WHAT IS A STROKE ?
A stroke is as type of injury to the brain. It is characterized by a a sudden loss of function of a particular part of the body because of a sudden interruption in the flow of blood to a part of the brain. This si usually caused by a block in a blood vessel carrying blood to the brain. Brain needs constant supply of sugar and oxygen for its function and they are normally delivered by the blood. If the blood supply to a part of the brain is compromised than that part of the brain ceases to function. This is called ischemic stroke. Sometimes a blood vessel in the brain bursts and blood spurts out into the brain tissue or over the surface of the brain. This is called hemorrhagic stroke. Here the mass of blood (hematoma) squashes the normal surrounding brain, preventing it from receiving any nourishing blood supply. There is another condition called transient ischemic attack (TIA) or a mini stroke. Here unlike a regular stroke the symptoms of abnormal functions of part of the body and brain recover completely with in 24 hours. This is because the block in the vessel clears by itself and the blood flow is restored. TIAs are important because they warn the patient and the treating doctor that there is a risk of a major impending stroke and that timely intervention is mandatory to prevent a major catastrophe.
WHAT ARE THE SYMPTOMS OF TIA AND STROKE ?
The symptoms of stroke depend on the part of the brain affected. Symptoms of stroke usually come on suddenly. Some patients may present with weakness of one half of the body. Weakness of right half of the body is due to impaired function of the left side of the brain. Some others may present with numbness o f one half of the body. Others may present with slurring of speech or difficulty in initiating speech. Other symptoms are loss of vision in one eye and sometimes double vision. Some individuals will present with giddiness and unsteady gait. Some others may present with head ache, vomiting and very rarely unconsciousness.
WHAT CAUSES STROKE ?
About 80% of strokes and TIAs are caused by a lack of blood supply to the brain. The commonest cause is narrowing of arteries due to hardening called atherosclerosis, which occurs in everyone as they get older. This process is similar to that which affects the water pipes in our houses. Atherosclerosis also affects arteries to other organs of the body (heart). It is not surprising that people who suffer a heart attack are also at increased risk of suffering a stroke or vice versa. Less commonly, ischemic stroke are caused by blood clots in the heart, which break away and are carried in the blood stream until they are lodged in a smaller vessel in the brain and block blood flow. About 20% of strokes are caused by a ruptured artery in the brain which causes bleeding into the brain or over the surface of the brain.
DOES STROKES RUN IN FAMILIES ?
Some families have a greater tendency to experience strokes. This is because they have a genetic predisposition to have high cholesterol (fat) in the blood and or high blood pressure. It can also be because of members of the family indulge in the same adverse behavior (eg. They all smoke or all eat fatty food). Atherosclerosis is accelerated if we are exposed over along period of time to high blood pressure, cigarette smoking, high blood pressure and diabetes. Physical inactivity and obesity also predispose to atherosclerosis. All these risk factors may be seen in some families and they run the risk of manifesting a stroke.
WHAT TESTS WILL THE DOCTORS DO AFTER A TIA OR STROKE ?
After a detailed physical examination the following tests are mandatory
Blood tests to check the levels of sugar and cholesterol (fat) in the body.
ECG to check the rhythm of the heart.
Echocardiogram to see whether there is any blood clot in nay chambers of the heart.
CT scan of the brain to know the type of stroke whether ischemic or hemorrhagic. CT scan will also show other causes of stroke (eg. Brain tumor).
Some times MRI scan of the brain may help in giving more details.
Carotid Doppler: Here the arteries of the brain are studied during their course in the neck. This test involves putting some jelly in the neck and then placing a probe on the neck which emits sound waves. This detects any narrowing of the artery that takes blood to the brain. It is a useful test not only to determine the cause of stroke but also for deciding whether to perform an operation that cleans out the artery in the neck (carotid endarterectomy).
Angiography: This is a scan obtained by injecting a medicine into the vessels of the brain. This involves inserting a fine plastic tube (catheter) into the major blood vessel in the groin(femoral artery) and passing the catheter up the femoral artery into the aorta in the abdomen and chest and then up the carotid arteries in the neck. This test shows the exact architecture of the blood vessels of the brain and is a pre requisite for nay definitive planning.
WHAT ARE THE TREATMENT OPTIONS ?
There are many treatment options. They all depend on the status of the blood vessels an dif the person has had a previous stroke. If the block is not very significant one can consider treatment with medication. This consists of blood thinners and medication to control blood pressure, diabetes and to reduce the cholesterol (fat) in the blood. If the block is significant one can consider dilating the block and putting a stent across the block. This entire procedure can be done under local anesthesia. This is called pinhole surgery since the entire procedure is done through a small hole in the groin. If the block is ulcerated with a fresh clot one has to undergo an open surgery to remove the blood clot and the block. This is called endarterectomy. This has to be done under general anesthesia. In some situations patients may present with acute symptoms. Here the clots may have to be dissolved by injecting clot busters directly into the ar4ea of the acute clot. This is called intra arterial thrombolysis and is done through pinhole surgery. What ever may be the treatment options, one has to give up risky habits like cigarette smoking, alcohol and fatty food consumption.
WHAT ARE THE CHANCES OF SURVIVAL AFTER A STROKE ?
Over all about 70% of people survive stroke. About 80% of those with ischemic stroke and 50% of those with hemorrhagic stroke survive. Among the survivors of stroke, about half make a good functional recovery and the remaining are left with some residual handicap. Recovery after stroke takes time. It is very good in the first few months and begins to plateau between 3 and 6 months.
WHAT SHOULD YOU DO IF YOU OR SOME ONE ELSE HAS A STROKE ?
If some one suddenly looses function of a particular part of the body, which is thought to be a stroke, they should be hospitalized immediately. At the onset of a stroke it is uncertain whether the symptoms will resole (TIA) or persist (stroke). If it is a TIA, he or she can be assessed and discharged with appropriate investigations, treatment and follow up. If it is a complete stroke it is a medical emergency and needs appropriate treatment like injecting clot busters in to the blood circulation.
WWHAT PROBLEMS MAY ARISE AFTER STROKE ?
About half of the patients have difficulty in swallowing. It is potentially very serious because the food can go the wrong way into the lungs and cause pneumonia. If swallowing difficulty is present on should start tube feeding by passing a tube through the nose into the stomach. Swallowing difficulty improves over a few weeks. About 50% of stroke patients have difficulty controlling their bladder and may leak urine. Constipation is another problem after stroke because of immobilization.
HOW CAN THE RISK OF STROKE BE REDUCED ?
Diet: A diet that includes all foods in moderation is advisable. It should be low in saturated fats, alcohol and salt and high in fiber, fruit and vegetables.
Smoking should be stopped at any cost to minimum the risk of stroke.
Blood pressure should be lowered with a change in lifestyle and with appropriate medication. Regular exercises to loose weight and avoiding excess alcohol and salt in the diet also will lower the blood pressure.
Blood thinning mediations are advised to prevent clot formation.
Carotid endarterectomy and carotid stenting may be needed in a selected few.