Remote Primary Health Care Manuals

Hyperthermia (heat illness)

  • May present as heat stroke (severe), heat exhaustion (moderate) or heat cramps (mild)

  • Heat stroke is a medical emergency requiring rapid cooling to avoid risk of sudden deterioration and death
  • Heat cramps and exhaustion can progress to heat stroke if not managed properly
  • Severity of illness may not be apparent straight away
  • Children, elderly, sick, people playing sport or working in heat are at most risk
Red Flags — Urgent Medical Consult
  • Change in conscious state
  • No urine being passed
  • Rhabdomyolysis — has more than 3+ protein or 3+ blood (urine looks like strong tea)
  • Heat stroke
  • Temp still more than 38°C after 1 hour
  • Person has not fully recovered after 1 hour
  • Other medical problems

Table 2.10 Features of heat illness

Feature Heat stroke Heat exhaustion
Temp More than 40°C Less than 40°C
Skin
  • Flushed, hot
  • Classic — no sweat
  • Exertional — may be sweaty
 Cold/clammy, sweating
BP Usually normal. Low in 20% of people Normal or low
Nausea/vomiting Bad nausea and vomiting Nausea, may be vomiting
Headache Severe, throbbing Mild
Response Drowsy, confusion, fits, delirium, unconscious Normal, drowsy, irritable, fainting
Breathing Short of breath Fast (hyperventilating)
Other
  • Acute kidney failure
  • Acute liver failure
  • Muscle breakdown
  • BP may be low
 Low BGL

Heat stroke or heat exhaustion

Do not

  • Do not use ice bath
    • Shuts down blood flow to skin and slows cooling
    • Makes monitoring and treatment harder
  • Do not give medicines to lower temp — antipyretics (eg paracetamol)

Do first

  • Start cooling person as soon as possible — the longer temperature is raised the more dangerous it is for the person
    • Get person into shade or indoors
    • Remove outer clothing
    • Sponge with cool water
    • Cover person with wet towels and fan them
    • Put cold packs under arms, on sides of neck, in groin
    • Stop actively cooling person when T 39°C

Ask

  • Headache, confusion or strange behaviour
  • Weakness, dizziness
  • Nausea or vomiting, abdominal pain
  • Amount and type of recent physical activity
  • Exposure to hot air, high temps
  • Medical problems — recent sickness, infection, fever
  • Any medicines (eg fluid tablets), recreational drugs
  • Fluid intake

Check

  • Calculate age-appropriate REWS
    • Adult — AVPU, RR, O2 sats, pulse, BP, Temp
    • Child (less than 13 years) — AVPU, respiratory distress, RR, O2 sats, pulse, central capillary refill time, Temp
  • Weight, BGL
  • U/A, pregnancy test
  • ECG and coma scale

Do

  • Medical consult
  • Give oxygen to target O2 sats 94–98% OR if moderate/severe COPD — 88–92%
  • Put in IV cannula. If not possible — put in intraosseous needle
  • POC Test — lactate, pH, sodium, urea/creatinine
  • Blood cultures, urine MC&S
  • If BGL less than 4mmol/L — see Hypoglycaemia (low blood glucose)
  • If systolic BP less than 100mmHg — give normal saline bolus
    • Adult or child over 12 years — 250–500mL
    • Child under 12 years — 20mL/kg
  • If systolic BP more than 100mmHg — run normal saline infusion
    • Adult or child over 12 years — 1L over 2 hours
    • Children and elderly — medical consult
  • If sepsis likely (eg elderly, alcoholic, chronic illness) — see Early recognition of sepsis
  • Put in indwelling urinary catheter — male, female

Heat cramps

Brief severe muscle cramps that come on suddenly

Do

  • Cool person
  • Give Oral Rehydration Solution (ORS)
  • Rub muscles to ease pain