Objective: Churg-Strauss syndrome (CSS) and microscopic polyangiitis (MPA) are commonly characterized by systemic necrotizing vasculitis and frequent occurrence of axonal neuropathy. We investigated whether the neuropathy in these 2 diseases reveals differences in clinicopathologic features and predicts survival and functional outcome.
Methods: We compared 30 patients with CSS associated neuropathy with 26 patients with MPA associated neuropathy in terms of clinical, laboratory, electrophysiologic, and outcome data.
Results: MPA cases showed a significantly higher age at onset, a higher male/female ratio, and more extensive systemic organ involvement than CSS. Inflammatory markers including antimyeloperoxidase antibody titers were also significantly higher in MPA. Both CSS and MPA showed similar neuropathic symptoms, electrophysiologic findings, and sural nerve biopsy findings representing acute axonal changes. Functional disability assessed by modified Rankin score, muscle strength, and nerve conduction variables were similar in CSS and MPA, both in the acute peak phase and during longterm followup. However, survival was significantly worse in MPA than CSS.
Conclusion: Neuropathy associated CSS and MPA shared common neuropathic features throughout the course, but systemic organ involvement, inflammatory marker concentrations, and relapse rates were significantly higher in MPA, which showed a poorer survival rate.