Coagulation (clotting)
Coagulation, or clotting, is a vital physiological process that helps the body prevent excessive bleeding after an injury by transforming part of the blood into a solid or semisolid state. This automatic response typically begins immediately following an injury, involving a sequence of events known as hemostasis. The body first constricts blood vessels to minimize blood loss, while platelets within the blood rapidly activate and aggregate at the injury site. They adhere to the damaged vessel walls with the help of specific proteins like von Willebrand factor and form a mesh-like structure of fibrin, creating a stable blood clot.
However, various factors can disrupt this intricate process, leading to clotting disorders. These disorders may manifest as either excessive bleeding, due to insufficient clotting factors, or unwanted clot formation, which can obstruct blood flow in the circulatory system. Certain medications, dietary components, and health conditions can influence coagulation, leading to complications. Clotting disorders can be inherited, such as hemophilia or von Willebrand disease, or acquired due to factors like prolonged inactivity or specific medical treatments. Understanding coagulation and its potential disorders is crucial for managing health risks and ensuring appropriate treatment in case of injuries.
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Coagulation (clotting)
Coagulation, or clotting, is the process by which the body slows and stops bleeding by turning part of the blood into a solid or semisolid substance. In most circumstances, the body starts this process automatically when there is an injury. However, in some instances, something interferes with the complex process. Interference can come from a pharmaceutical product, some foods, and certain health conditions. Coagulation issues can result from blood that clots too quickly, not quickly enough, or not at all. These clotting issues can be temporary or permanent and can cause other problems.
Background
Blood has several components. These include red blood cells (erythrocytes) that carry oxygen and nutrients, white blood cells (leukocytes) that fight infection, plasma that transports the other components, and platelets, which help the blood coagulate. When a blood vessel is cut or otherwise injured, the platelets are part of an intricate process known as hemostasis that prevents the body from losing too much blood. Hemostasis is the process that stops bleeding; coagulation is one step in that process.
Immediately after an injury, the hemostasis process starts. First, the blood vessels narrow, or constrict. This reduces the amount of space for blood to pass through, limiting the amount of blood that is lost and allowing the clotting process to begin. At the same time, a hematoma made up of the pooling blood puts pressure on the damaged blood vessel and further reduces the amount of blood that can pass through it.
While the damaged vessel and the pooling blood begin the hemostasis process, the platelets in the blood receive a trigger to begin the next phase—coagulation. The platelets change shape from round to a spiny configuration that allows them to stick together more easily. They also begin to stick to the walls of the damaged blood vessel. At the same time, the blood vessel starts to release a protein known as von Willebrand factor. Named after Erik von Willebrand, a Finnish doctor who identified it in 1926, von Willebrand factor is made in the walls in the blood vessel and helps platelets stick. An enzyme called thrombin, which is formed in the blood that has escaped from the damaged vessel, and collagen, a protein found throughout the body, also help the platelets to stick to the walls of the cell.
The stuck platelets collect other platelets. They also work to form fibrin, a protein that collects other proteins and platelets into a mesh-like structure known as a clot, which begins to fill in the damaged area of the blood vessel. Fibrin strengthens the developing clot and helps hold it in place until new cells are generated to repair the damaged blood vessel. Often, when an injury is not life threatening, this process happens very quickly and efficiently, limiting blood loss from the injury.
As the body heals, the clotting process is balanced by the generation of enzymes and other chemicals that help to dissolve the clots when they are no longer needed. However, sometimes the body cannot produce enough of the necessary clotting components to stop blood loss from even small injuries. Other times, the body produces too many clotting factors or fails to dissolve clots that are no longer needed, resulting in blood clots traveling to other parts of the body. When this happens, the person will have what is known as a clotting disorder.
Clotting Disorders
Some clotting disorders are the result of a medication—for example, aspirin suppresses the clotting process—or certain food products, such as cinnamon, turmeric, ginger, and cayenne peppers, all of which thin the blood and increase bleeding risks. Clotting problems related to ingesting these substances can be alleviated by avoiding them. However, sometimes a person lacks a protein or enzyme that is part of the clotting process, or the person produces too much of it. Clotting disorders can be the result of too little clotting or too much clotting and can be life threatening.
The clotting process is complicated and involves a number of components known as factors, such as von Willebrand factor. When these factors are missing or not present in sufficient amounts, a person will have one of several bleeding conditions. These conditions are named after the factor that is missing and include hemophilia A and B; Factor II, V, VII, X, and XII deficiencies; and von Willebrand disease. Of these, von Willebrand disease is the most common.
These conditions are inherited and can cause bleeding both inside and outside of the body. For example, a fall that might leave a bruise on most people can cause extensive internal bleeding in a person with a clotting disorder, which can result in painful swelling or even death. A simple cut that might require nothing more than the application of a little pressure to stop in a healthy person can become life threatening in a person with a bleeding disorder. After an injury, persons with these conditions are given doses of the missing clotting factor that are made from either human plasma or genetically manufactured from DNA.
In some cases, the opposite condition exists, and the blood clots too easily or in areas that have not suffered an injury. Sometimes, blood clots while simply moving through the circulatory system and can block veins or arteries. Such a blockage, which is also called an embolus or a thrombus, can cause pain or even impair blood flow to the point where it damages the heart, lungs, or limbs. These clots can lead to a heart attack, a stroke, or result in the amputation of a limb. When the blood coagulates when it should not, the person is said to have a hypercoagulable condition, or thrombophilia.
Hypercoagulable states are also often inherited but can be caused by another condition. Inherited conditions include Factor V Leiden and prothrombin gene mutation. There are also several conditions that cause either a deficiency of the proteins that limit or break down clots or cause an abundance of the factors that support clotting. A person may also develop a hypercoagulable state from taking medications—such as birth control pills, hormone replacement therapies, and some cancer treatments. Obesity, pregnancy, recent injury or surgery, the placement of a central venous catheter, and any instance that results in prolonged inactivity, including long car or air trips and lengthy illnesses or injuries, can also result in a hypercoagulable state.
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