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This is a clinician-written, evidence-based summary aligned to the USMLE Step 2 CK Content Outline. It is intended for medical students preparing for USMLE Step 2 CK. Management reflects current ACC/AHA, USPSTF, and APA guidelines. Always cross-reference with UpToDate, institutional protocols, and clinical judgment.
The Bottom Line
- Electrical injury severity depends on voltage, current type, pathway, duration, resistance, and associated trauma.
- High-voltage exposure can cause deep tissue injury with deceptively small skin wounds.
- Cardiac arrest, syncope, chest pain, abnormal ECG, transthoracic current, pregnancy, or high voltage requires monitoring/evaluation.
- Check CK, renal function, electrolytes, and urine for myoglobin in high-voltage, deep burns, or prolonged contact.
- Lightning triage is reversed: prioritize apparently lifeless patients because respiratory arrest may precede cardiac arrest and can be reversible.
Overview
Injury from electrical current causing arrhythmias, deep tissue burns, rhabdomyolysis, neurologic injury, trauma, and compartment syndrome. Emergency management focuses on early recognition, stabilization, targeted investigation, and prompt definitive therapy while avoiding common pitfalls tested on USMLE Step 2 CK.
Epidemiology
This presentation is encountered in emergency and acute care settings. Risk varies by exposure, comorbidity, age, mechanism, and timeliness of treatment. Morbidity and mortality increase when recognition is delayed or when airway, breathing, circulation, antidotal therapy, or definitive source control is postponed.
Clinical Features
Symptoms
Shock sensation, pain, numbness, weakness, burns, or inability to let go during AC exposure
Loss of consciousness, palpitations, chest pain, dyspnea, or cardiac arrest
Muscle pain, swelling, dark urine, or weakness suggesting rhabdomyolysis
Fall, blast, or thrown injury causing head, spine, or orthopedic trauma
Hearing loss or ear pain after lightning/electrical blast
Signs
Entry and exit burns, full-thickness burns, or deep tissue tenderness
Abnormal ECG, dysrhythmia, cardiac arrest, hypotension
Compartment syndrome signs: pain with passive stretch, tense compartments, paresthesia, weakness, diminished pulses late
Neurologic deficits, confusion, seizure, spinal tenderness, or focal weakness
Lichtenberg figures after lightning are transient and not true burns
Investigations
First-line
ECGMandatory for high voltage, chest pathway, syncope, chest pain, palpitations, pregnancy, or cardiac history.
CK, BMP, urinalysisEvaluate rhabdomyolysis, hyperkalemia, AKI, and myoglobinuria in high-voltage/deep injury.
Trauma assessmentAssess for falls, blast injuries, head injury, spine injury, fractures, dislocations, and burns.
Second-line
Cardiac monitoringIndicated for abnormal ECG, arrhythmia, syncope, chest pain, high voltage, transthoracic current, or significant comorbidity.
TroponinIf chest pain, abnormal ECG, cardiac arrest, or suspected myocardial injury.
Compartment pressureIf compartment syndrome suspected and exam is unclear; do not delay surgical consultation in obvious cases.
Specialist
Burn/trauma/surgical consultationFor high-voltage injuries, deep burns, compartment syndrome, vascular compromise, major trauma, or need for fasciotomy/escharotomy.
1
Scene and initial resuscitation
- Ensure power source is off before touching patient.
- ABCs with cervical spine precautions if trauma possible.
- Cardiac arrest: CPR and defibrillation/ACLS; lightning victims in arrest should be prioritized when multiple casualties.
- Treat burns and trauma simultaneously.
2
Rhabdomyolysis and deep injury
- Aggressive IV crystalloid for rhabdomyolysis to maintain urine output.
- Monitor potassium, calcium, phosphate, CK, creatinine, and urine output.
- Treat hyperkalemia immediately if ECG changes or significant elevation.
- Assess compartments frequently; fasciotomy for compartment syndrome.
3
Burn and wound care
- Remove constrictive items and cover burns with clean dry dressings.
- Tetanus prophylaxis.
- Analgesia and burn center referral for high-voltage injury, significant burns, face/hands/genitals/joints, or suspected deep tissue injury.
- Do not underestimate injury based on small entry/exit wounds.
4
Disposition
- Discharge may be considered after low-voltage exposure if asymptomatic, normal exam, no pregnancy, no syncope/chest pain, and normal ECG.
- Admit/monitor high-voltage exposure, abnormal ECG, syncope, chest pain, significant burns, rhabdomyolysis, pregnancy, or neurologic symptoms.
Complications
- Cardiac dysrhythmia: VF/asystole can occur immediately
- Rhabdomyolysis: Deep muscle necrosis may cause hyperkalemia and AKI
- Compartment syndrome: Progressive swelling after deep electrical burns
- Neurologic injury: Peripheral neuropathy, spinal cord injury, seizures, cognitive symptoms
- Ocular/otic injury: Cataracts and tympanic membrane rupture can occur
USMLE Step 2 CK Exam Tips
- 1Electrical skin burns can underestimate deep tissue damage.
- 2High-voltage injury = ECG, CK/renal/electrolyte testing, monitoring, and burn/trauma consultation.
- 3Low-voltage asymptomatic patient with normal ECG may often be discharged.
- 4Lightning triage is reverse triage — resuscitate apparently dead first.
- 5Dark urine after electrical injury = myoglobinuria/rhabdomyolysis; give IV fluids.
- 6Compartment syndrome diagnosis is clinical; pulses can be present early.
practicetest your knowledge on electrical injuriesApply what you've learnt with USMLE Step 2 CK-style questions from the iatroX Q-Bank — emergency medicine and beyond.
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