Stroke

A stroke can be classified as a hemorrhagic stroke, in which bleeding occurs in the brain, or an ischemic stroke, in which there is interruption of blood supply to an aspect of the brain due to a blockage of an artery. The most common type of stroke is an ischemic stroke. In both cases, an interruption in blood flow occurs and a part of the brain dies due to a lack of oxygen. It only takes a few minutes of interrupted blood flow in order to start killing brain cells, which do not regenerate.

In an ischemic stroke, a blood clot interrupts the blood supply. The clot may form directly in a narrowed artery or it can break off from another part of the brain or other part of the body. This is known as an embolism and is called an embolic stroke. The former type of stroke is called a thrombotic stroke. An ischemic stroke is often caused by atherosclerosis of the arteries. Plaques form that are made from fat, cholesterol and calcium, and build up over time. The blood flows poorly over these areas, making the areas prime candidates for embolism or thrombotic strokes.

Certain medications and conditions can increase your risk for stroke. This can occur, for example, if you have carotid dissection or a tear in the lining of the carotid artery, the main artery leading to the brain.

Hemorrhagic strokes occur when a blood vessel ruptures, causing blood to leak within the brain. It can happen if you have a congenital defect in the artery or vein. It can happen with damage to the brain.

The risks for stroke include having atrial fibrillation, high blood pressure, a family history of stroke, heart disease, diabetes, increasing age or high cholesterol. You can have a greater incidence of ischemic strokes if you take birth control pills, especially if you are over the age of 35. Men are at greater risks for stroke than women but women have a higher risk during pregnancy or just after being pregnant.

Bleeding as a cause of stroke can be increased with high blood pressure, use of alcohol, cocaine use, bleeding disorders resulting in increased bleeding risk, and head injury.

Symptoms of stroke are variable and depend on where the damage to the brain has occurred. Symptoms usually develop without warning or can occur off and on for a day or two. Symptoms generally are worse at onset and gradually improve over time. In rare cases, a stroke comes on gradually. Strokes may be related to headache, particularly if bleeding is the cause of the stroke. Other symptoms of stroke include coma or decreased level of consciousness, change in taste or hearing, being clumsy, being confused, having difficulty swallowing, having weakness or numbness of one side of the body, having problems reading, writing or swallowing, having a bout of dizziness or vertigo, having loss of coordination or balance, having personality changes, and having problems with sensation or eyesight. Speaking can be impaired and you may not be able to walk.

The tests for stroke that help the diagnosis of stroke include a CT scan or MRI scan of the head. The doctor will do a complete neurological exam to include vision, reflexes, swallowing and other aspects of the neurological system. The doctor will listen for a bruit or turbulent sound over the carotid arteries indicating poor flow in the carotid arteries. The blood pressure may be high, which is a is sign of stroke. An echocardiogram can show if there are heart abnormalities that can lead to stroke. An angiogram of the head can show where there are bleeding areas or areas of blockage in the brain. A Doppler examination of the carotid artery uses ultrasound to see if there are narrowed areas of the carotid arteries. A spinal tap may show if blood is in the cerebrospinal fluid.

Treatment of stroke should be prompt. A patient with stroke has only about five hours to prevent its complications. A CT scan is done to make sure the patient has an ischemic stroke. Then clot busters are given (if the stroke is ischemic) in order to break up the clot and restore the circulation of the brain. In hemorrhagic strokes, the blood pressure is kept as low as possible to avoid further brain injury from further bleeding. All of this must be done in the hospital in order to save the brain cells from dying.

After a stroke has stabilized and the person still has deficits, physical, occupational and speech therapy are begun to improve the functioning of the patient's skills. This can continue for months after a stroke, as long as progress is continuing.