Stroke
Stroke Information: The Basics Strokes, or brain attacks, are the third leading cause of death in the Western world: only heart disease and cancer have higher mortality rates. Stroke damage can affect mental, physical, and emotional functioning. In fact, survivors of strokes often lose their independence, due to the disabling effects of the condition. Stroke is the second most common cause of neurologic disability, ranking only behind Alzheimer's disease.
This site provides general stroke information, including the causes, types, diagnosis, and treatment of stroke. Recognizing and detecting stroke symptoms quickly is essential; with prompt treatment brain cell damage can be minimized.
What is a Stroke?
A stroke is a form of cerebrovascular disease: disease caused by circulation problems and obstructed blood flow in the brain. When blood flow is compromised, brain cells are deprived of oxygen and begin to die. Circulation in the vessels of the brain may be restricted by blood clots, bleeding in the brain, high blood pressure, or heart disease.
Stroke Symptoms: Rapid Onset
When blood flow is impaired, stroke symptoms develop rapidly. This distinguishes strokes from more progressive brain diseases, such as dementia and brain tumors.
Ischemic Stroke, Atherosclerosis, and Heart Disease
Ischemic stroke is caused by obstructed blood flow, often due to atherosclerosis, the same process that narrows arteries and causes heart disease. More information about this type of stroke can be found on the ischemic stroke page.
Hemorrhagic Stroke and Hypertension
Bleeding from ruptured blood vessels causes hemorrhagic strokes. When blood vessels rupture, blood spills into the tissue of the brain and is not delivered where it is needed. Hypertension and head injuries are the usual causes of hemorrhagic strokes. Follow the link for additional information on hemorrhagic stroke.
Stroke Categories
Ischemia in the brain is subdivided into three categories, based on symptom duration. All three categories refer to the same disease: the categories help doctors determine the best tactics for stroke prevention and treatment. No matter what the classification, all three events should be treated seriously – ignoring symptoms can be deadly.
TIA: Transient ischemic attack, or "mini stroke," symptoms last less than 24 hours, and occur when circulation to an area of the brain is temporarily restricted. On average, in fact, TIA symptoms last only two to thirty minutes and no permanent brain damage occurs. TIAs do, however, suggest blood vessel disease and a third of all people who experience TIA will go on to suffer a stroke.
RIND: Reversible ischemic neurologic deficit symptoms last longer than those of a TIA. In fact, RIND symptoms generally last longer than 24 hours, but less than a week. Fortunately, however, RIND symptoms are transitory, occurring when blood flow to the brain is restricted temporarily. No permanent brain damage occurs, but RIND further increase the risk of having a stroke.
Stroke: Symptoms of a major stroke persist for longer than 24 hours and are usually more severe than those of a TIA or RIND. A stroke occurs when blood flow is blocked significantly for a prolonged period or when circulation is stopped completely. Brain damage from this condition is permanent. Stroke injury can lead to paralysis, sensory problems, speech impairment, and even sudden death.
RIND: Reversible ischemic neurologic deficit symptoms last longer than those of a TIA. In fact, RIND symptoms generally last longer than 24 hours, but less than a week. Fortunately, however, RIND symptoms are transitory, occurring when blood flow to the brain is restricted temporarily. No permanent brain damage occurs, but RIND further increase the risk of having a stroke.
Stroke: Symptoms of a major stroke persist for longer than 24 hours and are usually more severe than those of a TIA or RIND. A stroke occurs when blood flow is blocked significantly for a prolonged period or when circulation is stopped completely. Brain damage from this condition is permanent. Stroke injury can lead to paralysis, sensory problems, speech impairment, and even sudden death.
Understanding Ischemic Stroke
Ischemic stroke results from restricted blood flow to portions of the brain. The majority of strokes (approximately 80 percent) are ischemic, according to the American Stroke Association. Blood flow to the brain may be restricted by a blood clot (thrombus) or by progressive narrowing of the arteries. People with high cholesterol, diabetes, or heart disease are at increased risk of ischemic stroke.
An ischemic stroke develops quickly. Brain cells begin to die within minutes of the interruption of blood flow to the brain. Prompt medical intervention minimizes cell death and may help restore partial function to damaged areas. Stroke prevention strategies can lower the risk of developing an ischemic stroke.
Atherosclerosis, Cholesterol Plaques, and the Carotid Arteries
Atherosclerosis is the most common cause of ischemic strokes. Atherosclerosis causes cholesterol "plaques" to build up on artery walls, slowing blood flow and depriving organs of oxygen. Cholesterol plaques are often associated with heart disease, but they can develop in any blood vessel.
