Lightning injuries

Background

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

Injury Mechanisms

• 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 content with an object (e.g. metal fence) 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
• 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 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

• 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
• Cannot neuroprognosticate anyone for 24hrs based on pupils^{[citation needed]}

Vascular

• Vasomotor spasm may cause loss of distal pulses, coolness of extremities, loss of sensation
• Keraunoparalysis - temporary paralysis due to sympathetic nervous system activation and vascular spasm
  • Resolves spontaneously
  • Compartment syndrome is rarely the cause (skeletal muscle unaffected in strikes)

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

Perforated TM

Derm

• Lichtenberg figures (ferning pattern) - pathognomonic for lightning strike
  • Occur due to electron showering over the skin, not 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

Neuro

• Keraunoparalysis - a neurologic and muscular "stunning" that can follow lightning strikes and usually resolves spontaneously. It is thought of as a neurologic phenomenon but is a result of arterial vasospasm from catecholamine release. It will resolve within hours.
  • Limb weakness, sensory abnormalities, absent pulses, cold temperature extremities

Ortho

• Compartment Syndrome and rhabdomyolysis are unlikely due to short duration of lightning current

Special Populations

• 50% of pregnancies have fetal demise^{[citation needed]}

Differential Diagnosis

• Blast injury

Evaluation

• Clinical diagnosis

Work-Up

• CBC, chem, total CK, UA
• ECG
• CT Brain(for patients with coma, altered mental status, confusion)
• Other imaging and workup is directed toward visible or suspected injuries

Management

• 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

Disposition

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

See Also

• Electrical Injuries

References

Authors

Ross Donaldson