Hypothermia

Definition: Rectal temperature < 35 degrees celcius
Epidemiology: Mortality 30-80%. Often due to falls/illness
Causes: Exposure, ↓heat production (e.g. hypothyroid, Addisons), ↓heat loss (↓fat, Pagets), drugs & psychosocial (alcohol, sedatives, depressants), social (no money for heating)

Clinical

Signs insidious & may be transient. Patients no longer complain of being cold after a while. Drowsy, disorientated, paranoid, hallucinating.
Examination: cold, pale, waxy features. Coma.

Effects on systems

• CVS:↓HR, HB, arrhythmias (VT/VF), hypovolaemia, pulmonary oedema
• Respiratory: Tissue anoxia, bronchopneumonia
• GI: Gastric dilatation with vomiting, pancreatitis
• Renal (↓volume): oliguria, acute tubular necrosis
• Bloods:↓Hbg, ↑WCC, ↓platelets
• Neurological: Slurring, ataxia, dilated pupils, absent shivering

Investigation

Bloods: tissue anoxia & acidoses if circulation inadequate. Glucose falls. K, Na falls causing arrhythmias
Airway: Endotracheal tube may be necessary
Dehydration: Warm fluids, electrolytes
Slow surface rewarming
Antibiotics may be necessary
Monitor: BP (hypotension), glucose, K, Na, ECG (arrhythmias)