Heat Stroke Patients

Question 1

Define hyperthermia.

Answer 1

Increased body temperature >39.2 degrees C

Question 2

What can cause hyperthermia?

Answer 2

Pyrexia
Increased heat production due to increased muscular activity
Classic heat stroke (reduced heat loss)
Exertional heat stroke (overheating due to over-exercising at inappropriate temperatures)

Question 3

What can cause heat stroke?

Answer 3

Caused by failure of heat dissipation!
Upper respiratory obstruction e.g. BOAS
Increased environmental temperature/humidity
Poor environmental ventilation
Circulator compromise e.g. heart disease, poor CO, hypovolaemia
Obesity
Breed disposition

Question 4

How can heat stroke cause organ damage/failure?

Answer 4

Risk of (permanent) organ damage/failure caused by cell death due to large increase in oxygen demand and DIC (disseminated intravascular coagulation)

Question 5

What are some clinical signs of heat stroke?

Answer 5

Stress
Hyperthermia
Tachycardia, hyperdynamic pulses
Hypovolaemia
Peripheral vasodilation
Collapse
Hyperaemic MMs with rapid CRT

Question 6

Describe hypovolaemia related to heat stroke.

Answer 6

GI losses
Vasodilation - relative hypovolaemia due to systemic compromise

Question 7

What secondary respiratory complications can be associated with heat stroke?

Answer 7

Aspiration pneumonia
Pulmonary oedema
Pulmonary haemorrhage (DIC)

Question 8

What are some less common consequences of heat stroke?

Answer 8

Acute kidney injury
CNS compromise
Disseminated intravascular coagulation
Electrolyte derangements e.g. hypoglycaemia, hyperbilirubinaemia
Thrombosis
Myopathy

Question 9

How should we initially manage a heat stroke patient?

Answer 9

> 41 degrees C - actively cool patient
Stop active cooling at 39.4 degrees C to avoid hypothermia
Oxygen supplementation - monitor oxygenation
Maintain patent airway
IVFT - isotonic crystalloids, measure BP
Use lukewarm water, take temp. every 5 mins

Question 10

What bloods should we be monitoring in heat stroke patients?

Answer 10

PCV and TS
Glucose
Electrolytes
Abnormal coagulation factors?

Question 11

Describe pyrexia.

Answer 11

Beneficial to patients with infection - decreases replication of pathogens and increases function of WBCs
Avoid actively cooling

Question 12

What can cause pyrexia?

Answer 12

Inflammatory disease - infectious / immune-mediated
Neoplastic disease
Other causes e.g. opioids, hepatic encephalopathy, blood transfusions