Acquired coagulation disorders

Abstract

Abstract Acquired disorders of coagulation may be the consequence of many underlying conditions, and although they may share abnormality of a coagulation test, for example, a prolonged prothrombin time, their clinical effects are diverse and often opposing. General clinical approach: diagnosis—most acquired disorders of coagulation can be identified by screening haemostasis tests, including (1) prothrombin time; (2) activated partial thromboplastin time; (3) thrombin clotting time; (4) fibrinogen degradation products, including (5) the cross-linked fibrin assay (D-dimer); and (6) complete blood count with examination of a blood film. Few bleeding disorders give normal results in all these tests, but disorders predisposed to thrombosis as a result of deficiency of natural anticoagulants (e.g. antithrombin, protein C, and protein S) or certain mutations (e.g. factor V Leiden) must be specifically sought. Treatment—patients with coagulopathies who are bleeding or who require surgery are usually treated with blood products such as platelets and frozen plasma. Other treatments used in particular circumstances include (1) vitamin K—required for the post-translational modification of factors II, VII, IX, and X as well as the anticoagulant factors, protein C, and protein S; (2) cryoprecipitate—used principally for the treatment of hypofibrinogenaemia; (3) concentrates of specific factors—used in isolated deficiencies (e.g. of factors VIII, IX, XI, VIIa, or fibrinogen); (4) antifibrinolytic agents (e.g. ε-aminocaproic acid and tranexamic acid); (5) desmopressin (1-deamino-8-d-arginine vasopressin)—increases factor VIII and von Willebrand factor.