What is Takayasu's arteritis?
Arteritis is a general term that refers to the inflammation of arteries, or blood vessels (vasculitis), that carry blood away from the heart.
Takayasu's arteritis (TAK) 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.
Segments of blood vessels can weaken and stretch, resulting in an aneurysm. They can also become inflamed and narrowed, resulting in restricted blood flow. Lastly, blood vessels can become completely blocked (called an occlusion).
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).
Who is affected by Takayasu's arteritis ?
TAK often affects young Asian women, but it can affect children, women and men of all ages and ethnic backgrounds. At diagnosis, TAK 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.
What are the symptoms of Takayasu's arteritis ?
Approximately half of all patients with TAK will have a sense of generalized illness. This may include fevers, fatigue, muscle aches, pain in the joints, 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 TAK 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 TAK 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 TAK?
The exact cause of TAK is unknown.