Polyarteritis Nodosa

What is Polyarteritis Nodosa?

Polyarteritis Nodosa (PAN) is a very rare form of vasculitis involving predominantly medium-sized blood vessels. Inflammation of the blood vessels may cause segments of vessels to weaken and stretch, resulting in an aneurysm (weakening of the vessel wall). Inflammation of the vessel wall can also lead to thickening and subsequent partial blockage (stenosis) or complete blockage (occlusion) of the artery. These aneurysms and blockages can result in the surrounding tissues being deprived of an adequate blood supply. The disease commonly affects the intestines, kidneys, skin, and peripheral nervous system but can affect most parts of the body. As is true in other forms of vasculitis, how PAN affects the body differs widely from patient to patient.

What causes Polyarteritis Nodosa?

PAN is thought to be an auto-immune disease, for which there is no known cause in most cases. There is an important known association between infection with hepatitis B or hepatitis C viruses and development of PAN. However, only a small fraction of patients infected with these viruses develop PAN, and only a small percentage of patients with PAN test positive for either of these viruses.

How is Polyarteritis Noda diagnosed?

The diagnosis of PAN is made by combining clinical features with the results of angiograms and tissue biopsies.

How is Polyarteritis Nodosa treated?

Treatment of PAN almost always involves use of prednisone in high doses that are slowly reduced over many months. Often an immunosuppressive drug such as cyclophosphamide, methotrexate, or azathioprine, is added to the prednisone therapy. If diagnosed early, treatment can produce remission and prevent organ damage. Many patients have only one episode of PAN, but many others suffer relapses and may require long-term treatment to reduce the risk of relapse.

*Note: This content has been adapted from the VCRC website