Although injury and deaths due to lightning strikes have decreased significantly over the last 50 years, lightning strikes still cause about 30 deaths and several hundred 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 has been observed to strike 10 or more miles away from a storm, even in areas with clear skies, creating the potential for unexpected risk (1). Lightning can also travel from outdoor power or electrical lines to indoor electrical equipment or telephone lines. The force of a lightning strike can throw the person up to several meters.
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 second). 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.
Davis C, Engeln A, Johnson EL: Wilderness Medical Society practice guidelines for the prevention and treatment of lightning injuries: 2014 Update Wilderness Environ Med 25(4 Suppl):S86-S95, 2014. doi: 10.1016/j.wem.2014.08.011.
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 plus sensory deficits; the cause is likely injury to the sympathetic nervous system. Keraunoparalysis is common and usually resolves within several hours, although some degree of permanent paresis occasionally results. Other manifestations of lightning injury may include
Neurologic problems may include confusion, cognitive deficits, and peripheral neuropathy. Neuropsychologic problems (eg, sleep disturbances, attention deficit, memory problems) may occur.
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. All patients struck by lightning should be evaluated for traumatic injuries.
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.
Cardiopulmonary resuscitation (CPR) is initiated for cardiac or respiratory arrest or both. If an automated external defibrillator is available, it should be used for cardiac arrest. Patients who are in cardiac arrest following a lightning strike, unlike patients in cardiac arrest from other types of trauma, often have an excellent prognosis if resuscitated. Thus, unlike in a typical mass-casualty event, in which patients in cardiac arrest are given low triage priority, such patients are given high priority when multiple casualties are caused by lightning strike.
Supportive care is provided. Fluids are usually restricted to minimize potential brain edema. Most patients 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 an escape plan involving evacuation to a safer area (ideally a large, habitable building). They should pay attention to the weather while outdoors so they can implement the escape plan if a 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 minutes 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 and other handheld devices and laptop computers are safe when used with battery power only because they do not attract lightning.
Lightning injuries tend to cause arrhythmias and brain dysfunction, unlike electrical injuries from generated sources, which tend to cause skin burns and internal tissue injury.
Suspect lightning injury if patients are found unconscious or amnestic outside after a storm.
When evaluating patients, consider traumatic injuries, arrhythmias, and brain and heart damage.
Treat patients supportively.
Most lightning injuries can be prevented by following lightning safety guidelines.