Carotid Arteries and Strokes Explained 

What is Carotid Disease? 

The carotid arteries provide the major blood supply to the brain. The arteries run up either side of the neck and divides into two branches just below the angle of the jaw. One branch supplies blood to the face (external carotid artery), the other to the brain (internal carotid artery).

Hardening and narrowing of the arteries (atheroma or atherosclerosis) is a disease of all arteries in the body. When this occurs in the carotid arteries it can cause strokes. Atheroma is caused by a combination of factors – smoking, high cholesterol, family history, obesity and lack of exercise.  

What causes a stroke? 

There are two main types of stroke. The most common is the ischemic stroke, when the blood supply to the brain is blocked by a clot. The other is a haemorrhagic stroke, which occurs when a blood vessel in the brain bursts. 

Atheroma causes narrowing and irregularity of the inside wall of the artery, particularly where it branches. This narrowing may restrict the blood supply to the brain, this usually causes no symptoms, and the brain adapts to the reduced blood supply. The irregular uneven walls to the artery can allow blood clots and debris to collect. These can break away and interrupt the blood supply to areas of the brain and cause a stroke, or the artery of the eye. 

Complete blockage of the carotid artery can occur without any symptoms if the brains blood supply can be supplemented by other vessels, however if this is not the case parts of the brain can be deprived of a blood supply which may lead to a permanent stroke. 

What are the symptoms of a stroke? 

Both types of stroke cause loss of oxygen and vital nutrients to brain cells which leads to damage or death of the cells. In the case of a TIA (transient ischemic attack) or mini stroke, the blood supply is only disrupted for a short while and the patient recovers within 24hours. It can affect the face, arm or leg on one side of the body. Sometimes there is loss of vision in one eye or jumbled or complete loss of speech.

A stroke can be fatal. Those who survive can be left with permanent or temporary paralysis on one side of the body and may loose the ability to speak.

 Who is at risk? 

Strokes affect those of increasing age, usually over 60years of age and are more common in smokers, people with high blood pressure, diabetics and people with high cholesterol levels. 

How is carotid disease detected? 

Ultrasound is the main way of diagnosing carotid disease. The ultrasound image shows the  narrowing and the speed of the blood flow can be seen to show the degree of narrowing.