(xref.See-also How Blood Clots.)
Abnormal bleeding can result from disorders of the blood clotting (coagulation) system, of platelets (see Platelet Disorders), or of blood vessels (see Bleeding Due to Abnormal Blood Vessels).
Clotting disorders occur when the body is unable to make sufficient amounts of the proteins that are needed to help the blood clot, stopping bleeding. These proteins are called clotting factors (coagulation factors). All clotting factors are made in the liver. The liver requires vitamin K to make some of the clotting factors.
Disorders of coagulation can be
The most common hereditary coagulation disorders are the hemophilias (see Hemophilia). The primary causes of coagulation disorders that develop as a result of another disorder are vitamin K deficiency (see Vitamin K Deficiency), severe liver disease (including cirrhosis, severe hepatitis, or acute fatty liver of pregnancy), disseminated intravascular coagulation (see Disseminated Intravascular Coagulation (DIC)), and development of circulating anticoagulants (see Clotting Disorders Caused by Circulating Anticoagulants).
Last full review/revision April 2014 by Joel L. Moake, MD