Understanding Stroke

What is a stroke?

Chances are, you're familiar with the term "stroke" and understand that it is a serious medical condition. However, you may be less familiar with what exactly a stroke is and why it's so dangerous.

It may be helpful to think of a stroke as a brain attack, because it occurs in the brain and causes harm. Medically speaking, a stroke is the result of reduced or blocked blood flow to your brain. If blood can't reach your brain, then oxygen can't reach your brain, and a lack of oxygen causes your brain cells to quickly die.

What causes a stroke?

A stroke is caused by one of two things — either a blood vessel in your brain becomes blocked, or a blood vessel starts to leak. To that end, there are two different kinds of stroke:

• An ischemic stroke occurs when a blood clot becomes stuck in one of the arteries in your brain, and prevents blood from flowing through that artery. If your arteries have become severely narrowed due to build-up of a sticky substance called plaque (a condition known as atherosclerosis), blood can't travel through them as easily. Blood clots that cause ischemic stroke can form in the brain, or they can travel to the brain from somewhere else in the body.
• A hemorrhagic stroke occurs when one of the blood vessels in your brain starts to leak, or even bursts like a balloon. When this occurs, blood flows out of the opening and into your brain, instead of continuing to travel through the blood vessel. This means the portions of your brain located beyond the damaged blood vessel can no longer receive blood and oxygen. Additionally, when blood leaks into your brain, it damages brain cells.

There is also a third, stroke-like condition known as a "mini-stroke." Formally called a transient ischemic attack, or TIA, it occurs when blood flow to your brain is reduced, but only temporarily (usually five minutes or less). During a TIA you may briefly experience symptoms that mimic those of a stroke. Unlike a true stroke though, the symptoms go away.

It is important to understand that even though TIA symptoms come and go, they often are warning signs of an impending stroke. That's why you should immediately report any stroke-like symptoms to your doctor, even if they lasted only a few minutes.

How harmful are strokes?

Regardless of the cause, a stroke can result in death or life-long disability if not treated quickly. If you survive, you may have temporary or long-term complications. The severity and duration of complications depends on how long your brain was without oxygen, and where in the brain your stroke occurred. Stroke complications can include:

• Paralysis, often on one side of the body
• Trouble speaking or understanding speech
• Difficulty swallowing
• Memory problems, including memory loss and trouble thinking or comprehending
• Emotional problems, including depression
• Pain or numbness in the parts of your body that were affected by the stroke

What are the symptoms of a stroke?

If you or a loved one suffers a stroke, the more quickly you receive treatment, the better your chances of surviving or avoiding permanent disability. That's why it is important to learn the warning signs.

Stroke symptoms vary by individual and depend on the cause (a blood clot versus a leaking blood vessel), and the area of the brain impacted. Different areas of the brain help control different functions, including speech, vision and muscle control.

In general, stroke symptoms tend to develop suddenly and can include:

• Numbness, weakness or paralysis in an arm, leg or your face, especially on one side of the body
• Trouble speaking, including slurred speech
• Confusion, including problems understanding speech
• Trouble seeing in one or both eyes, including blurred or double vision
• Severe headache, with or without vomiting
• Dizziness
• Loss of balance or coordination, including trouble walking
• Breathing problems
• Loss of consciousness

Take action if you develop stroke symptoms

It is imperative that you seek immediate medical attention if you experience any of the above symptoms, even if they start to go away (remember, symptoms of a TIA are temporary but may signal an impending stroke).

Do not try and drive yourself to the hospital. Instead, call 911. Not only is it safer and potentially faster for an ambulance to transport you to the nearest emergency room, the paramedics on board may be able to administer lifesaving treatment before you even reach the hospital.

If possible, make note of the time your symptoms began and alert the 911 dispatcher or paramedics. The type of treatment you receive may depend on the length of time you've been experiencing symptoms.

Who is at risk for a stroke?

While stroke can happen to anyone, there are numerous risk factors that can increase your likelihood of having a stroke. Some of these risk factors are preventable, and some are not.

Risk factors that usually can be controlled include:

• Smoking (or chronic exposure to secondhand smoke)
• Obesity
• High blood pressure
• High cholesterol
• Sedentary lifestyle (lack of exercise or other physical activity)
• Alcohol or illegal drug abuse (especially cocaine and methamphetamines)
• Chronic stress or depression
• Poorly managed or untreated medical conditions including diabetes, sleep apnea and heart disease

There are other stroke risk factors that cannot be controlled. These include:

• Age (our stroke risk increases as we get older, especially after age 55)
• Gender (at younger ages, men are at higher risk for stroke than women, although women are more likely to die from stroke at any age)
• Race and ethnicity (African-Americans and Native Americans have a higher risk of stroke than people of other ethnic backgrounds)
• Family history of stroke

How is a stroke diagnosed?

