SAQ 440 – Environmental – collapsed marathon runner with heat stroke and rhabdomyolysis

Environmental – collapsed marathon runner with heat stroke and rhabdomyolysis.

a. Differential diagnoses

• Heat stroke or heat exhaustion; heat stroke is most likely given hyperthermia and reduced GCS.
• Dehydration/hypovolaemia.
• Hypoglycaemia.
• Hyponatraemia or other metabolic disturbance.
• Serious infection including CNS infection.
• Seizure, intracranial haemorrhage, or head injury.
• Drug ingestion or withdrawal such as amphetamines, anticholinergics, thyroxine, or neuroleptic malignant syndrome.
• Thyroid storm.

b. Initial treatment aims

• Restore circulating volume with cooled IV crystalloid, for example 20 mL/kg initially with reassessment.
• Urgently cool the patient with a clear method and target core temperature.
• Support airway and breathing, and prepare for modified RSI/intubation if airway or ventilation becomes unsafe.
• Monitor core temperature, ECG, glucose, urine output, and electrolytes.
• Look for and treat alternative causes such as sepsis, trauma, or drugs.

c. Abnormalities and significance

d. Next management

• Continue cooled IV crystalloid while monitoring volume status.
• Insert urinary catheter and target urine output around 1-2 mL/kg/hr; consider urinary alkalinisation if used locally and monitor pH.
• Continue active cooling.
• Refer to ICU; dialysis may be required if renal failure, hyperkalaemia, acidosis, or low urine output does not improve.
• Correct coagulopathy/blood product deficits and monitor serial electrolytes.
• Give empiric antibiotics if infection remains a significant possibility.