Contributor: George A. Williams
Coagulation disorders (thrombophilia, hemorrhagic diathesis, hypercoagulable state) are characterized by disturbances of hemostasis resulting in hemorrhage or thrombosis. These disorders may occur at any age and in both sexes. The normal hemostatic mechanism is an intricately balanced system that precisely regulates the formation and clearance of blood clots. Coagulation disorders occur in a wide variety of pathologic states that cause congenital or acquired deficiencies or dysfunction of specific procoagulant or anticoagulant factors. Defects of blood coagulation proteins include congenital deficiencies of various factors involved in blood coagulation (factor VIII [von Willebrand disease], fibrinogen [afibrinogenemia], factor VIII:C [hemophilia A], factor IX [hemophilia B]) and complications of anticoagulant therapy. Because numerous coagulation proteins are synthesized in the liver cirrhosis [cirrhosis - liver] and other forms of hepatocellular disease [liver disease] can a cause coagulation disorder because of Vitamin K deficiency or a deficiency of other proteins involved in blood coagulation. These conditions cause pathologic hemorrhage. Anticoagulant abnormalities cause pathologic thrombosis and include congenital disorders of factor V, protein C, protein S, prothrombin and antithrombin III. Acquired anticoagulant disorders include hyperhomocystinemia, different types of antiphospholipid antibody syndrome and complications of anticoagulant therapy. Coagulation disorders can effect virtually all ocular tissues. The most common manifestations are retinal occlusovascular disease, vitreous [hemorrhage - vitreous] and subretinal hemorrhage and hyphema. The systemic manifestations of coagulation disorders are protean and include hemorrhagic and thrombotic complications.