Although stroke occurs in the brain, it can affect the entire body. The effects range from mild to severe, and can include paralysis, problems with thinking, problems with speaking, and emotional problems. The types and degrees of disability depend on which area of the brain is damaged.
Sources: Saver, J. L (2006). Time is brain - Quantified. Stroke, 37(1), 263-266. • NIH/National Institute of Neurological Disorders and Stroke. (n.d.). Know Stroke.
Stroke severely disrupts lives and can cause:
- Paralysis or movement problems, including trouble walking or standing and trouble balancing
- Sensory disturbances including loss of the ability to feel touch, pain, or temperature, incontinence, and chronic pain
- Problems communicating, including difficulty speaking or understanding language
- Trouble remembering and thinking, including dramatically shortened attention spans and confusion
- Emotional problems, including fear, anxiety, anger, sadness, and clinical depression
Diagnosing Stroke
Doctors use several tools to help diagnose stroke quickly and accurately. When a person is suspected of having a stroke, an emergency room doctor will carry out a detailed assessment of the person's signs and symptoms. They will also ask when the symptoms began. Because of the importance of early treatment, assessment might even begin in the ambulance. One test that helps doctors judge the severity of a stroke is the standardized NIH Stroke Scale, developed through research supported by NINDS. Other scales that may be used include the Glasgow Coma Scale, the Modified Rankin Scale, and the Barthel Index. These scales can sensitively measure any disabilities that result from stroke.
Healthcare professionals also use a variety of brain imaging techniques to assess stroke risk, diagnose stroke, determine stroke type (and the extent and exact location of damage), and evaluate individuals for clinical studies and beast treatment, including:
CT (Computed tomography)
CT uses x-rays and a computer to create a series of cross-sectional images of organs, bones, and tissue. A plain CT of the head and brain is the most widely used imaging procedure to rule out bleeding. Doctors must determine if there is any bleeding in the brain before giving certain medicines, such as thrombolytic therapy or t-PA (tissue plasmiogen activator), which might increase bleeding or worsen a hemorrhagic stroke. With the injection of a dye, the CT scan can show the large blood vessels supplying the brain and determine if there is a blockage. The dye can also help distinguish good tissue from tissue that is already damaged. A NINDS-funded study recently demonstrated that this technique, called perfusion imaging, can help identify some patients who will still benefit from having a clot removed from the large vessels up to 24 hours after stroke symptom onset.
MRI (Magnetic resonance imaging)
MRI uses magnetic fields and radio waves to produce detailed, 3D computerized images of bone structures, organs, nerves, and tissues, including brain tissue. One effect of ischemic stroke is that water can no longer move freely in injured brain tissue. Diffusion-weighted imaging (DWI), a special type of MRI, measures the movement of water in brain tissue. DWI can diagnose ischemic stroke before it is visible on a non-contract CT scan and is especially useful for detecting small areas of dead tissue caused by loss of blood supply. Using a dye (called a contrast agent) helps doctors see maps of brain blood flow that identify brain regions that have not yet been damaged and may be saved.
Catheter-based angiography
This is a procedure used to find blockages. A catheter (a thin, flexible tube) is inserted into the arteries supplying blood to the brain and a dye is injected. This can reveal the blockage in an ischemic stroke and detect stenosis or vascular malformations, such as an aneurysm or arteriovenous malformation, that put a person at risk for stroke.
Other tools include ultrasound, blood tests of the body's clotting system, an electrocardiogram (a display of the heart's electrical activity and rhythm), and a Holter monitor (which measures the EKG over days to identify episodes of atrial fibrillation).
Although MRI and CT are equally accurate in determining when bleeding is present, MRI provides a more accurate and earlier diagnosis of ischemic stroke, especially for smaller strokes and TIAs. Also, MRI can be more sensitive than CT in detecting other types of neurological disorders that mimic the symptoms of stroke. MRI cannot be performed in people with certain types of metallic or electronic implants, such as pacemakers.
Treating Stroke
A stroke can cause permanent damage to the brain within minutes. Calling 9-1-1 immediately and arriving at the hospital in an ambulance can aid in stroke treatment and recovery. Treatment following a stroke generally falls into three larger approaches:
- Emergency medical or surgical care immediately after a stroke to minimize the extent of injury
- Treatment to prevent a recurrent stroke
- Rehabilitation to manage changes in ability and function that result from stroke
Remarkable progress has been made in acute stroke therapy, especially with stenting and devices for clot removal to restore blood flow in brain arteries. Broadly speaking, treatment for ischemic stroke or TIA may include medicine and medical procedures. Treatment for hemorrhagic stroke involves finding and controlling the cause of bleeding.
