Prerenal azotemia in a diabetic patient with hyporeninemic hypoaldosteronism and autonomic neuropathy.

Patients with hyporeninemic hypoaldosteronism show mild to moderate renal insufficiency, with a creatinine clearance of 20-75 ml/min, and asymptomatic hyperkalemia. A low degree of sodium wasting and mild hyperchloremic metabolic acidosis are also usually present. However, severe sodium wasting and volume depletion are not typically seen unless the patient is placed on severe sodium restriction or has some other cause of extrarenal sodium loss. In fact, acute renal failure has not been reported in such patients. We describe a diabetic patient with hyporeninemic hypoaldosteronism and autonomic neuropathy who developed recurrent episodes of acute renal failure due to prerenal azotemia during acute exacerbations of diarrhoea. In our case, despite significant hypovolemia, the renin-aldosterone axis was markedly suppressed, implying that sympathetic tone played a decisive role in renin regulation.