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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?