Treatments for Ischemic Stroke
Medications
Medication is the most common treatment for ischemic stroke. The most effective kinds of drugs to prevent or treat acute ischemic stroke are antithrombotics (blood-thinning medicines) and thrombolytics (drugs that break up and dissolve existing clots). Another group of medications--called neuroprotectants--protect the brain from secondary injury caused by stroke are being tested in clinical trials.
Ischemic strokes can be treated by returning blood flow to the brain as soon as possible--either suing intravenous thrombolytic drugs or by placing a catheter into the blocked brain artery and removing the slot. In all cases, a person needs medial attention immediately after stroke symptoms start to preserve as much brain tissue as possible.
Surgery and related procedures
Brain blood vessels can be accessed by inserting catheters into large arteries in the leg, which can then be threaded into the brain. This is the basis of catheter angiography, but it is also used to treat vascular abnormalities (like blood clots) that cause stroke. Surgery can prevent or treat some types of stroke and repair damage to the blood vessels. It is also sometimes used to treat malformations in and around the brain.
Another surgical procedure used in stroke cases is carotid endarterectomy, which is a surgery to remove build-up from inside of the carotid artery. The carotid arteries, located in the neck, are the main supplies of blood to the brain. NINDS-sponsored large clinical trials showed that carotid endarterectomy is safe and very effective in preventing stroke in people with carotid-associated TIAs and somewhat effective for preventing stroke in most people without symptoms but who have more that 60% stenosis (narrowing of the carotid arteries). A NINDS-funded trial is now underway to examine the effectiveness of carotid endarterectomy in patients without symptoms to TIA or stroke who are taking aggressive stroke prevention medications.
Stenting
Stenting involves inserting a catheter with a wire inside of it into the diseased artery and then passing a tube-shaped device made of a type of mesh over the wire, known as a stent. The stent is compressed until it is threaded into position, where it is then expanded to widen the artery and flatten the blockage, like chicken wire inside a tube.
In the NINDS-funded Carotid Revascularization vs. Stenting Trial (CREST), scientists compared carotid endarterectomy with stenting. The findings showed that the overall safety and effectiveness of the two procedures was largely the same, with equal benefits for both women and men and for people who had previously had a stroke and for those who had not. However, the study showed that older people generally had a better outcome with surgery and younger people fared better with stenting.
In another NINDS study involving stenting, scientists compared the effectiveness of medical treatment plus stenting to medical treatment alone for the prevention of recurrent stroke in people with severe stenosis of an artery inside the head. The trial showed that aggressive medial treatment alone is better for preventing a second or recurrent stroke, and that stenting the artery increased a person's risk for developing a stroke or major bleeding from complications of the procedure.
Clot removal
Although the use of t-PA is the only medically proven treatment to dissolve a clot, it does not work well in people with larger arteries blocked by large clots because it does not open the vessel in time. To help the person's blood flow normally, clinicians will user either a catheter threaded though the artery to remove the blockage and use a variety of devices to open the artery, including suction to vacuum out the clot or a stent-like device to pull the clot out. Several large, recent clinical studies have shown the benefit of stent-like devices to retrieve clots and return blood flow in people with large clots resulting in severe strokes.
Treatments for Hemorrhagic Stroke
To treat hemorrhagic stroke, which is caused by a blood vessel in the brain that breaks and bleeds into the brain, doctors must find the source of the blood leak and stop or control it. Because these types of strokes get worse with thrombolytics (the medications commonly used to treat ischemic stroke), it is important to determine the type of stroke the person is experiencing before starting emergency treatment.
Because hemorrhagic stroke can be caused by a number of conditions, including cerebral aneurysm, arteriovenous malformations, long-term high blood pressure causing intracerebral hemorrhage, and other conditions, it is important to treat the underlying condition to stop the bleeding, reduce swelling and fluid buildup, remove excess blood from the brain, and avoid recurrence. These treatments can include surgeries, medications, or other related procedures.
Intensive care medical treatment of hydrocephalus (buildup of cerebrospinal fluid in the brain) and brain edema (swelling) is critical right after the stroke and in the weeks and months of rehabilitation. In some people, the blood is primarily in the fluid-filled ventricles of the brain, but the clots frequently block the flow of cerebrospinal fluid--leading to hydrocephalus. Managing hydrocephalus, often by inserting a shunt to drain the fluids and relieve pressure, is essential.
Bleeding from a ruptured cerebral aneurysm (also called a subarachnoid hemorrhage) requires emergency care. it is critically important to treat an aneurysm that has ruptured, because recurrent bleeding is almost always fatal.
One surgical procedure for treatment of brain aneurysms is a technique called "clipping." Clipping involves an operation during which an experienced brain surgeon places a tiny clip or clamp on the neck of the aneurysm (like the neck of a balloon) to prevent it dorm bursting. This is often enough to ensure that the aneurysm stops bleeding and permanently prevent current bleeding.
