This chapter focuses on the various etiologies for intracerebral hemorrhage (CH), ischemic stroke (IS), transient ischemic attack (TIA), and cerebral venous sinus thrombosis (CVST) that are caused by blood disorders. Bleeding disorders may be inherited or acquired. They include thrombocytopenia and platelet function disorders, coagulation factor deficiencies, excessive anticoagulation and hemorrhagic complications after thrombolysis. Blood disorders associated with myeloproliferative diseases and disseminated intravascular coagulation (DIC) can cause both bleeding and thrombosis. Heparin-induced thrombocytopenia (HIT), the anti-phospholipid antibody syndrome, and thrombotic thrombocytopenic purpura (TTP) are conditions that cause thrombocytopenia but are more frequently responsible for thrombosis than for bleeding. Blood transfusion therapy is recommended as the most important intervention for primary stroke prevention and secondary stroke prevention in children with sickle cell disease. Cytoreduction with hydroxyurea reduces the incidence of thrombosis in essential thrombocythemia, and aspirin reduces the incidence of thrombotic events in polycythemia vera.

Venous thromboembolism (VTE) is a common cause of morbidity and mortality and has been implicated in the pathophysiology of a number of obstetric complications. This chapter provides an overview of the more common genetic thrombophilias and the acquired thrombophilia associated with the presence of antiphospholipid antibodies. A limited number of genetic variants are proven to be independent risk factors for VTE. These include mutations in the genes controlling the function of both pro- and anticoagulant factors. The main benefit in screening thrombophilia is to prevent a first VTE in affected relatives rather than secondary prevention of recurrent VTE. Oral contraceptives increase the risk of VTE, particularly in the first year of use. Women with thrombophilic defects are at greater risk. Improved pregnancy outcomes in women with antiphospholipid syndrome can be achieved with the use of aspirin and low-dose heparin.