HYPOTHALAMIC DYSTHERMIA IN PERSONS WITH BRAIN-DAMAGE

Brain injury causing dysthermia has appeared to be not uncommon in ins titutionalized people with mental retardation. We sought to determine the characteristics and risks of patients of one institution. Of 1100 residents surveyed over 10 years 92 were reported to have unexplained high or low body temperatures, and 48 were monitored. Core temperature s were taken by non-invasive thermometers recording continuously for 2 4 h. Results were related to clinical conditions and aetiologies of me ntal retardation. Twenty-one per cent of the residents monitored showe d hyperthermia, often related to prenatal metabolic or chromosomal abn ormalities. Forty-two per cent had hypothermia, related to other cause s of brain injury. Seventy-five per cent had abnormal patterns, includ ing flat or exaggerated rhythms, reversed day-night cycle, unusual flu ctuations, or sleep phase delay. Sixty-two per cent of 21 deaths to da te have occurred in hypothermic patients. Occasional discrepancies bet ween history of dysthermia and monitored results are best explained by fluctuations of temperature control over several days, probably due t o changes in timing of hypothalamic rhythmicity. This could be better delineated by longer periods of monitoring.