Stroke

 

Overview (of Cerebrovascular Accident)

 

Stroke is the common term for Cerebrovascular Accident (CVA). Stroke is a neurological disorder caused by a lack of blood flow to portions of the brain. The result is the death of brain cells in the affected area of the brain. When brain cells die, the parts of the body that they controlled no longer function normally. Some examples of loss of function include loss of speech and loss of motor function in particular parts of the body.

 

Stroke is the third leading cause of death in the United States and is the major cause of disability in adults. Approximately 500,000 individuals in the U.S. have a stroke each year. Approximately 3,000,000 adults are living with the effects of a stroke. Every 3.5 minutes someone dies of a stroke in the U.S. Every 1 minute and 20 seconds someone in the U.S. survives a stroke. 9 presidents have died from stroke.

 

Types of stroke

 

     Occluded (blocked)

     Cerebral Thrombosis - clot that is formed and blocks blood flow

     Cerebral Embolism - clot that travels and blocks blood flow

     Haemorrhagic (ruptured) - when a blood vessel ruptures and leaks blood into the brain or the surrounding areas.

 

Some deficits that may result from a stroke

 

     Physical: hemiplegia or hemiparesis, seizures, dysphagia (swallowing problems), vision problems

     Emotional: inappropriate laughing or crying, depression, denial of problems

     Cognitive: aphasia (speech and language problems), attention deficits, visual neglect, memory, new learning problems, decreased reasoning skills

     Social: verbal outbursts, some social inappropriateness, lack of social inhibition

     Stroke: not limited to these deficits, nor does everyone who has had a stroke exhibit all the above deficits. Stroke is unique for each person

 

Treating Acute Ischaemic CVA

 

Brain attack

 

You may not be familiar with the term, but it's the third leading cause of death and the leading cause of disability in the United States. Better known as cerebrovascular accident (CVA) or stroke, brain attack strikes approximately 550,000 people in the United States each year, claiming the life of about 150,000 of its victims. But perhaps more significantly, 3 million people are currently CVA survivors, many with permanent disability.

 

To help reduce this staggering number, early treatment is vital. You have an essential role in getting treatment to the stroke victim in time (see Sending A New Message). In this article, I'll discuss how to minimise damage from a CVA.

 

Some terms

 

Cerebrovascular Accident CVA or Stroke (1) is a term which is used when there is damage to the brain due to bleeding inside the skull or blockage of the blood vessels carrying oxygen to the brain. Approximately 500,000 people per year have strokes in the United States. Possible consequences of stroke include weakness, loss of vision, difficulty talking, an inability to understand speech and death. The risk of stroke is greater with certain types of heart disease, diabetes mellitus and hypertension. Various medications used to prevent strokes include aspirin, warfarin (Coumadin) and ticlodipine (Ticlid). Surgery to open narrowing of the carotid arteries (blood vessels in the neck which carry blood and oxygen to the brain) has been shown to help prevent strokes in certain situations. The medical term for this operation is carotid endarterectomy.

 

Cerebrovascular Accident or Stroke (2) is the sudden interruption of blood flow to a part of the brain, killing brain cells and destroying or impairing body functions controlled by that part of the brain. An ischemic CVA occurs when an embolism or thrombus obstructs a cerebral artery, blocking the flow of blood to the brain. In contrast, a haemorrhagic CVA strikes when a vessel in the brain suddenly ruptures, allowing blood to permeate the brain tissue. (See Illustration.) Most strokes--over 80%--are ischemic; the remainder are haemorrhagic. Because the acute management of haemorrhagic and ischemic stroke differs and ischemic strokes predominate, I'll focus on ischemic CVA.

 

Ischemic CVA can be divided into two subtypes--embolic and thrombotic--based on the underlying cause. An embolic CVA results from an embolus that travels to a cerebral artery from a distant site, most commonly the heart or neck. Atrial fibrillation, an arrhythmia that allows blood to pool in the atria, is often an underlying cause. When the embolus reaches a cerebral artery that's too narrow to pass, it lodges, blocking blood flow to part of the brain. Embolic CVA causes a sudden deficit (within seconds to minutes) and usually occurs later in the day when the person is active.

 

Thrombotic CVA, unlike embolic CVA, results from a gradual process. Atherosclerosis is the main risk factor: As atherosclerotic plaque slowly accumulates in a cerebral artery, the potential for thrombotic stroke builds. If the plaque isn't treated, a thrombus, or clot, may form, further occluding the artery and causing ischemia and neurological deficits that evolve over hours to days. Symptoms usually begin when the person's blood pressure (BP) is relatively low (for example, in the early morning or during rest).

 

Transient Ischemic Attacks (TIAs) One or more may precede a thrombotic (but not an embolic) CVA. A TIA is a temporary interruption of blood supply to an area of the brain. The person experiences a sudden onset of stroke symptoms that last for a few minutes to as long as 24 hours before they disappear. The TIA symptoms correlate to the portion of the brain that isn't receiving sufficient perfusion. A TIA sounds a warning that treatment is essential to avert a CVA--one-third of persons who experience a TIA suffer a CVA. Like a CVA, a TIA is a medical emergency.

 

Heparin

 

Anticoagulation therapy with heparin (and later with warfarin [Coumadin]) allows the body's natural fibrinolytic processes to dissolve the existing clot and prevents new clots from forming. In this way, Heparin may halt or reverse the progression of neurological deficits.

