Stroke


What is stroke?

A stroke occurs when there is a blockage of blood and oxygen to the brain, which can kill or damage brain cells.

When someone experiences a stroke, every minute is critical. The more quickly they can receive care, the better chance they have of recovering.

About 80 percent of strokes are ischemic, which occur when the arteries the brain become narrowed or blocked, causing severely reduced blood flow.

The two types of ischemic stroke include thrombotic stroke and embolic stroke:

  • a thrombotic stroke occurs when a blood clot forms in an artery that supplies blood to the brain
  • an embolic stroke occurs when a blood clot or other debris forms away from the brain and is swept through the bloodstream, and becomes lodged in narrower brain arteries.

The other main type of stroke is a hemorrhagic stroke, which occurs when a blood vessel in the brain leaks or ruptures.


What causes stroke?

The top risk factors of stroke include:

  • High blood pressure
  • Heavy tobacco and alcohol use
  • Heart disease
  • High cholesterol
  • Diabetes
  • Obesity and lack of exercise
  • Use of anti-coagulant medication (blood thinners)
  • Old age
  • Family history of stroke

Signs and symptoms of stroke

If you think you or someone else might be suffering a stroke, you need to act fast. Use the word FAST to help remember the warning signs:

FACE: Ask the person to smile. Does one side of the face droop?
ARMS: Ask the person to raise both arms. Does one arm drift downward?
SPEECH: Ask the person to repeat a simple phrase. Is their speech slurred or strange?
TIME: If you observe any of these signs, don’t wait. Call 9-1-1 immediately, and write down the time when symptoms first began.

Other signs of stroke include the sudden onset of:

  • Change in alertness (including sleepiness, unconsciousness, and coma)
  • Severe headache with no known cause
  • Confusion or trouble understanding
  • Loss of vision in one or both eyes
  • Difficulty walking, dizziness, loss of balance or coordination

How is stroke diagnosed?

Physical exam. Your doctor will perform a physical exam to rule out any other conditions, and will measure your blood pressure and listen to your heartbeat to check for a “whooshing” sound over your carotid arteries, located in the neck.

If present, this sound can indicate the presence of plaque buildup within the walls of the heart’s arteries. Your doctor might also inspect your eyes to look for signs of tiny cholesterol crystals, or clots, in the blood vessels at the back of your eyes.

Blood tests. Blood tests can reveal how quickly your blood clots, measure levels of blood sugar and other key chemicals, and identify an infection.

Managing these components will be important to your stroke care.

Carotid ultrasound. This test uses sound waves to created detailed images of the inside of the carotid arteries in the neck, which can reveal plaque buildup and decreased blood flow.

Echocardiogram. Similar to an ultrasound, an echocardiogram uses sound waves to create detailed images of the heart, which help providers identify the clots in your heart that may have traveled to your brain and caused a stroke.

Cerebral angiogram. With the help of biplane interventional imaging, a small tube called a catheter is inserted into a major artery (typically, in the groin) and guided through the arteries in the heart up to the brain.

Biplane imaging technology produces detailed 3-D images of the structure and location of blood vessels, soft tissues and blood flow in real-time, enabling providers to identify a clot or hemorrhage and evaluate its condition.

CT scan (computerized tomography). A CT scan uses a series of X-rays to create detailed, 2-D images of the brain. Contrast dye is often injected into the blood vessels to help highlight blood flow throughout different areas of the brain, better enabling providers to detect any abnormalities.

When dye is used to assist in this type of scan, the variation is called a CT angiogram.

MRI (Magnetic resonance imaging). An MRI renders intricate images of the brain, utilizing powerful magnets and radio waves, rather than radiation, to produce 2-D and 3-D images of the soft tissue.

Compared to a CT scan, MRI technology can show more subtle changes in brain tissue and a more precise location of any malformation and related bleeding, which is helpful in diagnosing a stroke.


What are the treatment options?

For a patient who has suffered an ischemic stroke, it is critical that providers restore blood flow to the brain as quickly as possible.

EvergreenHealth’s specialized stroke team is available 24/7 to administer leading-edge clot-busting medication, tPA (tissue plasminogen activator), which must be administered within three hours of the onset of symptoms in order to most effectively dissolve the clot and reverse the symptoms.

Additionally, our experts can use biplane interventional imaging to perform a thrombectomy, an endovascular procedure in which a catheter is inserted through a main artery in the groin and guided up to the brain. Attached to the catheter is a stent or other device, which the physician maneuvers into the blocked blood vessel to trap and remove the clot. This procedure should be performed within six hours of the onset of systems, and is often performed in combination with administering tPA medication to dissolve larger clots.

Hemorrhagic strokes are often caused by aneurysms or AVMs