Renal tubular acidosis in infancy: a clinical approach to diagnosis and treatment.

Renal tubular acidosis is defined as the failure of the kidneys to respond appropriately to systemic acidosis. The usual criterion for diagnosis involves titration curves to establish renal bicarbonate threshold. This evaluation is time consuming, expensive, and probably avoidable in selected patients. We report four cases in which a presumptive diagnosis was based solely on clinical data. The criteria for diagnosis without bicarbonate titration curves include clinical and biochemical characteristics and therapeutic response. With use of such criteria, bicarbonate titration curves will be needed only for equivocal cases.