Conn's syndrome is another name for which disorder?

• A. Addison's disease
• B. Cushing's syndrome
• C. Hyperaldosteronism
• D. Pheochromocytoma

Answer: (C)

Conn's syndrome is primary hyperaldosteronism, an excess production of aldosterone by the adrenal cortex, usually from an aldosterone-secreting adenoma or bilateral adrenal hyperplasia. Aldosterone acts on the distal nephron to increase sodium reabsorption and potassium and hydrogen ion secretion, which raises blood pressure while causing potassium loss and metabolic alkalosis. Because aldosterone is high, renin secretion is suppressed, so plasma renin activity is low. Clinically this presents as hypertension often accompanied by hypokalemia and sometimes muscle weakness. Diagnosis centers on the combination of high aldosterone with low renin and hypokalemic metabolic alkalosis, and treatment may involve mineralocorticoid receptor antagonists like spironolactone or eplerenone; if a unilateral tumor is present, surgical removal can be curative. Addison's disease, Cushing's syndrome, and pheochromocytoma involve different adrenal or catecholamine abnormalities and do not describe this condition.