Review Question - QID 109738

The patient's hypertension and hypokalemia appreciated on electrocardiogram is concerning for hyperaldosteronism. Eplerenone is an aldosterone receptor antagonist that would address both the patient's hypertension and hypokalemia.

Aldosterone is secreted from the zona glomerulosa of the adrenal gland in response to angiotensin II stimulating aldosterone synthase. Aldosterone acts on the distal tubule and collecting ducts of the nephron to increase sodium reabsorption and increase potassium and hydrogen secretion. This results in hypertension, hypokalemia, and metabolic alkalosis when synthesized in excess (e.g. in aldosterone producing adenomas). When medical treatment is indicated in cases of primary hyperaldosteronism (e.g., bilateral adrenal hyperplasia or when surgery is contraindicated) an aldosterone receptor antagonist, such as spironolactone and eplerenone, is used to manage their hypertension and hypokalemia.

Figure A is an electrocardiogram demonstrating U wave and T wave inversions. These findings are indicative of hypokalemia.

Incorrect Answers:
Answer 1: Bumetinide is a loop diuretic. This can worsen this patient's hypokalemia and place her at risk for developing cardiac arrhythmias, such as torsades de pointes.

Answer 3: Hydrochlorothiazide acts on sodium-chloride transporters in the distal tubule. This medication can also worsen this patient's hypokalemia.

Answer 4: Mannitol is an osmotic diuretic that is typically used in cases of increased intracranial pressure, which is not present in this patient. It will also not treat the underlying problem.

Answer 5: Triamterene is a potassium-sparing diuretic that inhibits sodium channels in the distal tubule that are sensitive to aldosterone. This is not a first-line agent because of aldosterone's effect on cardiac remodeling.

Bullet Summary:
Pharmacologic therapy for hyperaldosteronism is with an aldosterone receptor antagonist, such as spironolactone and eplerenone.