Hyperaldosteronism

    • Accounts of 0.5 - 10% of patients with HTN

    • Etiologies:

      • Aldosterone-producing adenoma (Conn's disease). Accounts for 60% of primary aldosteronism; three times more common in women.

      • Idiopathic hyperaldosteronism: 1/3 of cases of primary aldosteronism; normal-appearing adrenals or bilateral hyperplasia is seen on CT scan.

      • Glucocorticoid-suppressible aldosteronism: A rare autosomal-dominant form.

      • Angiotensin II-responsive adenoma: Accounts for 5% of primary aldosteronism

      • Aldosterone-producing adrenocortical carcinoma: Rare, <1% of primary aldosteronism. Hyperandrogensim is a clue to the diagnosis.

    • Clinical features:

      • HTN

      • Hypokalemia: although classic, is not necessary for diagnosis. So if Sr K+ is normal, don't dismiss hyperaldosteronism. Repeat Sr. K+. HA, muscle weakness (from hypokalemia)

      • Polyuria

      • Most patients are asymptomatic.

      • Plasma aldosterone concentration and plasma renin activity best evaluated after the patient is on high-salt diet or salt supplementation for one week.

      • Aldosterone level may also be evaluated with a 24-hour urine collection.

      • If primary aldosteronism is diagnosed, obtain an adrenal CT to distinguish Conn's and idiopathic hypoaldosteronism.

      • In primary hyperaldosteronism:

        • Hypernatremia, hypokalemia, metabolic alkalosis, increased aldosterone, decreased renin. CT/MRI of adrenals may show adenoma. If no adenoma found do adrenal vein sampling. If no localization of aldosterone, consider hyperplasia.

        • A PAC/PRA ratio >25 is characteristic.

    • Treatment:

      • Spironolactone in high doses, up to 400 mg/day or eplerenone blocks the mineralocorticoid receptor and usually normalizes K+. In men, the most common side effect is gynecomastia, but other side effects may occur - e.g., rash, impotence, and epigastric discomfort.

      • Unilateral adrenalectomy

▲PRA (plasma renin activity), ▲PAC (plasma aldosterone concentration):

    • 2° hyperaldosteronism

      • Renovascular HTN

      • Diuretic use

      • Renin-secreting tumor

      • Malignant HTN

      • Coarctation of aorta

▼PRA, ▲PAC (>15 ng/dL) or (PAC/PRA ratio of >25): primary hyperaldosteronism

▼PRA, ▼PAC:

    • Congenital adrenal hyperplasia

    • DOC-producing tumor

    • Cushing's syndrome

    • Exogenous (mineralocorticoid)

    • Liddle's syndrome

    • 11 beta-HSD deficiency