Unmasking of isolated hypoaldosteronism after renal allotransplantation in familial Mediterranean fever.

A patient with familial Mediterranean fever and renal amyloidosis was maintained on intermittent hemodialysis for chronic renal failure. After renal allotransplantation, he became weak, lost 12 kg in weight over 7 wk, and developed marked orthostatic hypotension. His symptomatic volume depletion responded dramatically to i.v. 0.9% NaCl. Metabolic balance studies showed that he was in negative Na balance (on a 44 mEq/24 h Na diet, he excreted 71 mEq/24 h in his urine), which was corrected by mineralocorticoid therapy. Renin-aldosterone studies demonstrated a hyperreninemic hypoaldosteronism with normal glucocorticoid secretion. The patient probably suffered from amyloidosis selectively involving the glomerulosa zone of his adrenal cortices. While on dialysis he was anuric and therefore not volume depleted, but after successful renal allotransplantation the diuresis of the functioning kidney unmasked his mineralocorticoid deficiency which manifested as symptomatic volume depletion.