Electrical Injury: The Damage You Cannot See

Part of the ICU Emergencies Hub — browse every related guide in one place.

Updated July 2026  |  More ICU clinical guides →

Electrical injury is deceptive. The skin may show only two small burns — an entry and an exit wound — while the current has cooked a channel of muscle, nerve, and vessel deep between them. Current follows the path of least resistance through the body, generating heat as it goes, so the internal destruction is often far worse than the surface suggests. Two systems dominate the ICU concern: the heart, which can be thrown into a lethal arrhythmia at the moment of contact, and the deep muscle, whose breakdown drives rhabdomyolysis, kidney injury, and compartment syndrome. This guide covers the injury types, the monitoring rules, and the complications the nurse tracks.

Voltage and pathway determine severity

Not all shocks are equal. Severity depends on the voltage, the current type, the pathway through the body, and the contact duration.

A hand-to-hand or hand-to-foot pathway that crosses the heart and chest is more dangerous than a localized contact. Alternating current (household) can cause tetanic muscle contraction that freezes the victim to the source, prolonging exposure. Lightning is a special case: an enormous current over a few milliseconds, more likely to cause immediate cardiac and respiratory arrest and neurologic injury than the deep burn tunneling seen with sustained high-voltage contact.

The heart: monitor for arrhythmia

Electricity can depolarize the whole myocardium at once, producing ventricular fibrillation or asystole at the instant of the shock — this is the mechanism of sudden death in electrocution. Survivors may have ongoing rhythm disturbances, ECG changes, or evidence of myocardial injury. The practical rule: obtain an ECG, and place patients on continuous cardiac monitoring if there is any loss of consciousness, ECG abnormality, high-voltage exposure, chest symptoms, or a transthoracic current path. A truly low-risk exposure — a brief low-voltage household shock in an asymptomatic patient with a normal ECG — may not need prolonged monitoring, but anything more concerning does.

Deep muscle damage: rhabdo, kidneys, and compartments

Because current heats and destroys muscle along its path, electrical injury is a classic cause of rhabdomyolysis. Breakdown products, especially myoglobin, flood the circulation and threaten the kidneys. The nurse trends the creatine kinase, watches for dark, tea-colored urine, and supports aggressive fluid resuscitation to protect renal function — and electrical burns need more fluid than the visible skin burn would predict, because standard burn formulas underestimate the hidden deep injury. Potassium released from dying muscle can climb dangerously.

The swelling of injured muscle inside its fascial sheath can also produce compartment syndrome, cutting off perfusion to the limb. Perform serial neurovascular checks — pain out of proportion, pain on passive stretch, tense compartments, and sensory changes are warning signs — and escalate promptly, because a limb can be lost or a fasciotomy required. Other delayed problems include neurologic deficits, cataracts, and, with entry/exit wounds, the need for surgical debridement of tissue that declares itself dead over days.

Where to go from here

Pair this with the rhabdomyolysis guide for the muscle-breakdown pathway, the hyperkalemia emergency guide for the potassium danger, and the cardioversion vs. defibrillation guide for managing the arrhythmias.