Microscopic Polyangiitis With Selective Involvement of Central and Peripheral Nervous System: A Case Report

Area of Science:

• Neurology
• Rheumatology
• Immunology

Background:

• Microscopic polyangiitis (MPA) is a small-vessel vasculitis impacting multiple organ systems.
• MPA commonly causes glomerulonephritis, lung damage, arthritis, and neuropathy.
• Exclusive central nervous system (CNS) and peripheral nervous system (PNS) involvement in MPA is exceptionally rare.

Observation:

• A 62-year-old woman presented with foot drop, myalgia, arthralgia, and allodynia.
• Neurophysiological tests indicated multiple mononeuritis, and brain MRI revealed ischemic lesions in the basal ganglia and thalamus.
• High-titer myeloperoxidase-specific anti-neutrophil cytoplasmic antibodies (MPO-ANCA) were detected.

Findings:

• The patient was diagnosed with microscopic polyangiitis (MPA).
• Treatment with intravenous methylprednisolone and rituximab resulted in successful recovery.
• The case highlights a rare presentation of MPA with concurrent CNS and PNS involvement.

Implications:

• Diagnostic evaluation for MPA should include assessment of both CNS and PNS.
• PNS involvement in MPA may increase the risk of relapse and treatment failure.
• Considering PNS involvement is vital for selecting appropriate induction and maintenance therapies for MPA.