Heat Exhaustion & Heat Stroke Disease

BASICS

DESCRIPTION

A continuum of increasingly severe heat illnesses caused by dehydration, electrolyte losses, and failure of the body's thermoregulatory mechanisms

Heat exhaustion is an acute heat injury with hyperthermia due to dehydration
Heat stroke is extreme hyperthermia with thermoregulatory failure and profound central nervous system dysfunction
System(s) affected: Endocrine/Metabolic, Nervous
Genetics: N/A
Incidence/Prevalence in USA: Dependent on predisposing conditions in combination with environmental factors
Predominant age: More likely in children or elderly
Predominant sex: Male = Female

SIGNS AND SYMPTOMS

Heat Exhaustion
- Fatigue and lethargy
- Weakness
- Dizziness
- Nausea, vomiting
- Myalgias
- Headache
- Profuse sweating
- Tachycardia
- Hypotension
- Lack of coordination
- Agitation
- Intense thirst
- Hyperventilation
- Paresthesias
- Core temperature elevated but < 103°F (< 39.4°C)
Heat Stroke
- Exhaustion
- Confusion, disorientation
- Coma
- Hot, flushed, dry skin
- Core temperature > 105°F (> 40.5°C)

CAUSES

Failure of heat-dissipating mechanisms or an overwhelming heat stress leading to a rise in core temperature, dehydration and salt depletion

RISK FACTORS

Poor acclimatization to heat or poor physical conditioning
Salt or water depletion
Obesity
Acute febrile or gastrointestinal illnesses
Chronic illnesses - uncontrolled diabetes or hypertension, cardiac disease
Alcohol and other substance abuse
High heat and humidity, poor air circulation in environment
Heavy, restrictive clothing

DIAGNOSIS

LABORATORY

Used primarily to detect end-organ damage
Electrolytes, urinalysis
Creatinine, blood urea nitrogen
Liver enzymes
Complete blood count
Increased urine specific gravity
Results of above studies yield hypernatremia, hyperchloremia, hemoconcentration

Drugs that may alter lab results: Diuretics
Disorders that may alter lab results: N/A

PATHOLOGICAL FINDINGS

Only those associated with major organ system failure

SPECIAL TESTS

N/A

IMAGING

N/A

DIAGNOSTIC PROCEDURES

Rectal temperature monitoring

TREATMENT

APPROPRIATE HEALTH CARE

Emergency treatment - best in a hospital setting

GENERAL MEASURES

Rapid cooling - remove clothing, wet patient down, ice packs
Fluid and electrolyte replacement with hypotonic oral fluids or IV 0.5-1.0 liter normal saline
Consider central venous pressure monitoring

SURGICAL MEASURES

N/A

ACTIVITY

Rest with legs elevated

DIET

Cool or cold clear liquids only (non-carbonated)
Avoid caffeine
Unrestricted sodium

PATIENT EDUCATION

Stress the importance of proper conditioning and acclimatization
Instruct patients to recognize heat stress signs and symptoms
Maintain as much skin exposure as possible in hot, humid conditions, while using proper sun block protection
Avoid dehydration with proper fluids during activity or exercise - 8 oz fluid intake for every 15 minutes of moderate exercise

FOLLOW UP

PREVENTION/AVOIDANCE

Most important factor in preventing heat stress is adequate fluid replacement. Allow acclimatization to hot weather through proper conditioning and activity modification. Dress appropriately with loose-fitting, open weave, light-colored clothing.

POSSIBLE COMPLICATIONS

May involve failure of any major organ system
Cardiac arrhythmias or infarction
Pulmonary edema, adult respiratory distress syndrome
Coma, seizures
Acute renal failure
Rhabdomyolysis
Disseminated intravascular coagulation
Hepatocellular necrosis

EXPECTED COURSE AND PROGNOSIS

Good prognosis when mental function is not altered and serum enzymes are not elevated; recovery usually occurs within 24-48 hours.
The mortality rate for heat stroke (10-80%) is directly related to the duration and intensity of hyperthermia, as well as the speed and effectiveness of diagnosis and treatment.

MISCELLANEOUS

ASSOCIATED CONDITIONS

N/A

AGE-RELATED FACTORS

Pediatric: Children are more susceptible
Geriatric: Elderly are more susceptible
Others: N/A

PREGNANCY

May be more prone to volume depletion with heat stress

OTHER NOTES

N/A

ABBREVIATIONS

N/A

Clinical Investigations

ROLE OF HOMOEOPATHY

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