Brachial and lumbar neuropathies.

Sporadic acute brachial plexus neuropathy occurs in approximately 1.64/100,000 population, but may present in epidemic form. Sporadic lumbosacral plexus neuropathy is far less common and has to be distinguished from more common disorders affecting the plexus and roots such as diabetes. Early this century, when serum therapy became popular to treat or prevent prevalent infectious diseases, it became apparent that a plexopathy could follow treatment. It has thus been assumed that many of the cases are due to an autoimmune or inflammatory lesion of the plexus. A wide variety of vaccines, infections and medications seem able to precipitate the disorder. Recent work has shown that cultured lymphocytes from affected patients, but not controls, are able to mount a blastogenic response to components of cadaver brachial plexus. This response seems to be selective not only to the brachial plexus, but also to discrete components of the plexus. The recovery rate in brachial plexus neuropathy is good, being almost 90% at 3 years. Recovery with lumbosacral disease is less satisfactory. Histological material and descriptions of acute brachial plexus neuropathy are rare. There is some evidence that an inflammatory process is present, but the role of demyelination and axonal atrophy in producing the observed clinical signs, is still uncertain. Virtually nothing is known about the histological changes in lumbosacral plexus neuropathy. Treatment is mainly supportive, but important in limiting disability. Steroids may help relieve pain in the acute stages, but do not seem to alter the prognosis.