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Most strokes occur due to years of high blood pressure…or when the gradual buildup of fatty substances (plaque) in the arteries cuts off blood flow to the brain.
An unusual and little-recognized trigger: Some people get strokes from simply moving the neck in an extreme way or holding it in an odd position. This sort of neck movement might occur during a car accident, for example—but it might also be caused by normal activities such as riding a roller coaster, craning your neck to paint a ceiling or leaning back to have your hair shampooed at a hair salon (the so-called "beauty parlor syndrome").
The culprit in such strokes is a vertebral artery dissection (VAD), a tear in the innermost or middle layer of the three-layered vertebral artery wall, which can disrupt blood flow to the brain. Sometimes, the damage is minor and the artery repairs itself without difficulty. In other cases, however, the arterial injury leads to a stroke.
For more on this topic, see
How to Prevent a Stroke
New development: The American Heart Association (AHA) recently issued a warning that neck manipulation (used, for example, during certain chiropractic or physical therapy treatments) has been linked to stroke due to such arterial injuries. While no direct cause-and-effect relationship has been found, the AHA now advises health-care practitioners to inform their patients of the association before performing neck manipulation.
WHEN AN ARTERY SHREDS
The right and left vertebral arteries run up the back of the neck and into the skull, carrying blood to the brain. A stroke-inducing arterial tear can result from virtually any sudden and/or extreme movement that turns or stretches the neck excessively. But in many cases, people with VAD can recall nothing more unusual than a sneeze or vigorous sexual activity in the preceding days, and sometimes there is nothing to blame it on.
Why the cause can be elusive: Some people are apparently more vulnerable to VAD than others. It is more common in those with known connective tissue disorders such as Marfan's syndrome or fibromuscular dysplasia. Also, some studies have found that artery walls in people who have suffered dissections look subtly abnormal under the microscope, suggesting a congenital abnormality.
But practically speaking, there is no way to predict who will get a VAD or what will cause it. There are warning signs, though. And if you've already suffered a VAD, there are steps you can take to help prevent another one.
RED FLAGS FOR VAD
Each year, approximately 4,500 Americans suffer VAD. The condition is a leading cause of stroke in adults under age 45. VAD also can occur, though less commonly, in older adults. Of course, the best course is to spot a VAD early—before it can cause a stroke.
Recent finding: An analysis of 75 studies involving nearly 2,000 people diagnosed with VAD found that dizziness or vertigo was the most common symptom, reported by 58% of sufferers, with headache (51%) and neck pain (46%) close behind.
The trouble is that dizziness, headache and neck pain are extremely common and can be caused by many different conditions. And you can't run to the doctor to check out every headache or dizzy spell.
When to be concerned: If you have a headache that is more severe than usual…suffer extreme dizziness…have neck pain that is unusual for you…or if any of these symptoms occur at the same time or last longer than a day. Call or visit your doctor without delay.
When to be very concerned: If you develop symptoms such as double vision, difficulty walking, speaking or swallowing, and/or weakness on one side of your face or body, particularly if they occur with dizziness, neck pain or headache. These could be signs that a stroke or transient ischemic attack (TIA), a temporary blockage of brain circulation, is occurring.
A sudden and severe "thunderclap" headache (the kind that people describe as "the worst headache of my life") may indicate that a brain hemorrhage is imminent or has happened.
Prompt emergency care in these situations could mean the difference between complete recovery and disability or death.
PREVENTING AN ARTERIAL TEAR
If you have ever had an episode of VAD, you are at increased risk for another. This doesn't mean that you should stop all exercise or keep your neck in a brace, but you may want to pass on activities that could easily lead to a neck injury, such as mountain biking and skydiving.
Also, if you've had a VAD, avoid any situations where your neck is stretched out for prolonged periods—for example, try to avoid hyperextending your neck at an extreme angle backward while getting your hair shampooed or styled. Don't give up yoga, but skip postures that stress your neck. If you receive chiropractic care, it's safest for manipulations to be performed below neck level.
DIAGNOSING AND TREATING AN ARTERIAL TEAR
If your doctor suspects that you've suffered a vertebral artery dissection (VAD), he/she will probably order a CT scan or MRI. Treatment for a VAD usually includes a drug to keep clots from forming, most commonly warfarin (Coumadin). If you have a VAD, it's common to take the drug for three to six months. If symptoms persist, your doctor may recommend that a stent or coil be surgically placed in the damaged artery.
Precautions: While VAD is less likely to cause a stroke once you begin taking an anticoagulant, anticlotting drugs themselves carry the risk of bleeding. Your doctor should advise you what activities to avoid during this time—this usually includes anything that could cause head injury. Patients on oral anticoagulants also should have their blood levels checked regularly and need to maintain a regular diet in order to keep their blood thin enough while they are taking this medication.
Source: Rebecca Gottesman, MD, associate professor of neurology and epidemiology at The Johns Hopkins University School of Medicine and director of clinical research at Johns Hopkins Bayview Neurology, both in Baltimore.
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