Stroke

(Cerebral Vascular Accident)

Incidence

Stroke is the leading cause of adult disability in the United States. There are approximately 4,500,000 stroke survivors (2,200,000 males and 2,300,000 females) living in the United States today. The incidence of stroke is about 600,000 people per year, shared about equally between men and women. 

Stroke is not only a disease of the elderly, as 28 percent of the people who suffer a stroke in a given year are under age 65. For people over age 55, the incidence of stroke more than doubles in each successive decade. The chance of having a stroke before age 70 is one in twenty.

Stroke kills approximately 280,000 Americans per year, accounting for about one of every 14.8 deaths in the United States. At all ages, more women than men die of stroke. When considered separately from other cardiovascular diseases, stroke ranks as the third leading cause of death in the United States, behind heart disease and cancer. 

The most common type of stroke is atherothrombotic brain infarction, in which, blood supply is cut off to an area of the brain, accounting for 61 percent of all strokes. Cerebral embolus accounts for 24 percent of strokes. Hemorrhagic (bleeding in the brain) strokes account for 14 percent of strokes, and are the most lethal form of stroke -- 37.5 percent of hemorrhagic strokes are fatal within 30 days. 

Risk Factors

General risk factors for Stroke include:

Racial and ethnic minority populations in some age groups have a higher relative risk of stroke deaths when compared with the U.S. non-Hispanic white population:

Pathophysiology

A stroke, or "brain attack," occurs when blood flow to an area of the brain is interrupted by vascular occlusion or rupture. When a stroke occurs, the brain cells supplied by the blood vessel die within minutes, to a few hours. The dying brain cells cause an "ischemic cascade" through the release of chemicals. 

This chain reaction endangers the brain cells in the surrounding area of brain tissue, causing further brain injury. Given the rapid pace of the ischemic cascade, the "window of opportunity" for interventional treatment is about six hours. 

The brain is an incredibly complex organ. Each area within the brain controls a particular function or ability. The specific abilities that will be lost or affected by any given stroke depend on the location of the stroke and the extent of the brain damage. This includes functions such as speech, intellect, sensation, perception and movement. Any stroke is significant, especially for the individual affected. 


Clinical Manifestations

The skills of intellect, sensation, perception and movement, which are honed over the course of a lifetime and which so characterize the individual, are the very abilities most compromised by stroke. A stroke can cause an individual to loose the most basic methods of interacting with the world. The specific abilities that will be lost or affected by stroke depend on the extent of the brain damage and most importantly where in the brain the stroke occurred:

Right-Hemisphere Stroke: The right hemisphere of the brain controls the movement of the left side of the body. It also controls analytical and perceptual tasks, such as judging distance, size, speed, or position and seeing how parts are connected to wholes. Therefore, right hemisphere strokes may cause:

Left-Hemisphere Stroke: The left hemisphere of the brain controls the movement of the right side of the body. It also controls speech and language abilities for most people. Therefore, a left-hemisphere stroke may cause:

Cerebellar Stroke: The cerebellum controls balance and coordination. A stroke that takes place in the cerebellum can cause abnormal reflexes of the head and torso, coordination and balance problems, dizziness, nausea and vomiting.

Brain Stem Stroke: The brain stem is the area of the brain that controls automatic, "life-support" functions, such as breathing rate, blood pressure and heartbeat. The brain stem also controls eye movements, hearing, speech and swallowing. Since impulses generated in the brain's hemispheres must travel through the brain stem, a brain stem stroke may also cause paralysis in one or both sides of the body. 

Silent Strokes: Approximately 11 million Americans experience a “silent stroke” annually. Termed silent, as the patient does not experience any immediate loss of functioning or symptoms. Instead, these tiny spots of dead cells may result in a cumulative effect over time and multiple silent strokes may result in mood problems, memory lapses and difficulty with ambulating may develop. Silent strokes, rare before age 30, double in prevalence every ten years. Silent strokes may well be a precursor for a full-blown stroke down the line.

Recovery from a stroke is the result of a combination of factors. General recovery guidelines show:

Diagnosis

In many instances, proper diagnostic and therapeutic management has a profound influence on the outcome. Stroke is a medical emergency, with early signs more commonly ignored by the affected individual. Therefore, persons presenting with complaints consistent with the clinical manifestations of stroke should receive full clinical evaluation immediately. Presence of the clinical manifestations associated with stroke suggest anatomic location and etiology. Past medical history of presence of previous stroke or TIA, cardiovascular disease or risk factors suggest etiology and may direct further evaluation. 