 

About 48 hours after the onset of symptoms in embolic stroke, the embolus may dissolve or collateral blood flow around the blockage may develop. This may result in haemorrhagic transformation, in which bleeding occurs spontaneously because vessels that have been damaged during the CVA begin to leak. When you administer Heparin to a patient with an embolic stroke, realise that Heparin may increase the risk of haemorrhagic transformation. Monitor vigilantly for any indication of severe bleeding. If he has an acute change in neurological status, immediately discontinue the heparin and obtain an order for a stat CT scan to rule out haemorrhage.

 

Parkinson's disease is caused by abnormalities in an area of the brain called the basal ganglia. Symptoms of Parkinson's disease can include tremors (shaking), stiffness, and difficulty walking. Some medications including metoclopramide (Reglan), haloperidol (Haldol) and others can cause Parkinson's disease. A number of medications are available to treat Parkinson's disease. Some of these are levodopa (Sinemet), selegiline (ElUepryl), amantidine (Symmetrel), bromocryptine (Parlodel) and pergolide (Permax).

 

CVA, or stroke - interruption of blood supply to the brain, typically involves one of the larger arteries. Occurs most often in 50-70 age range.

 

     Stroke is produced in one of three ways:

 

1. Thrombosis - narrowing of blood vessel, with eventual complete blockage (thrombus) that cuts off blood supply to the rest of the artery and the surrounding brain tissue. Accounts for over 50% of CVA's

 

2. Embolism - an occlusion by material such as blood clot, fat body or bacterial clump that travels from a remote site, finally lodging as the vessel narrows. Less than 20% of CVA's

 

3. Haemorrhage - rupture of vessel wall releasing blood into surrounding tissue. Not only is blood supply cut off, but escaping blood acts as a foreign space-occupying body. Less than 20% of CVA's, but most likely fatal.

 

Stroke onset may take minutes or hours to complete. If stroke occurs in left hemisphere patient will probably display signs such as aphasia, right hemiplegia, identional or ideomotor apraxia. If stroke occurs in right hemisphere patient will probably display signs of left hemiplegia and constructional apraxia. In assessment -- there may be a strong discrepancy between verbal and performance IQ scores, with verbal scores significantly lower in LH patient and performance scores lower in RH patient. Patients may show severe sensory or motor deficits on the side contralateral to the lesion. Specific behavioural effects depend on type of CVA, brain area affected, and to some extent personal characteristics of the individual (dominant hand, age, educational levels, gender, etc).

 

Recovery

 

Ranges from minimal to almost complete. It is important that rehab begins as early as feasible and be multi disciplinary in nature. Supportive therapy with the family is also a part of the rehab process.

 

     Three different types of tumours (neoplasms):

 

1. Encapsulated - have definite boundaries and are often cyst like, and are operable.

 

2. Infiltrating - do not have boundaries between healthy tissue and tumour itself., treated with drugs, surgery and radiation.

 

3. Metastatic - occur in remote areas of body such as lungs and breasts and spread throughout the body, including the brain.

 

Depending on type and location, a tumour can produce effects through increased cranial pressure, direct tissue destruction, and direct pressure effects on other brain structures. With the exception of metastatic tumours, the classic pattern of a neoplastic disorder is that of a lateralised, progressive and relatively localised lesion. As tumours are considered low-velocity (compared to CVA's) acute signs may not occur until relatively late in the course of the disorder. Survival rates in certain carcinomas have increased since the early 70's, although chances of fatality are still somewhere around 50%

 

     Closed Head Trauma (Head Injury)

 

Involves a blow to the head in which skull and brain are not penetrated, although the skull may be fractured. Represents a significant and relatively frequent source of brain damage, particularly in children and young adults. After a blow to the skull, the brain is subjected to rapid acceleration and deceleration. It may slam against the opposite site of the skull, sometimes causing more damage than the original blow.

 

     Temporal, frontal and prefrontal lobes are particularly vulnerable to injury.

 

If patient has been unconscious for an extended length of time, the Glasgow Coma Scale is one of the commonly used assessments to measure depth of coma. Involves assessing eye opening (spontaneously, to speech, pain, or none), verbal response (oriented, confused, inappropriate, incomprehensible or none), and motor response (obey commands, localise pain, flexion to pain, or none).

 

     Once patient is conscious, amnesia is often a problem.

 

Most rapid recovery occurs in the first 6 months. Patients will continue to recover for 1 to 3 years. Verbal skills tend to return earlier than nonverbal ones. Most common problems with head injury are memory deficits, losses in higher adaptive functions, and personality changes.

 

     Warning Signs of a Stroke

 

If you have heart disease or high blood pressure, you are at increased risk of having a stroke. Many strokes give warning signals. Doctors can recognise symptoms and take stops that may prevent a serious stroke. These symptoms include:

 

Sudden weakness or numbness of the face, arm or leg on one side of the body. Sudden dimness or loss of vision, particularly in only one eye. Loss of speech--or trouble talking or understanding speech. Severe headaches that occur suddenly, with no apparent cause. Dizziness or falls that are sudden and unexplained.

 

If you notice any one or more of these signs, talk to your doctor immediately. The sooner that rehabilitation occurs, the better the chances of your recovery.

 

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