Stroke occurs when a part of the brain dies because it goes without blood supply for too long.

In the United States, 700,000 strokes happen each year. Stroke is the number one cause of long-lasting disability after the age of 50, and is among the top five causes of death. Early diagnosis and treatment can reduce the brain damage that occurs and improve one’s clinical outcome. On average, an American dies from stroke every four minutes.

What are the types of stroke?

There are two types:

Ischemic stroke

The most common type. It is caused by a blockage in one of the vessels that supply oxygen and other important nutrients to the brain. If the artery remains blocked for more than a few minutes, the brain can become damaged. There are two subtypes of ischemic stroke: thrombotic and embolic. Thrombotic stroke: This starts with the brain artery becoming slowly and partially blocked with fatty deposits called plaques. Plaques can then abruptly rupture, forming a blood clot on top of the plaque. This blood clot, known as a thrombus, can completely clog the artery, leading to an immediate stroke. Embolic stroke: It occurs when a blood clot, an embolus, travels from another part of the body, often the heart, through the bloodstream to the brain where it lodges and blocks flow to a given area resulting in a stroke. One common cause of embolic stroke is an irregular heart rhythm condition, atrial fibrillation.

Haemorrhagic stroke

This occurs when blood vessels in the brain leak or break causing bleeding, or haemorrhage, in or around the brain. This can lead to pressure within the head, which can cause brain damage. Also, blood is irritating to the brain tissue and can cause it to swell. Here also, there are two subtypes of haemorrhagic stroke: intracerebral and subarachnoid. Intracerebral haemorrhage: This takes place when bleeding occurs within the brain tissue itself; blood collects and puts pressure on the brain, causing damage. Subarachnoid haemorrhage: This happens when a blood vessel on the surface of the brain, rather than inside the brain tissue, ruptures. The blood builds up and causes pressure in the “subarachnoid” space, a fluid-filled cushioning area surrounding the brain.

The most common symptom of a subarachnoid haemorrhage is a severe headache called “thunderclap headache”, which many patients describe as the worst headache of their life.

What are transient ischemic attacks? They are episodes in which a person has signs or symptoms of a stroke (eg numbness; inability to speak) that last for a short time, but without any sign of stroke on brain scans such as MRI or CT. Symptoms of a TIA usually last between a few minutes and a few hours, then resolve. A TIA is a warning sign that a person is at high risk for a stroke; immediate treatment can decrease this risk.

What are stroke risk factors?

While a stroke could happen in healthy people, it is most commonly associated with the following risk factors:

Ischemic stroke

Age older than 40 years

Heart disease

High blood pressure

Smoking

Diabetes

High cholesterol levels

Atrial fibrillation

Illegal drug use

Recent childbirth

Inactive lifestyle

Obesity

Present or past history of blood clots

Oestrogen replacement therapy

Haemorrhagic stroke

High blood pressure

Smoking

Illegal drug use (especially cocaine and “crystal meth”)

Use of warfarin or other blood thinners

Brain aneurysms, deformities in the vessels’ lining causing them to dilate like small balloons.

What are the symptoms of a stroke?

They may begin suddenly or develop over hours or days. Depending upon the area of the brain affected, a person may lose the ability to move one side of the body, or the ability to speak or to see — often partially — or a number of other functions. The damage from a stroke may be temporary or permanent.

Reacting FAST

Classic stroke symptoms can be recalled with the acronym FAST. Each letter in the word stands for one of the things you should watch for: Face: Sudden weakness or droopiness of the face, or problems with vision

Arm: Sudden weakness or numbness of one or both arms

Speech: Difficulty speaking, slurred speech, or garbled speech

Time: Time is very important in stroke treatment. The sooner treatment begins, the better the chances are for recovery. A stroke is a medical emergency. If you think you or someone around you may be having a stroke, call 911 immediately. Do not drive yourself to the hospital.

How is a stroke diagnosed? After a history collection and a physical exam, the physician usually orders blood tests and an imaging test (CT scan or MRI) of the brain and the blood vessels of the neck and head.

This allows her/him to identify the area of the brain affected by the stroke, as well as to identify its type (ischemic or haemorrhagic).

Additional blood tests and cardiac work up are usually needed on a case-by-case decision. This initial work-up will significantly help with further treatment.

Joe Yammine is a cardiologist at Bermuda Hospitals Board. He trained at the State University of New York, Brown University and Brigham and Women’s Hospital. He holds five American Board certifications. He was in academic practice between 2007 and 2014, when he joined BHB. During his career in the US, he was awarded multiple teaching and patients’ care recognition awards. The information herein is not intended as medical advice nor as a substitute for professional medical opinion. Always seek the advice of your physician. You should never delay seeking medical advice, disregard medical advice or discontinue treatment because of any information in this article.