Clinical Approach to Proximal Renal Tubular Acidosis in Children

Proximal renal tubular acidosis (pRTA) is an inherited or acquired clinical syndrome in which there is a decreased bicarbonate reclamation in the proximal tubule resulting in normal anion gap hyperchloremic metabolic acidosis. In children, pRTA may be isolated but is often associated with a general proximal tubular dysfunction known as Fanconi syndrome which frequently heralds an underlying systemic disorder from which it arises. When accompanied by Fanconi syndrome, pRTA is characterized by additional renal wasting of phosphate, glucose, uric acid, and amino acids. The most common cause of inherited Fanconi syndrome in the pediatric age group is cystinosis, a disease with therapeutic implications. In this article, we summarize the clinical presentation and differential diagnosis of pRTA and Fanconi syndrome and provide a practical approach to their evaluation in children.