Cerebrovascular disorder
DR. MASWOODUR RAHMAN PRINCE
BLOOD is supplied to the brain through two pairs of large arteries: the carotid arteries bring blood from the heart along the front of the neck, and the vertebral arteries bring blood from the heart along the back of the neck inside the spinal column. These large arteries empty into a circle of other arteries, from which smaller arteries branch off like roads from a traffic island. The branches carry the blood to all parts of the brain.
When blood flow to the brain is disrupted, brain cells can die or be damaged if bleeding occurs in or around the brain. The resulting neurological problems are called cerebrovascular disorders because of the involvement of the brain (cerebrum) and blood vessel (vascular).
Insufficient blood supply to parts of the brain for brief periods causes transient ischemic attacks, temporary disturbances in brain function. Because the blood supply is restored quickly, brain tissue does not die, as it does in a stroke. A transient ischemic attack is often an early warning sign of a stroke.
How a stroke or transient ischemic attack affects the body depends on precisely wherein the brain the blood supply was cut off or where bleeding occurred. Each area of the brain is served by specific blood vessels. For example, if a blood vessel in the area that controls the left legs muscle movements becomes blocked, the leg will be weak or paralysed. If the area that senses touch to the right arm is damaged, the right, arm will lose feeling (sensation).
The loss of function is greatest immediately after a stroke. However, some functions are usually regained because, while some brain cells die, others are only injured and may recover.
Occasionally, a stroke or transient ischemic attack occurs when blood flow to the brain is normal but the blood does not contain enough oxygen. This may happen in a severely anaemic person or a person with carbon monoxide poisoning or a condition which produces abnormal blood cells or abnormal blood clotting, such as leukemia or polycythemia.
TIA: Transient Ischemia Attack or T1A is a disturbance
Signs of a Stroke
A stroke occurs when blood vessels carrying oxygen and other nutrients to a specific part of the brain suddenly burst or become blocked.
The brain requires about 20 per cent of the circulation of blood in the body. Brain cells must have a continuous supply of oxygen and other nutrients from the blood in order to function. When this continuous blood supply is disrupted, a stroke results. Ther are several different kinds of strokes, categorised by whether the blood supply was disrupted because of a blocked blood vessel
(ischemic stroke) or a haemorrhage. Each type of stroke has a different kind of treatment so it is very important for the physician to determine the cause of the stroke, as well as its location, as
quickly as possible.
Ways to help prevent a stroke
Many lifestyle changes can be made to reduce the risk of stroke, such as quitting smoking, limiting alcohol intake and exercising regularly. Other risk factors that can be controlled are hypertension (high blood pressure), heart disease, high cholesterol level, obesity, diabetes, elevated hematocrit (increase in red blood cells), use of oral contraceptives (especially for women who smoke) and stress.
Most of the controllable risk factors are linked to cardiovascular fitness. Some conditions such as heart disease, high blood pressure and elevated cholesterol may also be controlled by proper
medical treatment along with appropriate diet and lifestyle changes. Eating a heart-health diet will also help reduce the risk of stroke.
Do you know your stroke risk?
Some of the most important risk factors for stroke can be determined during a physical exam at your doctors officc. If you are over 55 years old, a worksheet in a pamphlet available from the UNDS can help you estimate your risk of stroke and show the benefit of risk-factor control.
The worksheet was developed from NINDS-supported work in the well-known Framingham Study. Working with your doctor, you can develop a strategy to lower your risk to average or even below average for your age. Many risk factors for stroke can be managed, some very successfully. Although risk is never zero at any age, by starting early and controlling your risk factors you can lower your risk of death or disability from stroke. With good control, the risk of stroke in most age groups can be kept below that for accidental injury or death.
in brain function resulting from a temporary deficiency in the brains blood supply.
What causes TIA: Small pieces of fatty material and calcium that build up on the wall of an artery (called atheromas) can break off and lodge in the small blood vessels leading to the brain, temporarily blocking the blood supply and causing a TIA. Clumps of platelets or blood clots can also block a blood vessel leading to a TIA. The risk of TIA is increased if a person has high blood pressure, atherosclerosis, heart disease (especially when the heart valve of the heart rhythm is abnormal), diabetes, or an excess of red blood cells (polycythemia). TIAs are more common in middle age and are progressively more likely with advancing age.
Symptoms of TIA: TIA starts suddenly and usually lasts 2 to 30 minutes. Rarely it lasts more than an hour.
Many different symptoms can occur such as the following:-
(i) Loss of or abnormal sensations in an arm or leg or one-side of the body.
(ii) Weakness or paralysis of an arm or leg or one side of the body.
(iii) Partial loss of vision of
hearing
(iv) Double vision
(v) Dizziness
(vi) Slurred speech
(vii) Difficulty in thinking of the appropriate words or saying it
(viii) Inability of recognise parts of the body
(ix) Unusual movements
(x) Loss of bladder control
(xi) Imbalance and falling
(xii) Fainting
While the symptoms are similar to those of a stroke, they are temporary and reversible. However, TIAs tend to recur. About one-third of the time a TIA is followed by a stroke. Roughly half of such strokes occur within one year of TIA.
Diagnosis of TIA basically depends of the clinical assessment of the symptoms. However similar symptoms may be observed in patients of other disorders such as seizures, migraine headaches, abnormal blood sugar level, tumours etc. So further evaluation is needed.
Since brain damage does not occur, CT scan or MRI scan cannot help diagnosis.
Several techniques may be used to evaluate a possible blockage in one or both carotid arteries. Bruits, a special sound made by the uneven flow of blood may be heard with the stethoscope. An ultrasound scan and a Doppler flow study may be done.
