Seasonal Hypothermia, Hypersomnolence, Encephalopathy, and Hypoventilation Following Hypothalamus Injury - A Case of Human Hibernation?

Objective: Nearly all land-dwelling mammalian orders, including primates (the fat tailed lemur of Madagascar, Cheirogaleus medius ) have at least one species that hibernates. Its evolutionary persistence suggests that seasonal hibernation is a deeply ingrained trait that could plausibly occur in Homo sapiens . Background: We present the case of a 51-year-old retired Nigerian physician living in Minneapolis, Minnesota (45° north latitude) who presented with transient seasonal episodes of profound hypothermia, hypersomnolence, bradycardia, encephalopathy, and hypoventilation consistent with mammalian hibernation. Approximately 20 years prior, he acquired HIV via accidental needle stick and subsequently presented with CNS toxoplasmosis, an AIDS defining illness, extending to the region of the hypothalamus. He was treated with clindamycin and pyrimethamine after sulfadiazine caused hives. Serial MRIs revealed a stable contrast enhancing lesion involving the left medial thalamus extending to the left cerebral peduncle via the hypothalamus. Additional FLAIR hyperintensities were noted in the left corona radiata and right parietal subcortical white matter. Design/Methods: NA Results: Following his initial presentation, he had multiple re-admissions for stereotyped episodes of hypothermia (nadir 31° Celsius), hypersomnolence, bradycardia, hypoventilation, and altered mental status. They would last for several weeks. The only intervention which appeared to hasten his improvement would be external warming. The episodes have been temporally grouped in the fall and spring months while living in Minneapolis, MN. After discharge, particularly during winter months, he would monitor his condition through frequent measurements of body temperature. Body rewarming appeared to help prevent further hospitalizations Conclusions: We suspect that injury to the hypothalamus is responsible for his symptoms. This patient’s syndrome, while plausibly an epiphenomena, is remarkably similar to the expected physiologic changes of hibernating mammals and may represent the first report of hibernation in humans. This case highlights the importance of hypothalamic influence on autonomic function and sleep. Disclosure: Dr. Mohl has nothing to disclose. Dr. Howell has nothing to disclose.