Review article: blood platelet number and function in chronic liver disease and cirrhosis

Abstract
Background The liver plays a central role in coagulation and fibrinolysis but is also closely intertwined with the function and number of blood platelets. Aim To describe and integrate all literature concerning blood platelets and liver disease by performing a thorough literature research. Methods A thorough literature research on ‘blood platelets’ and ‘liver disease’ was performed. Results Thrombocytopenia is a marked feature of chronic liver disease and cirrhosis. Traditionally, this thrombocytopenia was attributed to passive platelet sequestration in the spleen. More recent insights suggest an increased platelet breakdown and to a lesser extent decreased platelet production plays a more important role. Besides the reduction in number, other studies suggest functional platelet defects. This platelet dysfunction is probably both intrinsic to the platelets and secondary to soluble plasma factors. It reflects not only a decrease in aggregability, but also an activation of the intrinsic inhibitory pathways. The net effect, finally, is a decreased platelet function in the various types of chronic liver diseases and cirrhosis. Finally, recent data suggest that platelets are not only affected by but can also contribute to the liver disease process, as for instance, in viral hepatitis and cholestatic liver disease. Conclusion Platelet research in liver disease is a growing area of investigation and could provide new pathophysiological insights.