Hypoxic-ischemic spinal cord injury following perinatal asphyxia

The role of spinal cord injury in the pathogenesis of abnormal motor signs (depressed tone and reflexes) following severe perinatal hypoxia-ischemia was prospectively evaluated by clinical, electrophysiological, and neuropathological examinations in 18 asphyxiated neonates. All infants had an abnormal mental status (lethargy or coma), and seizures were present in 12. Neuromuscular examinations revealed hypotonia or flaccidity and hyporeflexia or areflexia in all infants. Neuropathological examinations of the cerebrum and spinal cord were conducted in the 12 neonates who expired. Cerebral pathological findings included cortical neuronal necrosis in 10 of 12 and subcortical white matter injury in 5 of 12. All infants with coma or seizures displayed diffuse cortical injury, but no injury conformed to a parasagittal "watershed" distribution. Spinal cord gray matter displayed prominent ischemic necrosis in 5 patients who were typically flaccid and areflexic. Electromyographic examinations of all 6 survivors were abnormal, consistent with recent injury to the lower motor neuron above the level of the dorsal root ganglion. We conclude that ischemic injury to anterior horn cells within spinal cord gray matter is relatively common among hypotonic-hyporeflexic neonates following severe perinatal hypoxia-ischemia. Although the acute neurological syndrome of neonatal asphyxia is often overshadowed by prominent cerebral signs such as coma and seizures, the motor abnormalities may be partially attributed to concurrent spinal cord injury.