What happens during a tear in a carotid?

The first part of each carotid artery is called the common carotid artery. Each common carotid artery has an inner and an outer branch. The outer branch carries blood to your face and scalp. The inner branch carries blood to the front part of your brain.

A carotid dissection is a tear of the inner layer of the wall of the artery. The tear lets blood get in between the layers of the wall. This separates them and causes the artery wall to bulge. The bulge can slow or stop blood flow through the artery. It can also cause problems by pressing on things nearby, such as nerves.

The tear can also trigger the body's clotting system. A clot can then block blood flow at the site of the tear. Or pieces of the clot can break off and block blood flow in smaller branches of the artery. Blocked or decreased blood flow can lead to a mini-stroke (TIA) or stroke. These stop blood flow to the brain. A TIA does this for only a short period of time.

A carotid dissection can happen at any age. It tends to happen more often in younger adults than in older adults. It's a common cause of stroke in people under age 50.

What causes carotid dissection?

An injury to the neck can cause carotid dissection. The injury may be caused by something like a car crash. A carotid dissection can also happen with no known cause. Or it may happen after a normal activity, such as:

• Swimming

• Scuba diving

• Skating

• Dancing

• Play sports, such as tennis, basketball, or volleyball

• Yoga

• Riding a roller coaster or other ride

• Jumping on a trampoline

• Giving birth

• Having sex

• Sneezing or coughing

• Getting chiropractic treatment

Who is at risk for carotid dissection?

Some things may raise the risk of having a carotid dissection. But some people who get carotid dissections don't have any of those risk factors. In some cases, genes may play a part. If you have a family member who has had an artery dissection, you may have a greater risk. Other things that may raise your risk:

• Infection

• High blood pressure

• Migraine headaches

• Smoking

• Use of birth control pills

• Alcohol use

• An extra-long bone near the jaw (styloid process)

What are the symptoms of carotid dissection?

You may not have symptoms. Or they may happen quickly or happen over several days. Common symptoms are:

• Headache

• Scalp pain

• Eye pain

• Neck pain

• One eye with a droopy lid and small pupil (partial Horner syndrome)

• One-sided weakness or numbness

• Pulsing sound in an ear

• Trouble swallowing

• Abnormal or lost sense of taste

How is carotid dissection diagnosed?

Your healthcare provider will ask about your past health and your symptoms. They may ask about recent injuries and activities. During the exam, your healthcare provider may look at your face and eyes, strength, reflexes, and areas of numbness. If you may have a health problem that raises your risk for carotid dissection, you may need more tests. Your healthcare provider may refer you to a neurologist, vascular surgeon, or neurosurgeon.

Tests may also be done to rule out other problems. These can include different types of headaches, nerve disorders, bleeding of the brain, and stroke from other causes. Tests may include:

• Blood tests

• MRI of the brain

• Magnetic resonance angiography (MRA) of the brain

• Cranial CT scan

• Cranial CT angiography (CTA)