Definition
Vasculitis refers to a condition that causes inflammation of blood vessels (arteries, capillaries, and/or veins). When the blood vessels become inflamed, scarring, thickening of the vessel walls, and narrowing of the vessel caliber decrease the amount of blood flow through the blood vessels. When there is less blood flow, the organs or tissues that should be receiving blood flow are deprived of oxygen, causing damage to them. Because blood vessels anywhere in the body can be affected by vasculitis, organs and tissues anywhere in the body can be damaged by its consequences. Vasculitis can occur very focally (in a relatively small, circumscribed area) or diffusely (a widespread network of blood vessels are inflamed).
Description
Vasculitis describes a large number of conditions. Vasculitis can be primary (the vessel inflammation occurs spontaneously, with no other associated disease process) or secondary (the vessel inflammation occurs due to some other preexisting disease). Secondary vasculitis can be a manifestation of a large number of disease processes, including a variety of connective tissue or autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, Raynaud's phenomenon, Sjogren's syndrome, sclerodactyly, polymyositis, and dermatomyositis, as well as sarcoidosis, malignancy, hepatitis B and hepatitis C infections, allergic reactions to antibiotics and/or diuretics, and severe bacterial infections such as endocarditis, pneumonia, meningitis, gonorrhea, or syphilis.
Normally, inflammation is an immune system response to the presence of either an injury or an infection with an invading organism such as a virus, bacteria, or fungi. When faced with either of these threats, the immune system produces a variety of cells and chemicals that cause blood vessels in the injured or infected area to dilate and then become leaky. Fluid, protein, and blood cells leak out of the blood vessels and into the surrounding tissues, causing swelling. The affected area turns red, warm, and painful.
Inflammation causes a cascade of effects, both in the tissues adjacent to the initial area of inflammation and at distant sites throughout the body. Locally, the process of inflammation causes various chemicals of inflammation to leak out into the neighboring tissues, prompting the same cycle of vessel dilatation and leakiness, resulting in swelling of those neighboring tissues. Chemicals of inflammation traveling through the bloodstream can precipitate the cycle of inflammation in tissues and/or organs at a distance from the initial site of inflammation.
In vasculitis, the inflammation response has gone awry: it may be kicked off initially by the presence of an invader such as vasculitis secondary to a severe bacterial infection; it may be part of an overall immune system over-reactiveness as occurs when vasculitis occurs secondary to an autoimmune disease such as systemic lupus erythematosus and rheumatoid arthritis; or it may erupt spontaneously as in cases of primary vasculitis. The end results, however, are inflammation and destruction of blood vessel walls, blood clot blockages within blood vessels, aneurysms (weakened bulging areas of blood vessel walls which can rupture, causing catastrophic bleeding), and oxygen deprivation of the affected organs and/or tissues, leading to damage and destruction of various tissue or organs throughout the body.
A variety of classification systems have been developed to describe and organize the various types of vasculitis. These include systems that are based on the specific organs affected, and systems that are based on the size and type of vessels affected, and the kinds of microscopic, cellular changes seen within those vessels. One of the most popular systems for classification of vasculitis is called the Chapel Hill system, named for the creators at the University of North Carolina-Chapel Hill. This system divides the types of vasculitis into three categories: large-vessel vasculitis (including giant cell or temporal arteritis and Takayasu's arteritis); medium-vessel vasculitis (including polyarteritis nodosa and Kawasaki's disease); and small-vessel vasculitis (including Wegener's granulomatosis, Churg-Strauss syndrome, microsopic polynagiitis, Henoch-Schonlein purpura, essential cryoglobulinemic vasculitis, and cutaneous leukocytoclastic angiitis).
Demographics
Each type of vasculitis has its own primary demographic. Those that tend to strike older individuals include polyarteritis nodosa, giant cell or temporal arteritis, and Wegener's granulomatosis. Takayasu's arteritis tends to strike individuals in middle age. Henoch-Schonlein pupura and Kawaskai disease tend to strike children.
Causes and symptoms
Some researchers believe that vasculitis is prompted by the deposition of antibody-antigen complexes along the inside of blood vessel walls. Antibodies are immune cells that recognize and attach to specific markers (antigens) on foreign cells such as bacteria, viruses, and fungi. The presence of antibody-antigen complexes serves to jumpstart the immune cell response, prompting it to produce a variety of other cells and chemicals in an effort to rid the body of a foreign invader. Sometimes, however, the body accidentally produces antibodies that accidentally identify antigens on the body's own cells as foreign. When these antibodies bind to the body's antigens, the same immune response is provoked, but instead of being directed against a foreign invader, it is directed against the body itself.
Some researchers believe that the immune system is prompted into action by the presence of an actual threat (in the case of secondary vasculitis due to a bacterial infection), or is already overreacting (in the case of secondary vasculitis due to a preexisting autoimmune disease), or spontaneously swings into an overreactive state (in the case of primary vasculitis).
Symptoms of vasculitis depend on the specific organs or tissues affected. Affected body systems and potential symptoms include:
- Skin. Vasculitis of the skin may lead to a variety of rashes, bumps, bruises, or areas of subtle bleeding suchas petechia (tiny red dots), pupura (larger reddish purple spots), or ecchymoses (large, complexly colored areas of bruising). When areas of skin are completely deprived of any blood flow, and therefore of any oxygen delivery, the skin may die and turn black (gangrene).
- Joints. Vasculitis-induced arthritis occurs when the lining of the joints is affected by vasculitis, causing swelling, pain, decreased range of motion, and reduced functioning.
