Clinically, body temperature is normal and there is rarely evidence of dehydration. Fluid and electrolyte losses due to sweating coupled with inadequate replacement result in hypovolemia and tissue hypoperfusion. Symptoms include fatigue, vertigo, headache, nausea, vomiting, and finally impaired judgement, hyperventilation, tachycardia, and hypotension. A headache, weakness, or transient confusion may be present but there should be no signs of significant global mental status changes. If left untreated, heat exhaustion may lead to heat stroke.
Treatment includes rest in a cool environment with volume and electrolyte replacement.
It represents a failure of the body's thermoregulatory mechanisms. In contradistinction to heat cramps and heat exhaustion, heat stroke is a medical emergency which may result in multisystem tissue damage and organ dysfunction with a potentially high mortality rate. Irritability, bizarre behavior, combativeness, hallucinations, or coma may occur. Virtually any neurological abnormality may be present, and signs of trauma should be assessed. A conservative approach should be taken as the patient may present with a lower than peak core temperature if cooling measures have already been initiated.