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. It is considered 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 on pathology 5.
It typically occurs mainly in young males between the ages 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 5.The amyotrophy is unilateral in most patients, asymmetrically bilateral in some and rarely symmetric 5.
On myelograms and flexion-extension MR images, there can be forward migration of the posterior wall of the dura mater. The posterior epidural space becomes enlarged with flexion and is seen as a crescent of high signal intensity on T1- and T2-weighted MR images, with or without epidural flow voids. Uniform enhancement of this epidural space occurs with administration of contrast material
Initially described Keizo Hirayama et.al in 1959 2.
- 1. Chen CJ, Chen CM, Wu CL et-al. Hirayama disease: MR diagnosis. AJNR Am J Neuroradiol. 1998;19 (2): 365-8. AJNR Am J Neuroradiol (abstract) - Pubmed citation
- 2. Gandhi D, Goyal M, Bourque PR et-al. Case 68: Hirayama disease. Radiology. 2004;230 (3): 692-6. doi:10.1148/radiol.2303021089 - Pubmed citation
- 3. Hirayama K, Tokumaru Y. Cervical dural sac and spinal cord in juvenile muscular atrophy of distal upper extremity. Neurology. 2000;54 (10): 1922-6. Neurology (full text) - Pubmed citation
- 4. Hirayama K. Juvenile muscular atrophy of distal upper extremity (Hirayama disease). Intern. Med. 2000;39 (4): 283-90. Intern. Med. (link) - Pubmed citation
- 5.Raval M, Kumari R, Dung Dung AA,et.all. MRI findings in Hirayama disease. Indian J Radiol Imaging [serial online] 2010 [cited 2013 Feb 28];20:245-9. Available from: http://www.ijri.org/text.asp?2010/20/4/245/73528
Synonyms & Alternative Spellings
|Synonyms or Alternative Spelling||Include in Listings?|
|Non-progressive juvenile spinal muscular atrophy||✓|
|Benign focal amyotrophy||✓|
|Juvenile asymmetric segmental spinal muscular atrophy||✓|