Stroke From Carotid Dissection
- brain attack
- stroke following carotid dissection
A stroke is the death of brain tissue that occurs when a part of 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, thus interrupting the blood supply to the brain.
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 may cause a blockage of the artery and impair blood flow to the brain, or it may be the source of an embolism (traveling clot) that may lodge in one of the smaller arteries in the brain and cause a stroke. The brain cells then die from lack of oxygen.
What are the causes and risks of the condition?
Carotid dissection can be brought on by:
severe whiplash injury, which occurs when the neck is suddenly and forcibly bent backwards and forwards, as in a motor vehicle crash
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 American Heart Association has recently issued guidelines for stroke prevention. The guidelines discuss risk factors for stroke in 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 increases markedly with each year of age after 55.
race. Strokes occur approximately twice as often in blacks and Hispanics as they do in whites.
sex. 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 healthcare professional. 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:
high blood pressure
asymptomatic carotid stenosis, or narrowing of one of the arteries in the neck
sickle cell anemia, a blood disorder that forms abnormal red blood cells
high cholesterol levels in the blood, including total cholesterol and LDL ("bad" cholesterol). Low levels of HDL ("good" cholesterol) are also cause for concern.
- atrial fibrillation, an abnormal heart rhythm
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:
- 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:
People who were treated for high blood pressure with thiazide diuretics, such as hydrochlorothiazide, had a significantly lower stroke risk than people on ACE inhibitors or calcium channel blockers.
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.
Persons who drank the equivalent of approximately one glass of wine a day had a 32 percent lower risk of stroke than individuals who did not drink alcohol.
Phenylpropanolamine, a compound contained in appetite suppressants and cold remedies, significantly increased the risk of hemorrhagic stroke in women 18 to 49 years of age. The Food and Drug Administration (FDA) has since asked manufacturers to remove phenylpropanolamine from their products.
In one study, people who were treated in emergency departments for transient ischemic attacks (TIA) had a 25% chance of having a stroke or other serious health event within the next 90 days.
What can be done to prevent the condition?
Carotid dissection can be prevented by avoiding any trauma to the head or neck. It's important to use seat belts while driving. Head injuries and neck injuries can be minimized 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. The American Heart Association guidelines for stroke prevention address both modifiable and less well-documented or potentially modifiable risk factors.
Measures to reduce the modifiable risk of high blood pressure
- 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, counseling, 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 healthcare providers to control other risk factors for stroke.
- semiannual screening of children with sickle cell anemia, using ultrasound to determine the child's risk of 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. The AHA defines moderate drinking as no more than 2 drinks a day for men and 1 drink a day for women.
- seeking treatment for drug abuse
- monitoring of blood levels of homocysteine. For most individuals, a well-balanced diet following the food guide pyramid will provide enough folic acid and B vitamins to maintain a healthy homocysteine level. For people with elevated homocysteine levels, supplements containing folic acid and B vitamins may be recommended.
- 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?
Diagnosis begins with a careful history and physical examination. A magnetic resonance angiogram, CT angiogram, or conventional angiogram which involves injecting a dye into an artery or blood vessel for better viewing, may be ordered to detect carotid dissection.
On an angiogram, 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. Cranial MRIs and cranial CT scans may be ordered to show the type, size, and location of the stroke.
Long Term Effects
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 lose a little bit more function 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 intravenously. After heparin, another blood-thinning medication called 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:
weakness or numbness of the face, arm, or leg, especially on one side of the body
trouble walking or loss of balance, known as ataxia
speech impairments, including trouble speaking or understanding speech
- visual impairments
Supportive therapy may also be needed with some strokes. This may include a ventilator (artificial breathing machine), and an artificial feeding tube if the person cannot swallow. Rehabilitation services can help to improve a person's function after a stroke. Physical therapy and other therapy, such as speech therapy or occupational therapy, may be used to maximize recovery.
What are the side effects of the treatments?
Excessive bleeding from the anticoagulants (blood-thinning medications) 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, if used, may be discontinued in several months or a year depending upon the results of a repeat imaging test. The healthcare professional 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.
Rehabilitation and prevention of further strokes are the mainstays of treatment once a stroke has occurred.
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 healthcare professional know if the person's blood is clotting too slowly or too rapidly, which may require a dosage adjustment. Any new or worsening symptoms should be reported to the healthcare professional.