Stroke

Description

A stroke occurs when the blood supply to the brain is interrupted. This interruption of blood supply causes irreversible damage to the brain. There are two types of stroke: Ischemic and Hemorrhagic. The distinction between the two types is determined by CT and MRI scans.

Ischemic Stroke

This is most common type of stroke, accounting for 87% of stroke cases. An ischemic stroke occurs when a blood vessel in the brain becomes blocked and is unable to carry the vital nutrients and oxygen needed for brain function. The blockage is created by blood vessel plaque, or more commonly, a blood clot. The blood clot normally develops in the heart or lungs. When the blood clot migrates to the brain via the circulatory system, it can lodge itself in the smaller blood vessels of the brain causing a blockage.

Hemorrhagic Stroke

This stroke occurs when an artery in the brain ruptures and bleeds. A subarachnoid hemorrhage occurs on the surface of the brain under the tissue that covers it. An intracerebral hemorrhage occurs inside the brain.

Causes

Anyone, regardless of age, race, or gender, can suffer a stroke. However, chances of suffering a stroke increase if a person has certain risk factors. The most common risk factors for stroke are high blood pressure, smoking, high cholesterol, and drinking excess alcohol. Risk factors can be broken into three groups, and when controlled, the mortality of stroke is reduced.

Non-Modifiable

These are risk factors that cannot be changed such as age, gender, race, and an incidence of a previous stroke. Some risk factors, such as sickle cell disease (a disease that causes plaque buildup in the blood vessels), blood clotting abnormalities, and congenital heart disease are caused by genetics. Fibromuscular dysplasia (a disease where the artery walls grow abnormal tissue, causing them to narrow and become obstructed) is an uncontrollable risk factor common in women.

Medically Treatable

These include medical disorders and diseases such as high blood pressure, irregular heartbeat, high cholesterol, diabetes, and circulatory problems.

Lifestyle Alterable

Stroke development has been linked to modifiable lifestyle factors such as tobacco smoking, excess alcohol intake, physical inactivity, and obesity.

Treatment

Treatment of stroke requires immediate intervention to stop the bleeding or blockage and preventative treatment to lower the risk of a subsequent stroke. CT and MRI scans of the brain are performed to determine whether it is an ischemic or a hemorrhagic stroke.

Hemorrhagic Stroke

Surgical procedures, such as clipping or coiling of the ruptured blood vessel, are performed to prevent further bleeding. This takes place as soon as possible after hospital admission to reduce the rate of bleeding.

Ischemic Stroke

Thrombolytic therapy aims to restore blood flow by clearing the blocked blood vessel. This is carried out using an intravenous drug, such as alteplase (Activase*), that helps dissolve blood clots. While in the hospital, a patient is closely monitored for brain hemorrhage when receiving this type of treatment.

Risk Factors

These are usually managed by drugs. High blood pressure is controlled by blood pressure lowering agents. For atrial fibrillation, warfarin is often used to reduce the risk of blood clots forming in the heart. Lipids (fatty acids) that can cause high cholesterol are reduced by the use of a class of drugs known as statins.

Lifestyle

Smokers are encouraged to stop smoking completely. Any alcohol consumption is advised to be in moderation and avoid drinking binges. Eating a well-balanced diet is recommended to control weight and high cholesterol levels. Regular exercise is encouraged to maintain a healthy body mass index (BMI).