The neurological and cognitive consequences of hyperthermia

Abstract

An elevated temperature has many aetiologies, both infective and non-infective, and while the fever of sepsis probably confers benefit, there is increasing evidence that the central nervous system is particularly vulnerable to damage from hyperthermia. A single episode of hyperthermia may cause short-term neurological and cognitive dysfunction, which may be prolonged or become permanent. The cerebellum is particularly intolerant to the effects of heat. Hyperthermia in the presence of acute brain injury worsens outcome. The thermotoxicity involved occurs via cellular, local, and systemic mechanisms. This article reviews both the cognitive and neurological consequences and examines the mechanisms of cerebral damage caused by high temperature.

Human Physiology in Extreme Heat and Cold

“…The affected connections in the limbic system (consistent with the emotional imbalances, memory and learning ability), in the dorsolateral prefrontal cortex (related to executive functions such as planning, cognition and reasoning) and the intraparietal sulcus (which is involved in the processing of new information and memory); may explain all of the neurological changes [38]. Other causes of neurologic dysfunction may be direct heat-related neuronal damage, changes in cell signalling, ischemia, oedema, changes in cerebral blood flow and inflammatory changes [38]. Blood-brain-barrier permeability increases generating oedema and allowing potential sub- [28].…”

“…Shivering thermogenesis has been re-stances and metabolites to enter into the central nervous system [1,38]. Cerebral blood flow may increase at first but with temperatures above 40-41 °C; cerebral blood flow may fall to baseline or below although this is incompletely understood [38]. The neuromuscular system characterises with muscular weakness and cramps due to electrolyte imbalances [20].…”

Cadet dies from hyperthermia and exertional heat stroke during indoor SCBA maze training - Texas.

“…Heat stroke is a life-threatening emergency of failed thermoregulation with severe hyperthermia (> 104.9°F / 40.5°C) and central nervous system dysfunction, often with loss of consciousness [ACSM et al 2007]. The brain is particularly sensitive to hyperthermia, but damage can occur to multiple organs [Bouchama et al 2005;Walter and Carraretto 2016].…”

Контрольована Нормотермія В Пацієнтів У Критичному Стані З Травматичним Ушкодженням Головного Мозку

“…Гипертермия вызывает церебральное повреж-дение в результате реализации трех механиз-мов [6]: 1) клеточных эффектов: мембранного, митохон-дриального и ДНК-повреждения, активации эксай-тотоксичности, денатурации белков;…”