- Brain and nervous system. When vasculitis affects the nervous system, a variety of symptoms may result. Vasculitis of blood vessels in the brain can lead to headaches, confusion, personality changes, seizures, and coma. Depending on the area of the brain affected, other senses may suffer, including vision, hearing, and/or balance. Vasculitis of the nerves that provide sensation to the arms or legs can lead to pain and paresthesias (odd sensations of tingling, burning, pinpricks, lightning-flashes of pain, or numbness). A stroke occurs when an area of the brain tissue is completely deprived of oxygen, causing severe damage or destruction. The results of a stroke may be temporary or permanent, and the specific types of potential disability depend on what functions are normally controlled by the area of brain injured by the stroke.
- Gastrointestinal system. Any part of the gastrointestinal system can be affected by vasculitis, including the liver. Symptoms referable to the gastrointestinal system include pain, diarrhea, constipation, and vomiting. When blood flow is cut off to an area of the intestine, that area will become gangrenous or necrotic and die. This is a medical emergency.
- Heart. Vasculitis of the coronary arteries, which normally feed the heart muscle, can result in weakening of the heart muscle with compensatory enlargement, heart attack, or myocardial infarcation. When the walls of the arteries or the aorta undergo serious destruction due to vasculitis, weakened bulges called aneurysms may develop. If these aneurysms rupture, hemorrhage may occur.
- Lungs. Vasculitis of the complex network of blood vessels throughout the lungs can result in severe shortness of breath, cough, chest pain, and wheezing.
- Kidneys. When the kidney or renal arteries are damaged by vasculitis, high blood pressure results. The kidneys may fall behind in their normal role of filtering the blood, and kidney or renal failure may occur.
Diagnosis
Initial attempts to diagnosis vasculitis will depend on the area of the body affected and the kinds of symptoms exhibited. Blood tests that can demonstrate the presence of a strong inflammatory process include erythrocyte sedimentation rate, C-reactive protein, increased white blood cell count, and a variety of tests that can identify the presence of immune complexes or antibodies circulating within the blood. A variety of imaging techniques may reveal blood vessel inflammation, including ultrasound, echocardiography, computed tomography (CT), and magnetic resonance imaging (MRI) scanning. When the kidneys are involved, urine tests may reveal abnormalities. An x-ray procedure called angiography involves the injection of dye into a major artery to allow the detection of inflammation in the walls of blood vessels. Biopsies (tissue samples) may be taken from the blood vessels that serve affected organs or tissues to look for the presence of inflammation or scarring.
Treatment team
While rheumatologists specialize in the treatment of various autoimmune diseases (including various forms of vasculitis), patients may also be treated by specialists who concentrate on diseases that affect specific organs or tissues. For example, a patient may need to consult a cardiologist if the heart is affected; a nephrologist if the kidneys are affected; a neurologist if the nervous system is affected; a pulmonologist if the lungs are affected; a gastroenterologist if the gastrointestinal tract is affected; an ophthomologist if the eyes are affected; an otorhinolaryngologist if the ear, nose, and/or throat are affected; or a dermatologist if the skin is affected.
Treatment
Medications that calm the immune system and decrease inflammation are the mainstay of treatment for the various types of vasculitis. These include nonsteroidal anti-inflammatory medications (such as ibuprofen or aspirin) and corticosteroids (such as prednisone). More severe cases of vasculitis may require potent immunosuppressant drugs (such as cyclophosphamide or azathioprine).
Prognosis
The prognosis of vasculitis depends on the specific organ system affected and the severity of the particular case. In general, most people who receive appropriate treatment have a good recovery from vasculitis. However, when the disease causes kidney failure or affects the heart, the prognosis may be worse. Basic prognosis statistics of treated vasculitis include:
- Polyarteritis nodosa: about 90% of cases go into long-term remission.
- Hypersensitivity vasculitis: Most people recover completely, even without treatment.
- Giant cell arteritis: May require one to two years of steroid treatment, but most people recover completely.
- Wegener's granulomatosis: With treatment, 90% can expect symptom relief, and 75% go into complete remission.
- Takayasu's arteritis: 90% survive, with some spontaneous remission.
- Kawasaki disease: Under 3% of patients suffer fatal complications; most children recover uneventfully.
Resources
BOOKS
Fauci, Anthony S. "The Vasculitis Syndromes." In Harrison's Principles of Internal Medicine, edited by Eugene Braunwald, et al. New York: McGraw-Hill Professional, 2001.
Cercomb, Clare T. "Systemic Lupus Erythematosus and the Vasculitides." In Rosen's Emergency Medicine: Concepts and Clinical Practice, 5th ed., edited by Lee Goldman, et al. St. Louis: Mosby, Inc., 2002.
Sergent, John S. "Vasculitic Syndromes." In Kelley's Textbook of Rheumatology, edited by Shaun Ruddy, et al. Philadelphia: W. B. Saunders Company, 2001.
PERIODICALS
González-Gay, M. A. "Epidemiology of the Vasculitides." Rheumatic Disease Clinics of North America 27, no. 4 (1 November 2001): 729–749.
Langford, C. A. "Vasculitis." Journal of Allergy and Clinical Immunology 111, no. 2 (1 February 2003): 602–612.
Naides, Stanley. "Known Infectious Causes of Vasculitis in Man." Cleveland Clinic Journal of Medicine 69, no. 2.
ORGANIZATIONS
Johns Hopkins Vasculitis Center. Bayview Medical Center, 5501 Hopkins Bayview Circle, JHAAC, Room 1B.1A, Baltimore, MD 21224. (410) 550-6825. http://vasculitis.med.jhu.edu/index.html.
Rosalyn Carson-DeWitt, MD
