Delayed radiation-induced bulbar palsy mimicking ALS

We describe a patient presenting with progressive bulbar dysfunction and spasticity that clinically mimicked amyotrophic lateral sclerosis (ALS). Electromyography, however, showed no evidence of denervation and revealed a rare combination of peripheral and central myokymia. We feel that this pattern of myokymia represented a marker of neural injury from remote radiation therapy. Nervous system disorders resulting from therapeutic radiation are described, and potential pathophysiologic mechanisms underlying myokymia are discussed. (C) 2000 John Wiley and Sons, Inc.