[The changing face of medium-sized vasculitis]

Area of Science:

• Rheumatology
• Immunology
• Pathology

Background:

• Polyarteritis nodosa (PAN) is a rare systemic necrotizing vasculitis primarily affecting medium-sized arteries.
• Classification has evolved, distinguishing classical PAN from PAN associated with infections (e.g., viral hepatitis B, C, HIV) or genetic disorders.
• The pathogenesis of idiopathic PAN involves adaptive immune system dysregulation, while immune complexes are implicated in hepatitis B virus-related vasculitis.

Purpose of the Study:

• To provide a comprehensive overview of polyarteritis nodosa, including its classification, pathogenesis, clinical manifestations, and diagnostic approaches.
• To emphasize the importance of accurate diagnosis and disease characterization for guiding treatment strategies.

Main Methods:

• Review of current literature on polyarteritis nodosa.
• Integration of clinical, angiographic, and biopsy findings for diagnosis.
• Analysis of disease associations and pathogenetic mechanisms.

Main Results:

• Polyarteritis nodosa presents a wide spectrum of clinical manifestations, potentially affecting nearly all organs except the lungs.
• Special forms include single-organ disease and cutaneous PAN.
• Diagnosis requires a multidisciplinary approach, integrating various diagnostic modalities.

Conclusions:

• Accurate identification of PAN subtype, affected organs, and disease progression is crucial for tailoring treatment.
• Understanding the diverse etiologies and pathogenetic pathways is essential for managing this rare vasculitis.