What causes narrowing of the blood vessels in the brain

What is intracranial stenosis?

Intracranial stenosis is the severe narrowing of an artery within the skull. A blood vessel narrows when fatty deposits (plaque) build up inside the vessel, a condition known as atherosclerosis. Stenosis can restrict blood flow to areas of the brain, increasing the risk of stroke.

Stenosis can occur in other parts of the body, such as the spine. Typical areas where stenosis occurs in the head and neck are the internal carotid artery, middle cerebral artery, vertebral artery, and basilar artery.

Symptoms of Intracranial Stenosis

The main symptom of intracranial stenosis is having a transient ischemic attack (TIA) or stroke.

Symptoms of a stroke or TIA (“mini stroke”) include:

• Sudden, severe headache
• Paralysis or weakness on one side of the body
• Numbness or tingling
• Difficulty speaking or understanding
• Vision problems
• Dizziness or vertigo

If you think you are having a TIA or stroke, call 9-1-1 immediately.

Treatments for Intracranial Stenosis

The goal of treatment is to decrease the risk of stroke. Your doctor will recommend a treatment based on factors such as the size of the blockage and your risk for a first stroke or recurrent strokes.

Medications may be used to minimize risk factors, such as high cholesterol and high blood pressure. Blood thinners, such as aspirin, may be recommended to prevent clotting in a narrowed artery.

If there is a large blockage and high risk for stroke, your doctor may recommend surgery. Possible surgical procedures include:

• Angioplasty and stent placement is a minimally invasive endovascular procedure. A catheter is inserted into the femoral artery in the groin or the radial artery in the wrist and navigated through the arteries until it reaches the site of the blockage. A small balloon is then slowly inflated to push plaque outward and open up the artery, and a stent is placed to hold the vessel open.
• Bypass surgery reroutes blood flow around a blocked blood vessel. Your surgeon may create a graft bypass using a vessel from another part of your body or a tube made of synthetic fabric.

Additional Information

How common is intracranial stenosis?

Intracranial stenosis is responsible for about 10 percent of strokes each year. More than 795,000 Americans suffer a stroke each year.

Who gets intracranial stenosis?

Plaque can begin accumulating in a blood vessel as early as childhood, but atherosclerosis that is severe enough to cause symptoms is more likely to occur in older adults.

Risk factors include:

• High blood pressure
• High cholesterol
• Diabetes
• Obesity
• Smoking and other tobacco use
• Family history of atherosclerosis
• Lack of exercise

How is intracranial stenosis diagnosed?

The following tests may be used to diagnose intracranial stenosis:

• CT angiography
• MR angiography
• Catheter-based angiography
• Transcranial doppler ultrasound
• Positron emission tomography (PET)

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Intracranial stenosis is responsible for about 10 percent of strokes each year.

Vertebrobasilar circulatory disorders are conditions that cause reduced blood flow to the back of the brain.

Symptoms of restricted blood flow to the back of the brain, also called vertebrobasilar insufficiency, include dizziness and slurred speech.

If something stops or disrupts blood flow to an area of the body, it is known as ischemia. When this happens to the brain, it can damage brain cells and result in health problems.

In this article, we look at vertebrobasilar circulatory disorders, how to spot telltale symptoms, and what causes these conditions.

There are various reasons why a person might not have enough blood reaching their brain. Causes include:

• narrowing of blood vessels
• blocked blood vessel
• blood clot
• ruptured blood vessel

Atherosclerosis is a common cause of narrow or blocked blood vessels. Atherosclerosis is the medical term for a buildup of a fatty substance, known as plaque, in the arteries.

Plaque is mostly made up of cholesterol and calcium, which cause the arteries to harden. This hardening and buildup of plaque happen gradually over time.

As well as narrowing blood vessels, plaque can break away and travel in the blood to block a vein or artery elsewhere in the body.

Symptoms of reduced blood flow to the brain can be similar to those of stroke.

