Hirayama Disease: Review on Pathophysiology, Clinical Features, Diagnosis and Treatment.

Hirayama disease is a relatively unusual cause of cervical myelopathy characterized by uni- or bilateral asymmetric weakness, fasciculations and atrophy of the distal upper limbs, mostly seen in young males. The insidious weakness progresses over 3-5 years, after which it stops. Hirayama disease results from the abnormal anterior shifting of the posterior cervical dura that occurs during cervical flexion, leading to cord impingement. Electrophysiologic studies reveal denervation of C7-T1 myotomes and absence of sensory involvement. Dynamic magnetic resonance imaging of the cervical spine is essential in confirming the diagnosis. Treatment is aimed at primarily avoiding neck flexion, which is achieved with the help of a cervical brace; however, progressive disease calls for surgical intervention. Although the disease is self-limiting, it causes many functional impairments in affected individuals. In this review, we describe the epidemiology, pathophysiology, clinical manifestations, imaging characteristics, electrophysiologic findings, differential diagnoses and updates in the treatment of Hirayama disease. This review also aims to improve the awareness of this disease among clinicians, enabling early suspicion, diagnosis and management. [ABSTRACT FROM AUTHOR]