indicated by the initial ACR analysis, suggested their potential usefulness for diagnostic purposes as well. Subsequent studies did not confirm their diagnostic utility, demonstrating a significant dependence of their discriminative abilities on the prevalence of the various vasculitides in the analyzed populations. Recently, an original study, combining the analysis of more than 100 items used to describe patients' characteristics in a large sample of vasculitides with a computer simulation technique designed to test the potential diagnostic utility of the various criteria, proposed a set of eight positively or negatively discriminating items to be used as a screening tool for diagnosis in patients suspected of systemic vasculitis. Differential diagnosis Polyarteritis nodosa rarely affects the blood vessels of the lungs and this feature can help to differentiate it from other vasculitides that may have similar signs and symptoms (e.g., granulomatosis with polyangiitis or microscopic polyangiitis). Treatment Treatment involves medications to suppress the immune system, including prednisone and cyclophosphamide. When present, underlying hepatitis B virus infection should be immediately treated. In some cases, methotrexate or leflunomide may be helpful. Some patients have entered a remission phase when a four-dose infusion of rituximab is used before the leflunomide treatment is begun. Therapy results in remissions or cures in 90% of cases. Untreated, the disease is fatal in most cases. The most serious associated conditions generally involve the kidneys and gastrointestinal tract. A fatal course usually involves gastrointestinal bleeding, infection, myocardial infarction, and/or kidney failure. In case of remission, about 60% experience relapse within five years. In cases caused by hepatitis B virus, however, recurrence rate is only around 6%. Epidemiology The condition affects adults more frequently than children and males more frequently than females. Most cases occur between the ages of 40 and 60. Polyarteritis nodosa is more common in people with hepatitis B infection. History The medical eponyms Kussmaul disease or Kussmaul-Maier disease reflect the seminal description of the disease in the medical literature by Adolph Kussmaul and Rudolf Robert Maier. Culture In the 1956 American film Bigger Than Life, the protagonist character played by James Mason is diagnosed with polyarteritis nodosa after experiencing excruciating chest pain and is treated with cortisone. References External links Disorders of fascia Rheumatology Steroid-responsive inflammatory conditions Systemic connective tissue disorders Vascular-related cutaneous conditions Hepatitis C virus-associated diseases