Cardiac arrest in infancy: don't forget glucose!

A 2-year-old girl was brought to the Emergency Department having collapsed at home. She was unconscious and apnoeic with a sinus bradycardia of 50 beats/min. Cardiopulonary resuscitation (CPR) was commenced and her airway was secured. Epinephrine and atropine were administered. The blood glucose was found to be <0.5 mmol/l. There were minimal ketones found in both urine and serum. A bolus of 5 ml/kg of 10% dextrose was administered. Following a third cycle of CPR, a strong pulse was palpated with a sinus tachycardia. Subsequent metabolic screening tests confirmed a diagnosis of medium chain acyl-CoA dehydrogenase (MCAD) deficiency. Despite the higher prevalence of hypoglycaemia in children requiring non-trauma-related resuscitation care, there is significant variability in time to checking blood glucose. In any clinical situation necessitating fatty acid oxidation, such as periods of fasting or metabolic stress due to intercurrent illness or infection, patients with MCAD deficiency will have continued glucose consumption with reduced or absent formation of ketones. The result of this is severe hypoglycaemia and hypoketonuria. 18% of patients with MCAD deficiency present with sudden death, and total mortality rate before diagnosis is estimated at 24%. Without diagnosis, preventative interventions to avoid further metabolic decompensation and possible neurological involvement could not be made.