Hyperthermia

Question 1

What is hyperthermia?

Answer 1

An uncontrolled rise in body temperature due to failed heat dissipation — not a raised hypothalamic set point.

Question 2

How is hyperthermia different from fever?

Answer 2

Hyperthermia: no change in set point, cooling mechanisms fail
Fever: hypothalamic set point is increased.

Question 3

What core temperature usually defines hyperthermia?

Answer 3

Typically > 40°C

Question 4

What are the main mechanisms of heat loss in the body?

Answer 4

• Radiation
• Convection
• Conduction
• Evaporation (sweating — most important in heat)

Question 5

What happens physiologically in hyperthermia?

Answer 5

Heat production exceeds heat loss → cellular injury + enzyme failure

Question 6

What is heat exhaustion?

Answer 6

Moderate heat illness with dehydration and salt loss without CNS dysfunction.

Question 7

Key symptoms of heat exhaustion?

Answer 7

• Weakness
• Dizziness
• Nausea
• Heavy sweating
• Tachycardia

Question 8

What is heat stroke?

Answer 8

Severe hyperthermia with CNS dysfunction.

Question 9

Diagnostic triad of heat stroke?

Answer 9

• Core temp > 40°C
• CNS dysfunction
• Heat exposure/exertion

Question 11

CNS features of heat stroke?

Answer 11

• Confusion
• Seizures
• Coma
• Delirium

Question 12

Skin findings in classic heat stroke?

Answer 12

Often hot and dry (may still be sweaty in exertional heat stroke).

Question 13

What are the two types of heat stroke?

Answer 13

1️⃣ Classic (environmental)
2️⃣ Exertional

Question 14

Who gets classic heat stroke?

Answer 14

• Elderly
• Chronically ill
• Poor ventilation/heat waves

Question 15

Who gets exertional heat stroke?

Answer 15

• Athletes
• Military
• Heavy laborers

Question 16

What drug classes can cause hyperthermia?

Answer 16

• Anticholinergics
• Sympathomimetics
• Serotonergic drugs
• Anaesthetic triggers

Question 17

What toxidrome causes hyperthermia with dry skin and no sweating?

Answer 17

Anticholinergic toxicity

Question 18

What toxidrome causes hyperthermia with agitation and sweating?

Answer 18

Sympathomimetic toxicity

Question 19

What is malignant hyperthermia?

Answer 19

A genetic skeletal muscle disorder triggered by certain anaesthetics

Question 20

What triggers malignant hyperthermia?

Answer 20

• Volatile anaesthetics
• Succinylcholine

Question 21

Key features of malignant hyperthermia?

Answer 21

• Rapid temperature rise
• Muscle rigidity
• Acidosis
• Hyperkalemia

Question 22

Antidote for malignant hyperthermia?

Answer 22

Dantrolene

Question 23

First priority in hyperthermia management?

Answer 23

Rapid cooling

Question 24

Most effective emergency cooling method?

Answer 24

Cold water immersion (if feasible)

Question 25

Other cooling methods?

Answer 25

• Ice packs (groin/axilla/neck) • Evaporative cooling • Cooled IV fluids

Question 26

What should be monitored closely during treatment?

Answer 26

• Core temperature • Electrolytes • Renal function • CK

Question 27

Target temperature during active cooling?

Answer 27

Stop at about 38–38.5°C to avoid overshoot hypothermia