Posterior interosseous nerve palsy in rheumatoid arthritis: case report and literature review.

Posterior interosseous nerve (PIN) palsy, presenting with a loss of digital extension, is a rare neurological complication of rheumatoid arthritis (RA). It may be caused by nerve entrapment, vasculitis or drug toxicity. There is no consensus regarding the treatment of PIN palsy in RA. We present a case in which the diagnosis of PIN palsy was confounded by previous surgical intervention. It represents the first report of PIN palsy treated with anti-TNF-alpha therapy leading to full recovery without surgical intervention. We highlight the importance of electrophysiological studies in elucidating the underlying cause and hence the treatment. We suggest that the apparent success of surgical intervention in the literature may be misleading, but new pharmacological advances may obviate the need for surgery where electrophysiology demonstrates vasculitis as the cause. A literature review is presented and a treatment algorithm proposed.