If you're taken to a hospital with a suspected stroke, your health care team will need to confirm whether you are having an ischemic or hemorrhagic stroke, and where in the brain it is occurring. They will use a combination of some of the following diagnostic tests:

• A medical history and physical exam can give your medical team important clues about your stroke risk. A doctor will ask you or a loved one about your symptoms, including what they are and what time they began. He or she will evaluate you to see if you are still experiencing these symptoms, and will check other vital signs including your blood pressure. The doctor also will ask you about any medications you take, your overall health and your family history of stroke.
• Blood tests may be used to check several important stroke indicators, including your blood sugar level and how quickly your blood clots.
• A computerized tomography (CT) scan captures X-ray images of the head and can confirm whether there is bleeding in your brain. Your doctor may pair this scan with a special dye injected into your blood stream, so he or she can observe how well blood is flowing in your brain. This is called CT angiography.
• A magnetic resonance imaging (MRI) scan captures 3-D images of your brain and can confirm whether brain tissue has been damaged by the stroke. Your doctor may use a variation of this test, called MR angiography or MRA, which shows the arteries in your brain in greater detail.
• A cerebral angiogram is a minimally invasive test that combines X-rays and a special dye to see inside the arteries in your brain and evaluate how well blood is flowing through them.
• A carotid ultrasound is a painless test performed with a small ultrasound wand. Once the wand is placed against your neck, it produces pictures of your carotid arteries to confirm whether plaque has built up inside of them (these are the main arteries that run through your neck, carrying blood from your heart to your brain). People with narrowed carotid arteries, a condition called carotid stenosis, are at an increased risk for stroke.
• An echocardiogram, which uses sound waves to create pictures of your heart, may be used to see whether there are blood clots in your heart. Sometimes strokes are caused by blood clots that travel from the heart to the brain.

How is a stroke treated?

If you require emergency medical care for a stroke, the treatment you receive will depend on the type of stroke you're having and what time your symptoms started.

If you're having an ischemic stroke, your medical team will need to quickly dissolve or remove the blood clot that is limiting blood flow to your brain.

Treatments for ischemic stroke include:

• Aspirin helps prevent blood clots from forming, and may prevent another stroke from occurring. That's why many stroke patients receive an immediate dose of aspirin when they arrive in the emergency room.
• Tissue plasminogen activator, also known as tPA, is a medication that helps dissolve blood clots. In order for tPA to increase the odds of survival and decrease the risk of complications, it must be injected into an arm vein as soon as possible (within four hours of the time that stroke symptoms first appeared).
• Thrombolysis is a minimally invasive procedure that helps break up a clot stuck inside an artery. During the procedure, a neurosurgeon threads a small, flexible tube called a catheter through the arteries (often starting in the groin area) until it reaches the area of the brain where the stroke is located. A clot-dissolving drug is then delivered through the catheter, directly to the brain.
• Mechanical clot removal is also a minimally invasive procedure that allows a neurosurgeon to access the brain via a catheter threaded through the arteries. During the procedure, a tiny device attached to the end of the catheter either breaks up the clot, or grabs it and removes it.

If your doctor suspects your ischemic stroke may be related to carotid stenosis, he or she may recommend you also have one of the following surgical procedures. Both treatments are used to open up a narrowed or blocked carotid artery, to help prevent another stroke from occurring.

• During a carotid endarterectomy, a surgeon makes an incision in the neck, opens the carotid artery and removes any plaque that is blocking the vessel.
• Carotid angioplasty and stenting is a minimally invasive procedure that uses a balloon-tipped catheter to first inflate the narrowed artery, and then insert a tiny device called a stent to keep the artery propped open.

If you're having a hemorrhagic stroke caused by a leaking or ruptured blood vessel, the medical team will use medication or surgery to stop the bleeding in your brain.

Treatments for hemorrhagic stroke include:

• Medication may be used to help get the bleeding in your brain under control. If you regularly take a blood thinner (such as Coumadin) or an anti-platelet drug that prevents blood clots (including Plavix), its presence in your bloodstream can make the bleeding in your brain worse. Your medical team may give you drugs that cancel out the effects of your regular medication. Depending on your situation, you also may be given drugs to lower your blood pressure or the pressure in your brain.
• Surgical clipping is an "open" surgical treatment that may be used for hemorrhagic strokes caused by an aneurysm. During the procedure, a neurosurgeon removes a piece of skull located near the aneurysm. Once the surgeon finds the bulging artery, he clamps a tiny metal clip at the neck of the aneurysm to stop blood from flowing into it.
• Endovascular coiling is a minimally invasive treatment that does not require open brain surgery, and is also used to treat hemorrhagic stroke caused by an aneurysm. During the procedure, a surgeon threads a catheter through the arteries (usually starting in the groin area) until it reaches the aneurysm. He then pushes a tiny coiled wire through the catheter and into the bulging artery. Once inside the aneurysm sac, the coil reduces or blocks blood flow, significantly reducing or eliminating the risk of rupture.
• Endovascular or open AVM treatments may be used if your hemorrhagic stroke was caused by an arteriovenous malformation in your brain. Neurosurgeons use a variety of procedures to remove or seal a bleeding brain AVM.

Recovering from stroke

Following emergency stroke treatment, you may need additional medical care (including physical, occupational or speech therapy) to address any short-term or long-term complications caused by your stroke. The services you may need, and the length of time you need them, will depend on the severity of your complications.

Before you are discharged from the hospital, a member of your medical team will discuss your ongoing care needs with you and your loved ones.

A lifesaving collaboration

Since Lyerly Neurosurgery was founded in 1934, our physicians have cared for thousands of people who need treatment for a brain or spine condition.

Today our practice continues to build upon a legacy that blends compassion, safety and innovation. Our neurosurgeons provide the full spectrum of evidence-based care, including the latest minimally invasive procedures that can only be offered by neurosurgeons with advanced training and experience.

Together with Baptist Medical Center Jacksonville, a certified Comprehensive Stroke Center, our team performs emergency neurosurgery services, including new endovascular treatments, for patients who have had a stroke or TIA.

The Joint Commission and the American Heart Association grant their elite Comprehensive Stroke Center certification to only a select number of hospitals that meet and exceed rigorous standards of care designed to help stroke patients survive and recover.