Lethal late onset cblB methylmalonic aciduria

OBJECTIVETo alert the physicians to the possibility of a late-onset inborn error of metabolism in an apparently previously healthy patient with acute clinical presentation. DESIGNCase report. SETTINGPediatric unit and general intensive care unit PATIENTAn apparently previously healthy 12-yr-old female presented acutely with vomiting, fever, bronchopneumonia, and progressive loss of consciousness associated with ketoacidosis, hyperglycemia, and hyperammonemia. She died 3 days later with a diagnosis of insulin-dependent diabetes mellitus. INTERVENTIONSIntravenous hydration, glucose and insulin, mechanical ventilation. MEASUREMENTS AND MAIN RESULTSOrganic acid analysis on a postmortem sample of aqueous humor revealed high levels of methylmalonic acid. Enzymatic studies on cultured fibroblasts were consistent with the diagnosis of cblB methylmalonic aciduria. CONCLUSIONSThe diagnosis of cblB methylmalonic aciduria was made in a postmortem patient who died with a misdiagnosis of insulin-dependent diabetes mellitus. Unclear biochemical findings and positive family history should strongly lead to suspicion of an inborn error of metabolism in an apparently previously healthy critically ill patient.