MRCP2-3479

MRCP2-3479

A 63 year-old man with a history of osteoarthritis, type II diabetes and mild dementia presents to the neurology clinic with a 2 month history of weakness in his right arm. He has also noticed a decrease in his voice volume and difficulty with tasks such as opening jars and using door handles. His wife has observed him stumbling while walking on two occasions.

During the examination, fasciculations are noted over his right deltoid muscle and wasting of the interossei muscles of the right hand. There is 4/5 strength in right shoulder abduction on the MRC scale. Limb reflexes are absent in the right arm but detectable elsewhere. Coordination is normal, sensation is intact, and Romberg’s test is negative.

What is the most likely diagnosis?