Lightning injuries

Background

• Second most common storm-related injury
• Approximately 30 million ground strikes per year

Injury Mechanisms

• Direct effect of electrical current on body
• Electrical to thermal conversion of energy causing superficial and deep burns
• Direct strike = patient is hit directly by lightning current
  • Often fatal and may cause penetrating injuries
• Splash Injury = current "splashes" to the patient from another object which is struck first
• Conduction = patient is in contact with an object (e.g. metal fence, tree) that is struck by lightning
• Ground current = Also known as step voltage. Occurs when the current spreads out from the initial strike point and then travels through the patient's body
  • Most common mechanism of injury
• Blunt Trauma = Secondary injury pattern that results when the lightning causes a wave of force to propagate through the air to the patient or as a secondary object strikes the patient.

Prehospital Care

• Reverse triage = in lightning-related MCI cases, care should be delivered to patients in cardiac and respiratory arrest first
  • Patients struck by lightning who are alive on EMS arrival will likely survive
• All patients should be transported, preferably to a burn center
• Consider spinal precautions in all patients

Clinical Features

Superficial second degree burn from lightning injury.

Lichtenberg figure.

Patterned charring along the contact points of a metallic locket due to lightning strike.

Lightning-induced cataract.

Perforated TM

Injuries often involve multiple organ systems

Cardiopulmonary

• Both cardiac and respiratory arrest may be present without evidence of external injury
• Ventricular dysrhythmias, asystole, and QT prolongation most common
• Although cardiac automaticity may spontaneously return, apnea may persist
  • Duration of apnea rather than cardiac arrest is the critical prognostic factor
• Myocardial infarction after lightning injury is unusual

Neuro

• Symptoms are usually immediate and transient or delayed and permanent
• Seizure, LOC, confusion, amnesia, extremity paralysis
• Pupillary dilation or anisocoria may occur that is unrelated to brain injury
  • Neuroprognostication should not be based on dilated pupils alone in setting of lightning strike
• Keraunoparalysis - neuromuscular "stunning" that usually resolves spontaneously within hours
  • Thought of as a neurologic phenomenon but actually result of arterial vasospasm from catecholamine release

Vascular

• Vasomotor spasm may cause loss of distal pulses, coolness of extremities, loss of sensation
• Keraunoparalysis - see above

Ocular

• Cataracts may occur weeks to years after injury (must document careful eye exam in all patients)
• Other injuries include vitreous hemorrhage, corneal abrasion, retinal detachment

Auditory

• Blast effect producing Tympanic Membrane Rupture is relatively common

Derm

• Lichtenberg figures (ferning pattern) - pathognomonic for lightning strike
  • Occur due to electron showering over the skin leading to extravasation of RBC's, not a true burn; disappear within 24hr
• Flash burns
  • Similar to those found in arc welders; appear as mild erythema, may involve cornea
• Punctate burns
  • Look similar to cigarette burns; are full-thickness
• Contact burns
  • Occur when metal close to the skin is heated from the lightning current

Ortho

• Compartment Syndrome and rhabdomyolysis are unlikely due to short duration of lightning current
• Associated with posterior shoulder dislocation

Special Populations

• 50% of pregnancies have fetal demise, though literature is sparse
  • Third trimester appears to carry the greatest risk of adverse outcomes
  • Most surviving fetuses have no long term morbidity when carried to term
  • Any lightning strikes in pregnancy requires fetal monitoring, comprehensive testing in-hospital performed by Ob/Gyn

Differential Diagnosis

• Blast injury

Burns

• Smoke inhalation injury (airway compromise)
• Chemical injury
  • Acrolein
  • Hydrochloric acid
  • Tuolene diisocyanate
  • Nitrogen dioxide
• Systemic chemical injury
  • Carbon monoxide toxicity
  • Cyanide toxicity
• Specific types of burns
  • Caustic burns
    • Airbag-related burns
    • Tar burn
    • Cement burn
  • Electrical injuries
    • Lightning Injuries
• Associated toxicities
  • Carbon monoxide toxicity
  • Cyanide toxicity
  • Hydrogen fluoride toxicity

Evaluation

Work-Up

• Exposure: complete and thorough physical exam head to toe
• ECG
• CBC
• Chem
• Total CK
• UA - to evaluate for myoglobinuria
• CT brain (for patients with coma, altered mental status, confusion)
• Other imaging and workup is directed toward visible or suspected injuries

Diagnosis

• Clinical diagnosis

Burn Thickness Chart

Thickness	Deepest Skin Structure Involved	Pain & Sensation	Appearance	Expected Course	Image
Superficial (first-degree)	Epidermis	Painful	Dry, erythema (no blisters) Blanching (intact cap refill)	Heals without scarring, 5-10 days
Superficial Partial (second-degree)	Superficial dermis (papillary region)	Painful	Wet, pale pink, blisters Blanching (intact cap refill)	Heals without scarring, <3 weeks
Deep Partial (second-degree)	Deep dermis (reticular region)	Decreased sensation	Pale white-yellow, blisters Does not blanch (absent cap refill)	Heals in 3-8 weeks Likely to scar if healing >3 weeks May require skin-graft if does not heal within 3 weeks
Full (third-degree)	Hypodermis (subcutaneous tissue)	Decreased sensation	White, leathery Does not blanch (absent cap refill)	Heals by contracture, >8 weeks Almost always requires skin grafting
Fourth-degree	Underlying fat, muscle and bone	Decreased sensation	Black; charred with eschar Does not blanch (absent cap refill)	Does not heal Frequently requires amputation

Management

• Reverse triage - prolonged on-scene CPR and ACLS protocol is indicated even if there are no initial signs of life
• Aggressive resuscitation
  • Lightning-induced Cardiac Arrest has better prognosis than CAD-induced Cardiac Arrest
  • Hypotension is not an expected finding (i.e. suggests traumatic blood loss)
  • Maintain cervical spine precautions
  • Targeted Temperature Management between 32 and 36 degrees Celsius shown to be neuroprotective in setting of hypoxic ischemic encephalopathy after cardiac arrest

Disposition

• Admit patients with persistent muscle pain or neuro, cardiac rhythm, or vascular abnormalities
• Discharged patients require follow up to assess for delayed effects of lightning injury

See Also

• Electrical Injuries