Vasculitis is defined as an inflammation of the blood vessels, arteries, veins or capillaries. When this inflammation occurs, it changes the walls of the blood vessels, such as weakening and narrowing them. This can progress to the point where the blood vessel becomes blocked. As a result of vasculitis, the tissues and organs that are supplied by the affected blood vessels do not get enough blood. This lack of blood can cause organ and tissue damage that can lead to death. Vasculitis is diagnosed by clinical and laboratory findings such as, blood tests, radiographic imaging and other tests. A tissue biopsy is the most definitive test.

There are many types of vasculitis.  The different types of vasculitis are classified according to the size and location of the blood vessels affected – small, medium, large. Vasculitis, such as Microscopic Polyangiitis (MPA) and Henoch-Schönlein Purpura (HSP) are called small vessel vasculitis because they cause inflammation in the smallest blood vessels, the capillaries, as they supply the insides of the organs. Polyarteritis Nodosa (PAN) and Kawasaki Disease (KD) are called medium vessel vasculitis because they affect the middle sized arteries as they go into the organs. Takayasu Arteritis (TA) and Aortitis are called large vessel vasculitis because they mainly affect the aorta and the biggest arteries as they branch off.

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CAUSE

The exact cause of vasculitis is generally unknown. Often a combination of factors can cause the inflammatory process to begin. Research suggests that people probably develop vasculitis because of the complex interaction of their genetic inheritance, and exposure to chemicals in the environment or possibly some types of infection (including hepatitis B virus) which may trigger the vasculitis in someone who is susceptible.

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DIAGNOSIS

Vasculitis is diagnosed by clinical and laboratory findings such as, blood tests, radiographic imaging and other tests. A tissue biopsy is the most definitive test.

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TREATMENT

Treatment depends on the severity and symptoms along with the patient’s general health. It can include corticosteroids, immunosuppressive drugs and antibiotics. Other treatments may also be used.

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OTHER FACTS ABOUT VASCULITIS

Vasculitis can affect people of all ages and races, although some forms may be more common among certain age or ethnic groups. The different types of vasculitis are classified according to the size and location of the blood vessels affected – Small, Medium. Large. The most serious types of vasculitis involve both small and medium-sized arteries.

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Download a PDF document about vasculitis here

The Khan Academy has produced a video that explains what vasculitis is, click here