Hyperkalemic distal renal tubular acidosis caused by immunosuppressant treatment with tacrolimus in a liver transplant patient: case report

Nephrotoxicity is one of the most common side effects of long-term immunosuppressive therapy with calcineurin inhibitors. We describe a case of distal renal tubular acidosis secondary to tacrolimus administration. A 43-year-old man with end-stage liver disease due to hepatitis C and B virus infections and alcoholic cirrhosis received a liver transplantation under immunosuppressive treatment with tacrolimus and mycophenolate mofetil. In the postoperative period, the patient developed hyperkalemic hyperchloremic metabolic acidosis, with a normal serum anion gap and a positive urinary anion gap, suggesting distal renal tubular acidosis. We excluded other causes of hyperkalemia. Administration of intravenous bicarbonate, loop diuretics, and oral resin exchanger corrected the acidosis and potassium levels. Distal renal tubular acidosis is one of several types of nephrotoxicity induced by tacrolimus treatment, resulting from inhibition of potassium secretion in the collecting duct. Treatment to correct the acidosis and hyperkalemia should be promptly initiated, and the tacrolimus dose adjusted when possible.