History and exam

Key diagnostic factors

common

profound central nervous system disturbance

A host of central nervous system (CNS) alterations may be present, ranging in severity from confusion to coma. Typically, patients present with confusion and agitation. Ataxia and irritability may also be manifest. Presence of such CNS disturbance is a key factor in distinguishing heat stroke from heat exhaustion.

hyperthermia

Core temperature readings may be obtained with rectal or esophageal thermometers.[17] In heat stroke core temperature is classically >104°F (>40°C).

However, it should be noted that even patients with normal temperature can have heat stroke, either because of inaccurate measuring techniques or from effects of prior cooling.

Repeat readings are necessary to track temperature.

Other diagnostic factors

common

headache

Central nervous system symptom.

May also be present in heat exhaustion.

nausea and vomiting

Central nervous system symptom.

May also be present in heat exhaustion.

anxiety

Central nervous system symptom.

May also be present in heat exhaustion.

dizziness

Central nervous system symptom.

May also be present in heat exhaustion.

tachycardia

May result from hyperthermia or hypotension, and frequently accompanies both classic and exertional heat stroke.

jaundice

Hepatic injury, due to thermal stress, tissue hypoperfusion, and indirect effects of heat stroke.

muscle tenderness

Rhabdomyolysis may develop. Patients may report muscle tenderness and have hypo- or hypertonic muscles.

uncommon

hypotension

May result from cutaneous vasodilation, shock, or volume depletion. In severe heat stroke it can indicate cardiovascular collapse.

gastrointestinal bleeding

Gut hypoxia and hemorrhage can frequently occur, resulting from hypoperfusion and endotoxin release.

bruising and skin bleeding

Coagulopathy as a consequence of hepatic injury or direct thermal stress may also manifest (e.g., as epistaxis or bleeding from intravenous access sites). Disseminated intravascular coagulation may develop.

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