Clinical spectrum and outcomes of mononeuritis multiplex in rheumatic diseases: evidence from a nationwide multicenter study

Abstract

Background: Mononeuritis multiplex (MM) is a severe and clinically heterogeneous form of peripheral neuropathy, most commonly arising in the context of systemic vasculitis in rheumatology practice. Despite its potential to cause substantial functional impairment, data on its clinical spectrum, management, and outcomes remain limited.Objectives: This study aimed to comprehensively evaluate the clinical characteristics, underlying etiologies, treatment approaches, and outcomes of MM in a nationwide multicenter rheumatology cohort.Design: Retrospective, multicenter observational study.Methods: Adult patients diagnosed with MM by rheumatologists across 27 tertiary referral centers were included. Data were collected using a standardized case report form, encompassing demographic features, clinical presentation, electrophysiological findings, laboratory parameters, treatment modalities, and outcomes. Neurological status was assessed at the final follow-up visit.Results: A total of 72 patients were analyzed (mean age 53.5 +/- 14.9 years; 61.1% male). Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis was the most common underlying etiology (68%), with eosinophilic granulomatosis with polyangiitis being the predominant subtype. The typical clinical presentation consisted of acute-onset, asymmetric, distal involvement of the lower extremities, with foot drop as the most frequent manifestation (69.4%). Electrophysiological findings were consistent with a classical MM pattern in the majority of patients. Most patients received high-dose glucocorticoids combined with immunosuppressive therapy. Over a median follow-up of 29 months, 81.9% of patients achieved complete or partial neurological improvement. Outcomes were similar between ANCA-associated and non-ANCA-related diseases.Conclusion: MM represents a clinically diverse but potentially manageable neurological complication of rheumatic diseases. Early recognition supported by electrophysiological assessment, together with timely immunosuppressive treatment, may improve clinical outcomes. A multidisciplinary approach is essential to optimize long-term recovery and functional status.