A Guide to Stroke Risk Factors and Treatment
The term stroke encompasses a wide diversity of vascular diseases of the central nervous system (cerebrovascular diseases.) Stroke is a leading cause of death and disability in the United States and throughout the world. Annually, approximately 750,000 Americans have a stroke. Approximately 150,000 Americans die from stroke and a similar number die as an indirect consequence of stroke. Stroke is a leading cause of long-term disability, and many persons fear stroke not because it might lead to death but that independence will be lost. Stroke is second to dementia as a reason for long-term institutionalized care, and the effects of stroke can potentiate the effects of other diseases such as Alzheimer's disease. Stroke changes the life of the patient and his/her family and friends. The economic consequences of stroke are huge. Besides the expenses of acute care and prevention strategies, the financial costs of rehabilitation and long-term care are considerable. In addition, stroke often means that a person no longer can work or that family members will need to change employment in order to become a care giver. As a result, the costs from stroke exceed $40 billion.
Several factors identify persons who have the highest risk for stroke. The leading risk factor for stroke is advancing age. Thus, stroke is an important public health problem for Iowa because of its large elderly population. With lengthening of life expectancy and advancing age of Americans, the frequency of stroke will increase dramatically during the next 50 years. Measures to prevent or treat stroke will become a leading component of public health in Iowa and the United States. Still, stroke does affect persons of all ages, including children. Cerebrovascular disease is among the leading causes of death in children.
At most age groups, stroke occurs at a higher frequency among men than among women. The exception is in young adults, in which stroke as a complication of pregnancy can lead to increased frequency in women. Because of the older age in women and because of the strong relationship between the rate of stroke and advanced age, women constitute the majority of Americans who have stroke. Approximately 1 in 6 American women die of stroke; this rate is considerably higher than the risk of death from carcinoma of the breast. Stroke is more common among African-Americans and Hispanic Americans than among persons of European heritage. The differences in risk are particularly prominent among young adults. In addition, a history of family members with stroke or other vascular disease (Vascular Surgery), particularly at a young age, is associated with an increased risk of stroke. While some of this association can be attributed to genetic factors or diseases that predispose to stroke, shared environmental or behavioral risk factors such as diet or smoking also may contribute to the familial relationship.
Several conditions, which can be controlled or managed, are associated with an increased risk for atherosclerosis (hardening of the arteries) and stroke. Among the leading conditions are:
- Arterial hypertension (high blood pressure)
- Diabetes mellitus
- Hypercholesterolemia (high cholesterol)
In addition, other factors including inactivity and obesity can aggravate the effects of the above conditions. Other conditions that increase the risk of stroke include alcohol or drug abuse.
Measures to control these conditions can lower the risk of stroke. These measures include diet, changes in lifestyle, and medications. Persons with these conditions should discuss potential treatment options with their physicians.
In addition, persons with structural diseases of the heart, such as an abnormal heart valve or recent heart attack, or an irregular heartbeat (atrial fibrillation) are at high risk for blood clots to go to the brain (cerebral embolism). Less common causes of stroke include injury to an artery (dissection), inflammation of the artery, or disorders of blood clotting.
Approximately 20% of strokes involve bleeding into or around the brain. In general, patients with brain hemorrhages are very seriously ill. Brain hemorrhage is second to heart attack as a medical cause of sudden death. Among the causes of brain hemorrhages are hypertension, abnormalities of blood vessels (vascular malformations or aneurysms), or blood disorders that predispose to bleeding. Bleeding also is a potential complication of medications, such as blood thinners, which are prescribed to prevent heart attack or ischemic stroke.
The blood thinning drugs are given to lower the risk of blood clots forming--and thus prevent heart attack, ischemic stroke, blood clots to the lungs, or blood clots in the legs. Among the medications that are prescribed are aspirin, clopidogrel (Plavix ®), ticlopidine (Ticlid ®), aspirin and dipyridamole (Aggrenox ®), and warfarin (Coumadin ®). The selection of medications is based on several factors including the patient's age and presentation, the likely cause of stroke, overall health, other medical disorders, and previous treatment. In addition, measures to treat local areas of artery disease can include surgery (carotid endarterectomy) and endovascular treatment (angioplasty and stenting). New medical and local interventions to prevent stroke are being evaluated in clinical studies.
