Lightning injury

Lightning injuries occur when someone is struck by lightning. Initial symptoms may include heart asystole and respiratory arrest. While the asystole may spontaneously resolve fairly rapidly, the respiratory arrest is typically more prolonged. Other symptoms may include burns and blunt injuries. Of those who survive, about 75% have ongoing health problems as a result, such as cataracts and hearing loss. If death occurs it is typically from either an abnormal heart rhythm or respiratory failure.

Lightning injuries are divided into direct strikes, side splash, contact injury, and ground current. Ground current occurs when the lightning strikes nearby and travels to the person through the ground. Side splash makes up about a third of cases and occurs when lightning strikes nearby and jumps through the air to the person. Contact injury occurs when the person is touching the object that is hit. Direct strikes make up about 5% of injuries. The mechanism of the injuries may include electrical injury, burns from heat, and mechanical trauma. Diagnosis is typically based on history of the injury and examination.

Prevention includes avoiding being outdoors during a thunderstorm, and sheltering in a fully enclosed structure (such a closed building or metal car). If being outdoors is unavoidable, bringing the feet and knees together is recommended (if possible, while crouching low in the 'lightning position'— crouched low, hands over ears, feet touching if possible) so as to provide only one point of contact with the ground. When indoors the use of devices connected to electrical outlets and contact with water is not recommended. Among those who appear in cardiac arrest and have no central pulse, cardiopulmonary resuscitation (CPR) should be started. In those who have a central pulse but are not breathing artificial ventilation, such as mouth to mouth, is recommended.

As of 2019, it has been estimated that lightning injuries occur 240,000 times a year with 24,000 deaths. Areas with mountainous terrain and moisture-heavy airflow, such as Central Africa, have the highest rates of lightning strikes. Among pregnant women who are hit by lightning, the death of the fetus occurs in about half. In the United States, about 1 in 10,000 people are hit by lightning during their lifetime. Males are affected four times more often than females. The age group most commonly affected is 20 to 45 years old.

Common injuries caused by lightning include: muscle pains, broken bones, cardiac arrest, confusion, hearing loss, seizures, burns, behavioral changes, and ocular cataracts. Loss of consciousness is very common immediately after a strike.

Lightning burns result from energy caused by lightning strikes, and are characterized by a unique pattern of skin lesions. These tree-like lesions resemble feathering or ferning, and are also called Lichtenberg figures. The marks are formed when capillaries beneath the skin rupture due to the electrical discharge and they usually appear "within hours" of the strike though they tend to disappear within a few days. They also generally occur on the upper body. The brief duration of the exposure frequently limits the damage to the outer layer of skin.

The intense heat generated by a lightning strike can burn tissue, and cause lung damage, and the chest can be damaged by the mechanical force of rapidly expanding heated air.

Just as heat can cause expanding air in the lungs, the explosive shock wave created by lightning (the cause of thunder) can cause concussive and hearing damage at extremely close range. Other physical injury can be caused by objects damaged or thrown by the lightning strike. For example, lightning striking a nearby tree may vaporize sap, and the steam explosion often causes bark and wood fragments to be explosively ejected.