Another treatment is the endovascular coil technique (also known as endovascular embolization), in which small platinum coils are inserted through an artery in the thigh and threaded through the vessel to the site of the aneurysm. The coil is then released into the aneurysm, where it trigger clotting and an immune response from the body. This immune response strengthens the artery calls and reduces the risk of rupture.
In cases where clipping or using the coil technique is not possible, and the individual has a high risk of bleeding, doctors may close or block off the artery that is feeding the aneurysm. This approach is used to treat aneurysms that have ruptured, large aneurysms in individuals without symptoms, and small aneurysms in individuals with a prior aneurysms bleed or a family history of aneurysmal bleeding.
Patients with a ruptured cerebral aneurysm require intensive care. They are at a high risk of developing a widespread narrowing, or vasospasm, of brain blood vessels in the two weeks after the rupture. Vasospasm can cause ischemic stroke and is managed by medical and endovascular treatments. Such patients also frequently have blood clots blocking the flow of cerebrospinal fluid in the brain. This can cause pressure to build up inside the head, which may need to be relieved with a shunt catheter to divert the flow of fluid. CT scanning can monitor the degree of enlargement of the ventricles, called hydrocephalus.
Spotlight on NINDS Research Impact
The body produces thrombolytic proteins that clear blood clots, and some of these have been engineered into drugs. Decades ago, NINDS-funded research found a thrombolytic drug known as t-PA (tissue plasminogen activator) can be effective if a person receives it intravenously (through a vein) within three hours of the onset of stroke symptoms. Study results showed that individuals who were given intravenous t-PA were 30% more likely to have minimal or no disability three months after treatment. This led to the first treatment approved by the U.S. Food and Drug Administration (FDA) for acute ischemic stroke. In more recent studies, scientists have identified cases in which individuals may benefit from t-PA beyond the three-hour window after stroke symptoms begin. Most clinicians now treat within a four and a half-hour window, meaning more people are able to get brain-saving treatments thanks to NINDS research.
Other NINDS-funded research has been exploring whether giving anti-clotting or antiplatelet drugs alongside t-PA can provide additional benefit. And for people who are unable to receive t-PA, whether these drugs can help reduce damage from stroke. The Trial of Org 10172 in Acute Stroke Treatment or TOAST, a NINDS-sponsored trial, was designed to determine if stroke could be treated with a form of the anticoagulant drug heparin, which was less likely to cause bleeding. This study found that the drug produced no significant benefit. however, scientists were able to develop a set of guidelines--called the TOAST criteria--for defining different kinds of ischemic stroke. These guidelines now are widely used in other studies.
Additionally, for many years, aspirin was warfarin an anticoagulant drug used to prevent blood clots) were used to prevent stroke in people with atrial fibrillation--the most common heart condition that can lead to stroke. Researchers attempted to definitively determine if a daily regimen of aspirin or warfarin could benefit people at risk for ischemic stroke. Two NINDS studies showed that daily warfarin is best for people with atrial fibrillation who are over age 65 or who have additional stroke risk factors. Results also showed that daily aspirin provides adequate protection against stroke among younger people (under age 60) with atrial fibrillation. More recently, a number of new blood thinners, including dabigatran, rivaroxaban, and apixaban, have been shown to be as effective as warfarin in stroke prevention. These newer drugs do not require regular blood test monitoring and may be less likely to cause bleeding.
Two other NINDS-sponsored trials compared the effectiveness of daily warfarin and aspirin in people who did not have atrial fibrillation but who had experienced a prior stroke, and thus were at risk for another stroke. Both trials concluded that aspirin is equal to warfarin for reducing stroke risk in people without atrial fibrillation. More research is needed to identify if anticoagulation with a direct thrombin inhibitor is more effective than antiplatelet therapy to prevent recurrent stoke in people with suspected atrial dysfunction.
Recent advances have helped researchers to seek protective therapies that can extend the time after a stroke to restore blood flow to the brain and reduce the effects of the stroke on the person's function. Studies planned through the NIH Stroke Preclinical Assessment Network will determine if an add-on intervention to protect the brain can improve a person's post-stroke outcome compared to restoring blood flow alone. Hopefully, this research will lead to clinical trials to test the most promising neuroprotective therapies.
NINDS Patient and Provider Resources
Download Know Stroke materials for use in medical schools, educational settings, hospitals, clinics, and other health care facilities. Additional public education materials on stroke are also available for free from NINDS
NINDS Clinical Trials
For information about NINDS-funded trials for people who have had a stroke, view NINDS clinical trials and search for "post-stroke" or "stroke."