Lightning injuries include cardiac arrest, loss of consciousness, and temporary or permanent neurologic deficits; serious burns and internal tissue injury are rare. Diagnosis is clinical; evaluation requires ECG and cardiac monitoring. Treatment is supportive.
Lightning strikes cause about 30 to 50 deaths and several times more injuries annually in the US. Lightning tends to strike tall or isolated objects, including trees, towers, shelters, flagpoles, bleachers, and fences. A person may be the tallest object in an open field. Metal objects and water do not attract lightning but easily transmit electricity once they are hit. Lightning can strike a person directly, or the current can be transferred to the person through the ground or a nearby object. Lightning can also travel from outdoor power or electrical lines to indoor electrical equipment or telephone lines. The force may throw the person several yards.
Because the physics of lightning injury is different from that of generated electrical energy, knowledge of the effects of exposure to household current or high voltage cannot be extrapolated to lightning injuries. For example, damage from lightning injury is not determined by voltage or amperage. Although lightning current contains a large amount of energy, it flows for an extremely brief period (1/10,000 to 1/1000 sec). It rarely, if ever, causes serious skin wounds and seldom causes rhabdomyolysis or serious internal tissue damage, unlike high-voltage and high-current electrical injury from generated sources. Patients may have intracranial hemorrhage resulting from secondary injury or, rarely, from lightning itself.
Lightning can affect the heart but primarily affects the nervous system, damaging the brain, autonomic nervous system, and peripheral nerves.
Symptoms and Signs
The electrical charge can cause asystole or other arrhythmias or cause symptoms of brain dysfunction, such as loss of consciousness, confusion, or amnesia.
Keraunoparalysis is paralysis and mottling, coldness, and pulselessness of the lower and sometimes upper extremities with sensory deficits; the cause is probably sympathetic nervous system injury. Keraunoparalysis is common and usually resolves within several hours, although some degree of permanent paresis occasionally results. Other manifestations of lightning injury may include minor skin burns in a punctate or feathered, branched pattern, tympanic membrane perforation, and, within days, cataracts. Neurologic problems may include confusion, cognitive deficits, and peripheral neuropathy. Neuropsychologic problems (eg, sleep disturbances, attention deficit, memory problems) may occur. Cardiopulmonary arrest at the time of the strike is the most common cause of death. Cognitive deficits, pain syndromes, and sympathetic nervous system damage are the most common long-term sequelae.
Lightning injuries may be witnessed or unwitnessed. Unwitnessed injuries should be suspected when people found outside during or after storms have amnesia or are unconscious.
ECG may be done if injury is severe. Cardiac enzymes are measured for patients with the following:
Patients with initially abnormal or deteriorating mental status or focal neurologic deficits compatible with a brain lesion require a head CT or MRI.
CPR is initiated for cardiac or respiratory arrest or both. If an automated external defibrillator is available, it should be used.
Supportive care is provided. Fluids are usually restricted to minimize potential brain edema. Most people who have been injured by lightning can be safely discharged unless cardiac effects or brain lesions are suspected.
Most lightning injuries can be prevented by following lightning safety guidelines. People should know the weather forecast and have backup plans if a storm is predicted. They should have an escape plan involving evacuation to a safer area (ideally a large habitable building) and pay attention to the weather while outdoors so they can implement the escape plan if an unexpected storm comes up. By the time thunder is heard, people are already in danger and should seek shelter (eg, in a building or fully enclosed metal vehicle). Small, open structures, such as gazebos, are not safe. People should not go outdoors until 30 min after the last lightning is seen or thunder is heard. When indoors during an electrical storm, people should avoid plumbing and electrical appliances, stay away from windows and doors, and not use hard-wired telephones, video game consoles, or computers. Cellular phones, personal digital assistants (PDAs), and MP3 players are safe because they do not attract lightning.
Last full review/revision January 2009 by Mary Ann Cooper, MD