[Clinical features and MRI characteristics in neuralgic amyotrophy].

Neuralgic amyotrophy (NA) is a distinct peripheral nervous system (PNS) disorder characterised by sudden attacks of neuropathic pain, usually in a unilateral upper extremity, and patchy paresis with amyotrophy. Under-recognition of NA patients may be frequent because symptoms of NA can be similar to those of common orthopedic disorders. The lesion sites of NA are commonly considered to be brachial plexus (BP) and/or individual branches of the BP. The cause of NA remains unknown. Some evidence support the concept of a complex pathogenesis in NA that includes underlying predisposition and susceptible PNS structures, and it can be triggered by infection, trauma, and strenuous exercise. Typical presentation of NA is characterized by patchy paresis of the periscapular and periglenohumeral muscles. In such cases, STIR-MRI often shows hyperintense signal abnormalities on the affected side of the proximal upper BP. NA is considered to be broad and encompasses a spectrum of atypical presentations, including involvement of lower part of BP, isolated nerves (anterior interosseous nerve or posterior interosseous nerve), or lumbosacral plexuses. Functional prognosis of NA is less favorable than previously assumed. Administration of corticosteroids and intravenous immunoglobulin was described as potential therapeutics for NA, although their efficacy remains unestablished.