neurologic disorders
Ischemic Stroke
Introduction
Ischemic stroke is sudden neurologic deficits that result from focal cerebral ischemia associated with permanent brain infarction (eg, positive results on diffusion-weighted MRI). Common causes are atherothrombotic occlusion of large arteries; cerebral embolism (embolic infarction); nonthrombotic occlusion of small, deep cerebral arteries (lacunar infarction); and proximal arterial stenosis with hypotension that decreases cerebral blood flow in arterial watershed zones (hemodynamic stroke). No cause is identified in one-third of ischemic strokes at the time of patient discharge; these strokes are categorized as cryptogenic. Diagnosis is clinical, but CT or MRI is done to exclude hemorrhage and confirm the presence and extent of stroke. Thrombolytic therapy may be useful acutely in certain patients. Depending on the cause of stroke, carotid endarterectomy or stenting, antiplatelet medications, or anticoagulants may help reduce risk of subsequent strokes. 