CEREBROVASCULAR ACCIDENT

INTRODUCTION: A cerebrovascular accident (CVA), or stroke, is damage to a blood vessel in the brain, resulting in lack of oxygen to that part of the brain. Possible types of vessel damage are thrombosis or hemorrhage. A thrombus is a blood clot, which most often is a consequence of atherosclerosis, abnormal lipid deposits in cerebral arteries.

PATHOPHYSIOLOGY: The rough surface stimulates clot formation, which obstructs the blood flow to the part of the brain supplied by the artery. The symptoms depend on the part of the brain affected and may be gradual in onset if clot formation is slow. Approximately 80% of CVAs are of this type.

Hemorrhagic stroke: A hemorrhage, the result of arteriosclerosis or aneurysm of a cerebral artery, allows blood out into brain tissue, which destroys brain neurons by putting excessive pressure on them as well as depriving them of oxygen. Onset of symptoms in this type of CVA is usually rapid. If, for example, the CVA is in the left frontal lobe, paralysis of the right side of the body will occur. Speech may also be affected if the speech areas are involved. Some CVAs are fatal because the damage they cause is very widespread or affects vital centers in the medulla or pons. For CVAs of the thrombus type, a clot-dissolving drug may help reestablish blood flow. To be effective, however, the drug must be administered within 3 hours of symptom onset. Recovery from a CVA depends on its location and the extent of damage, as well as other factors. One of these is the redundancy of the brain. Redundancy means repetition or exceeding what is necessary; the cerebral cortex has many more neurons than we actually use in daily activities. The characteristic of plasticity means that these neurons are available for use, especially in younger people, less than 50 years of age.

When a patient recovers from a disabling stroke, what has often happened is that the brain has established new pathways, with previously little-used neurons now carrying impulses “full time.” Such recovery is highly individual and may take months. Yet another important factor is that CVA patients be started on rehabilitation therapy as soon as their condition permits.

RELATED;

1. MEDICAL MANAGEMENT OF STROKE

2. HYPERTENSION

3. BLOOD AND HEMATOLOGICAL CONDITIONS

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