Takayasu’s arteritis

Synonyms

3

Overview

Takayasu's disease (also known as "aortic arch syndrome", "nonspecific aortoarteritis" and the "pulseless disease") is a form of large vessel granulomatous vasculitis with massive intimal fibrosis and vascular narrowing, affecting often young or middle-aged women of Asian descent. It mainly affects the aorta (the main blood vessel leaving the heart) and its branches, as well as the pulmonary arteries. Females are about 8–9 times more likely to be affected than males. Those with the disease often notice symptoms between 15 and 30 years of age. In the Western world, atherosclerosis is a more frequent cause of obstruction of the aortic arch vessels than Takayasu's arteritis. Takayasu's arteritis is similar to other forms of vasculitis, including giant cell arteritis which typically affects older individuals. Due to obstruction of the main branches of the aorta, including the left common carotid artery, the brachiocephalic artery, and the left subclavian artery, Takayasu's arteritis can present as pulseless upper extremities (arms, hands, and wrists with weak or absent pulses on the physical examination) which may be why it is also commonly referred to as the "pulseless disease". Involvement of renal arteries may lead to presentation as renovascular hypertension.

Symptoms

Some people develop an initial "inflammatory phase" characterized by systemic illness with signs and symptoms of malaise, fever, night sweats, weight loss, joint pain, fatigue, and fainting. Fainting may result from subclavian steal syndrome or carotid sinus hypersensitivity. There is also often anemia and marked elevation of the ESR or C-reactive protein (nonspecific markers of inflammation). The initial "inflammatory phase" is often followed by a secondary "pulseless phase".The "pulseless phase" is characterized by vascular insufficiency from intimal narrowing of the vessels manifesting as arm or leg claudication, renal artery stenosis causing hypertension, and neurological manifestations due to decreased blood flow to the brain. Of note is the function of renal artery stenosis in causation of high blood pressure: Normally perfused kidneys produce proportionate amount of a substance called renin. Stenosis of the renal arteries causes hypo-perfusion (decreased blood flow) of the juxtaglomerular apparatus, resulting in exaggerated secretion of renin, and high blood levels of aldosterone, eventually leading to water and salt retention and high blood pressure. The neurological symptoms of the disease vary depending on the degree, and the nature of the blood vessel obstruction and can range from lightheadedness, to seizures in severe cases. One rare but important feature of the Takayasu's arteritis is ocular involvement in form of visual field defects, vision loss, or retinal hemorrhage. Some individuals with Takayasu's arteritis may present with only late vascular changes, without a preceding systemic illness. In the late stage, weakness of the arterial walls may give rise to localized aneurysms. As with all aneurysms, possibility of rupture and vascular bleeding is existent and requires monitoring. In view of chronic process and good collateral development, Raynaud's phenomenon or digital gangrene are very rare in Takayasu arteritis.

Causes

In Takayasu's arteritis, the aorta and other major arteries, including those leading to the head and kidneys, become inflamed. Over time, the inflammation causes changes in these arteries, including thickening, narrowing and scarring. The result is reduced blood flow to vital tissues and organs, which can lead to serious complications and even death. Sometimes arteries become abnormally dilated, leading to aneurysms that may rupture.

Just what causes the initial inflammation in Takayasu's arteritis isn't known. It's likely that Takayasu's arteritis is an autoimmune disease in which the immune system malfunctions and attacks own arteries as if they were foreign substances. The disease may be triggered by a virus or other infection.

Prevention

There is no way to prevent Takayasu's arteritis.

Diagnosis

Diagnosis is based on the demonstration of vascular lesions in large and middle-sized vessels on angiography, CT, or magnetic resonance angiography. 

Contrast angiography has been the gold standard. The earliest detectable lesion is a local narrowing or irregularity of the lumen. This may develop into stenosis and occlusion. The characteristic finding is the presence of "skip lesions," where stenosis or aneurysms alterante with normal vessels. Angiography provides information on vessel anatomy and patency, but does not provide information on the degree of inflammation in the wall.

The age at onset helps to differentiate Takayasu's arteritis from other types of large vessel vasculitis such as. For example, Takaysu's arteritis has an age of onset of <40 years, while Giant Cell Arteritis has an age of onset >60 years. 

Takayasu arteritis is not associated with ANCA, Rheumatoid factor, ANA, and Anticardiolipin antibodies

Prognosis

In 60 percent of people with Takayasu's arteritis symptoms resolve when they are treated with glucocorticoids alone. However, symptoms return in about half of these patients. When symptoms return, retreatment with a combination of glucocorticoids and other immunosuppressive drugs has a 40 percent to 80 percent success rate. But, it's common for symptoms to return again. Overall, about 80 percent to 90 percent of cases with Takayasu's arteritis respond to some form of medical treatment.

In general, about 85 percent of people survive for at least 15 years after diagnosis. This figure drops to 70 percent for those with severe high blood pressure or significant damage to the aorta.

Treatment

Most people with Takayasu’s arteritis respond to steroids such as prednisone. The usual starting dose is approximately 1 milligram per kilogram of body weight per day (for most people, this is approximately 60 milligrams a day). Because of the significant side effects of long-term high–dose prednisone use, the starting dose is tapered over several weeks to a dose that the physician feels is tolerable for the patient. Promising results are achieved with mycophenolate and tocilizumab. If treatment is not kept to a high standard then long term damage or death can occur. Stress is a major factor that should be avoided at all costs; if this is not taken into account the surge of adrenaline can have a damaging effect on the heart.

Surgical options may need to be explored for those who do not respond to steroids. Re-perfusion of tissue can be achieved by large vessel reconstructive surgery such as bypass grafting. Grafting autologous tissue has the highest rates of success. Stenting often obviates the need for surgery. Percutaneous transluminal coronary angioplasty (PTCA) is not as effective in the long term but has fewer risks.