Primary aldosteronism. Issues in diagnosis and management.

The clinical manifestations of primary aldosteronism are not distinctive, but additional studies are warranted in certain hypertensive patients, including patients with either spontaneous or diuretic-induced hypokalemia and those with refractory hypertension without an obvious secondary cause. The best test for identifying patients with primary aldosteronism is measuring the aldosterone excretion rate during salt loading. A rate exceeding 14 micrograms/24 hour provides the highest sensitivity and specificity. The presence of hypokalemia and suppressed plasma renin activity provides corroborative evidence but their absence does not preclude the diagnosis. An adenoma is likely in the presence of significant spontaneous hypokalemia (serum potassium concentration < or = 3 mEq/L), a paradoxic decrease in ambulatory plasma aldosterone concentration, and plasma 18-hydroxycorticosterone values equal to or greater than 100 ng/dL. The adrenal CT scan should be considered the initial step in localization. Primary aldosteronism can be associated with severe and drug-resistant hypertension, and maintained hypervolemia is the reason for resistance to therapy. Sustained volume depletion is the most important therapeutic goal for these patients. Medical therapy is indicated for patients with hyperplasia and for patients with bilateral adenomas that may require total bilateral adrenalectomy. Whenever feasible, surgical excision is recommended for unilateral tumors, and cure can be achieved despite prolonged and severe hypertension.