Diagnosis and classification of polyarteritis nodosa

Area of Science:

• Rheumatology
• Immunology
• Pathology

Background:

• Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis affecting medium-sized arteries.
• It is typically negative for anti-neutrophil cytoplasmic antibodies and not associated with glomerulonephritis.
• PAN can be triggered by viral infections, notably hepatitis B virus, but is often idiopathic.

Purpose of the Study:

• To review the key features, diagnostic approaches, and current treatment strategies for Polyarteritis Nodosa.
• To highlight the challenges in classification and the ongoing efforts to develop new diagnostic criteria.

Main Methods:

• Review of clinical manifestations, laboratory findings, and diagnostic modalities for PAN.
• Discussion of current treatment policies, including corticosteroids and immunosuppressive agents.
• Analysis of recent advancements in classification criteria, including the EULAR/ACR initiative.

Main Results:

• PAN presents with multisystemic manifestations, commonly affecting peripheral nerves and skin.
• Histologic confirmation via biopsy of symptomatic organs (skin, muscle, nerve) is preferred for diagnosis.
• Visceral angiography may reveal micro-aneurysms when biopsies are inconclusive.

Conclusions:

• PAN requires a high index of suspicion due to its varied presentation and non-specific laboratory findings.
• Treatment involves a combination of corticosteroids and immunosuppressants, tailored to organ involvement.
• New international diagnostic and classification criteria are under development to improve accuracy and address limitations of previous criteria.