ESSENTIALS OF DIAGNOSIS
Extent of injury is determined by the type, amount, duration, and pathway of electrical current.
Clinical findings of death are unreliable; therefore, resuscitation efforts must be attempted before assuming the electrical injury victim is dead.
Skin findings may be misleading and are not indicative of the degree of deeper tissue injury.
Electricity-induced injuries are common and yet most are preventable. These injuries occur by exposure to electrical current of low voltage, high voltage, or lightning. Electrical current type is either alternating current (AC) or direct current (DC) and is measured in volts (V). Electricity causes acute injury by direct tissue damage, muscle tetany, direct thermal injury and coagulation necrosis, and associated trauma.
Alternating current (AC) is an electric current that periodically reverses direction in a sine wave pattern and may cause muscle tetany, which prolongs the duration and amount of current exposure. AC can be low voltage or high voltage. Most households and businesses use electric power in the form of AC at low voltages (less than 1000 V). Low voltage electrical injuries can range from minor to significant damage and death. High voltage (greater than 1000 V) AC electrical injuries are often related to occupational exposure and associated with deep tissue damage and higher morbidity and mortality. Alternating currents that pass through the thoracic cavity at lower voltages of 25–300 V may lead to ventricular fibrillation, or to respiratory arrest at higher voltages (greater than 1000 V). Direct current (DC) is unidirectional electrical flow (ie, lightning, batteries, and automotive electrical systems). It is more likely to cause a single intense muscle contraction and asystole. Lightning differs from other high-voltage electrical shock in that lightning delivers a direct current of millions of volts in a fraction of a second.
The extent of damage from electrical injuries depends on the following factors: voltage (high or low, whether greater or less than 1000 V), current type, tissue resistance, moisture, pathway, duration of exposure, associated trauma, and comorbidities. Current is the most important determinant of tissue damage. Current passes through the tissues of least resistance as energy, which produces heat and causes direct thermal injury. Tissue resistance varies throughout the body with nerve cells being the most vulnerable and bone the most resistant to electrical current.
Electrical burns are of three distinct types: flash (arcing) burns, flame (clothing) burns, and the direct heating effect of tissues by the electrical current. The latter lesions are usually sharply demarcated, round or oval, painless yellow-brown areas (Joule burn) with inflammatory reaction.
Skin damage does not correlate with the degree of injury. Not all electrical injuries cause skin damage; very minor skin damage may be present with massive internal injuries. Significant subcutaneous damage can be accompanied by little skin injury, particularly with larger skin surface area electrical contact. Symptoms and signs may ...