Thromboangitis Obliterans ( TAO ) may not cause a disease that you frequently heard. But for most clinicians, this disease is not uncommon. That may be due to its main causative factor. TAO is an inflammatory condition in small and medium-sized arteries. It is not caused by atherosclerosis, and these inflammation are progressive over time. The most commonly affected areas of the body are hands, feet, and calves.
The prevalence of the disease generally worldwide. But studies have found that specific populations in the world have higher reported cases than others. Those are Israeli Jews of Ashkenazi descent, native Indians, Korean and Japanese. There is a fewer number of cases reported from the northern European region. Although most of the similar issues are reported from old age groups, the significant factor of this condition is, it’s targeted age range is between 20 to 50. So there is a high chance of getting the disease at a young age.
What are the causes of Thromboangitis Obliterans?
Even the TAO has known for the past few decades, an exact cause for the condition is still doubtful. But clinicians have identified there is a direct relationship between smoking and TAO. Studies have shown that tobacco exposure directly affects disease initiation and progression. Scientists determined that immunological imbalances and reactions due to excessive sensitivity for tobacco can damage the vessel walls and initiate the antigen-antibody response.
Several studies quantify disease progression from tobacco use, and they show about 43% of patients with TAO need one or more amputations within 7.6 years.
What happens inside vessels?
In the initial stage of the disease, blood clots are formed inside vessels. And gradually, immune cell clusters formed nearby. Small abscesses are also formed within vessel walls. This mechanism happens for an extended period. Therefore due to frequent damage to blood vessels causes fibrosis of the vessel wall.
Although the disease is similar to atherosclerosis, there are specific differences that have been identified by tissue biopsies. Three layers form the wall of a blood vessel. Atherosclerosis only affects the inner and middle layer of the vessel wall, but in TAO, all three layers are involved. And the immunological reactions happen in TAO are specific for the disease.
What are the symptoms and signs of Thromboangitis obliterans?
The typical clinical presentation of the disease is feet and calf pain occurs while walking. The patient is most probably a young male. The problem will be resolved after resting for some time. Gradually patient get used to this, and he knows when will calf pain occurs. When the disease progresses, the distance patient can walk progressively reduced. If the condition is severe patient may get pain even at rest. At that time, vessels are blocked entirely, and amputation would be the best treatment method.
The cause for pain is low blood supply for muscles because of the blockage of supplying blood vessels.
In addition to this type of characteristic pain, the patient may get Raynaud’s phenomena, which is pain with bluish discoloration of the fingers when exposed to cold environments or after contact with water. Livedo reticularis is also a recognized sign in TAO, which is a reddish-blue net-like pattern of discoloration of the skin.
The initial symptoms arise from the distal ends of the limbs. Once the disease progresses, proximal parts of the limbs also get involved. Clinicians have identified that inflammation of the superficial veins, which is called superficial thrombophlebitis, is present about half of the Thromboangitis obliterans cases.
Some worst-case scenarios can present with long-standing ulcers as well.
TAO is associated with neurological problems as well. Thereby patients may experience reduced muscle power and loss of sensation over certain limbs’ limbs can be noted.
How Thromboangitis obliterans is diagnosed?
Sadly there is no specific test or investigation to diagnose TAO. But certain investigations can be used to determine the condition. Blood investigations are performed to detect associated diabetes, autoimmune diseases. Anticardiolipin antibodies are specific for an antiphospholipid syndrome, which is also used to determine the age in which the condition started and the amputation risk.
Allen’s test is famous for the TAO. It is performed by making a tight fist and blocking the arteries on both sides of the wrist by squeezing with the other hand. Then the opening of the hand will show color change on your hand. Then gradually release one side artery on each time can determine the rate of refilling of blood. If one side takes more time than the other, there may be a significant problem in vessel walls. TAO or Buerger’s disease is one possibility that gives positive results on Allen’s test like this.
Arteriography can detect the vessel blocks and new vessel formation, but the test is not specific for TAO. Tissue biopsies show cellular changes. According to particular changes, clinicians can determine the stage of the disease, and it also helps to plan further treatment methods.
What are the treatment options for Thromboangitis obliterans?
There is no specific method to treat TAO. Studies showed that stopping smoking has a significant effect on a cure. There is scientific proof that the condition is reversible with smoking cessation. Even using 2 to 3 cigarettes per day can worsen the disease.
There are certain drugs used in pain relief and vessel wall dilatation as treatment methods. Although Thromboangitis obliterans is not causing deaths, there is a significant effect reducing the quality of life of the patient.
Bosentan shows significant positive results.
Bosentan is a drug that can dilate vessel walls. Studies showed that using Bosentan significantly affects controlling the disease and even healing the ulcers related to TAO. It shows that about 80% of patients with TAO experienced pain relief with the drug. 12% of patients had partial relief. But no doubt avoids smoking is a rule of thumb in treating the disease. Bosentan shows long term disease-free time than traditional treatment methods.