Postpartum neuralgic amyotrophy.

We report 11 women with at least one episode of neuralgic amyotrophy occurring postpartum. One woman had three episodes-two postpartum and a third occurring after minor foot surgery. Two others had a second episode, one following a first trimester spontaneous abortion and one after a viral syndrome. Pain followed delivery from as little as 1 to 2 hours to up to 2 weeks and usually lasted from a few weeks to several months. Weakness, if delayed, followed onset of pain by 2 or 3 days up to 5 weeks. Four of the episodes were bilateral. Clinical weakness and electrodiagnostic findings varied widely, from involvement of a single peripheral nerve (e.g., long thoracic, anterior interosseous) to multiple bilateral proximal and distal nerves. Functional recovery was excellent (90 to 100%) in 8 of the 10 with adequate follow-up, requiring as little as 2 weeks or up to 3 years. Two women have moderate persisting weakness (both bilateral) at 3 years and 2 years. Five patients went on to subsequent deliveries without recurrence of neuralgic amyotrophy. Only one of the 11 women had a history suggesting familial neuralgic amyotrophy, a disorder generally thought to be associated particularly with postpartum episodes. Although the etiology of postpartum neuralgic amyotrophy remains unknown, an immunologic mechanism is suspected. Focal demyelination may play a role in some, but clearly axonal degeneration is predominant in the majority.