Emergency treatment of neonatal hyperammonaemic coma with mild systemic hypothermia

An infant aged 3 days presented with hyperammonaemic coma and seizures, whi ch were found to be a result of it urea-cycle defect. Haemofiltration, alte rnative pathway metabolites, and glucose and insulin failed to lower the pl asma ammonia concentration below 2000 mu mol/L. The infant was then cooled to a rectal temperature of 34 degreesC for 48 h and put on haemofiltration for 12 h. Plasma ammonia fell to around 100 mu mol/L and remained at this c oncentration after haemofiltration. He roused from his coma, breathed spont aneously, and resumed bottle feeding. Hypothermia may be therapeutic in suc h instances of metabolic coma because it lowers the enzymatic rate of produ ction of the toxin while non-enzymatic methods remove the toxin.