What is arteritis?
Arteritis is a general term that refers to the inflammation of arteries, or blood vessels (vasculitis), that carry blood away from the heart.
What is Takayasu's arteritis?
Takayasu's arteritis (TA) is an uncommon form of vasculitis. Inflammation damages large- and medium-sized blood vessels. The vessels most commonly affected are the branches of the aorta (the main blood vessel that leaves the heart), including the blood vessels that supply blood to the arms and travel through the neck to provide blood to the brain. The aorta itself is also often affected.
Less commonly, arteries that provide blood flow to the heart, intestines, kidneys and legs may be involved.
Inflammation of large blood vessels may cause segments of the vessels to weaken and stretch, resulting in an aneurysm. Vessels can also become narrowed or even completely blocked (called an occlusion).
What are the symptoms?
Approximately half of all patients with TA will have a sense of generalized illness. This may include fevers, anemia, muscle aches, arthritis and/or headaches. Narrowed vessels cause decreased blood flow to the areas that are supplied "downstream" from the narrowed area.
The changes that occur in TA are often gradual, allowing alternate (or collateral) routes of blood flow to develop. These alternate routes are often smaller "side roads." The collateral vessels may or may not be adequate to carry as much blood as was present normally.
In general, the blood flow that occurs beyond an area of narrowing is almost always adequate to allow tissues to survive. In rare cases, if collateral blood vessels are not available in sufficient quantity, the tissue that is no longer supplied by blood and oxygen will die. This is called an "infarction."
Narrowing of blood vessels to the arms or legs may cause fatigue, pain, or aching due to reduced blood supply -- especially during activities such as shampooing the hair, exercising or walking. It is much less common for decreased blood flow to cause a stroke or a heart attack (myocardial infarction). In some patients, decreased blood flow to the intestines may lead to abdominal pain, especially after meals.
Decreased blood flow to the kidneys may cause high blood pressure, but rarely causes kidney failure.
Some patients with TA may not have any symptoms. Their diagnosis may be stumbled upon by a doctor who has difficulty measuring blood pressure in one or both arms. Similarly, a doctor may notice that the strength of pulses in the wrists, neck or groin may not be equal, or the pulse on one side may be absent.
What causes TA?
The exact cause of TA is unknown.
Who is affected by TA?
TA often affects young Asian women, but it can affect children, women and men of all ages and ethnic backgrounds. At diagnosis, TA patients are often between 15-35 years old.
Every year in the United States, two to three new cases of TA per million Americans are diagnosed.
How is TA diagnosed?
The diagnosis of TA is based on a combination of factors, including:
-Magnetic resonance imaging (MRI): a test that produces images of the human body without the use of X-rays. MRI uses a large magnet, electromagnetic energy waves and a computer to produce these images.
- Computed axial tomography (CAT scan): X-rays and computers are used to produce images of internal organs, including large blood vessels.
-Angiography: X-ray pictures of the inside of blood vessels. During angiography, a long slender tube called a catheter is inserted into a large artery (generally, in the groin area or arm). The catheter is slowly and carefully threaded through the artery until its tip reaches the segment of vessel to be examined. A small amount of contrast material is injected into the blood vessel through the catheter, and X-rays are taken. The contrast agent enables the blood vessels to appear on the X-ray pictures.
Note: With most other forms of vasculitis, a biopsy (tissue sample) of the affected area may confirm the presence of blood vessel inflammation. A biopsy is most appropriate when easily accessible areas, such as the skin, are affected. However, when large blood vessels are affected, a biopsy is often not practical because of the risks of surgery.
How is TA treated?
Corticosteroids are the most common treatment for TA. The most frequently used drug in this category is prednisone or prednisolone. Corticosteroids work within hours after the first dose is given. While this drug is often dramatically effective, it may be only partially effective for some patients.
The goal of therapy is to stop all damage due to vasculitis. Once it is apparent that the disease is under control, doctors slowly reduce the dose of prednisone to the lowest effective dose in order to minimize treatment side effects. In some patients, it is possible to gradually discontinue medication without a relapse.
As the dose of prednisone is gradually reduced, over half of all patients will have recurrent symptoms or progression of illness. This has led to exploring additional therapies to produce remission. Among drugs that have been tried, with varying degrees of success, are non-steroidal immunosuppressive medications such as cyclophosphamide (Cytoxan®) and methotrexate (Rheumatrex®). Preliminary reports also suggest encouraging results with use of certain biologic agents. These experiences will have to be confirmed in formal studies before they can be generally recommended.
When these drugs are added to prednisone to treat TA, 50% of patients who had previously relapsed will achieve remission and be able to gradually discontinue prednisone. Overall, about 25% of patients will have disease that is not entirely controlled without continued use of these therapies. This emphasizes the need for continuing research to identify better and less toxic treatments for TA and other forms of vasculitis.
Many patients with TA have high blood pressure (hypertension). Careful control of blood pressure is very important. Inadequate treatment of high blood pressure may result in stroke, heart disease, or kidney failure.
In some instances, narrowing of arteries to the kidney may be the cause of hypertension. Whenever possible, it is desirable to stretch narrow vessel openings with a balloon (angioplasty) or to do a bypass operation to restore normal flow to the kidney. This may result in normal blood pressure, without the need to use antihypertensive medications.
Some patients may have serious disabilities because of narrowed blood vessels to other sites such as the arms or legs. Bypass operations may correct these abnormalities. Aneurysms can also be surgically repaired or bypassed.
What is the outlook?
In the United States and Japan, only about 3% of patients with TA die after having the disease for an average period of 5 years. This encouraging statistic is the product of recognizing the disease and treating it appropriately. Reports from certain other parts of the world have been less optimistic. This may be the result of delayed recognition and treatment or poor access to care.
For patients who live long lives, in spite of having Takayasu's disease, there are significant problems that must be recognized. Having a chronic illness requires periodic evaluation and adjustment of drugs whenever necessary. The drugs for TA have side effects, and these must be monitored by a doctor, as well as by blood tests. The effects of illness on function may be significant.
In our experience, 25% of patients have an entirely normal lifestyle. Another 25% have had to make some adjustments in their activities. About half of our patients had to modify their jobs and some within that group were occupationally disabled.
TA is clearly a treatable disease, and most patients improve. However, it is apparent that many patients have to deal with consequences of this illness that may be partially, or less often, completely disabling. These effects can be minimized by a team of doctors that includes specialists in vascular and immunologic diseases (rheumatology, immunology, radiology, vascular medicine, vascular and cardiac surgery). For best results, a team leader should coordinate diagnostic tests and the different forms of treatment that TA patients may require.
Clinical Specialists, Orthopaedic and Rheumatologic Institute, Cleveland Clinic
Vasculitis Foundation. Takayasu Arteritis. www.vasculitisfoundation.org/takayasusarteritis Accessed 9/30/2010.
American College of Rheumatology. Takayasu’s Arteritis. www.rheumatology.org/practice/clinical/patients/diseases_and_conditions/takayasusartritis.asp Accessed 9/30/2010.
Orphanet -- The portal for rare diseases and orphan drugs. Takayasu arteritis. www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=3287 Accessed 9/30/2010.
National Heart Lung and Blood Institute. Diseases and Condition Index. Vasculitis. www.nhlbi.nih.gov/health/dci/Diseases/vas/vas_types.html Accessed 9/30/2010.
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