View source for Electrical injuries

==Background==
*Tissue damage occurs via electrical energy (becomes thermal energy once it enters the body) and mechanical injury from trauma
**Fat, bone, tendon, dry skin all have very high resistance
**Muscle, nerves, vasculature have lower resistance, more often damaged
*'''The primary determinant of injury is the amount of current flowing through the body, which depends on:'''
**Voltage
**Amperage
**Resistance
**Type of current (DC or AC)
**Current pathway
**Duration of contact

===Electrical Injury Types===
#'''Low-Voltage''' <1000V
#'''High-Voltage''' >1000V - typically seen in industrial settings or transmission line injuries
#*Associated with electrical burns
#'''[[Lightning Injuries|Lightning]] Strike'''
#'''Electric Arc'''
#*Associated with high voltage sources
#*Ionized particles with temperature 3000 °C–20,000 °C<ref name="Epidemiology">Kym D, Seo DK, Hur GY, Lee JW. Epidemiology of electrical injury: Differences between low- and high-voltage electrical injuries during a 7-year study period in South Korea. Scand J Surg. 2015 Jun;104(2):108-14.</ref>
#*Can jump 2-3cm per 1000V<ref name="Epidemiology" />
#*May radiate enough heat to burn persons 10ft or more away from the arc
#*Blast force may result in trauma

===DC vs AC===
Direct current (DC) injuries typically due to [[lightning]] while alternating current (AC) are household injuries

====DC====
*Direct current most often demonstrates flow-over phenomenon
*Lightning can reach 1-5 million volts, but current flows over the body and exits to the ground
*May result in little tissue damage but [[cardiac dysrrhythmias]] are still of great concern

====AC====
*Current arcs onto body, envelops surface of body, then arcs to lower electromotive potential (ground)
*With alternative cycle of the current there is contraction and release of muscle preventing full release from source
*Current flows through body tissues

==Clinical Features==
[[File:PMC5253516 icrp a 1275646 f0001 c.png|thumb|Superficial second degree burn from [[lightning injury]].]]
[[File:PMC4763624 IJD-61-109-g002.png|thumb|Lichtenberg figure from [[lightning injury]].]]
[[File:PMC4891493 CCR3-4-618-g001.png|thumb|Patterned charring along the contact points of a metallic locket due to [[lightning strike]].]]
[[File:Verbrennung Grad 2b.jpg|thumb|Second-degree burn after a high tension line electrical injury.]]
===Immediate Effects===
*[[Cardiac dysrhythmias]]
*[[Respiratory arrest]]
*[[Seizures]]

===[[Cardiac Dysrhythmias]]===
*Fatalities due to [[asystole]] or [[V-fib]] usually occur prior to arrival
**Most common [[dysrhythmia]] at presentation is [[A-fib]] ([[V-fi]]b is more common, but patients are dead PTA)
**Asymptomatic patients with normal [[ECGs]] do not develop later dysrhythmias after <1000V injuries
***For uncomplicated electrical injuries if normal EKG then routine ECG monitoring and cardiac biomarkers unnecessary<ref>Pilecky D, Vamos M, Bogyi P, et al. Risk of cardiac arrhythmias after electrical accident: a single-center study of 480 patients. Clin Res Cardiol. 2019;108(8):901–908. doi:10.1007/s00392-019-01420-2 Abstract at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6652167/</ref>.

===Cardiovascular Injury===
*Contraction band necrosis<ref>Koumbourlis AC. Electrical injuries. Crit Care Med. 2002 Nov;30(11 Suppl):S424-30.</ref>
*Medial necrosis of large vessels
**[[LV aneurysm|Aneurysm]] formation
*Coagulation necrosis of small vessels
**Can lead to [[compartment syndrome]]

===CNS Injury===
*Occurs in 50% of patients with high-voltage injuries
*Brain injury ranges from transient [[syncope|LOC]] to [[CVA]] to [[respiratory arrest]]
*High voltage injuries involving head are frequently associated with [[coma]] and [[Persistent Vegetative State|persistent vegetative state]]

===Orthopedic Injury===
*Forceful muscle contractions can cause [[fracture]] and [[joint dislocations]] (especially shoulder)
**May occur with voltages as low as 120V
*[[Compartment Syndrome]]
**Usually associated with high-voltage injuries
**May occur even with 120V shocks if contact is sustained for longer than few seconds
**Patient experiences ongoing muscle pain with movement
**Need for [[fasciotomy]] predicted by:
***Myoglobinuria
***Burns >20% [[BSA]]
***Full-thickness [[burn]] >12% [[BSA]]
*[[Rhabdomyolysis]]
**Associated with:
***Contact with >1000V
***Prehospital [[cardiac arrest]]
***[[Crush injury]]
***[[Compartment syndrome]]
***Full-thickness skin [[burns]]

