Objective: To alert the physicians to the possibility of a late-onset inborn error of metabolism in an apparently previously healthy patient with acute clinical presentation.
Design: Case report.
Setting: Pediatric unit and general intensive care unit.
Patient: An 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.
Interventions: Intravenous hydration, glucose and insulin, mechanical ventilation.
Measurements and main results: Organic 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.
Conclusions: The 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.