Late-convalescent poliomyelitis. Corticospinal tract integrity.

Since both poliomyelitis and amyotrophic lateral sclerosis affect spinal motor neurons, a relationship between these two diseases has been suggested. Corticospinal tract (CST) degeneration, a prominent aspect of amyotrophic lateral sclerosis, is rarely observed in acute poliomyelitis. Autopsy material from seven patients who had survived long periods after severe paralytic poliomyelitis was examined for evidence of CST degeneration. Although there was severe motor neuron loss and destruction of ventral horn cytoarchitecture, none of the spinal cords showed significant demyelination, fiber loss, or gliosis in the region of the CST. The structural integrity of the CST is maintained for many years after severe motor neuron loss due to poliomyelitis.