Lightning Injury

See Also

Precautions

Consider Lightning Injury in patients found outside after a storm, unconscious or amnestic

Pathophysiology

Average lightning bolt
1. Current: 10,000 to 200,000 amps (undirectional, DC-like current)
2. Voltage: 5 to 30 Million up to 1 Billion Volts
3. Duration: 10 to 100 ms
4. Temperature: 30,000 Kelvin (53,000 F) which is 5 fold higher than the surface of the sun
5. Most of the lightning energy "flashes over" the body instead of through the body
  1. Responsible for 85% survival rate from lightning strike
Mechanisms
1. Direct strike (<5% of lightning injuries)
  1. Main lightning strike passes through patient (typically entering at the head) into ground
  2. Most dangerous mechanism, but rare
  3. Results in Cardiac Arrest, severe neurologic and other internal injuries
  4. Minimal external superficial signs of injury (due to short duration)
2. Contact exposure
  1. Patient in contact with an object (e.g. fence, indoor plumbing) in the path of lightning
3. Side splash
  1. Lightning jumps from primary object (e.g. tree) into the nearby patient on its path to the ground
4. Ground current (50% of lightning injuries, most common)
  1. Lightning after striking an object, diffuses along ground and may contact a patient standing nearby
  2. Current may flow from ground up one leg and down the other (if standing with legs apart)
5. Upward streamer
  1. Upward current passing back up from the ground toward the clouds, passing through the patient
  2. Less current than a direct strike, but with risk of significant internal injuries
6. Blunt Trauma
  1. Primary Trauma occurs from large forces generated when superheated to rapidly cooled (e.g. TM Rupture)
  2. Tertiary Trauma occurs when the patient is thrown by the current

Exam

See Trauma Evaluation
Head (potential lightning entry point)
1. Skull Fracture
2. Intracranial injury
Cervical Spine
1. See Cervical Spine Imaging in Acute Traumatic Injury
Ears
1. Tympanic Membrane Rupture (50% of lightning strike survivors)
2. Sensorineural Hearing Loss
Eyes (exam includes Visual Acuity and fundoscopic exam)
1. Emergency ophthalmology consult for significant acute Eye Trauma or Decreased Visual Acuity
2. Transient Mydriasis (common with lightning strikes, do not confuse with fixed-dilated pupils in brain injury)
3. Corneal Abrasions
4. Intraocular Hemorrhage
5. Hyphemia
6. Uveitis
7. Retinal Detachment
8. Orbital Fracture
9. Macular Holes
10. Cataracts (delayed 2-4 years from lightning strike)
Cardiopulmonary
1. Early Cardiopulomonary Resuscitation may sustain a patient through cardiac and respiratory center acute injury
2. Cardiac Arrest (esp. Asystole)
  1. Most common cause of death
  2. However, sinus nodal automaticity may restart after 1-2 minutes if no significant cardiac injury
3. Respiratory Arrest
  1. Typically due to respiratory center (Medulla) stunning resulting in apnea
  2. Stunning effect (and secondary apnea) is typically prolonged beyond time of Asystole
4. Persistent Tachycardia
5. Persistent Hypertension
6. Takotsubo Cardiomyopathy (delayed)
Neurologic
1. Loss of consciousness
2. Seizures
3. Confusion
4. Behavior changes
5. Anterograde Amnesia
6. Headaches
7. Weakness
8. Paresthesias
9. Chronic Pain
10. Keraunoparalysis (autonomic reflex with vasospasm in up to 60% of victims)
  1. Transient paralysis and sensory changes (legs more than arms)
  2. Transient Cyanosis, pallor, immobile and pulseless legs secondary to vasospasm
  3. Evaluate first as Head Injury and Spinal Injury
  4. Typically resolves in 4-6 hours (although may cause Chronic Pain in some cases)
11. Persistent neurologic deficits (Hypoxia or Hemorrhage related)
  1. Hypoxic encephalopathy
  2. Peripheral Neuropathy
  3. Intracranial Hemorrhage
  4. Cerebrovascular Accident
  5. Progressive Myelopathy and other Movement Disorders (delayed)
  6. Neuropsychiatric complications such as memory, concentration, behavior, PTSD (delayed)
Skin
1. Significant superficial Burn Injury is uncommon (short duration of lightning contact)
2. Ferning or feathering (Lichtenberg figure)
  1. Occurs when Red Blood Cells are extruded through capillary beds
  2. Pathognomonic for Lightning Injury
  3. Transient injury, that resolves within 4 hours (but may persist for days)
3. Linear burn
  1. Steam injury to wet or sweaty skin that occurred when lightning flashed over the surface
  2. Chest and axilla most often affected
4. Punctate burn
  1. Grouped, small round burns form typically where lightning exits the body
5. Thermal Burn
  1. Secondary to clothing that lights on fire, or metals (e.g. belts, rings, necklaces) that are superheated
  2. May result in full thickness burns when these metal items are heated to >1000 degrees
Musculoskeletal
1. Tertiary Trauma (e.g. patient thrown)
2. Hypotension in a patient with intact cardiopulmonary function suggests Hypotension due to Traumatic Injury
3. Compartment Syndrome is less common in lightning strikes than with Electrical Burns (brief exposure)
  1. Distinguish pallor, pulselessness in Keraunoparalysis (see above)
Pregnancy
1. Fetal Monitoring (fetal mortality as high as 50% in some studies)

