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Sunday 5 July 2009

Cerebrovascular Accident or CVA

Commonly called a stroke, cerebrovascular accident (CVA) is a sudden impairment of cerebral circulation in one or more of the blood vessels supplying the brain. CVA interrupts or diminishes oxygen supply and often causes serious damage or necrosis in brain tissues.

The sooner circulation returns to normal after CVA, the better chances are for complete recovery. However,about half of those who survive a CVA remain permanently disabled and experience a recurrence within weeks, months, or years.

CVA is the third most common cause of death in the United States today and the most common cause of neurologic disability. It strikes 500,000 persons each year; half of them die as a result

Causes

The causes of stroke are many and various. Every individual is different and therefore no one stroke is ever the same as another.

  • Certain irregularities such as atrial fibrillation to the brain, cause the blood clot to move from the valve of the heart.
  • Blood vessels to the brain become narrow due to cholesterol blockage
  • The blood clot moves from the carotid arteries to the brain
  • Decreased oxygen in the blood due to lung problems
  • A heart arrythmia does not allow the heart to pump enough blood to the brain
  • Very High Blood Pressure
  • Severely Low Blood Sugar
  • Myocardial Infarction (heart attack), in which the heart does not pump enough blood to the brain

Signs and symptoms

The symptoms of a stroke depend on what part of the brain and how much of the brain tissue is affected. Stroke symptoms usually come on suddenly-in minutes to an hour. There is usually no pain associated with the symptoms. The symptoms may come and go, go away totally, or get worse over the course of several hours. Symptoms are usually classified according to the artery affected:

  • Sudden numbness or weakness, especially on one side of the body. Reflexes can be decreased on the affected side, but are often livelier than on the other side. The face is normally spared (as this is served by both hemispheres), but the corner of the mouth can be affected on the same side as the limb symptoms
  • Balance problems when walking
  • Sudden trouble seeing in one eye (or rarely both);
  • Confusion
  • You may have a headache, feel dizzy, confused, or pass out.

Diagnosis

Confirmation of CVA is based on observation of clinical features, a history of risk factors, and the results of diagnostic tests.

  • Computed tomography scan shows evidence of hemorrhagic stroke immediately but may not show evidence of thrombotic infarction for 48 to 72 hours.
  • Magnetic resonance imaging may help identify ischemic or infarcted areas and cerebral swelling.
  • Brain scan shows ischemic areas but may not be positive for up to 2 weeks after the CVA.
  • Lumbar puncture reveals bloody cerebrospinal fluid in hemorrhagic stroke.
  • Ophthalmoscopy may show signs of hypertension and atherosclerotic changes in retinal arteries.
  • Angiography outlines blood vessels and pinpoints occlusion or rupture site.
  • EEG helps to localize the damaged area.

Other baseline laboratory studies include urinalysis, coagulation studies, complete blood count, serum osmolality, and electrolyte, glucose, triglyceride, creatinine, and blood urea nitrogen levels.

Treatment

Treatment options vary, depending on the type of CVA the patient experiences. Early medical diagnosis of the type of CVA coupled with new drug treatments can greatly reduce the long-term disability secondary to ischemia.

Surgery performed to improve cerebral circulation for patients with thrombotic or embolic CVA includes an endarterectomy (the removal of atherosclerotic plaque from the inner arterial wall) or a microvascular bypass (the surgical anastomosis of an extracranial vessel to an intracranial vessel).

Medications useful in treating CVA include:

  • alteplase (recombinant tissue plasminogen activator, tPA), effective in emergency treatment of embolic CVA Patients with embolic or thrombotic CVA who aren't candidates for alteplase (3 to 6 hours post-CVA) should receive aspirin or heparin.
  • long-term use of aspirin or ticlopidine, used as antiplatelet agents to prevent recurrent CVA
  • anticoagulants (heparin, warfarin), which may be required to treat crescendo TIAs not responsive to antiplatelet agents
  • antihypertensives, antiarrhythmics, and antidiabetic agents, which may be used to treat risk factors associated with recurrent CVA.
Prevention

Prevention is an important public health concern. Identification of patients with treatable risk factors for stroke is paramount.

  • Medication or drug therapy is the most common method of stroke prevention.
  • If the patient has atrial fibrillation (a heart irregularity), Coumadin (Warfarin) is recommended. A secondary option here is aspirin.
  • Diabetes should be controlled.
  • Controlling blood pressure in the normal range decreases the chances of a stroke
  • You should stop smoking cigarettes.

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