Coagulation disorders occur when coagulation factors are insufficient or absent and clot formation is impaired.
Hemophilia
Hemophilia is a congenital disorder that, because it is x-linked, primarily affects males.
There are two main types of hemophilia: A and B.
Hemophilia A is characterized by absent or deficient factor VIII; this is the most common form and results from a mutation of the F8 gene.
Hemophilia B is characterized by absent or deficient factor IX; it results from a mutation of the F9 gene.
To understand their pathogenesis, quickly review a portion of the coagulation cascade:
Activated factor IX, complexed with activated co-factor VIII and calcium ions, activates factor X. In turn, activated factor X complexes with activated cofactor V and calcium ions to form prothrombinase. Prothrombinase then converts prothrombin to thrombin, which converts fibrinogen to fibrin, which creates a mesh-like clot surrounding blood cells and other circulating molecules.
Treatment for hemophilia typically involves replacement of the deficient factor.
Common bleeding sites in hemophilia include the oral mucosa and musculoskeletal sites; hemophilia is characterized by hemarthrosis, which is bleeding into the joint spaces. Intracerebral and gastrointestinal bleeding can be fatal.
Vitamin K Deficiency
Vitamin K is necessary for hepatic synthesis of prothrombin, factors VII, IX, and X.
Two key sources of vitamin K are the diet (especially green, leafy vegetables) and bacterial production (in the proximal intestine).
From the GI tract, vitamin K is absorbed and transported to the liver, where it is used to synthesize four of the coagulation factors.
These factors are then carried in the blood, ready to participate in the coagulation cascade and production of thrombin.
Thus, if the quantity of vitamin K present in GI tract is insufficient, or it is not properly absorbed and transported to the liver, thrombin production and clot formation will be impaired.
Be aware that liver diseases can also inhibit the production of coagulation factors, independent of vitamin K deficiencies.
