Neurology and the blood: haematological abnormalities in ischaemic stroke
- aDepartment of Clinical Neuroscience, King’s College School of Medicine and Dentistry London, UK, bDepartment of Haematology, King’s Healthcare, Denmark Hill, London, UK
- Dr H S Markus, Department of Clinical Neuroscience, Institute of Psychiatry, De Crespigny Park, Denmark Hill, London SE5 8AF, UK. Telephone 0171 346 5174; fax 0171 919 3407; emailh.markus{at}iop.bpmf.ac.uk
- Received 18 August 1997
- Accepted 22 August 1997
Haematological disorders account for up to 8% of all ischaemic strokes in different series. Table 1 shows the haematological disorders associated with ischaemic stroke. Most studies report them as being more common in younger stroke patients, particularly those who have undetermined stroke aetiology after extensive tests including full cardiac evaluation. Many primary haematological disorders have been associated with ischaemic stroke but in many patients with stroke other aetiological factors are also present making a cause and effect relation difficult to prove. Furthermore, some of these haematological factors, particularly deficiencies of natural anticoagulants, are more potent causes of venous thrombosis. Therefore in such cases paradoxical embolism from the venous system should be considered, and excluded, before arterial thrombosis is implicated.
- In this window
- In a new window
Haematological disorders associated with ischaemic stroke
Normal haemostatis
The haemostatic system is a major defence system of the body. It is the result of interaction of three components: (1) the vessel wall, particularly endothelial cells; (2) platelets; and (3) the coagulation system including the fibrinolytic system.
The aims are to maintain fluidity of the blood and, when there is a break in the integrity of the vessel wall, to rapidly initiate blood coagulation which is maintained locally at the site of vascular damage. The process involves several different proteins. Defects of these, which may be congenital or acquired, will result in disorders of haemostasis which may manifest in clinical syndromes of easy bleeding or bruising (“haemophilias”) or inappropriate thrombosis (“thrombophilia”). A more general breakdown in the initiation and control of haemostasis results in the syndrome of “disseminated intravascular coagulation”, in which there is the apparent paradox of concurrent bleeding and widespread thrombosis which is responsible for much of the organ damage.
The vascular endothelium plays a critical part in maintaining blood fluidity and vascular smooth muscle tone through (a) prostacyclin, a potent vasodilator …
