The analysis of the clinical and pathologic features in patients with peripheral neuropathy as main manifestation of microscopic polyangiitis

Abstract

Objective To investigate the clinical and pathologic features in patients of microscopic polyangiitis (MPA) with peripheral nerve abnormality. Methods We collected clinical data of 6 patients with MPA that was confirmed by immunological, pathological and clinical findings. Electroneurophysiologic examinations and sural nerve biopsies were performed in these patients. Two normal controls were included in these studies. Results All of 6 patients developed asymmetric polyneuropathies. Electrodiagnostic studies showed reduced amplitudes of the sensory nerve action potential and compound motor action potential with mild impaired conductive velocities. The patients presented vasculitis changes with cell infiltration by monocytes and lymphocytes. Sural nerve biopsies found loss of myelinated fibers in all of the patients indicating axonal degeneration. Some of them associated with regeneration clusters of myelinated fibers. Conclusions Asymmetric neuropathy with sensory nerve injuries is the mainfeature in the MPA associated polyneuropathy. Electrodiagnostic examination indicated axonal lesions in mononeuritis multiplex. Sural nerve biopsies confirmed the active axonal lesions and vasculitis. Key words: Vasculitis; Peripheral nervous system diseases; Nerve fibers, myelinated; Biopsy; Capillaries