A Case Report of Hirayama Disease Revealed by Upper Limb Weakness and Wasting

Abstract

Hirayama disease is a rare entity characterized by unilateral or asymmetrical bilateral focal weakness and wasting of muscles innervated by C7, C8, and T1. We report the case of a 20-year-old male who presented with gradual left upper limb weakness and wasting, confirmed by electrophysiological and radiological studies showing detachment of the posterior longitudinal ligament with dilatation of the epidural veins. Anterior displacement with flattening of the medullary cord from C4 to C7 was observed, where there was a T2 hypersignal abnormality involving the anterior horns and producing a "snake eye" appearance. The disease is believed to result from the forward displacement of the cervical dural sac and spinal cord induced by neck flexion, and should be suspected in male patients presenting with unilateral or asymmetrical bilateral lower motor weakness of hands and forearms.