There are several forms of vasculitis. While some forms are due to infection or may be associated with other diseases, the causes of the six kinds of vasculitis which are the main subject of the VCRC network are unknown. They are all autoimmune diseases.
Different forms of vasculitis cause inflammation in blood vessels of various sizes. Some affect mainly small blood vessels such as those in the skin and the back of the eye, while others can affect medium sized blood vessels like those going to the hands and feet and the coronary arteries. Others affect mainly large blood vessels, like the aorta. However, there can be considerable overlap in the blood vessels which are involved by a given form of vasculitis. In all forms, the wall of the vessel can become weakened, even resulting in rupture of the vessel and damage to the tissues supplied with blood by the vessel. The inflammation can also lead to thickening of the vessel wall, causing blockage of blood flow and therefore to tissue damage.
The diagnosis of vasculitis is based on a combination of symptoms, laboratory tests and biopsies of affected tissues. Most laboratory tests used to evaluate patients with vasculitis are non-specific. For example, the sedimentation rate may be high when the disease is active. One laboratory test is called antineutrophil cytoplasmic antibody, or ANCA, which can be present in some forms of vasculitis. Magnetic resonance imaging (MRI), computerized and dye studies of blood vessels called angiograms are among radiology tests used for evaluating patients with vasculitis. The specific tests used in diagnosis and in assessing the treatment of vasculitis depend on the type of vasculitis and the blood vessels and organs involved.
All forms of vasculitis are treated with glucocorticosteroids (“steroids”), and many require treatment with other drugs as well, including drugs used to suppress the immune system (“immunosuppressive agents”) as well as drugs used in the treatment of cancers and other conditions. Increasingly, drugs including newer “biologic agents” are being used in the treatment of some newer forms of vasculitis.