Q&A Medicine>>>>>Endocrine and Metabolic Disorders
Question 3#

A 74-year-old man with a history of New York Heart Association class III congestive heart failure presents with vague abdominal pain that has inconsistently responded to acetaminophen. He has a temperature of 37°C, blood pressure of 172/88 mmHg, heart rate of 75 beats per minute, respiratory rate of 18 breaths per minute, and oxygen saturation of 99% on room air. Physical examination reveals abdominal pain on deep palpation in all four quadrants. Laboratory studies reveal a serum sodium of 148 mEq/L, serum potassium of 2.8 mEq/L, and an increased plasma aldosterone to plasma renin activity ratio of 51 (normal range, 0.9 to 20). CT scan shows an incidental left adrenal mass. The patient is deemed a poor surgical candidate due to his cardiovascular state.

Which of the following is the next best step in management?

a. Hydrochlorothiazide
b. Phenoxybenzamine
c. Spironolactone
d. Verapamil

Correct Answer is C

Comment:

Spironolactone. The patient in question has primary hyperaldosteronism, as evidenced by hypertension, hypokalemia, and an adrenal mass on CT scan. Although this patient has a unilateral adrenal adenoma, patients with primary hyperaldosteronism can also have bilateral adrenal hyperplasia. Clues to diagnosis include an elevated plasma aldosterone to plasma renin activity ratio (>20). The increased aldosterone levels act via negative inhibition to decrease renin levels. CT scan can distinguish a unilateral adenoma from bilateral adrenal hyperplasia. Although surgery is preferred for patients with a unilateral adrenal adenoma, medical therapy is the preferred route for patients with bilateral adrenal hyperplasia or those with unilateral adrenal adenoma who are poor surgical candidates. Spironolactone is an aldosterone antagonist that also acts as an androgen receptor antagonist. Side effects include gynecomastia in men and menstrual irregularities in women among others. If side effects are a concern for the patient, eplerenone is an alternative treatment. Eplerenone is a selective mineralocorticoid antagonist, but with low affinity for androgen receptors. (A) Hydrochlorothiazide is indeed recommended for blood pressure control in primary hyperaldosteronism if aldosterone antagonist therapy is insufficient. However, it is not the first drug that should be administered. (B) Phenoxybenzamine is a nonspecific and irreversible α-blocker used in the medical management of pheochromocytoma. (D) Verapamil is another antihypertensive used in some patients, but is not first-line medical therapy in a patient with primary hyperaldosteronism.