Heat-Generated Tissue Injury: When electrical current travels through the body, tissue injury occurs along the path of travel as a result of the generation of heat. Interposed tissues provide varying degrees of resistance to current, and as a consequence, heat is generated. Injuries to nerves, muscles, and the vasculature (resulting in thrombosis) are the most significant types of injury. The extent of tissue damage is directly related to a number of factors:

High voltage (generally considered that in excess of 600-1,000 V) is associated with a higher incidence of death and serious injuries. Most household appliances operate at 110 V (dryers and house power lines are at 220 V), with residential feeding or trunk lines carrying 7,620 V. Commercially available “stun guns” or Tazers produce generalized, intense muscle contraction and result in the collapse of the victim; although the voltage produced with these weapons is high (50,000 V with the Tazer), serious injuries are unusual.

Direct contact burns are typically, but not always, seen at the point of current entry and exit from the body; these are characterized by a charred or dark center, with a surrounding area of pale or necrotic tissue. Electrical current may also produce injury via arcing; this is the phenomenon whereby current travels to the victim, through interposed air, from and between areas of high and differing electrical
potential. Arcing may occur across significant distances (approximately 1 ft for each 100,000 V of differing potential), may ignite the victim’s clothing, and, because of intense muscular contraction at the time of contact, produce falls and other injuries.

It is not possible to predict or define the extent or type of damage along the suspected course of current transmission, even when entry and exit wounds are found.

Tissue necrosis, which can be dramatic, extensive, and rapidly evolving, is classically delayed for several hours to days and may complicate injuries originally assessed as trivial in the emergency department. Compartment syndromes related to vascular injury and extensive muscular injury must also be suspected and treated aggressively.

Cardiac arrest caused by ventricular fibrillation is the most common cause of death in electrocuted patients; a variety of other cardiac arrhythmias, which may not be present initially, are also seen. Monitoring is therefore appropriate.

Extensive muscle necrosis may produce significant hyperkalemia, hypocalcemia, and renal failure caused by myoglobinuria.

Neurologic abnormalities are common in patients exposed to high voltage; a variety of mental status changes are reported and include loss of consciousness, restlessness, depersonalization, anxiety, and mild confusion. Most of these changes are transient. Coma, which may be prolonged, is also seen occasionally. Spinal cord damage, usually reported in association with hand-to-hand or head-to-hand transmission, is occasionally noted and may not be fully manifest when the patient is first seen. Interventricular hemorrhage can occur when high voltage passes through the brain.

As a result of intense muscular contraction at the time of contact, or as a result of a “blast,” patients may be thrown from ladders, etc., and significant musculoskeletal and other injuries may be sustained; these include vertebral compression and longbone fractures and dislocations (typically posterior dislocations of the shoulder). Similarly, loss of consciousness at the time of contact may also occur and result in injury. Fractures involving long bones frequently coexist, and occult injuries to the cervical and thoracic spine are common; these injuries are often not initially suspected.

“Kissing” or arc burns involving contact areas of the flexor surfaces of the upper extremity are common, occur when electricity-induced muscular contraction occurs, and are diagnostic of conductive-type injuries. These burns frequently involve the axilla, flexor creases of the palm and wrist, and the antecubital fossa; when they are present, a significant underlying injury should be suspected.

In pregnant patients, although uncommon, fetal death

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