This occurs when the core body temperature rises above 40°C and is a severe and life-threatening condition. The symptoms of heat exhaustion (see above) progress to include headache, nausea and vomiting. Neurological manifestations include a coarse muscle tremor and confusion, aggression or loss of consciousness. The patient's skin feels very hot, and sweating is often absent due to failure of thermoregulatory mechanisms. Complications include hypovolaemic shock, lactic acidosis, disseminated intravascular coagulation, rhabdomyolysis, hepatic and renal failure, and pulmonary and cerebral oedema.

SYMPTOMS

• Headache, nausea, dizziness
• Red, dry, very hot skin (sweating has ceased)
• Pulse-strong & rapid
• Small pupils
• Very high fever
• May become extremely disoriented
• Unconsciousness and possible convulsions