An acute stroke is the first manifestation of cerebrovascular disease for many persons. For many years, both the public and the medical community considered stroke as a disease that could not be treated. Those opinions are changing, as new treatments of proven usefulness are available. However for success, many of these interventions must be given as soon as possible after the onset of stroke. In order to convey the urgency of stroke treatment, the term brain attack is being used. The message is to treat acute stroke (brain attack) in the same way as acute myocardial infarction (heart attack). The key components of the brain attack program:
- Prompt recognition of the nature of the symptoms
- Immediate contact with emergency medical services
- Speedy transport to a hospital emergency department that has the resources and expertise to treat stroke
- Rapid evaluation
- Emergent treatment
While some other illnesses can mimic stroke, most persons with the sudden onset of the problems described below will have either a brain hemorrhage or infarction. Persons with these symptoms should seek medical attention promptly. Even if the symptoms are not due to stroke, the other diseases also are serious and warrant early treatment. Many persons will become aware of the problems upon awakening from a nap or sleep. Other persons literally will be "struck down" while in a store, at work, or other activity.
- Weakness, heaviness, clumsiness, paralysis of one side of the body--hand, arm, face, or leg. Can be the entire half of the body.
- Numbness of one side of the body--hand, arm, face, or leg. Can be the entire half of the body.
- Loss of vision (fog, haze, scum, cloud, blindness) in one or both eyes.
- Double vision.
- Dizziness (spinning), imbalance, or incoordination.
- Slurred speech or difficulty talking.
- Difficulty understanding what others are saying.
- Loss of consciousness.
- Unusually severe headache--often associated with nausea and vomiting and light and noise intolerance.
In general, many persons have more than one of these problems. Because the stroke affects the brain and because the person might have difficulty thinking or understanding what has happened, recognition of the importance of the problems by the family members, neighbors, co-workers, or the general public is critical. The correct response to a suspected stroke is to seek medical attention immediately. The best response is to call 911. An alternative is to immediately transport the affected person to an emergency department. Calling friends, neighbors or a physician's office for advice is not recommended.
Upon arrival to the emergency department, physicians and other medical personnel evaluate the person. The person might need emergent medical attention such as treatment of an elevated blood pressure. The evaluation also includes blood work and tests such as CT, which provides pictures of the brain. The CT is very effective in separating infarction from hemorrhage. Additional tests might include MRI (another imaging test) or examination of the blood vessels or heart. In some patients, examination of the cerebrospinal fluid (CSF) might be needed. In this situation, a lumbar puncture (spinal tap) is done to look for evidence of bleeding or infection.
Depending upon the results of the evaluation, a likely cause of stroke is determined, and the patient can be offered treatment including the administration of clot-busting drugs (thrombolytic agents). Other treatments, including early surgery, might be advised.
Following the initial treatment in the emergency department, the person usually is admitted to the hospital for additional care. There is strong evidence that hospitalization in a facility that has special expertise in stroke care can improve outcomes. These facilities, often called stroke units, are available at many larger hospitals. While in the unit, the patient will receive additional treatment aimed at limiting the brain injury from the stroke or preventing or controlling complications of the stroke. Among the important complications of stroke are pneumonia, bladder infections, and blood clots in the legs. In addition, additional tests often are done to screen for the cause of stroke. This information can influence recommendations about treatments to prevent a second (recurrent) stroke. Most patients also will receive measures to maximize recovery from the stroke (rehabilitation). Plans for return home or for longer-term medical care (going to a rehabilitation hospital for example) are made during the stay in the hospital. Depending upon the severity of the patient's illness, the stay in the hospital can be from 1 to 2 days to a week or longer.
Harold P. Adams, MD, Professor of Neurology
University of Iowa Department of Neurology