stollingsfactor

Stollingsfactor is the Dutch term for coagulation factors, a group of plasma proteins essential for normal blood clotting. Most are synthesized in the liver and circulate in inactive forms until they are activated in response to vascular injury. Once activated, they participate in a proteolytic cascade that converts fibrinogen to fibrin, forming a stable blood clot to stop bleeding.

The coagulation system is traditionally described as intrinsic, extrinsic, and common pathways. The extrinsic pathway begins with tissue factor and factor VII; the intrinsic pathway involves other contact factors leading to activation of factors VIII and IX. Both pathways converge on factor X, which, with prothrombin (factor II), generates thrombin to convert fibrinogen into fibrin. Key factors include II (prothrombin), VII, IX, and X, which are vitamin K-dependent, and VIII, XI, XII, and XIII, with VIII playing a central role in the classic hemophilia A pathway and IX in hemophilia B. von Willebrand factor helps platelets adhere and also stabilizes factor VIII.

Disorders of coagulation factors can cause bleeding diatheses. For example, deficiencies of factor VIII or IX lead to hemophilia A or B, respectively. Laboratory tests such as the prothrombin time (PT/INR) and the activated partial thromboplastin time (aPTT) assess different parts of the cascade and guide diagnosis and monitoring.

Treatment involves replacement of deficient factors using plasma-derived or recombinant concentrates, with desmopressin for some mild hemophilias. Anticoagulants that affect vitamin K–dependent synthesis (e.g., warfarin) impair multiple coagulation factors. Regular monitoring and consideration of inhibitors to infused factors are important in management.