Abnormal Nocturnal Behavior due to Hypoglycemia in a Patient with Type 2 Diabetes

Abnormal nocturnal behavior can have many causes, including primary sleep disorder, nocturnal seizures, and underlying medical or neurological disorders. A 79-year-old woman with type 2 diabetes was admitted for evaluation of abnormal nocturnal behavior. Every night at around 04:30 she was observed displaying abnormal behavior including leg shaking, fumbling with bedclothes, crawling around the room with her eyes closed, and non-responsiveness to verbal communication. Polysomnography with 20-channel electroencephalography (EEG) was performed. EEG showed that the posterior dominant rhythm was slower than that observed in the initial EEG, with diffuse theta and delta activities intermixed, and no epileptiform activity. The serum glucose level was 35 mg/dL at that time, and both the EEG findings and clinical symptoms were resolved after an intravenous injection of 50 mL of 50% glucose. These results indicate that nocturnal hypoglycemia should be considered as one of the possible etiologies in patients presenting with abnormal nocturnal behavior.