Lightning Injuries Clinical Presentation

Lightning injuries are obvious if they occur in a group setting where witnesses are present. However, lightning injuries can be difficult to diagnose if the person presents without witnesses or is unable to relate the details of his or her injury.

Often, the person can relate what happened. However, it is common for the person to have anterograde amnesia or confusion.^[14] While the person may be able to carry on a reasonably coherent social conversation, giving demographic and billing data, the examiner may also observe that he or she repeats the same questions multiple times or may not remember events in the emergency department (ED). More disturbing symptoms such as not recognizing a family member should draw suspicion for malingering or other litigious behavior.

Each patient must receive a complete physical examination, including a neurologic assessment and a thorough examination of the skin for wounds and burns. Physical presentation may vary from mild disorientation with no immediate physical signs to cardiac arrest (the only direct cause of death) and anoxic brain injury. Conscious patients most often complain of muscle aches, dysesthesias, and weakness, or other neurologic/musculoskeletal problems.^{[5, 14]}

Indications of lightning injury noted on physical examination include the following:

• Cold, pulseless extremities - A sign of vasomotor instability
• Confusion, amnesia, paralysis, and loss of consciousness
• Temporary hearing loss or tympanic membrane rupture - Caused by concussive shock wave
• Hypotension - Usually from vasomotor instability and spasm but spinal cord injuries and other more common causes should be ruled out
• Prolonged paresis or paralysis of the extremities - Indicates possible spinal cord injuries
• Fixed and dilated pupils - Typically a result of transient autonomic disturbances, not serious head injuries; pupillary areflexia and dilatation therefore cannot be used as a reason to stop resuscitation
• Lichtenberg figures - Rare but pathognomonic of lightning injury; also known as ferning pattern^[64]

Cardiorespiratory symptoms

Cardiorespiratory arrest is the only known direct cause of death. Lightning may send the heart into momentary asystole, from which the heart often spontaneously recovers. Autonomic nervous system control of cardiac rhythm has been shown to be affected by lightning. In some cases, respiratory arrest may last longer than the initial cardiac arrest and a secondary cardiac arrest from hypoxia, from more serious brain injury prolonging the respiratory arrest, or from other unknown causes may occur.^{[5, 11, 12, 14]}

Many changes may be observed on the electrocardiogram (ECG), but the most commonly reported is QT prolongation, which generally resolves over several months and does not commonly require treatment. The indicated treatment is not particular to lightning but standard depending on the abnormality observed.^{[5, 11, 12, 13]}

Neurologic symptoms

The immediate effect of the electrical current of a lightning strike on the CNS is an altered level of consciousness that varies from disorientation with retrograde amnesia to loss of consciousness. In the most severe cases, paralysis of the respiratory center may occur and cause sudden death. Rarely, the injury is so devastating that rapid onset of cerebral edema with brainstem herniation occurs. If the patient is unconscious, suspect and investigate anoxic brain injury or underlying brain injury.

Cerebral edema should be managed in the standard way.

Patients who are awake are usually able to carry on reasonably appropriate social conversation. However, they may develop disabling neurocognitive deficits similar to those of people with blunt head injury, which may not be apparent until survivors attempt to return to their previous work and are unable to process new information, organize their activities, and multitask.^{[5, 65]}

Acute pain, numbness, or other dysesthesias may be reported. Chronic pain syndromes may develop from lightning injuries and may be due to nerve injury, sympathetic nervous system injury, spinal column injury, or other causes.^[5]

Sympathetic nervous system injury may acutely cause vascular spasm; temporary paralysis and mottling of an extremity (keraunoparalysis); transient hypertension, which usually does not need treatment; and late problems with positive tilt test results, vertigo or dizziness, hypertension, and pain syndromes.^{[5, 57, 58]}

Mechanical trauma from a fall after a lightning strike can also account for neurologic sequelae. Rarely, lightning may cause the victim to fall or be thrown with sufficient force to cause skull fracture and intracranial hemorrhage. Because a comatose or semicomatose state may follow the lightning strike, it is often difficult to distinguish coma resulting from electrical shock from intracranial hematoma until lateralizing signs develop, so the threshold for imaging the patient with clouded mentation should be low.

Burns

Because lightning usually has extremely brief contact with the skin, deep burns are rare.^{[10, 66]} If burns occur, treat them like any other high-voltage injury, including investigating for myoglobinuria. Discrete entry and exit points rarely are seen with lightning injury.

The following types of burns are caused by lightning:

• Feathering
• Linear
• Punctate - multiple, closely spaced, discrete, circular, usually full-thickness burn that results from current passing through dry skin; a few millimeters to a centimeter in diameter and resembles a cigarette burn
• Thermal - Results when lightning ignites clothing; can be a full-thickness burn
• Contact - Occurs when metal, such as jewelry, zippers, or belt buckles, contacts the skin during a lightning strike; can be a full-thickness burn or can actually "tattoo" metal, such as a necklace, into the skin
• Flash - Superficial burn that results in brown discoloration of the skin

An almost pathognomonic cutaneous feature known as feathering or lightning prints consists of linear, fernlike, superficial skin markings (also called keraunographic marks) that disappear after several days.^[67] These cutaneous manifestations of lightning injury usually consist of erythematous streaks that do not blanch on diascopy. Erythema begins to fade in 4-6 hours with no residual skin changes. This bizarre cutaneous manifestation is probably related to the flashover phenomenon, from the transmission of static electricity along the superficial vasculature. Recognition of this sign may save the life of an unaccompanied, comatose patient and should signal the need for immediate resuscitation if a victim is not breathing and has no pulse.

