What is ischemic stroke?
Ischemic stroke is the most common type. It accounts for about 70–80 percent of all strokes. Ischemic stroke occurs when an artery to the brain is blocked. The brain depends on its arteries to bring fresh blood from the heart and lungs. The blood carries oxygen and nutrients to the brain, and takes away carbon dioxide and cellular waste. If an artery is blocked, the brain
cells (neurons) cannot make enough energy and will eventaully stop working. If the artery remains blocked for more than a few minutes, the brain cells may die. This is why immediate medical treatment is absolutely critical.
Ischemic stroke can be caused by several different kinds of diseases. The most common problem is narrowing of the arteries in the neck or head. This is most often caused atherosclerosis, or gradual cholesterol deposition. If the arteries become too narrow, blood cells may collect and form blood clots. These blood clots can block the artery where they are formed (thrombosis), or can dislodge and become trapped in arteries closer to the brain (embolism). Another cause of stroke is blood clots in the heart, which can occur as a result of irregular heartbeat (for example, atrial fibrillation), heart attack, or abnormalities of the heart valves. While these are the most common causes of ischemic stroke, there are many other possible causes. Examples include use of street drugs, traumatic injury to the blood vessels of the neck, or disorders of blood clotting.
Ischemic stroke can further be divided into two main types: thrombotic and embolic. A thrombotic stroke occurs when diseased or damaged cerbral arteries become blocked by the formation of a blood clot within the brain. Clinically referred to as cerebral thrombosis or cerebral infarction, this type of event is responsible for almost 50% of all strokes. Cerebral thrombosis can also be divided into an additional two categories that correlate to the location of the blockage within the brain: large-vessel thrombosis and small-vessel thrombosis. Large-vessel thrombosis is the term used when the blockage is in one of the brain's larger blood-supplying arteries such as the carotid or middle cerebral, while small-vessel thrombosis involves one (or more) of the brain's smaller, yet deeper penetrating arteries. This latter type of stroke is also called a lacuner stroke.
An embolic stroke is also caused by a clot within an artery, but in this case the clot (or emboli) was formed somewhere other than in the brain itself. Often from the heart, these emboli will travel the bloodstream until they become lodged and can not travel any further. This naturally restricts the flow of blood to the brain and results in almost immediate physical and neurological deficits.
Ischemic stroke is by far the most common kind of stroke, accounting for about 88% of all strokes. Stroke can affect people of all ages, including children. Many people with ischemic strokes are older (60 or more years old), and the risk of stroke increases with older ages. At each age, stroke is more common in men than women, and it is more common among African-Americans than white Americans. Many people with stroke have other problems or conditions which put them at higher risk for stroke, such as high blood pressure (hypertension), heart disease, smoking, or diabetes. Click here for information about stroke risk factors and how to reduce your risk.
More information on the stroke
What is a stroke? - Stroke (cerebrovascular accident) is a sudden loss of consciousness resulting when the rupture or occlusion of a blood vessel leads to oxygen lack in the brain.
What're the different types of strokes? - There are two main types of stroke. Ischemic stroke is the most common type of stroke. Hemorrhagic stroke is caused by bleeding.
What is ischemic stroke? - Ischemic stroke is the most common type. Ischemic stroke can further be divided into two main types: thrombotic and embolic.
What is a thrombotic stroke? - Thrombotic strokes are strokes caused by a thrombus (blood clot) that develops in the arteries supplying blood to the brain.
What is an embolic stroke? - Embolic strokes often result from heart disease or heart surgery and occur rapidly and without any warning signs.
What's transient ischemic attack (TIA) or mini stroke? - A transient ischemic attack (TIA) is often called a mini stroke. A transient ischemic attack (TIA) is a transient stroke that lasts only a few minutes.
What is hemorrhagic stroke? - In hemorrhagic stroke, bleeding in the brain itself or between the brain and the skull (subarachnoid hemorrhage) disrupts brain function.
What is an intracerebral hemorrhage? - Intracerebral hemorrhage is usually caused by hypertension (high blood pressure), and bleeding occurs suddenly and rapidly.
What is a subarachnoid hemorrhage? - Subarachnoid hemorrhage results when bleeding occurs between the brain and the meninges in the subarachnoid space.
What causes a stroke? - Stroke caused by damage to blood vessels in the brain. The ischemic stroke is usually caused by atherosclerosis (hardening) of blood vessels.
What are the symptoms of a stroke? - The symptoms of a stroke depend on what part of the brain and how much of the brain tissue is affected. Stroke symptoms usually come on suddenly.
What are the risk factors for a stroke? - Risk factors for a stroke include high blood pressure (hypertension), atherosclerosis, cigarette smoking, atrial fibrillation, diabetes.
How is a stroke diagnosed? - Stroke is diagnosed through several techniques: a short neurological examination, blood tests, CT scans or MRI scans, Doppler ultrasound, and arteriography.
What's the treatment for a stroke? - The aim of the therapy is to minimise the size of the stroke and therefore minimise subsequent disability by restoring blood flow to the area of the brain affected quickly.
What medications can be used for stroke treatment? - Intravenous thrombolytics. clot-busting, or thrombolytic drugs are now administered intravenously for ischemic (not hemorrhagic) stroke.
What can be done to prevent a stroke? - Prevention of stoke is an important public health concern. Medication or drug therapy is the most common method of stroke prevention.
What're the surgical treatments for stroke? - Surgical treatments for stroke include carotid endarterectomy, angioplasty, clipping. Clipping involves clamping off the aneurysm.
How to recover from a stroke? - Spontaneous recovery accounts for most improvements in the first month after a stroke. Successful recovery after a stroke depends on the extent of brain damage.
What is stroke rehabilitation? - Stroke rehabilitation is the process by which patients with disabling strokes undergo treatment to help them return to normal life.