NCMP-19. RADIATION-INDUCED CRANIAL NEUROPATHY PRESENTING AS PROGRESSIVE BULBAR SYNDROME

Abstract

Abstract Neuropathy is a well-known complication of radiation, especially when administered in proximity to the brachial plexus (BC), with symptoms usually appearing years after radiation. Pain is a less prominent feature when compared to neoplastic infiltration, with numbness and weakness being a more common and disabling complaint. Radiation-induced neuropathies tend to reach clinical stabilization after several months with por response to treatment. This is a case report of a 59 year-old Malaysian man who was diagnosed with nasopharyngeal carcinoma in 2002 treated with radiation to the nasopharynx in China. He has no evidence of disease to this date. In 2016 he started to develop progressive bulbar symptoms, such as hoarseness, hypophonia, and dysphagia. Symptoms worsened over the subsequent 18 months after presentation with clinical stabilization thereafter. Following the initial bulbar symptoms, he also developed bilateral hearing loss, atrophy of bilateral sternocleidomastoid muscles, significant tongue atrophy with fasciculations and tongue deviation. His clinical picture was consistent with bulbar amyotrophic lateral sclerosis. MRI brain and total spine did not show any intraparenchymal or nerve disease. An electromyography test was performed, which showed myokymia of the tongue and trapezius consistent with radiation-induced cranial neuropathy (CN). He received steroids without any clinical improvement, followed by hyperbaric oxygen with minimal improvement of his dysphagia, hoarseness and hypophonia. On last follow up his symptoms continued to be stable. Radiation to nasopharynx can cause radiation-induced CN with similar electromyographic findings to radiation-induced brachial plexopathy, such as myokymia. Symptoms can appear more than 10 years from radiotherapy, with progression over several months followed by clinical stabilization. Treatment with steroids, bevacizumab or hyperbaric oxygen only provide minimal benefit on this population.