Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis that typically affects medium-sized muscular arteries, with occasional involvement of small muscular arteries [1,2]. Patients often present with systemic symptoms. Autopsies indicate the most common organ involved is the kidney, followed by the skin. As with other vasculitides, PAN, can affect any organ system, including the cardiovascular, gastrointestinal, and central nervous systems.
The prognosis in untreated PAN is relatively poor, with one-year and five-year survival rates of approximately 50 and 13 percent [1,3]. The outcome has improved with therapy to approximately 80 percent survival at five years .
The treatment and prognosis of polyarteritis nodosa will be reviewed here. The clinical manifestations, diagnosis, and classification of PAN are presented separately. (See "Clinical manifestations and diagnosis of polyarteritis nodosa".)
The treatment of severe necrotizing arteritis of medium sized arteries in association with a connective tissue disease (eg, systemic lupus erythematosus, rheumatoid arthritis, Sjögren's syndrome), chronic viral infection (eg, hepatitis B or C), or hairy cell leukemia, is generally similar to that for idiopathic PAN. Interferon alfa may be beneficial in patients with PAN associated with hepatitis C or with hairy cell leukemia [5,6]. However, interferon alfa may also be associated with exacerbation of the vasculitis and new cases of PAN have occurred during interferon alfa therapy for hepatitis C .
Treatment of these disorders is discussed in detail elsewhere. (See "Treatment of rheumatoid vasculitis" and "Renal disease associated with hepatitis B virus infection", section on 'Polyarteritis nodosa' and "Renal disease associated with hepatitis C virus infection", section on 'Polyarteritis nodosa' and "Treatment of hairy cell leukemia".)