The medical injury caused by a lightning strike is known as keraunopathy, a violent biological event resulting from an immense, transient electrical discharge. Lightning channels carry currents that can peak between 30,000 and 100,000 amperes, with a voltage differential often exceeding 30,000 volts. This massive electrical energy flows for an incredibly short duration, typically lasting only a few milliseconds. Despite the sheer power involved, the majority of victims survive the initial strike. The brevity of the electrical contact is a primary factor in survival, as it limits the duration of current flow through the body.
How Lightning Interacts with the Human Body
A common misconception is that all lightning injuries result from a direct hit, which is actually the least frequent mechanism, accounting for only about 5% of cases. The electrical current can injure a person through four distinct pathways. One common method is a side flash, or splash, where lightning strikes a taller object, like a tree, and a portion of the charge jumps across the air gap to a nearby person. This side splash accounts for approximately 30% of lightning injuries and often occurs when people seek shelter under isolated tall objects.
Ground current is the most prevalent mechanism, responsible for 40% to 55% of lightning strike injuries. This happens when the lightning hits the ground, and the immense current spreads outward across the earth’s surface. The charge enters the victim’s body through one contact point, usually a foot, and exits through another, creating a voltage difference that can be lethal.
A contact injury occurs when a person is touching an object that is struck, such as a metal fence or an electrical appliance. In this scenario, the object acts as a conductor, channeling the current directly into the person. Regardless of the mechanism, the current often travels over the surface of the body, a phenomenon called flashover, but a significant portion can still pass through internal tissues, primarily affecting the nervous and cardiovascular systems.
Immediate Life-Threatening System Failure
The most immediate danger posed by a lightning strike is the disruption of the body’s electrical control systems, particularly the heart and lungs. The massive electrical surge typically causes instantaneous cardiac arrest, often manifesting as asystole, a complete cessation of the heart’s electrical activity. While the heart muscle sometimes spontaneously restarts, the respiratory system is frequently more compromised.
The current’s effect on the brainstem, which controls involuntary functions like breathing, can cause a prolonged respiratory paralysis. This respiratory arrest can persist even after the heart has successfully restarted its beat. If the victim is not assisted with breathing, the lack of oxygen leads to a secondary, and often fatal, cardiac arrest due to hypoxia.
Immediate neurological stunning is also common, which may include a temporary paralysis known as keraunoparalysis. This condition causes weakness, numbness, or paralysis, most commonly in the lower limbs. Although this paralysis is dramatic, it is generally transient and typically resolves completely within a few hours to a day. The immediate focus of emergency care is concentrated on restoring breathing and supporting the body’s central electrical function.
Visible and Localized Physical Damage
In contrast to high-voltage industrial electrical accidents, lightning strikes rarely cause deep, catastrophic thermal burns because of the current’s extremely brief duration. The visible burns that do occur are usually superficial flash burns or steam burns, caused by the superheating of air or the rapid vaporization of sweat on the skin’s surface. True deep burns are generally limited to areas where metal objects or clothing ignited and transferred heat directly to the skin.
A unique sign of lightning exposure is the appearance of Lichtenberg figures, also known as ferning patterns. These reddish, fern-like skin markings are not true thermal burns but are believed to be caused by the rupture of superficial capillaries beneath the skin due to the electrical discharge. Lichtenberg figures are painless, transient, and typically disappear completely within 24 to 48 hours, confirming a lightning strike has occurred.
Mechanical trauma is another significant component of a lightning injury, resulting from the powerful shockwave created by the rapid heating and expansion of air surrounding the lightning channel. This blast injury can be forceful enough to rupture internal organs, cause blunt force trauma from being thrown, or generate explosive concussive injuries. Ruptured eardrums are particularly common due to the immense pressure wave.
The eyes and ears are highly vulnerable sensory organs. Ocular damage, such as the formation of cataracts, is a frequent long-term complication that can develop immediately or years after the event. Vestibular and auditory injuries are also common, leading to hearing loss, tinnitus, or balance problems, often in conjunction with a ruptured eardrum.
Long-Term Recovery and Neurological Impact
The acute phase of injury gives way to a challenging recovery period characterized by lasting health issues, often referred to as Post-Lightning Syndrome. Since the nervous system is the primary target of the electrical current, long-term damage is frequent. Chronic neuropathic pain can persist indefinitely and is particularly difficult to manage.
Survivors commonly face debilitating neurological and psychological consequences:
- Cognitive deficits: These include difficulties with memory, concentration, and a general slowing of mental processing. Such issues resemble traumatic brain injury and create significant challenges with employment and personal relationships.
- Personality changes: Increased irritability, mood swings, and emotional lability are frequently observed.
- Psychological conditions: The violent nature of the injury, coupled with chronic physical and cognitive struggles, often results in the development of conditions like Post-Traumatic Stress Disorder, requiring specialized mental health support.