Chapter 84: Hemostatic Dysfunction Related to Liver Diseases

PATHOGENESIS

• Loss of hepatic parenchymal cells leads to decreased plasma levels of all plasma coagulation factors except factor VIII and von Willebrand factor, which are produced primarily by endothelial cells.

• Thrombocytopenia occurs frequently and is usually a result of splenic sequestration (see Chaps. 26 and 74) but may also be caused by an autoimmune mechanism, disseminated intravascular coagulation (DIC) (see Chap. 86), folic acid deficiency, and decreased platelet production due to thrombopoietin (TPO) deficiency. Platelet dysfunction also contributes to the hemostatic abnormalities.

• Enhanced fibrinolysis is common and appears to be caused by complex pathogenetic mechanisms, including release and impaired clearance of plasminogen activators.

• Dysfibrinogenemia is relatively frequently found in patients with chronic liver disease.

• Patients with chronic liver disease may develop a consumption coagulopathy—in its most extreme form, DIC (see Chap 86).

• Studies employing sophisticated coagulation tests have shown that due to a rebalancing of the coagulation system in patients with chronic liver failure, thrombin generation is basically normal in the majority of patients, whereas some patients may have a prothrombotic phenotype.

CLINICAL FEATURES

• Patients with liver disease may present with purpura, epistaxis, gingival bleeding, and/or menorrhagia. They are also predisposed to gastrointestinal bleeding from cirrhosis-driven esophageal or gastric varices.

• Bleeding typically follows trauma or surgical procedures, especially in sites with high fibrinolytic activity, such as the urogenital tract or oral mucosa.

• Patients with acute viral or toxic hepatitis usually develop abnormal bleeding only if the liver disease is very severe.

• Bleeding from esophageal varices requires primary attention to the bleeding site as well as efforts to correct the hemostatic abnormalities. In therapy-resistant cases, lowering of pressure in the esophageal varices by transjugular intrahepatic portosystemic shunting can be considered.

• The coagulopathy of liver disease may also predispose the patient to thromboembolic complications.

LABORATORY FEATURES

• Table 84–1 summarizes the laboratory abnormalities that can be found in patients with chronic liver disease. These abnormalities may contribute to bleeding or thrombosis.

• Determination of plasma levels of factors V, VII, and VIII may help differentiate among liver disease (factor VIII levels normal or increased; factors V and VII decreased), vitamin K deficiency (factor VII decreased; factors V and VIII normal), and DIC (all decreased).