Combined tubular dysfunction in medullary cystic disease.

A patient with medullary cystic disease presented with a combined tubular dysfunction, including severe salt wasting, renal tubular acidosis types I and IV, and marked aldosterone resistance. High-dose mineralocorticoid treatment partially corrected the defect in potassium excretion and did not affect natriuresis. Plasma aldosterone level was more than 30 times the upper normal level and was decreased but not normalized by captopril administration and volume expansion. The severe hemodynamic and metabolic consequences of these defects were corrected by renal transplantation.