Hirayama Disease-A Case Study

Hirayama disease is a type of cervical myelopathy related to flexion movements of the neck. It is considered to be a benign motor neuron disorder with a stationary stage after a progressive course. Chronic microcirculatory changes in the territory of the anterior spinal artery induced by repeated or sustained flexion account for the necrosis of the anterior horns of the lower cervical cord, which is the hallmark of pathology. It typically occurs mainly in young males between the age of 15–25 years. It is often of insidious onset presenting with a predominantly unilateral upper extremity weakness and atrophy, cold paresis and no sensory or pyramidal tract involvement. It is also characterized by muscle weakness and atrophy in the hand and forearm with sparing of the brachioradialis, giving the characteristic appearance of oblique amyotrophy that affects the C7, C8 and T1 myotomes. The amyotrophy is unilateral in most patients, asymmetrically bilateral in some and rarely symmetric.¹