Brachial plexus neuropathy in the population of Rochester, Minnesota, 1970-1981.

Brachial plexus neuropathy (BPN) is a clinical entity of unknown cause characterized by the acute or subacute onset of pain and weakness, with occasional atrophy of the arm muscles. Information on the incidence of the disease in a delineated population is lacking, as the data available on BPN have come essentially from case reports or selected series. Using the Mayo Clinic records-linkage system as the source of data, 579 clinical records were reviewed of Rochester, Minnesota, residents in which a diagnosis suggestive of BPN was reported for the period 1970 through 1981. Eleven cases fulfilled all criteria, providing an overall annual incidence rate of 1.64 cases per 100,000 population. An infectious disease and/or tetanus toxoid immunization preceded the onset of BPN in 4 cases. The upper brachial plexus was involved in 6 cases, the lower brachial plexus in 2, and the whole plexus in 3; in 1 case there was bilateral BPN. The neuropathy ran a mild to moderate course in 10 cases, and complete recovery was recorded in 6, with slight residua in the others. The occurrence of antecedent events and the features of the disease are supportive of the concept of an immune-mediated process.