Progress Reviews Red Blood Cell Disorders and Stroke

THE RELATIONSHIP OF THE BLOOD, the most easily analyzed organ of the body, to the brain, the most remote and the focus of neurologists' attention, is strikingly apparent in cerebrovascular disease where thrombosis, atherosclerotic obstruction of vessels, and consequent failure to transport a constant supply of oxygen demonstrate the dependence of the nervous system on a properly functioning circulation. Frequently overlooked in our emphasis on platelets, coagulation, and vascular endothelium, however, is the importance of the red blood cell, the keystone of the interaction between blood and brain. Without normally functioning erythrocytes, a constant and sufficient supply of oxygen cannot be provided to threatened neurons rendered ischemic by underlying disease processes. Furthermore, primary red blood cell abnormalities, most notably changes in concentration (polycythemia or anemia) or structural alterations in the hemoglobin molecule, may themselves be the cause of cerebrovascular disease. As a result, therapy of cerebral ischemia may be aimed at altering the concentration or properties of the red blood cell in order to improve oxygen delivery. This paper will discuss the pathophysiology of red blood cell disorders, their clinical aspects and therapy in the context of cerebrovascular disease.