Motor neuron disease caused prolonged mechanical ventilation after high-voltage electrical injury

Objective

In the literature, 65 cases with diagnoses of ALS/motor neuron disease after electrical injuries have been reported. However, in almost all of these cases the onset of the neurological findings was delayed and the evidence of the damage of spinal cord could not be shown. We describe a case, requiring prolonged mechanical ventilation, with the early onset neurological injury after high voltage electrical injury and showed evidence of the damage of the spinal cord on MR.

Case report

A 29-year old man was admitted into our ICU as a result of being exposed to high voltage (31,500 V) current and then falling down from 10 meters. He was unconscious and had second to third degrees of burned areas on the right side of his face (exit) and right lower limb (entry). There was no abnormality on his cervical CT and X-rays. After 1 week of his admission and mechanical ventilation, when he became conscious and cooperated, we noticed that there was no motor response on his four limbs with normal touch and pain sensation. DTR were not taken on the upper limbs.

Results

Needle EMG revealed diffuse, acute denervation potentials on all studied muscles. Cervical magnetic resonance imaging (MRI) indicated myelomalasic changes (transverse myelitis) on the C_2-5 segments of the spinal cord. The first motor response was noticed on the 55th day of his admission and he could be liberated from mechanical ventilation on the 70th day.

Conclusion

Electrical shocks commonly cause immediate damage to the heart and musculoskeletal system. However, a few cases with neurological complications secondary to electrical injury have been reported in the literature. In the reported cases, the onset of motor neuron disorder usually occurred in the limb through which the shock entered and none of them required prolonged mechanical ventilation due to respiratory muscle weakness. The pathogenesis of most acquired motor neuron disease is poorly understood, and treatment is mainly supportive.

We showed in this case the pathologic change of the spinal cord on MRI, which may lead to the motor weakness.