Delayed reversible motor neuronopathy caused by electrical injury

Electrical injury may cause central nervous system (CNS) complications and peripheral nerve disorders. Delayed neurologic complications are rarely reported. A case of delayed reversible motor neuronopathy caused by low-voltage electrical injury is reported due to its rarity. A 22-year-old female received an electric shock of 110 volts while pushing up a metal gate during a rainy morning on April 16, 2005. She initially suffered loss of consciousness for several hours, and then became quadriplegic, from which she completely recovered 10 days later. After return to work for I month, she developed weakness and numbness of bilateral upper limbs. Nerve conduction velocity study and bilateral median nerve somatosensory evoked potential were normal. Magnetic resonance imaging of the brain and cervical spine were also normal. Electromyography showed mild denervation, reduced interference and polyphasia over the upper arms, suggestive of anterior horn cell lesion. After rest and rehabilitation for 2 weeks, the patient completely recovered her muscle power over proximal upper limbs and partially over the distal upper limbs. Follow-up at the outpatient clinic 4 months later showed total recovery of muscle power. Low-voltage electrical current can cause acute transient quadriplegia and delayed motor neuronopathy. The mechanism of this patient's recovery from electric shock, followed by deterioration 1 month later, and then recovery after rest is unclear. We considered whether the mechanism of weakness after electric injury, with initial recovery followed later by the development of weakness, might be due to overuse, just like in post-poliomyelitis syndrome. This needs further investigation.