CASE 14341 Published on 17.01.2017

Hirayama disease a rare cause for distal upper limb weakness: case report with MRI findings



Case Type

Clinical Cases


Jagjeet Singh MD, Sanjiv Sharma MD, Sanjay Kumar Meena MD, Kamaljeet Kaur MBBS, Satnam Singh MD

All India Institute of Medical Sciences, Radiodiagnosis; Ansari Nagar 110029 New Delhi;

24 years, male

Area of Interest Spine, Musculoskeletal spine, Extremities, Trauma ; Imaging Technique MR, Experimental
Clinical History
A 24-year-old male patient came to the neurology department with a history of progressively decreasing power in both hands for the last four years.
On examination there was atrophy of hypothenar muscles of both hands (figure 1).
On EMG - bilateral median and ulnar showed low amplitude waves.
Imaging Findings
MRI showed localized cervical cord atrophy with asymmetric cord flattening in the lower cervical region (figure 2). There is a loss of attachment between the posterior dural sac and subjacent lamina (figure 3). Prominent epidural flow voids were also seen on T2W images. There was anterior shifting of the posterior dura causing compression of the lower cervical cord upon flexion of the neck (figure 4). There was an enhancing epidural component in the lower cervical region with extension into thoracic region (figure 5).
Hirayama disease, also termed non-progressive juvenile spinal muscular atrophy of the distal upper limbs, is a type of cervical myelopathy related to flexion movements of the neck [1-3]. It differs from the known types of motor neuron diseases because of its non-progressive behaviour and pathologic findings of focal ischemic changes in the anterior horn of the lower cervical cord.

It is considered a benign disorder with a stationary stage after a progressive course.
It occurs mainly in young males between the ages of 15 - 25 years [4]. It is often of insidious onset presenting with a predominantly upper extremity weakness and atrophy, cold paresis, and no sensory or pyramidal tract involvement

Pathophysiology is imbalanced growth between the patient's vertebral column and spinal canal contents will cause disproportional length between the patient's vertebral column and the spinal canal contents causing a tight dural sac. On neck flexion, the tight dural sac cannot compensate for the increased length of the posterior wall, which causes anterior shifting of the posterior dural wall and consequent compression of the cord against the posterior margin of adjacent vertebral bodies. This compression may cause microcirculatory disturbances in the territory of the anterior spinal artery in the lower cervical spinal cord. The chronic circulatory disturbance resulting from repeated or sustained flexion of the neck may produce gliosis and localized cord atrophy at the lower cervical region [5, 6].

MRI is the imaging modality of choice. Imaging features are :
1) Localised cervical cord atrophy with cord flattening in lower cervical cord.
2) Abnormal cervical curvature.
3) Loss of attachment between the posterior dural sac and subjacent lamina with anterior shifting of the posterior dura on neck flexion causing compression of cord.
4) Enhancing epidural component in lower cervical and thoracic region and prominent posterior epidural flow voids suggestive of dilated epidural venous plexus.
5) Prominent epidural flow voids.
6)Thoracic extension of enhancing epidural component .

Early diagnosis and therapeutic intervention in the form of cervical collar therapy to prevent neck flexion may minimize the functional disability of the young patients.
This induces a premature arrest of disease progression and is more beneficial in these cases, with shorter duration of illness [7, 8].
So in cases of young patients with asymmetrical distal upper limb weakness Hirayama disease should be kept in differential diagnosis.
Differential Diagnosis List
Hirayama disease.
Motor neuron disaese
Distal spinal muscular atrophy
Myotonic dystrophy
Final Diagnosis
Hirayama disease.
Case information
DOI: 10.1594/EURORAD/CASE.14341
ISSN: 1563-4086