Insulinoma presenting itself as a night paroxysmal disorder with spontaneous recovery

A 64-year-old woman with night paroxysmal episodes is described. Her symptoms began 9 months ago with attacks of bizarre movement, which were always present in the second part of the night. She had no attacks during the daytime. Her husband reported confusion and disorientation followed by long periods of unresponsiveness. The patient underwent a night polysomnography recording. Around 4 o'clock in the morning bizarre movements with stereotypic behaviour appeared. She was rolling her head from side to side, moaning, and stretching her limbs. These periods first lasted for minutes, and were constantly repeated during the night. EEG findings suggested metabolic encephalopathy. At that time finger prick test revealed a profound hypoglycaemia (1.2 mmol/l), high insulin (200 pmol/l), and C-peptide (6.63 nmol/l). Ultrasonography and MRI confirmed the insulinoma in the head of the pancreas. To our knowledge our case is the first patient with insulinoma attacks only during sleep time.