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stroke from carotid dissection Images (Click to view larger image)
Alternative Names
brain attack, stroke following carotid dissection
Definition
A stroke is the death of brain tissue that occurs when the brain does not get enough blood and oxygen. A stroke from carotid dissection occurs when one of the carotid arteries in the neck is torn, or dissected.
What is going on in the body?
A carotid dissection occurs when the layers of the wall of the carotid artery break down. Carotid dissection is sometimes caused by an injury to the head or neck.
The carotid dissection causes a blockage of the artery and impairs blood flow to the brain. The brain cells then die from lack of oxygen. In turn, the blood also damages the brain cells. The products released when cells die cause swelling in the brain. Since the skull doesn't allow much room for expansion, this swelling can damage the brain tissue even further.
What are the signs and symptoms of the condition?
Stroke from carotid dissection can cause different signs and symptoms, depending on the area of the brain that is damaged. Signs or symptoms may include: - problems with movement, such as weakness, clumsiness, or paralysis on one side of the body
- headache
- numbness or a lack of feeling on one side of the body
- speech impairments, including slurred speech or difficulty finding the correct word
- difficulty doing maths or writing
- difficulty understanding speech or writing
- inability to recognise family members or common objects
- dementia, a condition that affects memory, understanding, and the ability to carry out the normal activities of daily life
- facial pain on one side
- personality changes
- difficulty swallowing
- balance problems, known as ataxia
- coma
- the inability to breathe on one's own. This may require a person to be put on an artificial breathing machine, or ventilator.
What are the causes and risks of the condition?
Carotid dissection can be brought on by: - head injury
- neck injury
- severe whiplash injury, which occurs when the neck is suddenly and forcibly bent backwards and forwards
- bouts of violent coughing
- surgical procedures involving the neck
The person's risk of stroke from carotid dissection is increased if other risk factors for stroke are also present.
The risks for stroke can be broken into 3 categories: non-modifiable, well-documented modifiable, and less well-documented or potentially modifiable.
The non-modifiable factors are ones that cannot be changed by the individual and include: - increasing age. A person's risk of stroke doubles each year after age 55.
- race.
- gender. Men have a 50% higher chance of stroke than women do.
- family history of stroke or transient ischemic attack (TIA). A TIA is a short, reversible form of stroke that may serve as an early warning sign of stroke.
Well-documented modifiable risk factors are those that can be changed by the individual in conjunction with his or her doctor. These factors are linked to stroke by strong research findings, and there is documented proof that changing the risk factor lowers a person's risk of stroke. These factors include: Less well-documented or potentially modifiable risk factors for stroke are those that have less proof of either a link to stroke or the impact of modifying the risk factor. These factors include: - obesity
- sedentary lifestyle
- alcohol abuse
- high blood levels of homocysteine, a blood component sometimes associated with a higher risk of stroke
- drug abuse
- blood disorders, such as blood that clots easily or deficiencies of various blood components
- hormone replacement therapy (HRT). The AHA currently states that the risk of stroke associated with HRT appears low but needs further study.
- use of birth control pills, or oral contraceptives
- inflammatory processes, such as a chronic infection with chlamydia
Several recent studies have identified factors that seem to increase or decrease the risk of stroke in particular groups of people. These studies, which warrant further investigation, include these findings: - Women ages 39 to 50 who ate more fish and omega-3 polyunsaturated fatty acids had a reduced risk of stroke. This was particularly true in women who did not take aspirin regularly.
- Women ages 15 to 44 who had 2 drinks of wine a day had a 40% to 60% lower risk of stroke than women who did not drink alcohol.
- Phenylpropanolamine, a compound contained in appetite suppressants and cold remedies, significantly increased the risk of haemorrhagic stroke in women 18 to 49 years of age.
What can be done to prevent the condition?
Carotid dissection can be prevented by avoiding any trauma to the head or neck. Sometimes it occurs for no apparent reason. It's important to use seat belts while driving. Head injuries and neck injuries can be minimised by following sports safety guidelines for children, adolescents, and adults.
People can also lower their risk of stroke from carotid dissection by addressing other risk factors for stroke as stated above.
Measures to reduce the modifiable risk of high blood pressure include: - measurement of blood pressure in adults at least every 2 years to screen for high blood pressure
- weight control
- physical activity
- moderation in alcohol intake
- moderate sodium intake
- for those who smoke, quitting smoking
- medications to treat high blood pressure if the person's blood pressure is over 140/90 after 3 months of these lifestyle modifications, or if the initial blood pressure is over 180/100
Other measures to reduce an individual's modifiable risk factors for stroke may include: - smoking cessation using nicotine patches, counselling, and formal smoking programs
- control of blood sugar levels in a person with diabetes through medication, diet, and exercise
- the use of ramipril in people with diabetes. A recent study showed that people with diabetes have a 33% lower risk of ischemic stroke if they take ramipril.
