[Application of a clinical and laboratory protocol for the investigation of inborn errors of metabolism among critically ill children]

OBJECTIVE: The aim of this work was to evaluate a protocol for investigation of Inborn Errors of Metabolism (IEM) in children who are acutely ill.METHODS: Forty six children with clinical suspicion of a metabolic disorder were studied during 2 years. They were selected through request for investigation of IEM from Pediatrics or Neonatal Intensive Care Units located in the metropolitan area of Porto Alegre. Criteria for inclusion were presence of one or more of the following clinical alterations, without defined etiology: Metabolic acidosis, electrolyte disturbances, hypoglycemia, seizures, lethargy, liver disfunction, family history suggestive of IEM. The protocol included clinical evaluation, compulsory tests (performed in all patients) and optional tests (performed selectively according to the results from the first tests or through specific clinical hypothesis).RESULTS: Six cases of IEM were identified: galactosemia, non-ketotic hyperglycinaemia, propionic acidemia, isovaleric acidemia, 3-hydroxy-3-methylglutaric acidemia and deficiency of 3-ketothiolase deficiency.CONCLUSIONS: The frequency of organic acidurias in this group was 4/46 (8.7%), which justifies the inclusion of organic acids analysis among the first line exams in acutely and severely ill children with undefined etiology. The relatively high frequency of IEM (6/46 or 13%), which is comparable to the ones observed in other studies within high risk groups, indicates that the protocol suggested is efficient and justifies the systematic investigation of IEM in not explained critically ill children.