Abstract

MUNOZ-ARIZPE, Ricardo; ESCOBAR, Laura  and  MEDEIROS, Mara. Renal tubular acidosis in children: state of the art, diagnosis and treatment. Bol. Med. Hosp. Infant. Mex. [online]. 2013, vol.70, n.3, pp.178-194. ISSN 1665-1146.

Overdiagnosis of renal tubular acidosis (RTA) has been recently detected in Mexican children, perhaps due to diagnostic errors as well as in a lack of knowledge regarding the pathophysiology and molecular biochemistry involved in this illness. The objective of the present study is to facilitate the knowledge and diagnosis of RTA, a clinical condition infrequently seen worldwide. RTA is an alteration of the acid-base equilibrium due to a bicarbonate wasting in the proximal renal tubules (proximal RTA, pRTA or type 2 RTA) or due to a distal nephron hydrogen ion excretion defect (distal RTA, dRTA or type 1 RTA). Hyperkalemic, or type 4 RTA, is due to alterations in aldosterone metabolism. RTA may be primary, secondary, acquired or hereditary and frequently presents secondary to an array of systemic diseases, usually accompanied by multiple renal tubular defects. The main defect occurs in the transmembrane transporters such as carbonic anhydrase (CA I and II), H⁺-ATPase, HCO₃^-/Cl^- (AE1) exchanger and Na⁺/HCO₃^- (NBCe1) cotransporter. Diagnosis should include the presence of hyperchloremic metabolic acidosis with normal serum anion gap (done in an arterial or arterialized blood sample), lack of appetite, polyuria, thirst, growth failure, and rickets; nephrocalcinosis and renal stones (in dRTA); abnormal urine anion gap and abnormal urine/serum pCO₂ gradient. Diagnosis of a primary systemic disease must be made in cases of secondary RTA. Bicarbonate or potassium citrate therapy, as well as potassium, calcium and vitamin D administration depends on the type and severity of the RTA.

Keywords : acidosis; renal tubular acidosis; transmembrane transporters.

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