Widespread tissue damage as a result of patchy inflammation of the arteries
In polyarteritis nodosa, segments of small- to medium-sized arteries are inflamed, reducing the blood supply to skin, muscles, joints, and many of the internal organs. If the arteries that supply the heart or kidneys are affected, the condition may be life-threatening.
Polyarteritis nodosa is an autoimmune disorder in which the immune system attacks the body’s own arteries. The cause of the abnormal immune reaction is not known, but the hepatitis B and C viruses (see Acute hepatitis) have been found in some people who have polyarteritis nodosa, suggesting that these viruses may trigger the disorder. Polyarteritis nodosa is more common in middle-aged men.
The number and severity of symptoms vary. They may include:
Abdominal pain or discomfort.
Joint pain and muscle weakness.
Tingling and numbness in the fingers and toes.
A red-purple patchy rash on the skin that does not fade with pressure.
Polyarteritis nodosa commonly leads to an increase in blood pressure (see Hypertension) caused by kidney damage. In some people, the damage to the kidneys is severe and leads to kidney failure. Less commonly, polyarteritis may cause lung damage or a heart attack (see Myocardial infarction).
Your doctor may arrange for you to have blood tests to check for inflammation and to look for the hepatitis B or C viruses. To confirm the diagnosis, you may have a biopsy, in which a sample of an affected artery or organ is removed and examined under a microscope. You may also have angiography, in which an X-ray of the arteries is taken to look for abnormal areas in the blood vessels (see Femoral angiography).
Polyarteritis nodosa can be effectively treated to relieve symptoms and prevent tissue damage. Your doctor may initially prescribe a high dose of a corticosteroid, which will be reduced once the symptoms subside. If there is no improvement, an immunosuppressant drug may be prescribed. Without treatment, the condition may be life-threatening; with treatment, life expectancy is normal in about half of all cases.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.