Among all the neurologic diseases of adult life, stroke ranks first in frequency and importance. The common mode of expression of stroke is a relatively sudden occurrence of a focal neurologic deficit. Strokes are broadly categorized as ischemic or hemorrhagic. Ischemic stroke is due to occlusion of a cerebral blood vessel and causes cerebral infarction. The resultant neurologic syndrome corresponds to a portion of the brain that is supplied by one or more cerebral vessels. Knowledge of the stroke syndromes, the signs and symptoms that correspond to the region of brain that is supplied by each vessel, allows a degree of precision in determining the particular vessel that is occluded and from the temporal evolution of the syndrome, the underlying cause of vascular occlusion can be deduced.
Ischemic strokes are classified by the underlying cause of the vascular occlusion. One of three main processes is usually operative: (i) atherosclerosis with superimposed thrombosis affecting large cerebral or extracerebral blood vessels, (ii) cerebral embolism, and (iii) occlusion of small cerebral vessels within the parenchyma of the brain. There are many other pathologic processes that lead to ischemic brain damage, not all associated with occlusion of cerebral vessels, including arterial dissection, inflammatory conditions such as vasculitis, thrombosis of cerebral veins and dural sinuses, in situ thrombosis of large or small cerebral vessels due to hypercoagulable conditions, vasospasm from any of several mechanisms, unusual types of embolic materials such as fat, tumor, cholesterol, and several unique diseases that involve the cerebral vasculature (see further on). Closely allied with ischemic strokes is the transient ischemic attack (TIA), a temporary neurologic deficit caused by a cerebrovascular disease that leaves no clinical or imaging trace. The causes of stroke are so numerous that the listing given in Table 34-1 offers only a guide to the remainder of this chapter. As helpful is knowledge of the major causes of stroke by each epoch of age, particularly in childhood and young adults, a subject taken up in a later section and summarized in Table 34-2.
Table Graphic Jump Location Table 34-1 Causes of Ischemic and Hemorrhagic Stroke ||Download (.pdf)
Table 34-1 Causes of Ischemic and Hemorrhagic Stroke
Transient ischemic attacks
Ruptured or unruptured saccular aneurysm or arteriovenous malformation
Meningovascular syphilis, arteritis secondary to pyogenic and tuberculous meningitis, rare infective types (typhus, schistosomiasis, malaria, mucormycosis, etc.)
Autoimmune vasculopathies (polyarteritis nodosa, lupus erythematosus), necrotizing arteritis. Wegener arteritis, temporal arteritis, Takayasu disease, granulomatous or giant cell arteritis of the aorta, and giant cell granulomatous angiitis of cerebral arteries
Cerebral thrombophlebitis: secondary to infection of ear, paranasal sinus, face, etc.; with meningitis and subdural empyema; debilitating states, postpartum, postoperative, cardiac failure, hematologic disease (polycythemia, sickle cell disease), and of undetermined cause
Hematologic disorders: anticoagulants and thrombolytics, clotting factor disorders, polycythemia, sickle cell disease, thrombotic thrombocytopenic purpura, thrombocytosis, intravascular lymphoma, etc.
Trauma and dissection of carotid and basilar arteries
Dissecting aortic aneurysm