Bleeding disorders can be due to qualitative or quantitative abnormalities in either platelets or coagulation factors. Clinical manifestations often point to the underlying cause of excessive bleeding.
The general rule for abnormal bleeding not associated with trauma is:
The most common reasons for abnormal bleeding:
Thrombocytopenia (decreased platelets) is the most common cause of abnormal bleeding. Decreased platelet production or increased platelet destruction can result in thrombocytopenia. Bone marrow disease, side effects from drugs such as antineoplastics, and some infectious diseases can result in a decreased platelet count.
Idiopathic thrombocytopenic purpura (ITP) is a condition in which antibodies form against platelets. Patients with bleeding disorders due to platelet problems often experience immediate bleeding after trauma. The bleeding usually affects the skin, mucous membranes, nose, and urinary and gastrointestinal tracts. Bleeding may range from small petechiae to large ecchymotic areas.
Von Willebrand's disease is the most common hereditary coagulation disorder. It occurs in about 1% of the general population. Many cases go undiagnosed due to the mild nature of the bleeding which is often masked by an acute trauma. Deficiency or molecular defects in vWF result in problems with platelet adhesion. Adhesion is necessary for the activation of platelets.
Hemophilia is usually the result of an X chromosome mutation that causes a deficiency in factors VIII or IX. Liver transplant can correct for factor VIII deficiency in inherited hemophilia. Hemophilia can also be acquired through the development of antibodies to a coagulation factor.
Disseminated intravascular coagulation or DIC occurs as a result of obstetric complications such as abruptio placenta, saline abortion, retained products of conception, amniotic fluid embolism or severe pre-eclampsia/eclampsia. Other causes of DIC are septicemia, malignancies, cirrhosis of the liver, sickle cell disease, trauma or crushing injuries, snake bite, extracorporeal bypass, and incompatible blood transfusions. DIC, also known as consumption coagulopathy, is the result of continuous production of thrombin. The abnormal production of thrombin consumes clotting factors, leading to uncontrolled bleeding. DIC is always secondary to some other disease process, and begins when widespread tissue damage triggers blood clotting.
DIC produces multiple coagulation test abnormalities, including:
To reverse DIC, the underlying problem stimulating coagulation must always be treated. Paradoxically, in some situations, the treatment for uncontrolled bleeding in DIC is heparin administration. Heparin blocks thrombin formation, which then blocks consumption of the other clotting factors to facilitate hemostasis.
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