BMJ Case Reports 2009; doi:10.1136/bcr.09.2009.2292
  • Rare disease

A woman with forearm amyotrophy

  1. Emmanuel Sagui1,
  2. Éléonore Correa1,
  3. Diane Ricobono2,
  4. Michel Bregigeon1,
  5. Christian Brosset1
  1. 1
    Hôpital D’instruction Des Armées Laveran, Service de Neurologie, bd A Laveran, BP 60149, Marseille Cedex 13, 13384, France
  2. 2
    CRSSA, 24 Av Maquis Du Gresivaudan, BP 37, La Tronche, 38700, France
  1. Emmanuel Sagui, emlsmg{at}
  • Published 14 December 2009


We present the case of a 33-year-old woman with benign sporadic monomelic amyotrophy of the distal part of the arm, called Hirayama disease. Clinical features included forearm amyotrophy sparing the brachioradialis muscle, cold paresis and causalgia. Neck magnetic resonance imaging was normal in neutral and flexion position. Electromyography showed denervated patterns in the extensor digitorum communis, and conduction studies ruled out multifocal motor neuropathy. Motor evoked potentials were normal. Serum IgG anti-GM1 antibodies were moderately raised but were negative 8 months later. Outcome was favourable within 15 months, with partial motor recovery. Pathogenesis remains controversial: neck flexion induced myelopathy via chronic anterior horn ischaemia due to forward displacement of the posterior wall of the dura mater, or benign variant of lower motor neuron disease? Whatever the pathomechanism is, the clinical features and outcome are the same.


  • Competing interests: none.

  • Patient consent: Patient/guardian consent was obtained for publication

Register for free content

The full text of all Editor's Choice articles and summaries of every article are free without registration

The full text of Images in ... articles are free to registered users

Only fellows can access the full text of case reports (apart from Editor's Choice) - become a fellow today, or encourage your institution to, so that together we can grow and develop this resource

Don't forget to sign up for content alerts so you keep up to date with all the case reports as they are published, and let us know what you think by commenting on the Editor's blog

Navigate This Article