Cholesterol plaques in the vertebral and carotid arteries, the arteries that feed the brain, may lead to an ischemic stroke. These cholesterol plaques contribute to strokes because the plaques cause narrowing of the arteries and significantly restrict blood flow. The carotid arteries run alongside the jugular veins in the front of the neck, while the vertebral arteries run up the back of the neck. Both of these main arteries branch off into smaller vessels in the brain: a stroke can occur at any point along these arteries.
Cholesterol plaques in the vertebral and carotid arteries, the arteries that feed the brain, may lead to an ischemic stroke. These cholesterol plaques contribute to strokes because the plaques cause narrowing of the arteries and significantly restrict blood flow. The carotid arteries run alongside the jugular veins in the front of the neck, while the vertebral arteries run up the back of the neck. Both of these main arteries branch off into smaller vessels in the brain: a stroke can occur at any point along these arteries.
Thrombus Formation
A thrombus, or blood clot, can also cause an ischemic stroke. Cholesterol plaques in the vertebral or carotid arteries increase the risk of thrombus formation by slowing down the flow of blood.
Blood clots may also form in the heart after a heart attack, or as a result of an irregular heartbeat. A thrombus in the heart does not cause a stroke until it breaks away from its initial location and travels to the brain. The thrombus is then referred to as an embolus, a clot that travels through the blood vessels. The blood clot may then lodge in the arteries of the brain and cause an ischemic stroke.
Blood clots may also form in the heart after a heart attack, or as a result of an irregular heartbeat. A thrombus in the heart does not cause a stroke until it breaks away from its initial location and travels to the brain. The thrombus is then referred to as an embolus, a clot that travels through the blood vessels. The blood clot may then lodge in the arteries of the brain and cause an ischemic stroke.
Deep Vein Thrombosis
While the heart is the most common site for stroke-causing blood clot formation, a thrombus can develop in any blood vessel, even in the absence of cholesterol plaques. A deep vein thrombosis describes clot formation in the large veins of the body. The leg is the most common site for deep vein thrombosis. However, a deep vein thrombosis that breaks off and travels through the circulation is more likely to affect the lungs than the brain. A blood clot that travels into the lungs is referred to as a pulmonary embolism.
In unusual cases, a deep vein thrombosis can generate blood clots that travel to the brain, where they can cause a stroke. This is a rare occurrence, usually only occurring in combination with heart defects.
In unusual cases, a deep vein thrombosis can generate blood clots that travel to the brain, where they can cause a stroke. This is a rare occurrence, usually only occurring in combination with heart defects.
Understanding Hemorrhagic Stroke
Hemorrhagic stroke is caused by ruptured blood vessels in the brain. Blood escaping from the blood vessel damages surrounding tissue. Bleeding from the blood vessel also results in obstructed blood flow to other parts of the brain, causing damage similar to that caused by an ischemic stroke.
Causes: High Blood Pressure, Head Injury, and More
High blood pressure, or hypertension, is the most common cause of hemorrhagic stroke. This is because high blood pressure makes blood vessels weak and brittle. A blood vessel weakened by high blood pressure may eventually rupture, causing a stroke. Controlling high blood pressure is the best way to reduce the risk of having a hemorrhagic stroke. The website About Hypertension offers more information on high blood pressure.
Head injury can also cause blood vessels in the brain to tear or burst from sheer trauma. Head injury does not cause as many cases of hemorrhagic stroke as high blood pressure, however, head injury is often preventable. Wearing helmets, for instance, can reduce the risk of severe head trauma in children and adults who play sports or participate in other outdoor recreational activities.
In addition to high blood pressure and head injury, two other factors can result in hemorrhagic stroke. One condition that causes a high risk of hemorrhagic stroke is an aneurysm. This occurs when a weakened blood vessel "balloons" outwards, creating a weak area of the vessel. The aneurysm can rupture and bleed into the brain. Another high-risk condition is an arteriovenous malformation, or AVM, in which blood vessels form unusual clusters. An AVM is also more likely to rupture, causing bleeding in the brain.
Head injury can also cause blood vessels in the brain to tear or burst from sheer trauma. Head injury does not cause as many cases of hemorrhagic stroke as high blood pressure, however, head injury is often preventable. Wearing helmets, for instance, can reduce the risk of severe head trauma in children and adults who play sports or participate in other outdoor recreational activities.
In addition to high blood pressure and head injury, two other factors can result in hemorrhagic stroke. One condition that causes a high risk of hemorrhagic stroke is an aneurysm. This occurs when a weakened blood vessel "balloons" outwards, creating a weak area of the vessel. The aneurysm can rupture and bleed into the brain. Another high-risk condition is an arteriovenous malformation, or AVM, in which blood vessels form unusual clusters. An AVM is also more likely to rupture, causing bleeding in the brain.
