[A case of X-linked bulbospinal muscular atrophy with bilateral abductor vocal cord paralysis]

We report a 54-year-old man with X-linked bulbospinal muscular atrophy (BSMA) with bilateral abductor vocal cord paralysis. He noticed distal weakness in the lower limbs at age 20. In the following 18 years the weakness and atrophy of his leg muscles increased gradually. He has complained of stridors during respiratory tract infection and snored heavily during sleep since his age of 50. He was admitted to our hospital for the progressive stridors during meals. His two brothers were said to have similar complaints. Physical examination showed gynecomastia, hypertension and inspiratory stridor. Neurologic examination revealed distal muscular atrophy in his four extremities, especially more severe in bilateral lower limbs. Deep tendon reflexes were absent in all extremities. His tongue was slightly atrophic with fasciculation. Neurological diagnosis was made by family history, neurological findings, electromyography and a CAG repeat expansion in the androgen receptor gene. Lungs and diaphragm were normal on the chest radiograph. Cranial MRI including brain stem was also normal. Direct laryngoscopy showed a complete paralysis of both vocal cords in paramedian position. Tracheostomy was done right away; his respiratory distress showed prompt improvement after the tracheostomy. No previous report of bilateral vocal cord paralysis in BSMA has been found. Life expectancy in BSMA patients with vocal cord paralysis may be shortened because of respiratory distress or asphyxia. Of clinical importance is a careful assessment of vocal cord function in BSMA patients.