THROMBOANGIITIS OBLITERANS (TAO, BUERGER’S DISEASE, BUERGER DISEASE)
INTRODUCTION: TAO is a rare disease due to recurrent and evolutive inflammation of small and medium arteries and veins of the limb extremities. Blood vessels are blocked with blood clots (thrombi).
Though TAO is strongly associated with tobacco products and especially heavy smoking, it is not due to atherosclerosis. The underlying mechanisms are still largely unknown. An autoimmunity disorder is suspected.
SIGNS AND SYMPTOMS: The main symptoms are due to ischemia (impaired arterial circulation) of distal parts of limbs (the lower limb being more common). First there is pain in the affected areas while walking (claudication). Claudication may be located in the feet, legs. Foot or arch claudication may be erroneously attributed to an orthopedic problem. Patients often describe Raynaud’s phenomenon with finger turning color—white, blue, and then red—when exposed to the cold.
The colour of the skin may turn to permanent cyanotic or reddish blue with pain at rest. Skin becomes thin and shiny. Hair growth is reduced. Common complications are ulcerations, infection and gangrene, often requiring amputation of the involved extremity.
DIAGNOSIS: Diagnosis relies mostly on exclusion of other conditions : atherosclerosis (arterial occlusion, thrombotic emboli, cholesterol emboli…), endocarditis (an infection of the valves of the heart) and infectious emboli, other types of vasculitis, severe Raynaud’s phenomenon (“finger syncope” with skin turning to white when cold) associated with connective tissue disorders (e.g., lupus or scleroderma), clotting disorders of the blood, and others.
Diagnosis criteria may differ slightly. Here are the criteria proposed by Olin (2000) :
- Patient typically between 20–40 years old and male, although females have been diagnosed more frequently (active smokers)
- Current (or recent) history of tobacco use
- Presence of distal extremity ischemia (indicated by claudication, pain at rest, ischemic ulcers or gangrene) documented by noninvasive vascular testing such as ultrasound
- Exclusion of other autoimmune diseases, hypercoagulable states, and diabetes mellitus by laboratory tests
- Exclusion of a proximal source of emboli
- Consistent arteriographic findings in the clinically involved and noninvolved limbs
– CT scan (angiography) : CT angiography shows segmental stenosis in the limb arteries.
– Angiography : Angiograms can be helpful in making the diagnosis (“corkscrew”, “tree root” or “spider leg” appearance, distal arterial occlusions).
– Fingertips pressure assessment
TREATMENT: First it is important to rule out other disorders because their treatments differ substantially from that of TAO.
Smoking cessation (tobacco and/or cannabis) is mandatory because it has shown to slow the progression of the disease and decrease the severity of amputation.
There is no effective medication or surgery for this disease. In acute cases, vasodilators (prostaglandins), drugs that increase the diameter of the blood vessels, can give relief in pain, but do not change the course of the disease. Epidural anesthesia and hyperbaric oxygen therapy also have vasodilator effect and give relief.
Trauma and exposure of affected areas to heat or cold must be avoided. Infections must be treated promptly.
In chronic cases, lumbar sympathectomy may aid in healing and giving relief from pain. Debridement is required in necrotic ulcers. Amputation is performed in gangrenous digits but above-knee and below-knee amputation is rarely required.
PROGNOSIS: Death is rare, but amputation is common in patients who continue to smoke. The only way to slow the progression of the disease is to abstain from all tobacco products (smoking and chewing) and from cannabis too.