Polyarteritis nodosa

Polyarteritis nodosa (PAN), also known as periarteritis nodosa or panarteritis nodosa, is a systemic necrotizing vasculitis that primarily affects medium-sized muscular arteries. The disease causes inflammation and damage to the walls of these arteries, leading to weakening, narrowing, and sometimes aneurysm formation. This can result in reduced blood flow and ischemic damage to multiple organ systems. PAN can affect the kidneys, gastrointestinal tract, peripheral nervous system, skin, heart, and musculoskeletal system, though it characteristically spares the lungs and does not involve glomerulonephritis or venules. Key clinical features include fever, weight loss, fatigue, muscle and joint pain (myalgias and arthralgias), skin manifestations such as livedo reticularis, purpura, and subcutaneous nodules, peripheral neuropathy (particularly mononeuritis multiplex), abdominal pain due to mesenteric ischemia, renal involvement with hypertension, and testicular pain. The disease can range from mild, limited forms to severe, life-threatening multisystem involvement. In some cases, PAN is associated with hepatitis B virus (HBV) infection, though the proportion of HBV-associated cases has declined significantly with widespread vaccination. Treatment depends on disease severity. Mild cases may be managed with corticosteroids alone, while moderate to severe disease typically requires combination therapy with corticosteroids and immunosuppressive agents such as cyclophosphamide. For HBV-associated PAN, antiviral therapy combined with plasma exchange and a short course of corticosteroids is recommended. With appropriate treatment, prognosis has improved substantially, though relapses can occur. Biologic agents and other immunosuppressants may be considered in refractory cases. A rare monogenic form, deficiency of adenosine deaminase 2 (DADA2), has been identified as a genetic cause of a PAN-like vasculitis, particularly in childhood-onset cases.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Polyarteritis nodosa