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Environmental Injuries Part II
Heat EmergenciesDrowningLightning Injuries
Heat Emergencies
MODELS OF HEAT INJURY
Classic heat injury occurs during periods of high environmental heat
stress High-risk populations: the elderly, the young, and
those with psychological, physiologic, and pharmacologic impairments of heat loss mechanisms (e.g., diabetes; Raynaud's disease; drugs such as anticholinergics, diuretics, antipsychotics, cocaine).
Exertional heat injury usually affects individuals who are participating in
athletic events or performing jobs under conditions of high heat stress
Confinement hyperpyrexia special category of nonexertional hyperpyrexia occur in several circumstances: when children
are left inside cars, when stowaways are abandoned inside closed vehicles or railroad cars, and when workers are occupationally exposed to heat inside enclosed spaces
MINOR HEAT ILLNESSES
Heat edemaPrickly HeatHeat crampsHeat Stress
Heat edema
self-limitedmild swelling of dependent extremitiescutaneous vasodilation and pooling of interstitial
fluid Treatment
elevation of the extremities compressive stockings Diuretics: exacerbate volume depletion, avoided
Prickly Heat
Lichen tropicus, miliaria rubra, or heat rash
vesiculopapular eruption
clothed areas of the body
Prickly Heat
inflammation and obstruction of sweat ductsTx: Antihistamines, low potency topical
corticosteroids, or calamine lotionAdvise patients to wear light, loose fitting
clothing.
Heat cramps
painful muscle spasmsOccur when individuals replace evaporative
losses with free water but not with saltTreatment
rest administration of oral electrolyte solution or IV
normal saline
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.
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)
HEAT STROKE
acute life-threatening emergency with high mortality and is fatal if left untreated
HEAT STROKE
Exertional heat stroke usually occurs after strenuous physical activity in
a hot environmentNonexertional heat stroke
more commonly affects chronically ill or debilitated patients and persons at the extremes of age, especially during a prolonged heat wave
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
HEAT STROKE
Diagnosis no diagnostic tests for heat strokedetermined by history and clinical presentation,
and exclusion of other processes
HEAT STROKE
Diagnosis Laboratory abnormalities
Respiratory alkalosis lactic acidosis hypoglycemia, hypophosphatemia and
hypokalemia, elevated liver enzymes due to hepatocellular damage, hypercalcemia and an elevated hematocrit due to hemoconcentration, and elevated creatine phosphokinase and myoglobin from rhabdomyolysis
DIC, renal failure
HEAT STROKE
Treatmentgoals of therapy: immediate cooling and
aggressive support of organ system function
HEAT STROKE
Emergency Department Care and DispositionABCEvaporative cooling
Place fans near the completely disrobed patient and spray the patient with tepid water.
Goal: core temperature <39°C
HEAT STROKE
HEAT STROKE
HEAT STROKE
Emergency Department Care and DispositionSeizures: benzodiazepinesRhabdomyolysis: IV hydrationMonitor serum electrolytes every hour initially. admission to the ICU
Drowning
CLINICAL FEATURES
aspirate water into their lungs have washout of surfactant
diminished alveolar gas transfer, atelectasis,
ventilation perfusion mismatch, and hypoxia
Noncardiogenic pulmonary edemaMental status: normal - comatosehypothermia
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 acidosisEarly electrolyte disturbances: unusualA CXR is usually obtained but is frequently
normal in patients who are otherwise asymptomatic.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
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
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.
LIGHTNING INJURIES
most common in fishermen, but also occur in other outdoor recreational activities such as golf and camping
Approximately 70%-90% of persons struck by lightning survive, but as many as ¾ of these survivors have permanent sequelae.
PATHOPHYSIOLOGY
often travels over the surface of the body in a phenomenon called flashover
less likely to cause internal cardiac injury or muscle necrosis
Lightning emits brief but intense thermal radiation that produces rapid heating and expansion of the surrounding air.
Tympanic membrane perforation and internal organ contusion may occur.
PATHOPHYSIOLOGY
Stunning (keraunoparalysis)produce a variety of neurologic signs and
symptomsKeraunoparalysis is associated with successful
resuscitation after cardiorespiratory arrest.
TYPES OF LIGHTNING STRIKES
Both cardiac and respiratory arrest may be present without evidence of external injury.
CARE AT THE SCENE
In contrast to patients with cardiac arrest caused by mechanical trauma, persons with lightning injury who appear to be dead (in respiratory arrest, with or without cardiac arrest) should be treated first.
Such victims may have little physical damage, and they have a reasonable chance of successful resuscitation.
Prolonged CPR is sometimes successful.
ED DIAGNOSIS AND TREATMENT
ABCsLightning victims in cardiac arrest have a better
prognosis than those in cardiac arrest from coronary artery disease, so aggressive resuscitative efforts are indicated.
Initial ancillary studies: CBC, serum electrolyte levels, creatinine level, BUN level, glucose level, creatine kinase level, urinalysis, and ECG.
Lichtenberg figures
Diagnosis and Differential
Considered in any critically ill patient found outside during or after a thunderstorm
Differential diagnosis stroke or intracranial hemorrhage seizure disorder cerebral, spinal cord, or other neurologic trauma
Emergency Department Care and Disposition
provide aggressive resuscitation in patients with respiratory and cardiac arrest due to lightning strike
Treat traumatic injuries using standard trauma protocols.
Treat arrhythmias using standard ACLS protocols.
Treat seizures with standard therapy.
Treat keraunoparalysis with expectant management.
Administer tetanus prophylaxis, if not up to date.Admit
persistent musculoskeletal symptoms, neurologic, cardiac rhythm or vascular abnormalities, or significant burns
Patients with minor injuries and a negative workup may be discharged with outpatient follow-up to assess delayed effects of lightening injury.
ANY QUESTION?