Types of Hemorrhagic Stroke
There are two distinct types of hemorrhagic stroke: intracerebral and subarachnoid. The two varieties are defined by the location of bleeding in the brain.
Intracerebral Hemorrhage
An intracerebral hemorrhage occurs when blood vessels bleed into surrounding brain tissue. In addition to damage caused by blood itself, ischemic damage may occur due to impaired blood flow. High blood pressure is usually the cause of intracerebral hemorrhage, although bleeding may also be caused by head injury or AVM rupture.
Subarachnoid Hemorrhage and Headache Symptoms
Subarachnoid hemorrhage describes bleeding between the skull and the brain, and often results from an aneurysm. Head injury, high blood pressure, and AVM can also cause this type of hemorrhagic stroke. A subarachnoid hemorrhage can also cause vasospasm – blood vessels surrounding the ruptured blood vessels constrict, restricting blood flow to parts of the brain and causing further brain tissue damage.
A subarachnoid hemorrhage has a high mortality and morbidity rate. The stroke proves fatal in fifty percent of cases. Of the survivors, fifty percent are permanently disabled. One major key to detecting a subarachnoid hemorrhage comes from the patient's symptoms. During a subarachnoid hemorrhage, patients often describe having an "excruciating" headache, often calling the headache the worst they have ever experienced. When this type of headache occurs, seek medical attention immediately.
A subarachnoid hemorrhage has a high mortality and morbidity rate. The stroke proves fatal in fifty percent of cases. Of the survivors, fifty percent are permanently disabled. One major key to detecting a subarachnoid hemorrhage comes from the patient's symptoms. During a subarachnoid hemorrhage, patients often describe having an "excruciating" headache, often calling the headache the worst they have ever experienced. When this type of headache occurs, seek medical attention immediately.
Symptoms and Diagnosis of Stroke
Prompt medical diagnosis of a stroke is essential: the sooner stroke treatment begins, the better the chance of survival. This is especially true since the treatments for ischemic and hemorrhagic strokes are very different. Determining the type and severity of a stroke is the first step in minimizing damage from the event.
The diagnostic work-up begins as soon as stroke symptoms are reported. Symptoms such as a sudden and severe headache, weakness or paralysis on one side of the body, loss of speech, incontinence, or numbness suggest a stroke. Once a stroke is suspected, brain-imaging tools such as magnetic resonance imaging or computed tomography provide further clues about the nature of the stroke.
Stroke Recovery: Regaining Quality of Life
The most difficult aspect of having a stroke is living with the disability caused by the condition. Stroke is associated with high morbidity rates, meaning that many patients experience both physical and mental disability following the event. In fact, stroke morbidity is the leading cause of decreased independence and lowered quality of life among adults.
Stroke rehabilitation, however, offers a chance to restore quality of life after a stroke. While damaged brain tissue cannot be healed, stroke recovery techniques can offset some degree of disability. Ideally, rehabilitation helps a patient maintain existing abilities and provides strategies for handling stroke-related disabilities.
Stroke rehabilitation, however, offers a chance to restore quality of life after a stroke. While damaged brain tissue cannot be healed, stroke recovery techniques can offset some degree of disability. Ideally, rehabilitation helps a patient maintain existing abilities and provides strategies for handling stroke-related disabilities.
The Stroke Recovery Team
While the specific rehabilitation needs depend on the stroke patient's particular condition, a team approach can be used successfully for most people. A rehabilitation team may include physical therapists, speech therapists, rehabilitation nurses, and psychologists, as well as the stroke patient's doctor. Family members may also be part of the stroke recovery team. Even more important than the team, however, is the stroke patient's attitude. A positive attitude is vital to successful rehabilitation and the team of caregivers can work together to help the patient maintain an optimistic outlook.
Stabilizing Medical Conditions After Stroke
Stroke rehabilitation does not begin until the patient's medical condition has stabilized. Stabilizing a patient after a stroke includes treating the event and any medical conditions arising from the stroke. It may also include secondary prevention, which is essential for stroke survivors.
Having said this, stroke recovery begins as early as possible. If the patient's medical condition permits, rehabilitation may begin as early as one or two days after the stroke. Rehabilitation usually begins in the hospital. Once the patient is discharged, rehabilitation centers, inpatient facilities, and at-home programs continue to serve the patient's rehabilitation needs.
How Quickly Will Quality of Life Improve?
The effectiveness of stroke rehabilitation on improving quality of life depends on many factors: access to rehabilitation specialists, the extent of patient morbidity, the individual's commitment to recovery, and the patient's ongoing medical conditions. Generally speaking, the most significant improvements in quality of life occur within eighteen months of the stroke. However, further improvement in quality of life after this time frame remains possible and stroke rehabilitation should be continued until it becomes apparent that no further progress will occur.
