosis due to reduced cortisol-binding protein levels. (Choice F) Increased cortisol with reduced levels of aldosterone, ADH, and norepinephrine can occur with ectopic ACTH production (eg, due to small cell lung cancer). Aldosterone synthesis is mostly independent of ACTH and is suppressed because cortisol and other glucocorticoids have some mineralocorticoid activity. Levels of ADH and norepinephrine are also generally suppressed. Educational objective: Primary adrenal insufficiency usually involves autoimmune destruction of the bilateral adrenal cortex. Reduced aldosterone production leads to renal salt wasting with hypovolemia, hypotension, and hyperkalemia. The hypovolemia and reduced cortisol-induced inhibition of antidiuretic hormone lead to water retention and hyponatremia. Reduced cortisol also causes decreased circulating epinephrine with a compensatory increase in norepinephrine.

A 37-Year-Old Woman Comes to the Office Due to a Two-Month