Delayed radiation-induced bulbar palsy.

We report a man with a slowly progressive bulbar palsy 14 years after radiation therapy for nasopharyngeal carcinoma. Electromyography demonstrated prominent myokymic and neuromyotonic discharges in muscles innervated by the lower cranial nerves. Late effects of radiation therapy can occur in the cranial nerve musculature that are similar to well-recognized syndromes affecting the brachial plexus and spinal cord.