Electrical injury to the inner ear is an uncommon but potentially disabling consequence of contact with household current, high-voltage power lines, lightning, or electrical discharges from faulty equipment. The cochlea and vestibular labyrinth are vulnerable to both direct thermal and electrochemical damage and to secondary vascular injury. This article outlines the mechanisms, clinical presentation, evaluation, and management of inner ear electrical trauma.

Mechanisms of Injury

Current passing through the head can injure the inner ear in several ways. Direct heating causes coagulative necrosis of hair cells and supporting cells within the cochlea and vestibule. Electrical current may also produce ionic shifts in the endolymph and perilymph, disrupting the electrochemical gradient that drives mechanotransduction. In addition, current can cause vascular injury, including thrombosis and hemorrhage within the labyrinthine artery or its branches, leading to ischemic damage. Lightning and high-voltage shocks are more likely to produce blast injury through barotrauma, with rupture of the tympanic membrane and disruption of the ossicular chain.

Clinical Manifestations

Symptoms typically appear immediately after the event but may evolve over hours to days. Sensorineural hearing loss is the most frequent presentation and may be unilateral or bilateral, mild or profound. High-frequency losses are common, reflecting the greater sensitivity of the basal turn of the cochlea to metabolic stress. Tinnitus accompanies hearing loss in many cases and may be persistent. Vestibular dysfunction manifests as vertigo, disequilibrium, nausea, and gait instability. Some patients experience a delayed onset of dizziness weeks after the initial injury, possibly due to progressive vascular occlusion or endolymphatic hydrops. Facial nerve weakness or paralysis can occur if the current damages the intratemporal portion of the facial nerve.

Diagnosis

Assessment begins with a focused history of the electrical event, including voltage, current pathway, duration of contact, and whether the patient lost consciousness. Otoscopy may reveal a perforated tympanic membrane, hemotympanum, or burns of the external auditory canal. Audiometry documents the degree and configuration of hearing loss and should be obtained as soon as the patient is medically stable. Vestibular testing, including video nystagmography and caloric testing, can characterize the extent of labyrinthine dysfunction. Imaging with high-resolution computed tomography of the temporal bones is useful when fractures, ossicular disruption, or middle ear injury is suspected, while magnetic resonance imaging may identify labyrinthine hemorrhage or inflammatory changes.

Treatment and Prognosis

Management focuses on preserving residual auditory and vestibular function. Systemic corticosteroids are often administered within the first days after injury, based on evidence from sudden sensorineural hearing loss of other causes, although high-quality trials specific to electrical injury are lacking. Patients with tympanic membrane perforation may require repair if the perforation does not close spontaneously. Conductive hearing loss from ossicular disruption may be addressed surgically once the patient has recovered. Vestibular rehabilitation is valuable for those with persistent balance problems. Hearing aids or cochlear implantation may be considered for patients with significant permanent sensorineural hearing loss. Prognosis varies widely; some patients recover substantial hearing, while others sustain irreversible damage. Even after severe initial loss, partial recovery can continue for months.

Prevention and Public Health Considerations

Most electrical injuries are preventable through proper insulation, ground-fault circuit interrupters, adherence to electrical safety standards, and avoidance of electrical work during storms. Occupational settings require lockout-tagout procedures and appropriate personal protective equipment. Educational campaigns by occupational safety authorities reduce the incidence of high-voltage injuries, and prompt medical evaluation after any shock to the head or neck can improve outcomes.