Chapter 126. Electrical and Lightning Injuries

Electrical injuries present with a wide spectrum of damage, from superficial skin burns to multisystem injury. Electrical injuries are arbitrarily classified as low voltage (≤1000 V) and high voltage (>1000 V). At very high voltages, an electric arc may also travel from a voltage source to a person and cause severe burns. Standard household electricity is low voltage alternating current (AC), power lines are high voltage. Young children most often sustain low voltage injuries in the home from electrical outlets or chewing on electrical wires, whereas adults more often sustain high voltage injuries while at work.

Clinical Features

Electrical injuries cause injury via several mechanisms: direct tissue damage from electrical energy, thermal damage from heat created by tissue resistance, and mechanical injury induced by a fall or tetanic muscle contraction. Severity of injury and tissues affected depend on voltage, duration of contact, tissue resistance, and path of current. The risk for serious injury increases with as voltage increases. Patients may sustain immediate cardiac dysrthymias (including ventricular fibrillation), respiratory arrest or seizures. Cardiac complications, such as arrhythmias and QT prolongation are more commonly seen in high voltage injuries. Temporary loss of consciousness is common. Severe burns may results from contact with high voltage lines. Entrance and exit burns are typically painless, gray to yellow depressed areas. The size of the skin injury does not correlate well with internal injuries. Traumatic injuries frequently accompany electrical injuries. Details of specific immediate and delayed systemic injuries and complications are summarized in Table 126-1.

Diagnosis and Differential

Diagnosis of electrical injury is usually based on history of contact with an electrical source. The type of current and surrounding circumstances may help direct the initial evaluation.

Characteristic skin lesions or oral lesions (in children) may provide diagnostic clues if the patient or witnesses are unable to provide a history. Laboratory and radiographic evaluation of high voltage injures should follow standard trauma guidelines. (Chapter 156 “Trauma in Adults,” Chapter 157 “Trauma in Children,” Chapter 158 “Trauma in Elderly”). An elevated serum CK, myoglobin or urine myoglobin suggests extensive muscle injury and rhabdomyolysis. Atrial or ventricular arrhythmias, bradyarrthymias, prolonged QT intervals or ST-T wave abnormalities may be noted on ECG. Assessment and treatment of complications associated with electrical injuries are summarized in Table 126-2.

The differential diagnosis includes other causes of arrhythmias, such as myocardial ischemia, and neurologic dysfunction, such as stroke, closed head injury, spinal cord injury.

Emergency Department Care and Disposition

1. Assess and stabilize airway, breathing, and circulation abnormalities. Treat ventricular fibrillation, asystole, or ventricular tachycardia using standard ACLS protocols. Other dysrhythmias are usually transient and do not need immediate therapy. Treat traumatic injuries using standard trauma protocols. Treat seizures with standard therapy.

2. Provide continuous monitoring of vital signs, heart rate and rhythm, and pulse oximetry. Provide high-flow oxygen and begin IV crystalloids. Fluid requirements are usually greater than initially predicted using the Parkland Burn formula (Chapter 125). Monitor urine output with a Foley catheter.

3. Cover large burns with dry sterile dressings.

4. Monitor for rhabdomyolysis, compartment syndrome and renal failure. Treat rhabdomyolysis with aggressive fluid rehydration aiming for a urine output of 2 mL/kg/h (Chapter 51).

5. Provide pain control with opioids.

6. Reduce and immobilize fractures and dislocations.

7. Administer tetanus prophylaxis, if not up to date.

8. Clean and treat small cutaneous burns in the standard fashion. Prophylactic systemic antibiotics are usually not necessary unless large open contaminated wounds are present.

9. Consult with a general surgeon, trauma surgeon or burn surgeon as patients may require formal wound exploration, debridement, fasciotomy or transfer to a facility with specialty care. For pregnant patients, consult with an obstetrician for fetal monitoring and admission.

10. Table 126-3 summarizes admission criteria. Patients with more than a minor low voltage injury should be admitted for further monitoring.

