Stroke is a "brain attack." Just as an interruption of blood flow to the heart causes heart attack, an interruption of blood flow to the brain causes stroke.
Stroke happens when a blood vessel in the brain is blocked or ruptured by a blood clot. Starved of oxygen and nutrient-rich blood, surrounding brain cells die — 2 million brain cells each minute. Rapid medical treatment — started within three hours after the onset of symptoms — can make the difference between a lifetime of disability and full recovery.
Stroke typically affects persons who are aged 60 years or older. However, they affect women slightly later in life than men.
Thankfully, stroke can be prevented — by managing factors that contribute to the event, such as high blood pressure, smoking and high cholesterol. At John C. Lincoln, we are adopting the latest in proven emergency treatments that aid chances of survival and promote full neurological recovery.
Types of Stroke and their Causes
Strokes can be ischemic, hemorrhagic, or a transient ischemic attack.
Request a referral to a John C. Lincoln stroke specialist. In an emergency, please call 9-1-1.
Ischemic stroke accounts for approximately 85 percent of all stroke cases. Ischemic stroke takes place when a blood vessel within the brain becomes blocked by a blood clot, restricting the circulation of blood to an area of the brain. These strokes typically result from clogged arteries — or "atherosclerosis" — the build-up of fat, cholesterol and other substances (called plaques) on blood vessel walls. There are two categories of ischemic stroke:
- Thrombotic stroke is the result of a blood clot developing within a blood vessel that supplies blood to the brain, such as one of the two carotid (ka-ROT-id) arteries of the neck that carry blood to your brain.
- Embolic stroke occurs when a blood clot forms in a blood vessel outside of the brain, in another part of the body, breaks apart and is swept into the brain by blood flow. Often, embolic stroke is linked to atrial fibrillation, a heart rhythm irregularity. Because blood pools up in the heart's atrium, blood clots can form.
Hemorrhagic stroke occurs when a weakened blood vessel ruptures within the brain (a hemorrhage), causing immediate bleeding from the blood vessel.
There are two categories of hemorrhagic stroke:
- Intracerebral stroke occurs when bleeding spills into surrounding brain tissue, damaging brain cells. Brain cells are irritated by swelling.
- Subarachnoid stroke is caused when an artery on or near the surface of the brain begins to rupture, and blood begins to fill the space between the brain and the skull. Blood irritates brain tissue, causing it to swell. In turn, pressure is increased on the brain; it can be forced against the skull.
Either type of hemorrhagic stroke is most frequently caused by high blood pressure (hypertension), which exerts stress on artery walls. High blood pressure can cause blood vessels in the brain to become brittle. If a brittle artery wall develops a weak spot, it can rupture and bleed; this is called an aneurysm.
Transient ischemic attack (TIA) is often referred to as "mini-stroke," but should be treated just as seriously as stroke. A TIA is considered transient — or temporary — because blood flow is restricted to a specific part of the brain for just 15 minutes or less. Although TIA may be painless and temporary, it can serve as a warning of stroke. Like ischemic stroke, TIA is caused by a restriction of blood flow to the brain, due to a blood clot. However, unlike ischemic stroke, TIA does not lead to permanent damage.
» Learn how to recognize the signs and symptoms of stroke
Carotid Artery Disease
Stroke and transient ischemic attack can be caused by carotid artery disease — the development of atherosclerosis (fatty plaques) in a carotid artery. The body has two carotid arteries. From the heart to the temple, these highly important blood vessels deliver blood to the brain and head. As plaques build in these arteries, a blood vessel can be narrowed severely or blocked completely.
Carotid artery disease is very similar to coronary artery disease. In carotid artery disease, blood flow is restricted to the brain. In coronary artery disease, blood flow is restricted to the heart.
Carotid artery disease progresses slowly. For this reason, it often does not have noticeable symptoms. The condition may go unnoticed until a stroke or TIA occurs.
In the treatment of stroke, there is a saying that "time is brain." The sooner that a patient can receive treatment, the more the brain can be spared from irreversible damage. Stroke is a serious medical emergency. Every second counts.
Damage to the brain can be limited by cooling the body's core temperature. Doing so slows the heart, slows bleeding and therefore reduces swelling caused by bleeding in the brain.
Treatment given for stroke depends upon the type of stroke the patient is suffering:
For ischemic stroke, the goal of treatment is to remove blood vessel blockages and restore full blood flow to the brain, as quickly as possible. If a patient arrives within a few hours of first experiencing stroke symptoms, the patient can be given a drug called tPA, or tissue plasminogen activator. Administered by IV drip, tPA dissolves blood clots and reduces the severity of damage to the brain. Other blood thinning medications may be used.
Blockages in the carotid artery of the neck can be removed with carotid endarterectomy. Blockages within blood vessels of the brain can be removed by balloon angioplasty, a balloon-tipped catheter is maneuvered into the obstructed area of the artery. The balloon inflates, opening the artery and pushing plaque against the artery walls. This may be followed by inserting a wire-mesh tube, called a stent, to keep the artery open.
Treatment for hemorrhagic stroke depends upon the source and severity of bleeding. Medications are typically given to lower blood pressure and reduce swelling around brain tissue. If the patient has been taking blood-thinning medications, those are discontinued immediately.
In aneurysm, when a blood vessel ruptures, a procedure called aneurysm clipping involves placing a clip on the aneurysm, to prevent further leaking of blood from the artery. Meantime, endovascular surgery involves threading a catheter and pushing delicate wires into the aneurysm site; the wires create a coil, around which a blood clot forms, sealing the blood vessel.
Emergency Stroke Care at John C. Lincoln
At John C. Lincoln, emergency stroke care involves a skilled, highly coordinated team of neurologists, neurosurgeons, radiologists, nurses, rehabilitation physicians and therapists. Together, they use the latest diagnostic and surgical techniques to identify and reverse damage to the brain caused by stroke.
"Door to CT time" of 45 minutes is one of our standards for stroke care. It is a measurement of the time that passes between each stroke patient's arrival in the emergency room and the moment we interpret a diagnostic CT scan — the key instrument for determining the type of stroke. Faster diagnosis enables us to provide the necessary treatment, such as blood clot-bursting tPA for ischemic strokes, and help limit damage to the brain.
» Learn more about neurological stroke care at John C. Lincoln.