Polyarteritis nodosa, microscopic polyangiitis and Churg-Strauss syndrome

Area of Science:

• Rheumatology
• Immunology
• Nephrology

Background:

• Polyarteritis nodosa (PAN) is a necrotizing angiitis with systemic manifestations.
• Microscopic polyangiitis (MPA) and Churg Strauss syndrome (CSS) are distinct vasculitides with overlapping and unique clinical features.
• Etiologies include primary vasculitis and secondary causes like hepatitis B virus (HBV) infection.

Purpose of the Study:

• To differentiate PAN, MPA, and CSS based on their distinct clinical and etiological characteristics.
• To review the current understanding of the prognosis and treatment of these systemic vasculitides.

Main Methods:

• Comparative analysis of clinical manifestations and diagnostic criteria for PAN, MPA, and CSS.
• Review of literature regarding the role of etiologic factors, particularly HBV.
• Summary of treatment strategies, including corticosteroids and immunosuppressive drugs.

Main Results:

• PAN presents with weight loss, fever, neuropathy, renal, musculoskeletal, cutaneous, and gastrointestinal involvement.
• MPA is characterized by small-vessel vasculitis, rapidly progressive glomerulonephritis (RPGN), and typically lacks pulmonary involvement.
• CSS involves hypereosinophilia, asthma, and allergic rhinitis alongside systemic vasculitis.

Conclusions:

• Accurate differentiation of PAN, MPA, and CSS is crucial for appropriate management.
• Corticosteroids are the cornerstone of treatment for most systemic vasculitides, except for HBV-related PAN.
• Immunosuppressive agents like cyclophosphamide offer improved outcomes, but their optimal use requires further elucidation.