Systemic vasculitis of small- or medium-sized muscular arteries, usually involving renal and visceral vessels but not pulmonary circulation.KidneyEncyclopedia Entry for Polyarteritis Nodosa :Polyarteritis nodosa. Arteries are the blood vessels that carry oxygen-rich blood to organs and tissues. The cause of polyarteritis nodosa is unknown. The condition occurs when certain immune cells attack the affected arteries. The tissues that are fed by the affected arteries DO NOT get the oxygen and nourishment they need. Damage occurs as a result. More adults than children get this disease. People with active hepatitis B or hepatitis C may develop this disease.Symptoms are caused by damage to affected organs. The skin, joints, muscle, gastrointestinal tract, heart, kidneys, and nervous system are often affected. Symptoms include: Abdominal pain Decreased appetite Fatigue Fever Joint aches Muscle aches Unintentional weight loss Weakness If nerves are affected, you may have numbness, pain, burning, and weakness. Damage to the nervous system may cause strokes or seizures.No specific lab tests are available to diagnose polyarteritis nodosa. You will have a physical exam. Lab tests that can help make the diagnosis include: Complete blood count (CBC), creatinine, tests for hepatitis B and C, and urinalysis. Erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP). Serum protein electrophoresis, cryoglobulins. Serum complement levels. Arteriogram tissue biopsy. Other blood tests may be done to rule out similar conditions, such as systemic lupus erythematosus (ANA) or granulomatosis with polyangiitis (ANCA). Test for HIV.Treatment involves medicines to suppress inflammation and the immune system. These may include steroids, such as prednisone. Similar medicines, such as azathioprine, methotrexate or mycophenolate that allow for reducing the dose of steroids are often used as well. Cyclophosphamide is used in severe cases. For polyarteritis nodosa related to hepatitis, treatment may involve plasmapheresis and antiviral medicines.Current treatments with steroids and other drugs that suppress the immune system (such as azathioprine or cyclophosphamide) can improve symptoms and the chance of long-term survival. The most serious complications most often involve the kidneys and gastrointestinal tract. Without treatment, the outlook is poor.Complications may include: Heart attack Intestinal necrosis and perforation Kidney failure Stroke.Call your health care provider if you develop symptoms of this disorder. Early diagnosis and treatment may improve the chance of a good outcome.There is no known prevention. However, early treatment can prevent some damage and symptoms.Periarteritis nodosa; PAN; Systemic necrotizing vasculitis.Microscopic polyarteritis 2 Microscopic polyarteritis 2 Circulatory system Circulatory system.Luqmani R. Polyarteritis nodosa and related disorders.