Heat Stroke Flashcards
what produces most body heat?
muscular activity
which structures in the body control body temperature?
central and peripheral thermoreceptors
what acts as the thermoregulation centre in the brain?
anterior hypothalamus
what is the role of the thermoreceptors?
indicate when temperature is above or below the ideal set point
what does the body do if the temperature is above the set point?
heat dissipation
what does the body do if the temperature is below the set point?
heat conservation and production
what temperature is classed as hyperthermia?
> 39.2 C
what are some of the causes of hyperthermia?
pyrexia
increased heat production due to increased muscular activity
heat stroke
what are the 2 types of heat stroke?
classic heat stroke (reduced heat loss)
exertional heat stroke - overheating due to over-exercise in high temps
what causes heat stroke?
failure of heat dissipation
what may lead to failure of heat dissipation?
upper respiratory obstruction
increased environmental temperature/humidity
poor environmental ventilation
circulatory compromise
obesity
breed disposition
what body temperature carries risk of organ damage/failure?
> 41.6 C
why does a temperature of >41.6 C risk permanent organ damage/failure?
caused by cell death due to large increase in oxygen demand and DIC
what are the major clinical signs of heat stroke?
stress
hyperthermia
tachycardia
hypovolaemia
hyperdynamic pulses
peripheral vasodilation
collapse
hyperaemic mm (bright red) with rapid CRT
when might heat stroke patients appear normothermic?
due to impaired peripheral perfusion - widespread vasodilation
what are the symptoms of advanced stage heat stroke?
hypovolaemia
increased intestinal mucosal permeability and impaired GI perfusion
tachypnoea
secondary respiratory complications
why might a patient in advance stage heat stroke be hypovolaemic?
GI losses
vasodilation - relative hypovolaemia due to systemic compromise
why are patients in heat stroke at higher risk of sepsis?
increase intestinal mucosal permeability and impaired GI perfusion –> endotoxin translocation –> sepsis