Lactic acidosis in childhood: Part I.

Lactic acidosis accompanies many acquired and inherited metabolic diseases. The role of lactic acid in anaerobic glycolysis, gluconeogenesis, and acid-base balance is key to the understanding of these disorders. Because lactic acid can be formed only from pyruvic acid, disorders which increase pyruvate production, inhibit its catabolism, or shift the equilibrium toward lactic acid formation cause lactic acidosis. Lactic acidosis results from systemic diseases and toxins which produce tissue hypoxia or mitochondrial injury. Abnormalities of other metabolites such as glucose, pyruvate, amino acids, and organic acids may provide clues to inborn metabolic errors. Treatment must first be directed toward removing precipitating causes of the acquired disorders and then toward correcting the acidosis and other metabolic complications such as hypoglycemia. Some of the inborn errors respond to specific therapies.