Blood clots

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at December 9, 2015
StartSymptomsBlood clots

Blood clots happen to everyone, because the blood’s ability to clot is normal and essential in some situations. Blood clotting is a healthy response after an injury, because it seals the wound and helps healing. But blood clots in other locations in the body can be life threatening. Many blood clots can be prevented, though, so knowing causes and symptoms is crucial.


Definition & Facts

Blood normally does not clot. It needs to be able to flow freely throughout the body at all times. But under certain circumstances, freely flowing blood can be dangerous, such as when an injury occurs. In those situations, the body responds by shutting off the flow of blood by causing it to clot. When a blood vessel is damaged, platelets in the blood are activated. More and more platelets gather and stick together, forming a clot that continues to grow until the “leak” is plugged.

When the injury begins to heal, other proteins in the blood are activated to dissolve this temporary clot. But clots can also form inside arteries and veins for other reasons, and these can break loose and travel through the bloodstream to other locations such as the heart, lungs or brain. Blood clots can be treated with anticoagulant medications and in many cases prevented with simple lifestyle changes.


Blood clots are the body’s normal response to injury or other damage to the blood vessels. But a variety of conditions other than injury can create circumstances that cause blood to clot – and in those situations blood clots can cause severe damage. Cholesterol buildup in arteries can create plaque that breaks open, triggering a clotting response – the cause of many heart attacks and strokes.

Blood clots can also form when blood doesn’t flow properly. This can be caused by factors such as inactivity, which allows blood to pool in the lower legs in a condition called deep vein thrombosis (DVT), or health conditions such as atrial fibrillation, a heart disorder in which the heart beats irregularly for periods of time, so that blood is not pushed smoothly through the system.

Smoking narrows arteries and can put smokers at increased risk. Pregnancy, surgery that requires more than three days of bed rest, hormone therapy and inherited clotting disorders can also predispose an individual to a dangerous blood clot. Clots that reach the lungs, called Pulmonary embolism, can cause shortness of breath and symptoms similar to pneumonia or a stubborn respiratory infection.

When to see a doctor

Normal blood clots that form after an injury typically dissolve as the injury heals, and usually require no special medical attention. Some, that form just under the skin and cause localized redness and swelling – a condition called superficial thrombophlebitis – usually disappears on their own and pose little threat.

But because blood clots in other parts of the body can be life threatening, organizations such as the Mayo clinic and the National Blood Clot Alliance, a site dedicated to helping people understand and avoid deep vein thrombosis and other clot related problems, recommend seeing getting medical care quickly for leg pain and swelling, especially after a hospital stay or a long trip spent sitting down, trouble breathing, or if the symptoms of a stroke are present: difficulty with vision, speaking or balance, or numbness in the extremities. Doctors will perform tests to locate the blood clot and attempt or dissolve it with anticoagulants or remove it by surgery.

Treatment & Therapy

Depending on the location d cause of the clot, anticoagulant medications may be used to dissolve the clot quickly. Patients at high risk for developing blood clots may also be placed on long term doses of “blood thinning” medications that help to keep blood flowing easily through the body.

Those with a family history of clotting disorders or who are at risk for clots due to cardiovascular disease or conditions that require prolonged sitting or bed rest may also be prescribed anticoagulant medications. These medications involve regular blood testing and ongoing monitoring by a health care practitioner. Other therapies include increasing exercise, and lifestyle changes to eliminate external factors that can lead to the formation of clots.

For those with circulatory problems or who are at greater risk for clots, doctors may recommend wearing compression socks or wraps to help keep blood from pooling in the lower legs. New research is exploring the use of other treatments for clots that reduce the side effects associated with anticoagulants, such as a study reported by ClotCare that focuses on the use of testosterone to reduce the risk for clots.

Prevention & Prophylaxis

Unless an individual has a family history of blood clots, a clotting disorder, or other conditions that predispose toward blood clots, preventing clots before they start is within just about everyone’s reach. The usual recommendations for a healthy lifestyle can prevent blood clots.

Smoking increases the risk of blood clots, so quitting can reduce risk. A low fat, plant based diet that keeps cholesterol and saturated fat out of the arteries, plenty of exercise and maintaining a normal body weight are key to keeping the risk of blood clots low. Because those who must sit for long periods are at increased risk for deep vein thrombosis, medical experts advise taking breaks every hour or so to walk and stretch.

This is especially important when traveling, since long car, plane or bus trips involve hours of enforced sitting. People who must spend long periods of time in bed should also find ways to move and stretch the limbs regularly. Women who take hormonal birth control, especially if they smoke, may want to switch to other, safer methods of contraception.

The blood’s ability to clot is essential for healing injuries. But many other factors, including family history, lifestyle and circumstances such as pregnancy or surgery, can turn that healing ability into a life-threatening event. But awareness and lifestyle changes can help just about everyone to lower the risk of a blood clot.

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