Recurrent hypoglycaemia in a young man without diabetes

A 37 year old man presented with a sensation of weakness, irritability, and poor concentration. His blood glucose was 2.4 mmol/L (reference range 3.6-11; 1 mmol/L=18.02 mg/dL). Three months earlier he had noticed a craving for sweets and episodes of weakness, sometimes associated with foggy sensorium. He felt cold, clammy, and fatigued during these episodes and his wife noticed that he acted strangely and had no memory for long periods. After drinking large amounts of cola he felt better and had gained 30 lb (13 kg) in weight during this time. His symptoms recurred when he had not eaten for several hours, particularly at night and in the early morning.

Several days before his current presentation, he had presented to another hospital with similar symptoms and was found to have a blood glucose of 2.6 mmol/L. He responded well to dextrose infusion and was discharged home.

His medical history was unremarkable except for an umbilical hernia repair and back surgery 10 years earlier. He was taking no prescription or over the counter drugs. He did not smoke and drank beer socially. He denied taking illicit drugs. His family history was positive for diabetes but he had not been diagnosed as having diabetes.

On arrival his blood pressure was 124/76 mm Hg, pulse was 94 beats/min, and respiratory rate was 18 breaths/min. He was confused, cold, and clammy. Examination of the rest of the neurological system; skin; joints; and cardiovascular, respiratory, and abdominal systems was unremarkable. His haemoglobin, white blood cell count, and platelet count were in the normal range. Sodium, potassium, urea, creatinine, and liver panel results were normal. Glycated haemoglobin was 5% (31 mmol/mol). He responded to …