Peripheral neuropathy in systemic vasculitis and other autoimmune diseases – a report of five cases emphasizing the importance of etiologic characterization

INTRODUCTION: Peripheral neuropathies may present in the context of systemic vasculitis and other autoimmune diseases. The etiologic characterization is crucial to define the treatment and prognosis in secondary vasculitis. The purpose of this study is to describe the pathway of etiologic investigation including the role of nerve biopsy. METHODS: Retrospective analysis of patients seen in the neuromuscular outpatient clinic during the last four years with peripheral neuropathy in the context of systemic vasculitis or other autoimmune diseases. RESULTS: We present five patients with stepwise progressive sensorimotor deficits of upper and lower limbs. All patients presented with systemic features and one of them had an established diagnosis of systemic vasculitis. They underwent an extended blood panel, including autoimmune and serologic tests. Electromyography and nerve conduction studies revealed asymmetric axonal sensorimotor polyneuropathies in four patients, and an axonal sensorimotor multiple mononeuropathy in one. Four patients underwent nerve biopsy and the other performed a skin biopsy, with findings suggestive of possible vasculitic processes. The etiologies identified included microscopic polyangiitis, HBV-related polyarteritis nodosa and two eosinophilic granulomatosis with polyangiitis. In the last patient a specific etiology could not be established. CONCLUSION: This series reveals the etiologic and phenotypic diversity of peripheral neuropathies related with systemic vasculitis. The therapeutic approach and prognosis were distinct in each patient, emphasizing the importance of a prompt diagnosis and appropriate treatment.