Stroke

A stroke is a serious medical emergency involving the brain. It occurs when blood flow to a part of the brain is interrupted. This lack of blood causes brain cells to die. When these cells die, parts of the brain stop functioning correctly.

Because the brain controls everything the body does, a stroke can cause many different problems. Some people may lose the ability to walk or feel sensations. Others may have trouble speaking or understanding words. Some symptoms can even be permanent. Because of the urgency, some people call a stroke a "brain attack."

There are two primary categories of stroke: ischemic and hemorrhagic. Ischemic strokes are the most common, accounting for about 87% of all cases. In an ischemic stroke, a blood vessel becomes blocked. This blockage prevents oxygen-rich blood from reaching brain tissue.

There are four main ways this happens. Thrombosis occurs when a blood clot forms right at the site of a vessel. An embolism happens when a clot travels from another part of the body to the brain. Systemic hypoperfusion is a general decrease in blood supply, such as during shock. Finally, cerebral venous sinus thrombosis involves a blockage in the brain's veins. Some strokes have no obvious cause and are called cryptogenic strokes.

Hemorrhagic stroke is the second main type. This occurs when a blood vessel ruptures or leaks. This causes blood to pool in or around the brain.

This leaking increases the pressure inside the skull, which can compress the brain. There are two specific types of hemorrhagic stroke. Intracerebral hemorrhage is bleeding that happens within the brain tissue itself. Subarachnoid hemorrhage is bleeding that occurs in the space between the brain and its protective membranes. This type often causes a very severe headache known as a "thunderclap headache." One common cause for this bleeding is a ruptured brain aneurysm, which is a weak spot in a vessel wall.

Recognizing the signs of a stroke quickly is vital for survival. Medical professionals often use mnemonics to help people remember the warning signs. The most common is FAST, which stands for facial drooping, arm weakness, speech difficulty, and time to call emergency services.

To make this even more complete, some use the term BE FAST. This adds balance issues and eyesight changes, such as sudden blurry or double vision. If symptoms like these last for less than 24 hours, it is called a transient ischemic attack, or TIA. A TIA is often called a "mini-stroke." Even though symptoms go away in a TIA, it is still a serious warning sign.

Doctors use several tools to diagnose a stroke and determine its type. A physical exam is usually the first step. Doctors often use a CT scan to look for bleeding in the brain. While a CT scan is great for ruling out a hemorrhagic stroke, it might not show an ischemic stroke immediately. An MRI scan is another tool used for detailed imaging. Doctors may also use an electrocardiogram, or ECG, to check the heart for issues like atrial fibrillation. Blood tests are used to check for risk factors like diabetes or high cholesterol. These tests help doctors decide if the patient needs medication to break up a clot or surgery to stop bleeding.

There are many risk factors that can increase the chance of having a stroke. High blood pressure is the most significant risk factor. Other factors include high blood cholesterol, smoking, obesity, and diabetes mellitus. Conditions like end-stage kidney disease or atrial fibrillation also increase risk.

In 2023, an estimated 15 million people worldwide experienced a stroke. In 2021, strokes were the third leading cause of death globally, representing about 10% of all deaths. In 2015, stroke was the second most frequent cause of death, resulting in 6.3 million deaths. About half of the people who suffer a stroke do not live for more than one year. Two thirds of all stroke cases occur in people over the age of 65.

Treatment and recovery are possible if medical help is received quickly. For ischemic strokes, if detected within three to four and a half hours, doctors may use medication to break down the clot. Hemorrhagic strokes may sometimes require surgery to stop the bleeding. After the initial emergency, many people begin stroke rehabilitation. This is a process to help the brain and body recover lost functions.

Rehabilitation ideally takes place in a specialized stroke unit. While these units are helpful, they are not available in many parts of the world. Through various therapies, people work to regain their movement and independence.