Parasomnias and seizures can produce physical phenomena during sleep, but specific triggering factors are incompletely understood. We present a case of a gentleman with agitated nighttime behaviors apparently induced by nocturnal hypoglycemia.
A 73 year-old male presented with complaints of disruptive and violent movements during sleep that his wife had noticed over the past 6 months. Sleepwalking, yelling, growling like an animal, leaving the room in disarray and knocking down furniture marked these bizarre behaviors. Once she had found him trying to climb out the window. When she attempted to stop him he yelled and punched her. She had found him naked on the floor in a fetal position on several occasions. Episodes numbered 1-2 times weekly, usually in the first half of the night. The patient had no recollection of these events. His medical history was significant for insulin-requiring type II diabetes. The sleep history was remarkable only for snoring. His wife reported that his behaviors started at the time his nighttime insulin dosage was increased. He was usually too violent during the episodes to obtain a finger-stick glucose reading. The general and neurological exams were unremarkable. On the night of his sleep study similar combative behavior, yelling, and crawling occurred in an apparent sleep state before the recording was started. Several people were needed to restrain him. In addition the patient had urinary incontinence and diaphoresis. Immediate evaluation in the emergency room revealed a serum glucose of 33 mg/dl. His symptoms promptly resolved with administration of intravenous dextrose. He returned to the sleep lab the same night for completion of his study, which eventually showed frequent periodic limb movements with arousals and mild obstructive sleep apnea (respiratory disturbance index: 10). Full montage electroencephalogram (EEG) monitoring did not show epileptiform discharges. Prior daytime EEG monitoring was also unremarkable. His nighttime insulin dose was subsequently lowered with complete resolution of nocturnal behaviors. He also received clonazepam for periodic limb movement disorder.DISCUSSION: The differential diagnosis for bizarre nocturnal behaviors includes REM sleep behavior disorder (RBD), arousal disorders, sleep-related epilepsy and pseudoseizures. Our patient exhibited features that overlapped among these entities. The behaviors were complex, purposeful and elderly onset—all characteristics of RBD—but occurred early during the sleep cycle and were not related to dream content. The timing of the events and the lack of recall are instead consistent with disorders of arousal such as sleepwalking and confusional states. However these rarely produce such vigorous motor activity and typically occur in younger individuals. Nocturnal seizures generally trigger stereotyped movements rather than the complex actions exhibited by our patient. Yet the occurrence of incontinence is supportive, and frontal seizures can present with behavioral motor changes and paradoxical post-ictal agitation. The absence of epileptiform discharges on nocturnal and daytime EEG does not exclude this disorder. Unfortunately the inability to capture the event during polysomnography precludes an EEG-based specific diagnosis. The clinical course however strongly implicates nocturnal hypoglycemia in connection with the abnormal behaviors. Either nocturnal hypoglycemia produced a wakeful episode of bizarre activity, or it triggered a parasomnia or seizure. Since hypoglycemia alone usually manifests as obtundation and diaphoresis rather than vigorous, purposeful behavior, we favor the latter hypothesis. That our patient exhibited his bizarre activity only during apparent sleep states further implicates hypoglycemia as a trigger for a specific sleep disorder.
Nocturnal hypoglycemia should be considered in diabetic patients who present with abnormal physical behaviors at night. Hypoglycemia may lower the seizure threshold or unmask an underlying predisposition for parasomias such as RBD or arousal disorders.
A. Naik, None.