THROMBOANGIITIS OBLITERANS -FINAL MBBS REVISION

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OVERVIEW
 Thromboangiitis obliterans (TAO), earlier referred to as Burger’s disease is a rare, progressive, non-atherosclerotic, inflammatory condition that usually involves small and medium arteries of the upper and lower extremities
 The disease is segmental in distribution
 The swollen inflamed vessels can become narrowed or blocked by clots
 It typically occurs in male smokers
 Ages commonly affected are between 20-50 years
 The disorder is reported commonly in Asia, the Middle East, the Mediterranean, and Eastern Europe.
 Initial presentation may be with leg, foot arm, or hand claudication and can be misdiagnosed as joint or muscular issues
 With progression, there is calf claudication, and ultimately pain even at rest and ischemic ulcerations on the toes, feet, or fingers, referred to Raynaud's
 The treatment of TAO is mainly smoking cessation. In patients who cease smoking, the halt in progression is impressive, and risk of amputation is reduced

ETIOLOGY OF TAO
 The exact cause of Burger's disease remains unclear. Although, tobacco clearly plays a role in the development of TAO, the mechanism is not clear. It is believed that chemicals in tobacco may irritate the lining of the blood vessels, causing them to become inflamed and swollen
 Genetic predisposition and autoimmune pathology have also been suggested as possible causes

RISK FACTORS
 Smoking
 Male gender
 Chronic gum disease
 Age <45 years

PATHOLOGY OF TAO
There is thrombosis in small to medium arteries and veins accompanied by a dense neutrophil aggregation, presence of multinucleated giant cells and foci of microabscesses. In contrast to atherosclerosis, which affects only the intimal and medial layers of the artery, all three layers of the artery namely the adventitia, media and intima are affected in TAO

CLINICAL FEATURES OF TAO
 Pain in legs and feet or in your arms and hands that comes and goes. This pain is triggered by use of hands or feet and reduces when on stopping the activity (claudication). Rarely it may occur at rest.
 Tingling or numbness in the hands or feet.
 Pale, reddish or blue-tinted fingers and toes
 Painful swelling in the leg along the length of superficial veins due to presence of clot
 Fingers and toes that turn pale following cold exposure (Raynaud's phenomenon).
 Painful sores on fingers and toes due to occlusive clots

COMPLICATIONS OF TAO
Gangrene of fingers and toes. The affected toe or finger becomes bluish-black, loss of sensation and foul smell due to superadded bacterial infection of dead necrotic tissue. It is a potentially life threatening
condition and treatment involves amputation of the affected part

DIAGNOSIS
HISTORY & PHYSICAL EXAMINATION
 Typical history of claudication pain – pain triggered by activity such as walking and relieved by rest
 History of smoking
 Pain and tingling of extremities at rest in severe cases
 Reduced or absent pulse in the hands and feet.
 Perform Allen test (Ask patient to close hand tightly and occlude both radial & ulnar pulse for 30 seconds. Ask patient to open his hand. There will be pallor of the palm. Now release the ulnar pulse. A positive Allen test occurs when there is persistent pallor in the palm indicating absence of collateral blood flow to the hand. In negative Allen test, flushing of the palm will occur within seconds of releasing the ulnar pulse indicating normal blood flow in the hand
 More than half the cases have superficial vein thrombosis and thrombophlebitis

LAB TESTS
There are no specific tests to diagnose TAO. Serological tests must be done to rule out diabetes, autoimmune arteritis and thrombophilic states

IMAGING
 Doppler imaging may demonstrate non-atherosclerotic segmental occlusions of small and medium arteries of hands and feet).
 Arteriography may show the characteristic "pig-tailing" or "corkscrewing" of the arteries representing small collaterals around occluded segments. However, these are not specific to TAO.
 Echocardiography should be done to rule out proximal source of emboli.
 Biopsy – A small sample of blood vessel is obtained and examined under the microscope. Refer above for typical histological findings and distinguishing features from atherosclerotic disease

TREATMENT
 Although no specific treatment is there for TAO, the most effective way to stop the progression of disease is to quit using all tobacco products. Even a few cigarettes a day can be dangerous in Burger’s disease
 It is accepted that surgery is rarely indicated if patient stops smoking.
 To quit smoking, nicotine products should not be used as they can worsen the condition. Non-nicotine products must be used
 Symptomatic treatment with calcium channel blockers or other vasodilators may be advised particularly in the presence of concurrent Raynaud's phenomenon
 Prostaglandin analogs such as intravenous iloprost are used to treat associated pain and ischemic complications

NEWER TREATMENTS
 Nerve surgery – surgical sympathectomy
 Therapeutic angiogenesis – medications to stimulate growth of new blood vessels
 Bosentan (Tracleer) - This medication has been approved to treat pulmonary hypertension. The drug was shown to benefit some patients with TAO
 Endovascular therapy - A thin catheter is threaded into the blood vessels and may be able to open up narrowed blood vessels, restoring blood flow. However, this procedure isn't widely used because the success rate has not been impressive

LIFESTYLE REMEDIES
 Avoid exposure to secondhand smoke
 Gum care
 Skin and extremities care – prompt treatment and attention to minor cuts and bruises
 Regular physical activity

PROGNOSIS
The outcomes are good in patients who cease smoking, but for those who continue to smoke, amputation of toes or fingers is quite common