Hirayama Disease

Abstract

Hirayama disease (juvenile muscular atrophy of distal upper extremity) is a cervical myelopathy. Predominantly affecting male adolescents, it is characterized by progressive muscular weakness and atrophy of distal upper limbs, followed by spontaneous arrest within several years. Although the cause of cervical myelopathy remains unclear, neuropathologic and neuroradiologic findings suggest a forward displacement of the posterior cervical dural sac during neck flexion, causing compression of the cervical cord, and results in atrophic and ischemic changes in the anterior horn. A good understanding of Hirayama disease is essential because early recognition and management can effectively halt the progressive deterioration.

Cervical Spine MR Imaging Findings of Patients with Hirayama Disease in North America: A Multisite Study

“…Although there are reports of bilaterally symmetric HD and of patients with slight hypoesthesia in the hands, these cases are exceptions and we maintained the classic criteria. 12 We did not assign a specific diagnosis to patients who did not fulfill the criteria for HD, but the final diagnoses provided in the charts given by the patients' neurologists were recorded. Demographic features at the time of the MR imaging examination, including age, sex, self-reported ethnicity, and country of residence, were documented.…”

A severe case of Hirayama disease successfully treated by anterior cervical fusion

“…There are some subtle changes in the neutral MRI that should raise the suspicion of the condition, as described by Huang and Chen: 13 asymmetrical atrophy of the cord and loss of attachment of the posterior sac to the lamina. It is also important to note that the changes in the flexed position vary with the degree of flexion, and they might not be remarkable with the neck flexed less than 25°.…”

“…Over the past 50 years, with the advent of MRI, several researchers have established this illness as a different entity from the motor neuron diseases. [6][7][8][9][10]13,17,25,26 It has been characterized not as a primary disease of motor neurons, but as a myelopathy secondary to spinal cord compression during cervical flexion.The clinical features of Hirayama disease are: 1) asymmetrical weakness of the distal upper extremities, with atrophy of the thenar and hypothenar eminence and relative sparing of the brachioradialis muscle (oblique amyotrophy); 2) cold paresis (worsening of the weakness and distal tremor with cold); 3) lack of sensory, autonomic, or cranial nerve signs or symptoms; 4) insidious onset at the second to third decades of life (15-25 years), predominantly in males, with slow worsening over a variable period of time (mean 5 years) 31 and subsequent spontaneous arrest of progression; and 5) usually sporadic occurrence (although familial cases have been reported). 1,3,14,23 Radiological findings are essential for the diagnosis of Hirayama disease.…”

“…Over the past 50 years, with the advent of MRI, several researchers have established this illness as a different entity from the motor neuron diseases. [6][7][8][9][10]13,17,25,26 It has been characterized not as a primary disease of motor neurons, but as a myelopathy secondary to spinal cord compression during cervical flexion.…”

Segmental Spinal Muscular Atrophy Localised to the Lower Limbs: First case from Oman

“…11 In another case, Huang et al reported that movement-induced myelopathy could also be an underlying mechanism of Hirayama disease; however, an autopsy revealed only loss of the anterior horn cells without any other changes. 12 Hirayama disease is a sporadic disorder, although familial cases have been reported. 6 Similar to cases of upper limb atrophy, researchers have also reported amyotrophy restricted to the lower limbs, particularly the calf muscles.…”