Hyperthermia Flashcards
Define the heat illnesses:
Cramps
Syncope
Tetany
Heat exhaustion
Heat stroke
Heat cramps
Occurs in fatigued muscles, from salt depletion (serum Na normal)
Heat syncope
Vasodilation
Heat tetany
Carpopedal spasm
Hot —> hyperventilation —> alkalosis, hypocalcaemia
Heat exhaustion
Salt and/or water depletion
Symptomatic, but:
- No tissue damage
- CNS fine
- Can thermoregulate
Core temp often normal
Heat stroke
Salt and water depletion
CNS dysfunction
Multi organ failure
Loss of thermoregulation- core temp >40
Mortality in heatstroke:
60%
Neurological deficit in 15%
Types of heat stroke:
Classic
Ambient heat
Don’t sweat
Exertional
Exercise
DO sweat
Often also have lactic acidosis, rhabdo
Clinical features of heat stroke:
Temp >40
Skin warm, or cool (if shocked)
Classic = no sweat. Exertional = may sweat.
CNS dysfunction: ALOC, confusion, ataxia, coma, seizure. incl. focal
Tachycardia, hypoTN
Tachypnoea, ARDS,
Liver failure, transaminitis
Coagulopathy, DIC, WCC
Low phosphate, hyper/hypoglycaemia
Rhabdo
Renal failure: ATN, myoglobinuria,
Differential for heat stroke:
Heat exhaustion (or other heat illness)
Infection: sepsis, CNS
Thyroid storm
Tox: salicylate, stimulants, anticholinergic, NMS, SS, malig hyperthermia
Management of heat stroke:
Core temp monitoring: rectal, bladder, oesoph
Expose
Ice packs to axillae, groin
Ice bath immersion
Plan B: Body bag with ice and cold water
Plan C: ‘Tarp taco’ with ice
Plan D: Spray with water (or wet towels) under fans, on cooling blanket
Cooled fluids
—> 0.9% saline
—> fridge, down to 4deg
—> often many litres- diuresis
—> 5% dextrose if hypoglyc. Hypertonic saline PRN. (rare)
Cooled air
HFNP without humid
Remove heat/moist exchanger if intubated
Lavage
Iced water
Gastric, peritoneal, bladder, thoracic
TREAT SHIVERING
Benzos
Chlorpromazine 25mg IV
Thiopentone
CONTINUE UNTIL 38deg
ICU
Monitor- rebound is not uncommon
