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Lightning Injuries, Emergency Medicine

Basics

Description

- Lightning is a discharge of energy that occurs cloud to cloud (90%) or cloud to ground (10%). - Exposure to lightning: - Brief duration (1 " “100 msec) - Typically occurs during outdoor activity - Highest incidence in summer months, between 3 and 6 pm - Fatality rate of 8 " “10%

- Consider lightning strike in unwitnessed falls, cardiac arrests, or unexplained coma in an outdoor setting. - Conscious patients may report: - Muscle aches and pains - Chest pain - Shortness of breath - Extremity pain or discoloration - Burns - Neurologic deficits including: - Paresthesia - Dysesthesias - Weakness or paralysis - Visual disturbance or blindness - Headache - Confusion or amnesia - Hearing loss or deafness - Dizziness

- Hypertension: Transient - Pulmonary contusion or hemorrhage - Respiratory arrest: - Caused by paralysis of medullary respiratory center - May persist longer than primary cardiac arrest and lead to hypoxia-induced secondary cardiac arrest and/or brain injury

- Extremities: - Fractures/dislocations - Muscle tears, contusions - Compartment syndromes - Mottled or cold: - Caused by autonomic vasomotor instability - Usually resolves spontaneously in a few hours

- Neurologic injuries: - Confusion, cognitive or memory defects - Altered level of consciousness (>70% of cases) - Flaccid motor paralysis - Seizures - Cerebrovascular accident - Fixed dilated pupils due to either serious head injury or autonomic dysfunction

- Close follow-up with subspecialists may be required due to the risk for delayed sequelae: - Neurology: - Memory deficit - Attention deficit - Aphasia - Sleep disturbance - Prolonged paresthesia and dysesthesias

- Psychology/psychiatry: - Anxiety - Depression - Personality changes - Post-traumatic stress disorder

  • Lightning is a discharge of energy that occurs cloud to cloud (90%) or cloud to ground (10%).
  • Exposure to lightning:Brief duration (1 " “100 msec)Typically occurs during outdoor activityHighest incidence in summer months, between 3 and 6 pmFatality rate of 8 " “10%

Etiology

  • Mechanism of injury " ”electrical:Direct strike (5%)Contact potential (15 " “25%):Current passes through an object the victim is touching.Side splash (20 " “30%):Current jumps from nearby object to the victim.Earth potential rise/ground current (40 " “50%):Current moves through the ground surface and may injure multiple victims.Current moves through hard-wired telephone lines, metallic pipes, or a structures electrical equipment, causing lightning injury to victims indoors.Upward streamer (10 " “15%):Negatively charged lightning strikes from a cloud and induces positive current from the ground to rise and meet it to complete the lightning channel.
  • Mechanism of injury " ”trauma:BarotraumasBlunt trauma:Muscle contractions can throw the victim and/or cause a fall.Thermal burn

Diagnosis

Signs and Symptoms

History

  • Consider lightning strike in unwitnessed falls, cardiac arrests, or unexplained coma in an outdoor setting.
  • Conscious patients may report:Muscle aches and painsChest painShortness of breathExtremity pain or discolorationBurnsNeurologic deficits including:ParesthesiaDysesthesiasWeakness or paralysisVisual disturbance or blindnessHeadacheConfusion or amnesiaHearing loss or deafnessDizziness

Physical Exam

  • HEENT:Blunt head traumaRuptured tympanic membrane with ossicular disruption (up to 50%)Ophthalmic injuries:CataractsCorneal lesionsIntraocular hemorrhagesRetinal detachment
  • Neck:
  • Cardiopulmonary injuries:Primary cardiac arrest:Cardiac asystole:Due to direct current injuryMay resolve spontaneously as the hearts intrinsic automaticity resumes.Hypertension: TransientPulmonary contusion or hemorrhageRespiratory arrest:Caused by paralysis of medullary respiratory centerMay persist longer than primary cardiac arrest and lead to hypoxia-induced secondary cardiac arrest and/or brain injury
  • Extremities:Fractures/dislocationsMuscle tears, contusionsCompartment syndromesMottled or cold:Caused by autonomic vasomotor instabilityUsually resolves spontaneously in a few hours
  • Skin:Burns:May evolve over several hours after injuryDiscrete entrance and exit wounds are uncommon.Superficial in nature; deep burns uncommonDirect thermal injury is uncommon due to the brevity of electrical currents.Thermal burns can arise from evaporation of water on skin, ignited clothing, and heated metal objects (buckles, jewelry).Feathering pattern of fernlike "burns " ť are pathognomonic of lightning injuries and resolve within 24 hr.
  • Neurologic injuries:Confusion, cognitive or memory defectsAltered level of consciousness (>70% of cases)Flaccid motor paralysisSeizuresCerebrovascular accidentFixed dilated pupils due to either serious head injury or autonomic dysfunction
  • Shock:Neurogenic (spinal injury)Hypovolemic (trauma)

Essential Workup

Confirmatory history from bystanders or rescuers of the circumstances of the injury ‚

Diagnosis Tests & Interpretation

Lab

  • CBC
  • Urinalysis for myoglobin (rare)
  • Electrolytes for acidosis
  • BUN, creatinine for renal function
  • Troponin, creatine kinase, and cardiac enzymes for muscle/cardiac damage

Imaging

  • CXR:Pulmonary edemaPulmonary contusion/hemorrhageRib fractures
  • Cervical spine radiograph
  • Head CT for altered mental status or significant head trauma
  • Relevant imaging for specific injuries

