Hypokalemia with normal blood pressure, aldosterone and renin levels secondary to a renal or adrenal tumor

Abstract

A normotensive forty-two year old Negro woman had persistent hypokalemia (2.6 to 3.1 mEq per L) with high urine potassium levels (30 to 60 mEq per day) which improved with spironolactone but not with sodium restriction. On a 150 mEq sodium diet, aldosterone excretion was 4.6 and 8.6 μg per day (normal 5 to 19), aldosterone secretion was 91.6 μg per day (normal 50 to 250), and plasma renin (supine) was 103 plasma renin activity (PRA) units per 100 ml (normal 30 to 220); while on a 10 mEq sodium diet, renin levels (ambulatory) were 1,760 and 840 PRA units per 100 ml (normal 390 to 1,200). Urinary excretion of 17-ketogenic steroids was 3.4 to 7.2 mg per day, excretion of compounds “B” and tetrahydro-DOC was not increased. Differential ureteral potassium excretions were equal, urinary acidification following the administration of ammonium chloride was normal, the creatinine clearance was normal. Angiotensin infusion (0.0083 to 0.1 μg per kg per minute) produced normal pressor response. An intravenous pyelogram and aortogram revealed a mass in the right kidney. The right kidney, containing a large cystic renal cell carcinoma (cyst fluid renin 60 PRA units per 100 ml), and the adrenal gland, containing a 1.5 cm diameter cortical adenoma, were removed. The uninvolved kidney was normal histologically, without juxtaglomerular cell hyperplasia. Postoperatively, the serum potassium level (3.8 to 5.4 mEq per L) returned to normal and plasma renin levels were 128 and 1,590 PRA units per 100 ml on a high and low sodium diet. This unique syndrome may be due to secretion of a nonsodium-retaining, potassium-losing hormone by the renal or adrenal tumor.