From the Guidelines
Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis that primarily affects medium-sized vessels, characterized by mixed-cell inflammatory infiltrates in the vessel wall and fibrinoid necrosis, with an absence of granulomas and giant cells 1. The diagnosis of PAN is generally confirmed by tissue biopsy of an affected organ or angiography if tissue biopsy cannot be obtained, with typical findings including saccular or fusiform aneurysms and stenotic lesions in the mesenteric, hepatic, and renal arteries and their subsequent branches. Key clinical presentations of PAN include:
- Neurologic manifestations such as mononeuritis multiplex and peripheral neuropathy
- Cutaneous manifestations such as nodules and livedo reticularis
- Renal manifestations such as hypertension
- Gastrointestinal manifestations such as abdominal pain According to the 2021 American College of Rheumatology/Vasculitis Foundation guideline for the management of polyarteritis nodosa, the management of PAN involves a multidisciplinary approach, with treatment aimed at rapidly suppressing inflammation in the affected blood vessels to prevent further damage to organs and tissues 1. The prognosis of PAN remains potentially devastating, with severe PAN having a mortality rate of 40% at 5 years, highlighting the importance of prompt and effective treatment 1.
From the Research
Definition of Polyarteritis
- Polyarteritis, also known as Polyarteritis nodosa (PAN), is a rare and serious form of systemic necrotizing vasculitis that predominantly affects medium and small-sized arteries 2, 3, 4.
- It is characterized by necrotizing inflammation of medium-sized or small arteries without glomerulonephritis or vasculitis in arterioles, capillaries, or venules 3.
Clinical Manifestations
- The signs and symptoms of PAN are primarily attributable to diffuse vascular inflammation and ischemia of affected organs 3.
- Virtually any organ with the exception of the lungs may be affected, with peripheral neuropathy and symptoms from osteoarticular, renal artery, and gastrointestinal tract involvement being the most frequent clinical manifestations 3.
- PAN can also present with constitutional symptoms, such as fever and myalgia, and cardiac involvement is a common cause of mortality 5.
- In rare cases, patients may present with isolated abdominal pain, similar to the case presented in 6.
Diagnosis and Treatment
- Diagnosis requires the integration of clinical, angiographic, and biopsy findings 4.
- The treatment of PAN has a high success rate when a combination of cyclophosphamide and steroids is administered 6, 3, 4.
- Idiopathic generalized PAN should be treated with a combination of glucocorticoids and cyclophosphamide, while the treatment of HBV-associated PAN involves a different approach, centered on the use of an antiviral agent to control the infection 4.
- In severe cases, biologic agents such as infliximab may be critical for treatment 2.