Brain CT is highly sensitive and accurate in differentiating hemorrhages from ischemic infarction. However, it may not identify the ischemic infarct for several days after the clinical event has occurred, even if the neurologic deficit is major. In cases of subarachnoid hemorrhagic stroke, angiography may identify aneurysm and arterio-venous malformation. 

Differential diagnoses include seizure disorder, syncope, migraine, demyelinating disease, arteritis, hypoglycemia and tumor.

Therapeutic Management
The rise of chemical treatments is encouraging a new focus on prompt response after a stroke, both by patients and by physicians. Acute treatment of stoke is a medical emergency. Neuroprotective drugs work to minimize the effects of the ischemic cascade. While there are currently no neuroprotective agents available commercially, several different types of these drugs are in clinical trials for acute ischemic stroke. 

Because of their complementary functions of clot-busting and brain-protection, future acute treatment of ischemic stroke will most likely involve the combination of thrombolytic and neuroprotective therapies. Like thrombolytics, most neuroprotectives need to be administered quickly after a stroke to be effective. Some types of neuroprotectives currently in research include glutamate antagonists, calcium antagonists, opiate antagonists and antioxidants.

Neurosurgical and neuroradiological interventions for strokes, caused by aneurisms or arteriovenous malformations, significantly reduce mortality and morbidity. 

Once a stroke is completed, recovery from the neurologic sequelae may benefit from rehabilitation. The goal in rehabilitation is to improve function and level of independence. Rehabilitation should begin in the hospital, as soon as possible after the stroke. 

Early mobilization is key to preventing the complications of skin breakdown and contractures. In patients who are medically stable, rehabilitation should begin immediately, and advance as the individual becomes more able to participate. Once discharged from the hospital, home-based or outpatient rehabilitation is key to transition to the long-term residential setting and community. Depending on the severity of the stroke, rehabilitation options include:

Constraint-induced or movement-induced therapy is effective in improving movement following stroke. This technique relies on moving a limb through guided therapeutic exercise, rather than using the stronger limb to take over the affected side. 

Body weight supported exercise is a from of this and may make use of a suspension harness placed over a treadmill to support a patient’s “forced “ ambulation while in a supportive device

Cost Implications

The cost of stroke in the United States in 2001 is estimated at $45.4 billion. This figure includes health expenditures (direct costs, which include the cost of physicians and other professionals, hospital and nursing home services, the cost of medications, home health and other durable medical equipment) and lost productivity, resulting from morbidity and mortality (indirect costs). 

Stroke is a leading cause of serious, long-term disability in the United States. It is estimated that 15 to 30 percent of stroke survivors sustain permanent disability severe enough to require long-term assistance for daily living. Institutional care is required by 20 percent at three months after onset. Death occurs in 22 percent of men and 25 percent of women within a year after initial stroke. Half of men and women under age 65 who have a stroke die within eight years. 

Current statistics indicate that there are nearly four million people in the United States, who have survived a stroke and are living with the after-effects. These numbers do not reflect the scope of the problem and do not count the millions of husbands, wives and children who live with and care for stroke survivors and who are, because of their own altered lifestyle, greatly affected by stroke.

Prevention

Case Management Issues

Effective patient, family and care provider education is critical to assure the best outcome possible. Return demonstration, showing understanding of early detection of cardiovascular events, long term health maintenance, medication management, adaptive strategies, consistent home exercise, safety and precautions are very important.

Providers of care for the management of stroke must have a thorough understanding of the related medical, neurological, disability and psychological issues. 

A case manager, who is skilled in the management of medically complex individuals, can be very effective in coordinating complex care needs, reinforcing the physician’s plan of care, providing on-going patient and family education and assuring optimum compliance. This individual can also assist with arrangements for home care -- assuring that the individual is getting the appropriate services.

Links

www.stroke.org - National Stroke Association
www.strokecenter.org - American Stroke Center

Editors Note: This information was provided to the Professional Resource Network of IOA Re, Inc. by Paradigm Health Corporation.