More Than You Ever Wanted to Know About Strokes
By Kathy Hubbard
When we talk about strokes we’re most often referring to ischemic strokes. These are the ones that occur when a vessel supplying blood to the brain is obstructed and is credited with about 87 percent of all strokes.
“Fatty deposits lining the vessel walls, called atherosclerosis, are the main cause for ischemic stroke,” the American Stroke Association explains. These fatty deposits can cause two types of obstruction. Cerebral thrombosis is a blood clot that develops in the blood vessel, while cerebral embolism is one that forms somewhere else in your circulatory system, usually your heart and large arteries of the upper chest and neck.
“Part of the blood clot breaks loose, enters the bloodstream and travels through the brain’s blood vessels until it reaches vessels too small to let it pass,” ASA says.
In some instances, despite testing, the cause of the stroke can’t be determined. Strokes without a known cause are called “cryptogenic.” ASA says that approximately 25 percent of ischemic strokes are cryptogenic.
We’ve talked before about the signs of stroke, but to reiterate just think of the mnemonic FAST. You know, Face drooping, Arm weakness, Speech difficulty and Time to call 911. Other symptoms include sudden numbness especially on one side of the body, sudden confusion, and trouble walking.
Often called “mini strokes,” transient ischemic attacks (TIAs) are caused by a serious temporary clot. This temporary blockage of blood flow to the brain is a major warning that something much more serious may be on the horizon and should be reported to your primary care provider even though symptoms which can mirror those of an ischemic stroke have disappeared.
“TIA is a temporary blockage of blood flow to the brain. Since it doesn’t cause permanent damage, it’s often ignored. But this is a big mistake. TIAs may signal a full-blown stroke ahead,” ASA says.
Not to be confused with a TIA is a silent cerebral infarction (SCI). This is when you have a stroke and don’t know it. “Silent stroke is likely caused by a blood clot that interrupts blood flow in the brain. It’s a risk factor for future strokes and a sign of progressive brain damage,” ASA says.
People at high risk are those over 65 with a history of atrial fibrillation (irregular heartbeat) and those with a high systolic blood pressure. Preventing SCI is another really good reason to get hypertension (high blood pressure) under control.
Hemorrhagic strokes also called intracerebral hemorrhage (ICH) make up about 13 percent of stroke cases. What happens is that a weak vessel bursts and the resulting blood accumulates and compresses the surrounding brain tissue.
“Two types of weakened blood vessels usually cause hemorrhagic stroke: aneurysms and arteriovenous malformations (AVM),” ASA explains. “An aneurysm is a ballooning of a weakened region of a blood vessel. If left untreated the aneurysm continues to weaken until it ruptures and bleeds into the brain. An AVM is a cluster of abnormally formed blood vessels. Any one of these vessels can rupture, also causing bleeding into the brain.”
Although symptoms can vary, they most often include total or limited loss of consciousness, nausea, vomiting, sudden and severe headache, seizures, dizziness, loss of balance, and similar to ischemic stroke symptoms, the patient may have problems with speech or swallowing, confusion and disorientation.
If you are experiencing any combination of these symptoms you should get emergency medical assistance right away. Do not drive yourself to the hospital, call 911.
And, the last type of stroke we want to be aware of is a brain stem stroke which can have complex symptoms that are difficult to diagnose.
“A person may have vertigo, dizziness and severe imbalance without the hallmark of most strokes – weakness on one side of the body,” ASA explains. “The symptoms of vertigo dizziness or imbalance usually occur together; dizziness alone is not a sign of stroke. A brain stem stroke can also cause double vision, slurred speech and decreased level of consciousness.
The brain stem, only a half-inch in diameter, controls all basic activities of the nervous system. If the stroke in the brain stem results from a clot, the faster blood flow can be restored the better chances of recovery.
Bonner General Health’s Telestroke Network provides 24/7 access to neurologists via teleconference. If you experience any stroke-like symptoms, don’t wait, call 911.
Kathy Hubbard is a member of Bonner General Health Foundation Advisory Council. She can be reached at [email protected].