Diagnostic Procedures/Surgery

EKG: ‚

  • Prolonged QT (most common)
  • Nonspecific ST changes
  • Premature ventricular contractions
  • Atrial fibrillation
  • Ventricular tachycardia
  • Acute MI (rare)

Differential Diagnosis

Other causes of coma, cardiac dysrhythmias, or trauma: ‚

  • Hypoglycemia
  • Intoxication
  • Drug overdose
  • Cardiovascular disease
  • Cerebrovascular accident
  • Seizure
  • Syncope

Treatment

Pre-Hospital

  • Field triage should rapidly focus on providing ventilatory support to unconscious victims or those in cardiopulmonary arrest:Prevents primary cardiac arrest from degenerating into hypoxia-induced secondary cardiac arrestConscious victims are at lower risk for imminent demise.
  • Spine immobilization for:Cardiopulmonary arrest (suspected trauma)Significant mechanical traumaSuspected loss of consciousness at any time
  • Cover superficial burns with sterile saline dressings.
  • Immobilize injured extremities.
  • Rapid extrication to decrease risk for repeat lightning strikes

Initial Stabilization/Therapy

  • ABCs
  • Standard advanced cardiac life support measures for cardiac arrest
  • Diligent primary and secondary survey for traumatic injuries and other causes of collapse/injury:Maintain cervical spine precautions until cleared.
  • Treat altered mental status with glucose, naloxone, or thiamine as indicated.
  • Hypotension requires volume expansion, blood products, and/or pressor agents.

Ed Treatment/Procedures

  • IV access
  • Cardiac monitor and pulse oximetry
  • Clean and dress burns.
  • Tetanus prophylaxis
  • Treat myoglobinuria if present:Diuretics, such as furosemide or mannitolAlkalinize urine to a pH of 7.45 with IV sodium bicarbonate
  • Volume expansion:Do not follow burn treatment formulas because lightning burns are rarely the cause of fluid loss.Occult deep burn injury is rare when compared with other types of electrical current injury.Titrate volume administration to urine output.Fluid loading may be dangerous if patient has concomitant head injury.
  • Compartment syndrome:Must be distinguished from vasospasm, autonomic dysfunction, and paralysis, which are usually self-limited phenomena.Fasciotomy will rarely be necessary.
  • NSAIDs and high-dose steroids have been proposed to reduce long-term neurologic and corneal damage.

Medication

  • Furosemide: 1 mg/kg IV slow bolus q6h
  • Mannitol: 0.5 mg/kg IV, repeat PRN
  • Sodium bicarbonate: 1 amp IV push (peds: 1 mEq/kg) followed by 2 " “3 amps/L D5W IV fluid

Follow-Up

Disposition

Admission Criteria

  • Postcardiac arrest patients
  • History of change in mental status/altered level of consciousness
  • History of chest pain, dysrhythmias, or ECG changes:May not resolve spontaneously24 " “48 hr observation period to identify potentially unstable casesMyoglobinuriaAcidosisExtremity injury with or at risk for compartment syndrome

Discharge Criteria

Asymptomatic patients with no injuries ‚

Follow-Up Recommendations

  • Close follow-up with subspecialists may be required due to the risk for delayed sequelae:Neurology:Memory deficitAttention deficitAphasiaSleep disturbanceProlonged paresthesia and dysesthesiasOphthalmologyENT
  • Psychology/psychiatry:AnxietyDepressionPersonality changesPost-traumatic stress disorder

Pearls and Pitfalls

  • Do not follow burn treatment formulas for lightning burns and injuries.
  • Be diligent in the primary and secondary survey so as not to miss occult injuries.
  • Have a low threshold to admit and monitor patients with cardiopulmonary complaints, as unstable dysrhythmias may occur 24 " “48 hr post injury.

Additional Reading

  • Cooper ‚ MA, Andrews ‚ CJ, Holle ‚ RL. Lightning injuries. In: Auerbach ‚ PS, ed. Wilderness Medicine. 5th ed. St. Louis, MO: Mosby; 2007:67 " “108.
  • Cooper ‚ MA, Holle ‚ RL. Mechanisms of lightning injury should affect lightning safety messages. 21st International Lightning Detection Conference. April 19 " “20, 2010; Orlando, FL.
  • O 'Keefe Gatewood ‚ M, Zane ‚ RD. Lightning injuries. Emerg Med Clin North Am. 2004;22(2):369 " “403.
  • Price ‚ T, Cooper ‚ MA. Electrical and lightning injuries. In: Marx ‚ JA, Hockenberger ‚ RS, Walls ‚ RM, et al., eds. Rosens Emergency Medicine. 6th ed. Philadelphia, PA: Mosby; 2006.

See Also (Topic, Algorithm, Electronic Media Element)

Electrical Injury ‚

Codes

ICD9

  • 949.0 Burn of unspecified site, unspecified degree
  • 994.0 Effects of lightning
  • 994.8 Electrocution and nonfatal effects of electric current

ICD10

  • T30.0 Burn of unspecified body region, unspecified degree
  • T75.00XA Unspecified effects of lightning, initial encounter
  • T75.09XA Other effects of lightning, initial encounter

SNOMED

  • 38577009 Effects of lightning (disorder)
  • 242012005 Thermal burns from lightning (disorder)
  • 242011003 Injury from ground current from lightning (disorder)
  • 418723004 Effects of direct lightning strike (disorder)