Labs (typically normal in lightning strike injury)

Complete Blood Count
Basic Chemistry Panel
Creatine Kinase (CK)
1. Rhabdomyolysis is less common with Lightning Injury than with Electrical Burns
Cardiac enzymes (Troponin)
Urinalysis

Diagnostics

Indications for high risk patients (Wilderness Medical Society)
1. Direct Strike suspected
2. Loss of consciousness
3. Focal neurologic deficit
4. Chest Pain
5. Dyspnea
6. Major Trauma
7. Cranial burns
8. Leg burns
9. Burn Injury >10% of TBSA
10. Pregnancy
Testing
1. Electrocardiogram
2. Echocardiogram
References
1. Davis (2014) Wilderness Environ Med 25(suppl 4): S86-95 [PubMed]

Imaging

CT or MRI Imaging
1. As directed by Trauma Evaluation

Management

Electrical Burns (Thousands of volts) and lightning injuries (Millions of volts) are treated differently
Prehospital providers must Exercise environmental precautions to prevent their own injuries
1. Active thunderstorms may delay rescue
2. Patient handling does NOT pose a risk to rescuers
  1. Current from lightning strike is NOT maintained with the patient's body
  2. Contact with the patient does not risk Electrocution
3. Transport all patients struck by lightning to an appropriate medical facility
Resuscitation and Stabilization should follow ACLS and Trauma protocols
1. ABC Management
  1. Check for pulse at Carotid Artery (extremity pulses may be difficult to obtain with Vasoconstriction)
  2. Review all prehospital rhythm strips and EKGs for initial Arrhythmia
  3. Maintain continuous cardiac monitoring in the emergency department
  4. Initiate early cardiopulomonary Resuscitation
    1. Cardiac and Respiratory centers may be transiently stunned and resume spontaneous activity
2. See Trauma Evaluation
  1. Review history with prehospital providers (e.g. tertiary Trauma, loss of consciousness)
  2. Be alert to tertiary Trauma (Head Injury, Cervical Spine Injury)
  3. Remove all clothing with risk of continued Thermal Burns (e.g. belts, shoes)
  4. Intravenous Access and initiate crystalloid
3. Most lightning-related fatalities occur within the first hour from Asystole or Hypoxia-induced Cardiac Arrest
  1. Be ready with airway management, respiratory support and Defibrillation
4. When multiple patients are injured, respiratory arrest and Cardiac Arrest receive first priority
  1. Unlike Mass Casualty Incidents, immediate Resuscitation has a higher chance of survival
  2. Brief Asystole with spontaneous return of rhythm may be followed by respiratory arrest
  3. Most patients not in Cardiac Arrest (except cranial burns) will survive with supportive care
  4. Transient Mydriasis occurs in lightning strikes and should not be confused with fixed-dilated pupils
Disposition
1. Consultation with Otolaryngology, Ophthalmology, Cardiology, Neurology as needed
2. Hospital Admission Indications
  1. Resuscitated after Cardiopulmonary Arrest (ICU)
  2. Neurologic deficits or Altered Level of Consciousness
  3. Abnormal EKG or Echocardiogram (telemetry monitoring for at least 24 hours)
3. Discharge Indications
  1. Asymptomatic with normal examination, labs and diagnostics
  2. Follow-up regional burn center (risk of memory problems, Chronic Pain)

Prevention

During thunderstorms, when thunder is heard, seek shelter
1. Precaution: Estimating time between thunder and lightning is not sufficient to ensure safety
Safest enclosures
1. Enclosed building (avoid touching electrical appliances or plumbing fixtures)
2. All metal motor vehicle (without a convertible top)
3. Avoid three sided shelters (e.g. bus shelters) as these are inadequate for complete protection
Outdoors without access to safe enclosures
1. Relocate to dense forest, cave or ravine
2. Descend from summits and ridges
3. Avoid single trees and open spaces
4. Move away from water
  1. Swimmers should exit water and move away from shore
  2. Boaters should go below deck
5. Assume lightning position if stranded in open areas
  1. Crouch with knees and feet together
  2. Place hands over each ear
  3. If available, crouch on top of backpack or sleep pad (may provide insulation from ground)
6. Groups should separate
  1. Keep 20 feet between each person
  2. Prevents splash injury from person to person (or ground current affecting entire group)
7. Store away metal objects (e.g. poles)
  1. Risk of Thermal Burns from contact
8. Keep helmets on if available
  1. Prevents tertiary Trauma

Complications

See Exam above

Resources

Patient Support (LS & ESSI)
1. https://www.lightning-strike.org/

References

Swadron and Paquette in Herbert (2019) EM:Rap 19(11): 14-5
Walrath, Wood, Della-Giustina (2019) Crit Dec Emerg Med 33(6): 3-11
Ritenhour (2008) Burns 34(5):585-94 [PubMed]