Stroke is the third most common cause of death and the second most common cause of neurological deficits in Western countries, after Alzheimer’s disease. Its incidence has declined in recent decades, but this decline now appears to have stalled, and cerebrovascular disease remains the leading cause in adults placed in special institutions for loss of independent living. Most vascular damage to the brain is secondary to atherosclerosis or hypertension. Some of the major types of cerebrovascular disease are (1) cerebral blood supply deficiency, due to transient impairment of cerebral blood flow or, rarely, due to hypertensive encephalopathy; (2) cerebral infarction, caused by intracranial or extracranial arterial embolism or thrombosis; (3) cerebral hemorrhage, including hypertensive intracerebral parenchymal hemorrhage, versus subarachnoid hemorrhage due to rupture of a congenital cerebral aneurysm; (4) cerebral arteriovenous malformation, which can cause occupying lesions, symptoms of cerebral infarction or cerebral hemorrhage. Signs and symptoms of cerebrovascular disease reflect areas of the brain that are damaged and do not necessarily suggest a specific artery with a lesion. For example, occlusion of the middle cerebral artery or the internal carotid artery can cause similar clinical neurological abnormalities. However, in general, symptoms of cerebrovascular damage are consistent with the particular pattern of arterial supply; knowledge of the regional pattern of arterial supply can help distinguish stroke from other brain lesions, which can occasionally produce acute symptoms. An accurate history, including the mode of onset, duration of symptoms, and identification of stroke risk factors, is essential for the diagnosis of cerebrovascular lesions (Table 174-2). Both hemorrhagic and ischemic strokes have sudden onset, but hemorrhagic strokes have a more catastrophic acute onset. Brain CT or MRI can distinguish between ischemic or hemorrhagic stroke and can help in making decisions about emergency treatment. There are standard test scales that can be applied to assess the severity of a stroke. For example, the National Institutes of Health Stroke Scale (NIHSS) rates consciousness, vision, external eye muscle activity, facial palsy, limb strength, ataxia, sensation, speech and writing on a scale of 0 to 2 or 3, respectively. Higher scores indicate more severe neurological deficits; the highest possible score is 42. Not all cases require aggressive treatment, especially when the residual neurological deficits are severe or when there are other serious coexisting conditions. In this case, the focus should be on supportive treatment and care.