Polyarteritis nodosa is a rare, but potentially life threatening, inflammation of the blood vessels (vasculitis) that damages the walls of the body's small- and medium-sized arteries. This damage slows the supply of blood and nourishment to the arteries, causing nearby tissue in many parts of the body to be injured or even destroyed. The disease most commonly affects the kidneys, the nerves of the arms and legs and the abdominal organs, although it can also involve the skin, joints, muscles, brain, heart, eyes and reproductive organs.
In individual organs, polyarteritis nodosa can have the following effects:
Kidneys. Kidney failure and high blood pressure related to kidney injury
Nervous system. Nerve injury in the arms or legs, which may cause numbness, tingling, or loss of sensation and movement caused by injury to one specific nerve bundle. In the brain, damage can trigger strokes, seizures or sudden alterations in brain function.
Abdominal organs. Pain in the bowel, liver or pancreas, especially after eating, or even death of part of an organ caused by an interruption in blood supply. Arterial aneurysms, which are balloon-like swellings that develop along an artery in areas where vasculitis has weakened the arterial wall, may suddenly rupture. This can lead to life-threatening bleeding inside the abdomen, with severe abdominal pain.
Heart. Heart attack, as well as inflammation of the lining of the heart (pericarditis). Congestive heart failure can make breathing difficult, as fluid backs up behind the heart into the lungs.
Skin. Rashes, skin nodules and a rash (purpura) caused by bleeding from damaged capillaries
It is difficult to know exactly how many people have this illness because its symptoms can be confused with other diseases and other forms of vasculitis. One British study found that polyarteritis nodosa occurs in three or four of every 1 million people each year in the United Kingdom. In the United States, it may occur more often. According to one Minnesota study, it occurred in up to nine in every 1 million people.
Polyarteritis nodosa can affect people of all races and age groups, but most commonly strikes adults between the ages of 40 and 50. Men are affected about twice as often as women.
Although the cause of polyarteritis nodosa is unknown, some research has linked it to the presence of microscopic clumps of antibodies from the body's defense system, coupled with foreign proteins, such as portions of a virus. In some people with polyarteritis nodosa, the illness seems to be triggered by a viral liver infection, either hepatitis B or hepatitis C.
In some patients, researchers have found at least one autoantibody (an immune protein that attacks the body rather than a foreign invader) that appears to be related to the arterial damage of polyarteritis nodosa. This autoantibody, called antineutrophil cytoplasmic antibody, also has been found in the blood of patients with other vasculitic disorders, including granulomatosis with polyangiitis (Wegener's). However, most patients with polyarteritis nodosa do not have this antibody in their blood or tissues, and many experts do not believe this antibody plays an important role in this condition.