A 39 year old delivery man is admitted in the afternoon following a generalized tonic-clonic convulsion which lasted for 5 minutes. He had been transporting parcels by bicycle for the whole day.

He was completely well earlier, with an unremarkable medical and drug history. An urgent full blood count and non-contrast CT brain are normal, while an ECG shows sinus tachycardia only. His capillary glucose is 125 mg/dl.