[Renal tubular acidosis].

Renal tubular acidosis (RTA) can be separated into three main types: distal RTA (the defect in the excretion of hydrogen ion), proximal RTA (the defect in the reabsorption of bicarbonate), and hyperkalemic RTA. Some patients present combined types of proximal and distal RTA. Most of the pediatric patients with RTA manifest failure to thrive. They have hyperchloremic metabolic acidosis and normal plasma anion gap. Fractional excretion of bicarbonate is below 5% in dRTA and over 15% in pRTA. Renal complications of dRTA are nephrocalcinosis, renal calculi, renal cysts and reversible low molecular weight proteinuria. The patient with isolated pRTA is very rare.