- careful evaluation of asymptomatic carotid stenosis to determine the need for surgery. Coronary artery surgery, such as an endarterectomy, may be indicated. An endarterectomy opens the narrow portion of the artery and increases the blood flow to the brain. People with carotid stenosis should also work closely with their doctors to control other risk factors for stroke.
- treatment of atrial fibrillation with blood thinners such as aspirin or warfarin, depending on the person's age and other risk factors
- monitoring of high levels of total cholesterol or LDL, as well as low levels of HDL. Depending on the blood levels and the person's other risk factors, medications to lower cholesterol may be given.
Measures to reduce less well-documented or potentially modifiable risks for stroke may include: - weight reduction in overweight persons
- 30 or more minutes of moderate exercise a day for most individuals. People with heart disease or disabilities should be in a medically supervised exercise program.
- a healthy diet for preventing heart disease, containing at least 5 fruits and vegetables a day
- for those who drink alcohol, drinking in moderation. No more than 4 drinks a day for men and 2 drinks a day for women.
- seeking treatment for drug abuse
- monitoring of blood levels of homocysteine. For most individuals, a well-balanced diet following the Australian Guide To Healthy Eating.
- avoiding the use of oral contraceptives in women with other stroke risk factors
Some people have early warning signs that they are at risk for strokes. The most common warning sign is what is known as a transient ischemic attack, or TIA. This is a type of reversible stroke that often goes away after a few minutes. These people can often get treatment that will prevent a stroke in the future. For instance, people may be advised to take aspirin or have carotid artery surgery to correct a blockage in a neck artery.
How is the condition diagnosed?
A magnetic resonance angiogram, which involves injecting a dye into an artery or blood vessel for better viewing, may be ordered to detect carotid dissection. In this test, the carotid artery of a person with carotid dissection will show what is called a string sign. This is described as an elongated, irregular, narrow column of dye in the artery.
A carotid ultrasound can be used to make a diagnosis.
Cranial MRIs and cranial CT scans may be ordered to show the type, size, and location of the stroke.
What are the long-term effects of the condition?
Strokes can cause death or permanent disability. Though many people recover some function in the first several months after a stroke, others show no improvement. Some people have several small strokes over time and slowly get worse with each one.
What are the risks to others?
Strokes are not contagious and pose no risk to others.
What are the treatments for the condition?
A person with a stroke from carotid dissection is usually treated immediately with the blood thinner heparin administered through the vein. After heparin, another blood-thinning medication, warfarin, is taken orally.
If someone has the early warning signs of stroke, the emergency medical system should be contacted immediately. These signs include a sudden onset of: Supportive therapy may also be needed with some strokes. This may include an artificial breathing machine, or ventilator, and an artificial feeding tube if the person cannot swallow.
Rehabilitation services can help to improve a person's function after a stroke. Physiotherapy and other therapy, such as speech therapy or occupational therapy, may be used to maximise recovery.
What are the side effects of the treatments?
Excessive bleeding from the blood-thinning medications, or anticoagulants, is possible. People need to avoid activity that may cause bruises or cuts, such as rough sports or working with sharp tools.
What happens after treatment for the condition?
After the person is stable, treatment of the risk factors for stroke, as well as the cause of the stroke, is important to prevent further strokes. For instance, stopping smoking and controlling high blood pressure, diabetes, and high cholesterol are advised for most people.
Blood thinners such as warfarin may be discontinued in several months or a year depending upon the results of a repeat imaging test. The doctor may discontinue these medications if the angiogram shows that the opening of the carotid artery is unblocked so that enough blood can flow through the artery. This is known as a patent artery and is considered to be at least 50% of normal diameter with a smooth wall.
Many people need assistance of one form or another after a stroke. This may range from using a walking cane to needing 24-hour-a-day skilled nursing care. Ongoing therapy to improve function is usually advised for at least 6 months if the person is able.
How is the condition monitored?
If an individual takes blood thinners, blood tests are normally done to assure the correct dose. These tests let a doctor know if the person's blood is too "thin" or too "thick," which may require a dosage adjustment. Any new or worsening symptoms should be reported to the doctor. The doctor may order a repeat ultrasound, CT or MRI of the carotid artery or brain.
Author: Tamara Miller, MD
Reviewer: HealthAnswers Australia Medical Review Panel
Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia
Last Updated: 1/10/2001
Contributors
Potential conflict of interest information for reviewers available on request |
