Nonsystemic vasculitic neuropathy

Background: Nonsystemic vasculitic neuropathy (NSVN) is an infrequent type of vasculitic neuropathy that evolves without manifestations of vasculitis in other organs and in the absence of serological abnormalities. There are non clarified conjectures about the pathogenesis, outcome and treatment approach.

Methods: A retrospective study of a series of six patients diagnosed of NSVN during a period of 12 years. Clinical, electrophysiological and pathological features, as well as the response to therapy and outcome are analysed.

Results: Four cases presented with a pattern of multiple mononeuropathy, evolving towards a symmetrical sensory and motor polyneuropathy in two of them. One patient presented with an acute sensory neuropathy and another had a subacute asymmetric sensory and motor neuropathy. No signs of accompanying systemic vasculitis were observed during the follow-up (mean 35 months) and the only outstanding serological abnormality was the presence of antibodies against hepatitis B virus in four of them. The nerve conduction studies showed typical features of axonal degeneration. The diagnostic was obtained due to the presence of a necrotizing vasculitis in the sural nerve biopsy in all cases. The mean time from symptom onset to diagnosis was 11 months. All patients were treated with immunosuppressive therapy presenting a favourable response, except the case of the sensory neuropathy that remained stable.

Conclusions: NSVN is a benign type of vasculitic neuropathy with a variable clinical pattern of presentation and favourable response to immunosuppression. This neuropathy requires a high index of suspicion for diagnosis, so nerve biopsy must be carried out in all neuropathy of unknown etiology. Careful follow-up of patients is necessary, so that life-threatening systemic vasculitis neuropathy can be diagnosed early.