A person should seek immediate medical attention if they experience these symptoms. Quick treatment may reduce the damage done and can help with recovery.

Key symptoms include:

• slurred speech
• sudden weakness in the limbs
• difficulty swallowing
• loss of balance or feeling unbalanced
• partial or complete loss of vision or double vision
• dizziness or a spinning sensation
• numbness or a tingling feeling
• confusion
• vomiting or nausea

These symptoms may be ongoing or last only briefly.

Narrow or blocked blood vessels do not always present symptoms.

Reduced blood flow to the brain may cause the following complications:

Stroke

Brain cells do not get the nutrients they need if blood flow to the brain is reduced or stopped. This can prevent them from working correctly.

Blood flow that stops for long enough can damage or kill brain cells. This can cause a stroke.

Transient ischemic attack (TIA)

A blood clot or a piece of plaque that has come away from the artery wall can block a blood vessel. If this happens briefly and the blockage dislodges, it may cause a transient ischemic attack (TIA).

A TIA does not leave lasting damage, but it is a critical warning sign for stroke. The symptoms only last for a few minutes. A person may have sudden mental confusion, sudden weakness or numbness, sudden loss of balance, or a sudden and severe headache.

Cerebral aneurysm

Blood vessels in the brain can weaken and swell. When this happens, it is known as a cerebral aneurysm. High blood pressure, narrowed arteries, or a head injury can be the cause.

If a blood vessel in the brain breaks or bursts, it can cause bleeding in the brain that can damage or destroy brain cells.

It is not always possible to prevent vertebrobasilar circulatory disorders. Some risk factors are unavoidable, and others are related to lifestyle.

Risk factors include:

• sex
• age
• family history and genetics
• high blood pressure
• artery disease
• smoking
• inactivity and obesity

A person who has a vertebrobasilar condition may choose to make specific lifestyle changes to reduce their risk of stroke. Quitting smoking, eating a healthful diet to lower cholesterol, and doing regular exercise can all help.

A doctor may also prescribe medication to help lower cholesterol or control high blood pressure.

Multiple imaging tests allow doctors to look inside the body at the arteries and brain. Alongside asking questions about symptoms and medical history, a doctor may consider these tests the best way to diagnose vertebrobasilar circulatory disorders.

Imaging tests include:

Ultrasound

An ultrasound is often the preferred method for looking at the arteries, as it is noninvasive. This means that it does not break the skin or affect the inside of the body.

A medical professional will put a clear gel on the skin, then gently move a handheld device over it. This device sends out sound waves that bounce off the arteries to produce an image. This image can often show if a person has a blocked artery or a blood clot.

Magnetic resonance imaging (MRI)

An MRI can show a clear picture of the brain. A doctor can recommend this test to check if a person has had a stroke or similar medical condition in the past.

The MRI may be used to create a magnetic resonance angiogram. This gives an image of the vertebral and basilar arteries, which can help to show an aneurysm or blockage.

X-rays

Arteries do not usually show up in X-ray pictures. To see if an artery is damaged or blocked, a doctor can inject a harmless dye into an artery in the neck area. The dye will show up on an X-ray. This test is called an angiogram.

There are several possible treatment options for vertebrobasilar circulatory disorders. These include:

• medications to treat narrowed arteries if this is the cause of symptoms
• surgery in occasional cases with complete blockage or severe narrowing

Despite the occasional use of surgery, studies show mixed results, regarding its benefits in vertebrobasilar insufficiency.

The main aim of medication to treat a narrowing or stenosis of a blood vessel is to reduce the risk of stroke. A doctor can prescribe medication to:

• thin the blood and prevent blood clots
• reduce cholesterol
• manage high blood pressure

People who have vertebrobasilar circulatory disorders have a higher risk of stroke. A person who has had a previous stroke or TIA is more likely to experience one again. For this reason, lifestyle changes and preventive medication are crucial.

Vertebrobasilar circulatory disorders mostly affect older adults. Being aware of the symptoms, as a person ages, can be lifesaving.