Linear burns are partial-thickness burns, 1-4 cm wide, that occur over moisture-rich areas of the body, such as beneath the breasts, down the midchest, and in the midaxillary line. These first- and second-degree burns present minutes to hours after the lightning strike and result from vaporization of sweat into steam on the patient's body.

Full-thickness burns rarely result from lightning accidents in developed countries. However, lightning occasionally causes an electrical burn from direct current flow, with clinical manifestations similar to those from a commercial, high-voltage electrical injury. Extensive burn scars following lightning burns may develop into squamous cell carcinoma (Marjolin ulcer).

Therapy for burn injuries should include cleansing the burn wound with poloxamer 188, followed by treatment with a topical antimicrobial cream containing polymyxin (10,000 U/g), nystatin (4000 U/g), and nitrofurantoin (0.3%). Tetanus prophylaxis is mandatory, as the wound is considered tetanus prone. When full-thickness burns are evident, excision of the devitalized skin followed by the application of autogenous, split-thickness skin grafts is recommended.

In developing countries where marginal housing is still the norm, keraunoparalysis may result in the inability of the victim to escape from a hut with a burning thatched roof, resulting in much more severe thermal injuries. These can be treated in the standard fashion for thermal burns.^[68]

Blunt injury

Consider concomitant myoglobinuria if blunt injury is present. Fractures are uncommon and occur more rarely in lightning injuries than in high-voltage injuries. Being thrown tens of yards because of intense muscle contraction is frequently reported. Organ contusions, pulmonary hemorrhage, and cardiac contusions have been reported but are rare. If the patient has a history of a fall or being thrown a distance, investigate for fractures and blunt injuries.

Musculoskeletal system

Lightning may injure the musculoskeletal system either by mechanical trauma or by passage of the electrical current.^[69] When someone is struck by lightning, current may produce a violent muscular contraction that throws the victim several feet, possibly causing fractures and/or dislocations of the extremities. Fractures of the skull, ribs, extremities, and spine have been reported.

As current passes through tissue, electrical energy is converted to heat that may be sufficient to damage muscle tissue. Although very rare with lightning injuries, muscle necrosis has potentially severe local (compartmental syndrome) and systemic (rhabdomyolysis and renal failure) sequelae, although this is less frequent than in commercial electrical injuries.

Eyes and adnexa

Lightning can injure the eye and its adnexa.^[70] Nearly every type of eye injury has been reported with lightning injury, including cataracts, macular holes, retinal separation, and iritis.^[20] Cataracts may be an early of late sequela of lightning injury, as are chronic pain syndromes, sleep disturbance, and severe headaches.

Disruption of the autonomic nervous system causes dilated and/or nonreactive pupils. This reaction to lightning strike is usually short-term and should not be used as an indicator of brain death in patients who have been injured by lightning.

Cataracts are the most common intraocular lesions caused by lightning.^[71] Two types of cataracts are seen: (1) an ordinary traumatic cataract that develops shortly after the injury from a concussion that results in minute tears of the lens capsule, and (2) a type of cataract that is characteristic of an injury from either lightning or high-voltage current. In the latter, a high-voltage current produces anterior subcapsular changes, while lightning causes opacities in the anterior and posterior capsules. The cataract may appear within the first few days or as late as 24 months postinjury and is usually bilateral. Generally, opacification develops more rapidly after lightning injury than after commercial high-voltage electrical injury.

Retinal involvement after lightning injury is less frequently documented, although chorioretinal atrophy, macular holes, macular cyst, papilledema, hemorrhage, and detachment have been noted. Macular cyst can be diagnosed with optical coherence tomography. Consequently, consider the possibility of retinal damage when evaluating the visual potential of a patient who has developed a cataract following a lightning strike.

Lid lesions caused by lightning vary from a partial-thickness burn to ulcerated necrotic lesions. Conjunctival chemosis frequently occurs, and corneal lesions vary from transitory punctate keratitis to severe interstitial keratitis. Iridocyclitis may be mild or short-lived or more severe and chronic. Paresis of accommodation also may occur following a lightning strike.

Ears

Although injury to the ear is relatively rare in electrical-current accidents, it occurs in more than one half of patients with lightning injury.^[53] Lightning can injure the ear through 2 mechanisms: direct and blast effects. The direct effect of lightning results from passage of the electrical current. In lightning-damaged ears, substantial ear damage and hearing loss are common, as are tinnitus and other eighth nerve symptoms, including dizziness and unsteadiness.^[14] .

Temporal bone pathology shows tympanic membrane rupture, middle ear and mastoid effusion of pus and blood, total rupture of the Reissner membrane, degeneration of the stria vascularis and organ of Corti, edema of the intracanalicular portion of the facial nerve, herniation of a portion of cerebellum into the internal auditory meatus, and a possible microfracture of the otic capsule. These lightning-damaged ears often are associated with other injuries (eg, burns of the skin, acromioclavicular joint separation).

Perforation of the tympanic membrane occurs in more than half of patients injured by lightning. This injury is caused by the blast effect, basilar skull fracture, or direct burn damage from lightning. Ruptured tympanic membranes from lightning regenerate well without surgical intervention.

Occasionally, unilateral hearing loss can occur without other trauma after lightning injury.^[72] An audiogram shows typical nerve-type hearing loss. The tympanic membrane is intact but markedly inflamed. Hearing disability is temporary, and recovery occurs in 9 months.