Heat Illness

Published on 14/03/2015 by admin

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Last modified 14/03/2015

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Heat Illness

Definitions

The term heat illness encompasses a spectrum of syndromes ranging from muscle cramps to heatstroke, which is a life-threatening emergency. Predisposing factors include the following:

1. Environmental temperature exceeding 35° C (95° F) with humidity level greater than 80%

2. Dehydration (one indicator in the field is dark yellow urine)

4. Cardiovascular disease

6. Hyperactivity

c. Cocaine or amphetamine intoxication

7. Muscular exertion

8. Burns (including sunburn)

a. Anticholinergic agents (antihistamines, phenothiazines, antispasmodics)

b. β-Adrenergic blockers, angiotensin-converting enzyme (ACE) inhibitors, diuretics

d. α-Adrenergic agonists

10. Extremes of age

11. Fatigue or lack of sleep

13. Excessive clothing

Disorders

Signs and Symptoms

Peripheral edema develops during the first few days in a hot environment in unacclimatized travelers.

Treatment

The edema is usually self-limited and does not require medical therapy. Diuretics should be avoided because the dehydration that may ensue predisposes a person to more serious heat illness syndromes.

“Prickly Heat” (Miliaria Rubra)

Signs and Symptoms

1. Erythematous, papular, and pruritic rash

2. In dry climates, the rash is confined to skin sufficiently occluded by clothing to produce local sweating

Treatment

1. Cool and dry affected skin.

2. Administer antihistamines (diphenhydramine, adult dose 25 to 50 mg q4-6h) to relieve itching.

3. Desquamation of the affected epidermis and recovery of sweat gland function occurs in 7 to 10 days.

Heat Syncope

Signs and Symptoms

Syncope occurs after prolonged standing in a hot environment or after rapidly standing up from a lying or sitting position.

Treatment

1. Perform a full secondary assessment after the primary survey to assess for any trauma that may have occurred because of a fall.

2. Place the patient in the Trendelenburg position.

3. Cool the patient, and administer oral fluids when he or she is awake and alert. The body can absorb a carbohydrate-containing beverage, such as Gatorade, faster than plain water. The concentration of carbohydrates in such a beverage should not exceed 6%; otherwise, gastric emptying and fluid absorption by the intestines may be delayed. Responders should target an intake for the patient of 1 to 2 L (1.1 to 2.1 qt) over the first hour.

4. Patients with heat syncope usually recover rapidly with treatment. If the patient does not improve or worsens, he or she should be evaluated for heatstroke or other potential cause of syncope and transported to a hospital immediately.

Heat Cramps

Heat cramps result from fluid and electrolyte deficits and occur most often in persons who have not been fully acclimated to a combination of intense muscular activity and environmental heat. Individuals who are susceptible to heat cramps are often believed to be profuse sweaters who sustain large sweat sodium losses.

Signs and Symptoms

1. Painful, spasmodic muscle cramps that usually occur in heavily exercised muscles

2. Recurrent cramps that may be precipitated by manipulation of the muscle

3. Onset during or after exercise

Treatment

1. Administer an oral fluid containing sodium chloride (see later).

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