[Physiopathology and clinical aspects of type IV renal tubular acidosis].

Type IV Renal tubular acidosis (RTA) is a syndrome whose physiopathological and clinical peculiarities have been described in the last decade. This syndrome can be associated with several pathological conditions characterized by reduced aldosterone activity of which hyporeninemic hypoaldosteronism is the most frequent. Type IV RTA originates in a defect in the distal nephron responsible for hydrogen and kalium ion secretion. Renal hyperchloremic acidosis and hyperkalemia are evident; the net acid secretion is decreased especially because of the urinary reduction in ammonia. Besides the behaviour of the spontaneous humoral parameters, the diagnosis of RTA is based on the tests that explore distal nephron acidification.