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How can vitamin K deficiency and liver disease interfere with blood clotting?
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blood disease
Peripheral blood smear revealing histopathologic features indicative of a blast crisis in a case of chronic myelogenous leukemia (CML). Blast crisis occurs when one-fifth to one-third of the cells in the blood or bone marrow are immature blood cells, or blast cells. This phase of CML is characterized by fever, weakness, and an enlarged spleen.
Vitamin K deficiency and liver disease interfere with blood clotting by disrupting the production and function of essential coagulation proteins.
The Role of the Liver and Vitamin K
Most blood-clotting proteins are synthesized in the liver. Specifically, six proteinsâfactors VII, IX, X, prothrombin, protein C, and protein Sârequire vitamin K to become biologically active. During synthesis, vitamin K acts as a necessary cofactor for an enzyme-mediated reaction called -carboxylation, which modifies glutamic acid residues into -carboxyglutamic acid. This modification allows these proteins to bind to calcium and interact with cell membranes to form blood clots.12
Mechanisms of Interference
- Vitamin K Deficiency: Without adequate vitamin K, the liver produces inactive, non-functional precursor proteins that cannot bind to calcium or cell membranes, leading to prolonged clotting times and a tendency toward hemorrhage. This deficiency often arises from disorders that interrupt the flow of bile, which is required for the intestinal absorption of the vitamin.1324
- Liver Disease: Because the liver is the primary site for synthesizing coagulation factors, chronic liver injury or cirrhosis directly reduces the production of these essential proteins. Furthermore, liver disease can lead to portal hypertension, which may cause the spleen to sequester platelets, further impairing the body's ability to stop bleeding.15