Polyarteritis Nodosa can affect any organ of the body, but skin, peripheral nerves, joints, intestinal tract, and kidneys are most commonly involved. The lungs are usually spared. Although the severity varies, polyarteritis nodosa is a serious and often progressive and fatal illness. Vasculitis similar to polyarteritis nodosa may be an occasional secondary or associated manifestation of other diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE).
Polyarteritis nodosa is uncommon; estimates of its incidence in the general population have ranged from about 5 to 10 per million persons per year. The disease is twice as common in men. It may be ovserved in children and the elderly, but it is more common in middle age.
Constitutional symptoms such as fever and malaise are usually present. Cutaneous manifestations include palpable purpura, infarctive ulcers of varying sizes, and livedo reticularis. Joint pain is common, but synovitis is less frequent.
Multiple mononeuropathies are the most typical neurologic manifestation and occur in one-half or more of all patients. Sharp sudden pain of paresthesias in the distribution of a peripheral nerve are often the first symptoms, followed by weakness of the muscles supplied by that nerve. Several nerves may become involved progressively, resulting in a severe diffuse polyneuropathy.