Polyarteritis nodosa

From the Guidelines

The recommended initial treatment for Polyarteritis Nodosa (PAN) is a combination of high-dose corticosteroids and cyclophosphamide, as conditionally recommended by the 2021 American College of Rheumatology/Vasculitis Foundation guideline for the management of PAN 1. The treatment approach for PAN typically involves:

• High-dose corticosteroids: Prednisone 1 mg/kg/day (usually 60-80 mg/day) orally for 4 weeks, then gradually taper.
• Cyclophosphamide: 2 mg/kg/day orally or 15 mg/kg IV pulse every 2-3 weeks for 3-6 months. For less severe cases or maintenance therapy:
• Consider azathioprine (2 mg/kg/day) or methotrexate (15-25 mg/week) as steroid-sparing agents. Additional considerations:
• Monitor for side effects of medications, including infections and bone loss.
• Provide prophylaxis against Pneumocystis jirovecii pneumonia during treatment.
• Regular follow-up with blood tests and urinalysis to assess disease activity and medication toxicity. This aggressive treatment approach is necessary due to the potentially life-threatening nature of PAN, with a mortality rate of 40% at 5 years if left untreated or undertreated 1. The combination of corticosteroids and immunosuppressants helps to rapidly control inflammation in the affected blood vessels, preventing further organ damage and improving overall prognosis, as supported by the guideline recommendations 1. It is essential to note that the treatment approach may vary depending on the severity of the disease, patient's clinical condition, and response to therapy, as emphasized in the guideline recommendations 1.

From the Research

Definition and Characteristics of Polyarteritis Nodosa

• Polyarteritis nodosa (PAN) is a rare disease characterized by the necrotizing inflammation of medium-sized arteries 2.
• It is a systemic necrotizing vasculitis that predominantly affects medium and small-sized arteries 3, 4.
• The disease has heterogeneous presentations, severity, and therapeutic approaches 2.

Diagnosis of Polyarteritis Nodosa

• The diagnosis of PAN is primarily based on clinical findings, imaging, and histopathological investigations 2.
• Microbiological and genetic investigations complement the diagnostic work-up 2.
• Diagnosis requires the integration of clinical, angiographic, and biopsy findings 4.

Treatment of Polyarteritis Nodosa

• Idiopathic and hereditary variants of PAN are treated with immunomodulatory medications such as glucocorticoids, conventional immunomodulatory drugs, and biologic agents 2.
• Hepatitis B virus-associated PAN primarily requires antiviral therapy combined with plasma exchange 2.
• Biologic drugs, mostly anti-tumor necrosis factor (TNF)-α agents, have been shown to be effective in inducing and maintaining remission in patients with PAN 5.
• Infliximab, a TNF inhibitor, has been used to treat refractory PAN with significant improvement in 89% of patients 6.

Clinical Variants of Polyarteritis Nodosa

• There are different clinical variants of PAN, including idiopathic generalized PAN, cutaneous PAN, and hepatitis B virus (HBV)-associated PAN 4.
• Each variant has a different approach to treatment, with idiopathic generalized PAN being treated with a combination of glucocorticoids and cyclophosphamide, and HBV-associated PAN being treated with antiviral agents 4.
• Cutaneous PAN requires a less aggressive approach based on the administration of non-steroidal anti-inflammatory drugs over short periods of time 4.