A thromboembolism is a blood clot that forms and then breaks off and travels through the bloodstream to another part of the body.
What is going on in the body?
When a person is cut or injured, the blood clots, or clumps together. This life-saving system helps to stop the bleeding. However, sometimes the blood clotting system is activated inappropriately, and forms a clot inside an intact blood vessel or inside the heart.
A thromboembolism occurs when a blood clot breaks off from where it has formed and travels through the bloodstream. Eventually, the blood clot will get trapped inside a blood vessel that is too small to let it pass. Blood is then unable to flow through this vessel. The lack of blood flow can damage the body parts that normally receive blood from this vessel.
What are the causes and risks of the disease?
The blood clots that break off and form a thromboembolism can be caused by a number of disorders, including:
damage to the blood vessels or heart, which can occur from injury, surgery, infections, and other causes
poor blood circulation, which can occur from severe congestive heart failure, severe varicose veins, and certain irregular heartbeats, called arrhythmias
lack of activity, which can occur during any prolonged illness, surgery, travel, or injury
- blood that has a greater than normal tendency to form clots. This condition may occur due to cancer, certain medications, pregnancy, and some inherited conditions.
What can be done to prevent the disease?
Regular movement of the arms and legs, blood thinners, or special stockings are often used to help prevent blood clots in someone who is bedridden. A person with the tendency to clot inappropriately, or with certain arrhythmias, is often given blood-thinning medications to prevent the blood from clotting.
How is the disease diagnosed?
A thromboembolism is suspected based on a person's symptoms. Different imaging tests are done depending on where the clot is thought to be. Ultrasound can be used to check for a blood clot in a vein and to look at how the blood is flowing. Another ultrasound test, called echocardiography , can often confirm a blood clot in the heart.
If the person is having any trouble breathing or chest pain, a pulmonary embolus is often suspected. In this case, the healthcare professional may order:
a chest x-ray to see if areas of the lung have collapsed or contain fluid
a blood test called an arterial blood gas to check the amount of oxygen in the blood
a pulmonary ventilation scan to see how gases are being transferred across the lungs
- a pulmonary perfusion scan to check the blood supply to the lungs
If a stroke
is suspected, the provider may order:
- cerebral angiography, which shows the blood supply to the brain
- a cranial CT scan or a CT scan of the head
- a cranial MRI or an MRI of the head
Once the diagnosis is confirmed, other tests are often done to figure out what caused the initial blood clot. Blood tests called the prothrombin time (PT) and partial thromboplastin time (PTT) are commonly done to check the blood's ability to clot. Other specialized blood tests may be done to find out why the blood clotted.
Long Term Effects
What are the long-term effects of the disease?
A thromboembolism can cause permanent organ damage and even death. Blood clots in the leg may cause long-term swelling and pain in the leg even after the clot goes away. Permanent brain damage from a stroke can leave people unable to walk, talk, or take care of themselves.
What are the risks to others?
A thromboembolism is not contagious and poses no risks to others.
What are the treatments for the disease?
Once the diagnosis of thromboembolism is made, medications are usually given to help treat the disorder. These may include "clot busting" medications known as thrombolytics. Blood-thinners, such as heparin or warfarin (i.e., Coumadin), may also be given to help reduce the chance of new blood clots forming.
In some people, a special filter device is placed inside the main vein below the heart. This can help keep blood clots in the legs from traveling to the lungs and causing death. In some cases, surgery is needed to manually remove a blood clot. Other care may be needed for damage to different parts of the body. For example, those with a stroke may need long-term care or physical therapy for weakness.
What are the side effects of the treatments?
The most worrisome side effect of clot-busting or blood-thinning medications is serious bleeding. Sometimes this can cause bleeding into the brain. The filter placement procedure and other surgeries can be complicated by bleeding, infection, or an allergic reaction to the anesthetic.
What happens after treatment for the disease?
Further treatment may be needed for damage to different areas of the body in some cases. A blood thinning medicine might need to be continued in order to prevent further blood clots.
How is the disease monitored?
An individual on blood-thinning medications will be tested periodically with clotting tests. Any new or worsening symptoms should be reported to the healthcare professional.
Harrison's Principles of Internal Medicine, 1998, Fauci et al.