Vasculitis confined to peripheral nerves.

The clinical, electrophysiological and pathological features and prognosis of 25 patients with vasculitis selectively affecting the peripheral nervous system were evaluated. Although most patients had a history of mononeuritis multiplex or an asymmetrical neuropathy six out of 25 had a symmetrical neuropathy, both clinically and on neurophysiological testing, by the time of presentation. There were no signs of accompanying systemic vasculitis in any of the patients and serological abnormalities were limited to an elevated erythrocyte sedimentation rate (ESR) in nine out of 21 patients and low titre anti-nuclear antibodies in four out of 20 patients. Most patients had a necrotizing vasculitis on nerve biopsy, although in some cases the diagnosis was made on the association of inflammatory cell infiltrates with extensive axonal degeneration and immune complex deposition on immunofluorescence studies. The mean time from symptom onset to diagnosis was 46 weeks. All patients were treated with corticosteroids and most with additional immunosuppressive therapy. In contrast to vasculitic neuropathy associated with systemic vasculitis the prognosis was good with 24 out of 25 survivors at a mean of 176 weeks follow-up having a mean improvement of 1.4 units on a six-point disability scale.