Disorders of haemostasis and thrombosis

The balance between excessive bleeding or clot formation simplistically involves primary haemostasis (platelets and von Willebrand factor) and secondary haemostasis (coagulation factors). Disorders in any of these factors may be either congenital or acquired. We review the pathogenesis for bleeding, including low and high platelet levels, congenital platelet abnormalities and the subtypes of von Willebrand’s disease. Congenital coagulation factor deficiencies, the commonest being haemophilia A and B, carry the risk of deeper mucosal bleeds into joints and muscle. Acquired bleeding abnormalities, such as disseminated intravascular coagulation, acquired haemophilia and cardiopulmonary bypass, are presented individually along with their treatment options. Within the thrombotic section, risk factors, both inherited and environmental, are reviewed.