11. Children with isolated oral injuries or isolated hand wounds can usually be discharged home after consultation with an ENT specialist or plastic surgeon. Provide parents with instructions for controlling delayed labial artery bleeding. Arrange close follow-up with the consulting surgeon to assess scarring and stricture.

12. Asymptomatic patients who sustained a low voltage injury (≤240 V) and have a normal ECG on presentation and normal physical exam may be discharged home.

Electronic control devices, such as the cattle prod, stun gun, and the TASER®, deliver high-voltage, low-amperage electrical pulses that induce involuntary muscle contraction, neuromuscular incapacitation, and/or pain. The likelihood of electrical injury is minimal. Injuries are usually limited to superficial punctures, and minor lacerations and cutaneous burns. The majority of deaths that have followed the use of these devices have occurred in persons who were extremely ill and agitated due to psychosis, stimulant drugs, or other conditions. Ill-appearing and agitated patients should be evaluated and treated in the same way as all patients who may have sustained blunt trauma or who have ingested unknown substances. Cardiac monitoring and other testing are not needed just because a TASER® has been used.

Lightning is a unidirectional extremely high voltage current that causes substantially different injuries from those caused by high voltage AC electricity. Lightning emits brief, but intense, thermal radiation. Lightning often flashes over the skin, rather than through the body, which helps explain how some people survive a lightning strike with little or no injury.

Clinical Features

The most common immediate cause of death after lightning strike is cardiac arrest or respiratory arrest. In the patient with spontaneous circulation, hypertension and tachycardia are caused by sympathetic activation. Patients may experience temporary loss of consciousness, confusion, and amnesia. Feathering or fern-shaped burns on the skin are pathognomonic of lightning. Tympanic membrane rupture may occur. Deep tissue injuries, myoglobinuria, and renal failure are uncommon unless the lightning has traveled through, rather than over, the patient or as a result of associated trauma. Details of specific immediate and delayed systemic injuries and complications are summarized in Table 126-4.

Diagnosis and Differential

The diagnosis of lightning injury is based on history and should be considered in any critically ill patient found outside during or after a thunderstorm. While increasingly rare, indoor exposures to lightning may occur via indoor pools and use of hard-wired telephones. Carefully assess patients for burns, neurologic and cardiovascular complications, otologic and ophthalmologic injuries, and blunt trauma. Laboratory and radiographic evaluation of lightening injures should follow standard trauma guidelines. (Chapter 156 “Trauma in Adults,” Chapter 157 “Trauma in Children,” Chapter 158 “Trauma in Elderly”) Differential diagnosis includes stroke or intracranial hemorrhage, seizure disorder, and cerebral, spinal cord, or other neurologic trauma.

Emergency Department Care and Disposition

1. Even in a mass casualty situation, provide aggressive resuscitation in patients with respiratory and cardiac arrest due to lightning strike. Respiratory arrest may outlast initial cardiac arrest and adequate ventilation can prevent hypoxic injury until return of spontaneous circulation. Survival has been reported even after prolonged respiratory arrest.

2. Treat traumatic injuries using standard trauma protocols. Treat arrhythmias using standard ACLS protocols. Treat seizures with standard therapy.

3. Provide continuous monitoring of vital signs, heart rate and rhythm, and pulse oximetry. Provide high flow oxygen and begin IV crystalloids.

4. Hypotension is unexpected and should prompt investigation for hemorrhage.

5. Treat keraunoparalysis with expectant management.

6. Administer tetanus prophylaxis, if not up to date.

7. Admit patients with persistent musculoskeletal symptoms, neurologic, cardiac rhythm or vascular abnormalities, or significant burns to a critical care unit. Consult with a general surgeon, trauma surgeon or burn surgeon. All pregnant patients require obstetric consultation and admission for fetal monitoring.

8. Patients with minor injuries and a negative workup may be discharged with outpatient follow-up to assess delayed effects of lightening injury.