Simultaneous occurrence of hyperkalemia due to aldosterone suppression and hyperfunctioning parathyroid adenoma.

The change of the pattern of clinical presentation of primary hyperparathyroidism in older patients is illustrated by a case history of a 61-year-old woman with multicystic kidney disease in whom a thiazide antihypertensive drug (clopamide) induced a very severe symptomatic hypercalcemia. Withdrawal of the drug was followed by a prolonged complete clinical remission, normocalcemia, normocalciuria, but consistently elevated parathormone levels. This "normocalcemic biochemical hyperparathyroidism" was complicated with hyperkalemia due to aldosterone suppression, a counterpart of the recently described association with hypokalemia due to primary hyperaldosteronism, necessitating further studies on the occurrence and significance of altered production of aldosterone in geriatric patients with primary hyperparathyroidism.