===Ocular Injury===
*Cataract formation has been described weeks to years after electrical injury
**Document presence or absence of cataracts following all electrical injuries

===[[hearing loss|Auditory Injury]]===
*May be damaged by current or hemorrhage
*Check hearing in all patients

===Cutaneous [[Burns]]===
*Often seen at electrical contact areas
**Seriously injured patients often have burns on either arm or skull + feet
*Most patients with burns from electrical injury require admission and care by burn specialist
*Lichtenberg figures (not true burns) are pathognomonic for lightning strike

===GI Injury===
*Suspect in patients with:
**Electrical burns of abdominal wall
**History of a fall, nearby explosion, or other mechanical trauma

===Pediatric Considerations===
*In general, evaluate as for the adult, looking for multi-system involvement
*Perform an [[ECG]] in all patients, regardless of voltage
*An oral commissure burn (from chewing on power cord) will create significant edema and necrosis 
**The child may need Plastic Surgery or Head and Neck Surgery consultation to avoid microstomia
**1-2 weeks after the burn, the eschar may fall off, exposing the labial artery and causing significant hemorrhage
***Provide clear and thorough precautionary advice including first aid for bleeding (pinch buccal mucosa against outside of cheek until arrival to hospital)

==Differential Diagnosis==
{{Burn DDX}}

==Evaluation==
===Workup===
*12-lead [[ECG]]
*CBC
*CMP
*[[Lactate]]
*[[Troponin]]
*CK
*[[Urinalysis]]
**Urine myoglobin is poorly sensitive/specific, and most patients with rhabdomyolis will have grossly discolored urine<ref>https://emergencymedicinecases.com/electrical-injuries/</ref>

===Diagnosis===
*Typically a clinical diagnosis

{{Burn thickness chart}}

==Management==
*Usual trauma evaluation and resuscitation applies
*Use [[Parkland formula]] as starting point for [[fluid resuscitation]]
**Fluids in first 24 hrs = [[T[[BSA]]]] burned(%) x Wt(kg) x 4ml; Give 1/2 in first 8 hours, then give other 1/2 over next 16 hrs
**Parkland formula frequently underestimates fluid requirements in electrical burns<ref>https://emergencymedicinecases.com/electrical-injuries/</ref> because internal injuries are usually more significant than external burns
**In healthy individuals start continuous fluids at 300-500 mL/hr and titrate to urine output of 100 mL/hr<ref>https://emergencymedicinecases.com/electrical-injuries/</ref> 
*Treat [[rhabdomyolysis]] and [[compartment syndrome]] in usual manner
**If RBCs and/or myoglobin in UA, urine should be alkalinized at minimum of 2 cc/kg/hr until pigments eliminated<ref>Brandt CP, Yowler CJ, Fratianne RB. MetroHealth Medical Center Burn ICU Handbook (Not a policy manual), Cleveland, OH.</ref>
**[[Mannitol]] should be given early to prevent renal tubular damage but patient must remain adequately fluid resuscitated
**High voltage injuries to the hand frequently require carpal tunnel decompression as soon as patient is stable for OR

==Disposition==
===Discharge===
*Asymptomatic patients with normal ECG on presentation after a low-voltage electrical injury<ref>Rai J, Jeschke MG, Barrow RE, Herndon DN. Electrical Injuries: A 30-Year Review. J Trauma Acute Care Surg. 1999;46(5):933-936.</ref>

===Admit===
*All patients with high-voltage injuries (even if asymptomatic)
*Patients with low-voltage injury if symptomatic (e.g. LOC, severe [[burns]], ECG changes, ↑ CK)
*Abnormal [[ECG]] or observed dysrhythmia
*Cardiac biomarkers positive
*Persistent [[chest pain]], [[paresthesias]], or [[hypoxia]]
*[[Cardiac arrest]]
*History of significant cardiac disease or CAD risk factors

==See Also==
*[[Lightning Injuries]]
*[[Burns]]

==External Links==
*[http://pemplaybook.org/podcast/electrical-injuries-hertz-so-bad/ Electrical Injuries: Hertz So Bad - Pediatric Emergency Playbook]
*[https://emergencymedicinecases.com/electrical-injuries/ Emergency Medicine Cases - Electrical Injuries]

==References==
<references/>

[[Category:Environmental]]
[[Category:Trauma]]