Topic Overview

What is disseminated intravascular coagulation (DIC)?

Disseminated intravascular coagulation (DIC) is a rare, life-threatening condition that prevents a person's blood from clotting normally. It may cause excessive clotting (thrombosis) or bleeding (hemorrhage) throughout the body and lead to shock, organ failure, and death.

In DIC, the body's natural ability to regulate blood clotting does not function properly. This causes the blood's clotting cells (platelets) to clump together and clog small blood vessels throughout the body. This excessive clotting damages organs, destroys blood cells, and depletes the supply of platelets and other clotting factors so that the blood is no longer able to clot normally. This often causes widespread bleeding, both internally and externally.

What causes DIC?

DIC can be triggered by a health problem that sets the clotting cascade in motion. Such health problems include:

• Some types of bacterial, viral, or fungal infection.
• Severe trauma, especially from brain injuries, crushing injuries, burns, and extremely low body temperature (hypothermia).
• Some cancers.
• Complications during pregnancy.
• Some types of snakebite.

In most cases, the condition causing the DIC will be known (such as severe trauma). In rare cases, extensive bleeding caused by DIC will be the first symptom of the disease or condition causing it (such as cancer).

What are the symptoms?

When DIC causes the blood's platelets and clotting factors to become depleted, excessive bleeding (hemorrhage) occurs throughout the body. The severity of bleeding can range from small red dots and bruises under the skin to heavy bleeding from surgical wounds or body openings, such as the mouth, nose, rectum, or vagina.

Symptoms of organ damage caused by excessive blood clotting may include shortness of breath from lung damage, low urine output from kidney damage, or stroke from damage to the brain. In severe cases, shock, with low blood pressure and widespread organ failure, may occur.

In a less severe type of DIC called chronic DIC, the body is able to compensate for the abnormal clotting. Chronic DIC may produce no symptoms or only mild blood clotting or minimal bleeding from the skin or mouth.

How is DIC diagnosed?

DIC is a very complex condition that can be hard to diagnose. There is no single test that is used to diagnose DIC. In some cases, several different tests given over a period of time may be needed for an accurate diagnosis.

A doctor may suspect DIC in a person who has symptoms of excessive bleeding or clotting. Blood tests to measure the amount of platelets and other substances (such as prothrombin and fibrinogen) that affect clotting can help confirm the diagnosis.

Tests that may be used to diagnose DIC include:

• D-dimer test. This blood test helps determine whether a person's blood is clotting normally by measuring a substance (fibrin) that is released as a blood clot breaks up. D-dimer levels are often higher than normal in people who have abnormal blood clotting.
• Prothrombin time (PT/INR). This blood test measures how long it takes blood to clot. At least a dozen blood proteins, or clotting factors, are needed to clot blood and stop bleeding (coagulation). Prothrombin, or factor II, is one of several clotting factors produced by the liver. A long prothrombin time can be a sign of DIC.
• Fibrinogen. This blood test measures how much fibrinogen is in the blood. Fibrinogen is a protein that plays a part in blood clotting. A low fibrinogen level can be a sign of DIC. It happens when the body is using fibrinogen faster than the body can make it.
• Complete blood count (CBC). A complete blood count (CBC) involves taking a blood sample and counting the number of red blood cells and white blood cells. CBC results cannot diagnose DIC, but they provide information to help the doctor make a diagnosis. (DIC often causes the platelet count to drop.)
• Blood smear. In this test, a drop of blood is smeared on a slide and stained with a special dye. The slide is then examined under a microscope. The number, size, and shape of red blood cells, white blood cells, and platelets are recorded. Blood cells often look damaged and abnormal in people who have DIC.

How is it treated?

Treatment for DIC depends on the medical condition that is causing it. If that condition can be treated, the DIC may get better. People with acute DIC require hospitalization, often in an intensive care unit (ICU), where treatment will attempt to correct the problem causing the DIC while maintaining the function of the organs.

• Transfusions of blood cells and other blood products may be needed to replace blood that has been lost through bleeding and to replace clotting factors used up by the body.
• In some cases a blood thinner, such as heparin, is used. This shuts down the cascade of events that make the body overuse its blood clotting factors.