Blood clots can be a very dangerous medical condition. Blood needs to travel freely throughout the body in order to supply tissues and organs with needed oxygen and to remove wastes. If a clot forms, the supply of blood can be blocked. Depending on where the blockage is, you can have some reasonably severe problems. Clots that get in to places like the heart and brain can even be fatal. Let’s look at some of the more common causes of blood clots.
Medical students are taught to break up the causes of blood clots in to three major categories. These three categories are collectively known as Virchow’s Triad. Dr. Virchow was a 19th Century German doctor who first described these causes. These three categories are 1. Hypercoagulability, 2. Changes in the hemodynamics, such as statis, and 3. damage to the blood vessel inner lining.
Hypercoagulability
This is a group of conditions where, for various reasons, the blood becomes more likely to clot. There are genetic causes where a person’s blood is more likely to clot. Severe trauma, including burns can also induce this condition. Pregnancy, smoking, and late stage cancer all increase the risk of clot formation as well. There is also evidence that obesity and advancing age can cause the blood to coagulate inappropriately.
The treatments for blood clots due to hypercoagulability depend on the exact cause of the problem. Some conditions are quite treatable, while others are much harder to manage.
Changes in Hemodynamics
This category includes any condition where the blood flow through the veins and arteries is interrupted. The classic case is the traveler who sits for a long time in an airplane for car, and subsequently develops a clot in the lower leg. Blood that stops moving has a tendency to form clots. This condition is called stasis, and it can easily be a significant medical problem.
Stasis can be caused by simple inactivity, or it can be due to problems with the heart or blood vessels themselves (for example, vericose veins). In all cases, the primary management focuses on dealing with the reason the blood is pooling. Get up and walk around on long flights!
Damage to the lining of the blood vessels
The inner lining of the blood vessels is known as the endothelium. There are specific biochemical mechanisms in place to prevent a person from bleeding excessively if they are injured. When there is damage to the lining of a blood vessel, a series of clotting reactions begins in an attempt to stop the bleeding. This is normally a good thing.
Unfortunately, your body can’t always differentiate between real damage that needs to be dealt with, and “fake damage” such as the build-up of cholesterol in a blood vessel. A large chuck of cholesterol (for example) looks like any other type of damage to the vessel wall – and the body can respond by forming a clot.
Real damage, as caused by trauma, and even microscopic damage caused by hypertension, can also set off a clotting cascade.
Blood clots are not always bad. There are good reasons why your blood needs to form clots on occasion. Normally, these clots are then broken down when they are no longer needed. But from time to time, a clot forms that can cause a medical problem. If you suspect that you are at risk of forming a blood clot due to any of the conditions listed above (or others), have a talk with your doctor and see what can be done to limit the risk.
