Isolated vasculitis of the peripheral nervous system

Area of Science:

• Neurology
• Rheumatology
• Pathology

Background:

• Nonsystemic vasculitic neuropathy (NSVN) is a peripheral nervous system (PNS) vasculitis lacking uniform diagnostic criteria.
• It is often under-recognized and distinct from systemic vasculitides, though clinical overlap exists.
• Patients typically present with painful, progressive, asymmetric sensory-motor deficits.

Purpose of the Study:

• To review the current understanding of NSVN, including its diagnosis, pathology, and management.
• To highlight diagnostic challenges and the need for further research.

Main Methods:

• Review of existing literature and case reports on NSVN.
• Analysis of diagnostic criteria, clinical presentation, and pathological findings.
• Evaluation of treatment outcomes and prognosis.

Main Results:

• NSVN presents as axonal neuropathy, often with stepwise progression over months to years.
• Nerve biopsy is crucial for diagnosis, though sensitivity for necrotizing vasculitis is around 50%.
• Mildly elevated erythrocyte sedimentation rate (ESR) is common; high ESR, leukocytosis, rheumatoid factors, and ANCA suggest systemic vasculitis.

Conclusions:

• NSVN is a distinct entity from systemic vasculitis-associated neuropathies (SVNs) but shares axonal pathology.
• While many patients achieve a good outcome, over 30% relapse, and 60% report residual pain.
• Further research is needed to address diagnostic, pathogenic, and therapeutic questions in NSVN.