Keywords: Brachial Monomelic Amyotrophy, Hirayama disease, cervical spine flexion MRI


Background. Brachial Monomelic Amyotrophy (BMMA) has been called as Hirayama disease (HD) when it is characterized by unilateral distal upper limb weakness and atrophy that shows progression for a limited period and is associated with typical features on MRI of cervical spine in flexion.

Objective was to explore the differences when BMMA affects the proximal upper limb muscles with the help of case report.

Methods. A case report of BMMA in an adult Indian male is represented.

Results. A 30-year-old man presented to us with a history of weakness in the proximal aspect of his left upper limb that began four years ago. The weakness was progressive up until 6 months prior to his presentation since when the weakness had neither worsened nor improved. Cervical spine contrast enhanced MRI revealed mild loss of cervical lordosis, but no features of HD like localized cord atrophy, loss of attachment of dura from subjacent lamina on neutral position axial T2WI MRI, nor any presence of posterior epidural crescentic enhancing mass on flexion contrast sagittal T1WI MRI. The patient was managed with supportive therapy and has been under regular follow up ever since. His clinical status has been stable.

Conclusions. We support the suggestion to consider proximal Brachial Monomelic Amyotrophy to be a separate entity and to be distinguished from Hirayama disease that should be reserved for patients with distal upper limb involvement with cervical MRI findings on flexion studies.

Author Biography


assistant professor, department of General Medicine, Ramaiah Medical

College, MSRIT post, MSR nagar, Mathikere, Bangalore, Karnataka, India, PIN 560054



Hirayama K, Toyukura Y, Tsubaki T. Juvenile muscular atrophy of unilateral upper extremity: A new clinical entity. Psychiatr Neurol Jpn.1959;61:2190-7

Uncini A, Servidei S, Delli Pizzi C, Cutarella R, Di Muzio A, Gambi D, et al. Benign monomelic amyotrophy of lower limb: report of three cases. Acta Neurol Scand. 1992;85:397-400.

Hassan KM, Sahni H. Nosology of juvenile muscular atrophy of distal upper extremity: from monomelic amyotrophy to Hirayama disease--Indian perspective Nosology of juvenile muscular atrophy of distal upper extremity: from monomelic amyo­trophy to Hirayama disease – Indian perspective. Biomed Res Int. 2013;2013:478516.

Gourie-Devi M, Suresh T.,Shankar S. Monomelic Amyotrophy. Arch Neurol. 1984; 41:388-394.

De Frietas Marcos R. G., Nascimento Osvaldo J.M., Benign Monomelic Amyotrophy: A study of 21 cases. Arq Neuropsiquiatr.2000; 58(3-B):808-813.

Sonwalkar HA, Shah RS, Khan FK, Gupta AK, Bodhey NK, Vottath S, et al. Imaging features in Hirayama disease. Neurol India 2008;56:22-6.

Raval M, Kumari R, Dung AA, Guglani B, Gupta N, Gupta R. MRI findings in Hirayama disease. Indian J Radiol Imaging. 2010;20(4):245-9.

Turner MR, Talbot K Mimics and chameleons in motor neurone disease. Practical Neurology. 2013;13:153-164.

Hirayama K. Juvenile muscular atrophy of distal upper extremity (Hirayama disease). Intern Med. 2000;39:283-90.

Hirayama K., Tomonaga M., Kitano K., Yamada T., Kojima S., Arai K. The first autopsy case of 'juvenile muscular atrophy of unilateral upper extremity'. Shinkei Naika. 1985;22(2):85-86.

De Freitas MRG, Nascimento OJM. Benign monomelic amyotrophy- A study of twenty-one cases. Arq neuropsiquiatr. 2000;58(3-b):808-813.

Orsini M, Freitas MRG, Catharino A, Mello MP, Nascimento OJM. Upper Limb Proximal Form of Benign Monomelic Amyotrophy: on Purpose of 2 Cases. Rev Bras Neurol.2008; 44 (3): 13-17.

Yoo SD, Kim HS, Yun D H, Kim DH, Chon J, Lee SA, et al. Monomelic amyotrophy (hirayama disease) with upper motor neuron signs: a case report. Ann Rehabil Med. 2015; 39(1):122-7.

Aundhakar SC, Mahajan SK, Chhapra DA. Hirayama's Disease: A Rare Clinical Variant of Amyotrophic Lateral Sclerosis. Adv Biomed Res. 2017;6:95. Published 2017 Jul 28.

How to Cite
Rao, A. (2019). PROXIMAL BRACHIAL MONOMELIC AMYOTROPHY OR HIRAYAMA DISEASE: NO LONGER AN ALIAS? (case report). International Journal of Medicine and Medical Research, 5(1), 5-9.