The main symptom of ischemic stroke is an immediate or sub-acute occurrence of neurological deficits following prodromal symptoms. This kind of stroke usually attacks when the patient wakes up in the morning or when the person has no physical activity.
Ischemic stroke occurs when a blood vessel in the brain is blocked and blood flow is stopped. The blockage may be from a blood clot. A clot that forms in artery is called a thrombus. A thrombus usually does not occur in healthy brain artery, but tends to form at or adjacent to an area of a vessel damaged by atherosclerosis. A stroke caused by thrombus in brain artery is called cerebral atherothrombosis or atherothrombotic stroke.
A clot that forms in the heart or a blood vessel leading to the brain is called an embolus. This vessel may be the carotid artery in the front of the brain or the vertebral or basilar artery in the back of the brain. A stroke caused by embolus is called an embolic stroke. An embolus tends to form in the heart because of some diseases, e.g. atrial fibrillation (irregular heart beat), atrial septal defect (small hole in the heart chamber wall), and acute myocardial infarction (heart attack). An embolus occurs in the carotid artery because the vessel was narrowed.
The third form of ischemic stroke is called a lacunar stroke. This stroke results from occlusion of arterioles (small arteries) that penetrate deep into the brain. The small size of the vessel sometime makes lacunar stroke more difficult to diagnose than two types above.