Lecture for 5th year medical student

1. Environmental Injuries Part II

2. Heat Emergencies
Drowning

3. Heat Emergencies

4. MINOR HEAT ILLNESSES
Heat edema
Prickly Heat
Heat cramps
Heat Stress

5. Heat edema
self-limited
mild swelling of dependent extremities
cutaneous vasodilation and pooling of interstitial
fluid
Treatment
 elevation of the extremities
 compressive stockings
 Diuretics: exacerbate volume depletion, avoided

6. Prickly Heat
Lichen tropicus,
miliaria rubra, or heat
rash
vesiculopapular
eruption
clothed areas of the
body

7. Prickly Heat
inflammation and obstruction of sweat ducts
Tx: Antihistamines, low potency topical
corticosteroids, or calamine lotion
Advise patients to wear light, loose fitting
clothing.

8. Heat cramps
painful muscle spasms
Occur when individuals replace evaporative
losses with free water but not with salt
Treatment
 rest
 administration of oral electrolyte solution or IV
normal saline

9. Heat Stress
headache, nausea, vomiting, malaise, dizziness,
and muscle cramps as well as signs of
dehydration, such as tachycardia and orthostatic
hypotension or near-syncope
Because of the ill-defined and nonspecific
symptoms, heat stress is often a diagnosis of
exclusion.

10. Heat Stress
Tx: volume and electrolyte replacement, rest
 Removal from the heat-stressed environment
 mild heat stress: oral electrolyte solutions
 significant tissue hypoperfusion: rapid infusion of
moderate amounts of IV fluids (1-2 L of normal
saline)

11. HEAT STROKE
acute life-threatening emergency with high
mortality and is fatal if left untreated

12. HEAT STROKE
Exertional heat stroke
 usually occurs after strenuous physical activity in
a hot environment
Nonexertional heat stroke
 more commonly affects chronically ill or
debilitated patients and persons at the extremes
of age, especially during a prolonged heat wave

13. HEAT STROKE
cardinal features
 hyperthermia (core temperature > 40°C)
 altered mental status
Anhidrosis / profuse sweating
Prominent neurologic abnormalities
 confusion, agitation, bizarre behavior, ataxia,
seizures, obtundation, and coma

14. HEAT STROKE
Diagnosis
no diagnostic tests for heat stroke
determined by history and clinical presentation,
and exclusion of other processes

16. HEAT STROKE
Diagnosis
 Laboratory abnormalities
 Respiratory alkalosis
 lactic acidosis
 Hypoglycemia
 Hypophosphatemia, hypokalemia, hypercalcemia
 elevated liver enzymes due to hepatocellular damage
 elevated hematocrit due to hemoconcentration
 elevated creatine phosphokinase and myoglobin from
rhabdomyolysis
 DIC, renal failure

17. HEAT STROKE
Treatment
goals of therapy: immediate cooling and
aggressive support of organ system function

18. HEAT STROKE
Emergency Department Care and Disposition
ABC
Evaporative cooling
 Place fans near the completely disrobed patient
and spray the patient with tepid water.
 Goal: core temperature <39°C

19. HEAT STROKE

20. HEAT STROKE

21. HEAT STROKE
Emergency Department Care and Disposition
Seizures: benzodiazepines
Rhabdomyolysis: IV hydration
Monitor serum electrolytes every hour initially.
admission to the ICU

22. Drowning

23. CLINICAL FEATURES
aspirate water into their lungs have washout of
surfactant

diminished alveolar gas transfer, atelectasis,
ventilation perfusion mismatch, and hypoxia
Noncardiogenic pulmonary edema
Mental status: normal - comatose
hypothermia

24. DIAGNOSIS AND DIFFERENTIAL
Evaluate patients for associated injuries (spinal
cord) and underlying precipitating disorders
including syncope, seizures, hypoglycemia, and
acute myocardial infarction or dysrhythmias.
Respiratory acidosis  metabolic acidosis
Early electrolyte disturbances: unusual
A CXR is usually obtained but is frequently
normal in patients who are otherwise
asymptomatic.

26. EMERGENCY DEPARTMENT CARE AND DISPOSITION

29. EMERGENCY DEPARTMENT CARE AND DISPOSITION
Measure core temperature. Treat hypothermia if
present.
Data do not support routine antibiotic
prophylaxis for pulmonary aspiration.
Efforts at “brain resuscitation,” have not shown
benefit.
 mannitol, loop diuretics, hypertonic saline, fluid
restriction, mechanical hyperventilation,
controlled hypothermia, barbiturate coma, and
intracranial pressure monitoring

30. EMERGENCY DEPARTMENT CARE AND DISPOSITION
Hypothermic victims of cold-water submersion
with cardiac arrest should undergo prolonged
and aggressive resuscitation maneuvers until
they are normothermic or considered not viable.

31. ANY QUESTION?