Stroke occurs when the blood supply to the brain is cut off, resulting in brain cell death. This gives rise to symptoms like sudden onset of paralysis or weakness of one side of the body.
The blood supply to the brain can be cut off due to many reasons, depending on which strokes are divided into:
- Ischemic stroke: Occurs when there is a block in the arteries supplying the brain. This commonly occurs due to a process called atherosclerosis, where the walls of the arteries thicken with age
- Hemorrhagic stroke: Occurs when the arteries supplying the brain are damaged, resulting in bleeding inside or over the brain
Understanding the disease
Our brain depends on minute to minute supply of oxygenated blood. Hence, even a small reduction in the blood supply to the brain, severely hampers its function. This damage can be fully reversed if the blood supply is restored immediately. It becomes permanent when there is prolonged loss of blood supply to the brain.
Our brain plays a vital role in our survival. It is divided into many parts anatomically, with each part playing a crucial function:
Hence, the symptoms of stroke depend on which artery gets damaged or blocked. That part of the brain will show loss of function or abnormal function.
The signs and symptoms of stroke depend on the part of brain involved:
- Trouble with speaking and understanding: You may experience You may slur your words or have difficulty in understanding speech
- Paralysis or numbness of the face, arm or leg: You may develop sudden numbness, weakness or paralysis in your face, arm or leg. This often happens just on one side of your body. Try to raise both your arms over your head at the same time. If one arm begins to fall, you may be having a stroke. Also, one side of your mouth may droop when you try to smile
- Trouble with seeing with one or both eyes: You may suddenly have blurred or blackened vision in one or both eyes, or you may see double
- Headache: A sudden, severe headache, which may be accompanied by vomiting, dizziness or altered consciousness, may indicate you’re having a stroke
- Trouble with walking: You may stumble or experience sudden dizziness or loss of balance or loss of coordination
When to see a doctor?
Seek immediate medical attention if you notice any signs or symptoms of a stroke, even if they seem to fluctuate or disappear. Think “FAST” and do the following:
- Face: Ask the person to smile. Does one side of the face droop?
- Arms: Ask the person to raise both arms. Does one arm drift downward? Or is one arm unable to rise up?
- Speech: Ask the person to repeat a simple phrase. Is his or her speech slurred or strange?
- Time: If you observe any of these signs, seek medical attention immediately.
Who is at risk?
- Elderly people (above the age of 55 yrs)
- Men are at a higher risk of suffering from strokes than women. But women suffer from strokes when they’re much older than men, hence they’re more likely to die of strokes than men.
- People with high blood cholesterol levels
- People with high blood pressure
- People suffering from diabetes
- Cigarette smokers
- Factors like obesity, sedentary lifestyle, binge drinking
- Family history of stroke
- People suffering from heart problems like abnormal heart rhythms, heart failure, heart infection.
- Use of birth control pills or hormone replacement therapy having high levels of estrogen.
Ischemic stroke is caused by:
- Deposition of fat in the walls of arteries, thickening them (called atherosclerosis). Age related degeneration of arterial walls. (causes thrombotic stroke)
- Abnormal heart rhythm (atrial fibrillation) forms a clot within the atria which further gets dislodged into the circulation and blocks the arteries of the brain. (embolic stroke)
Hemorrhagic stroke is caused by:
- Uncontrolled high blood pressure
- Over-treatment with blood thinners
- Weakening of walls of arteries of the brain (aneurysms)
- Trauma to the brain
- Transient ischemic attacks (TIA): It is a warning signal for a stroke. These are attacks similar to stroke which result due to temporary reduction in blood supply and last for a maximum period of one hour. Though this is not a full fledged stroke, it can increase your risk of suffering from a stroke in the future. Hence, it is important to seek medical help to prevent stroke in the future.
A stroke can cause temporary or permanent disabilities depending on the duration of reduced blood flow:
- Paralysis or loss of muscle movement resulting in bedridden state
- Difficulty in talking or walking
- Memory loss and difficulty in thinking
- Pain and numbness
- Changes in behavior and self care abilities
Your doctor will do the following tests to diagnose stroke:
- Plain CT scan of brain: to differentiate ischemic stroke from hemorrhagic, and to find out the exact site of bleeding, if present
- Detailed physical examination
- MRI scan
- Cerebral Angiography: to assess the cerebral blood flow.
- ECG to detect abnormalities in heart rhythm.
- Blood tests: complete blood counts, tests to detect coagulation abnormalities, blood glucose levels, blood electrolyte levels
Stroke can be very disabling, especially in the elderly population, where recovery is slow. It can be prevented by:
- Lowering high blood pressure
- Controlling blood cholesterol and reducing saturated fat in diet
- Cessation of smoking and alcohol binges
- Maintaining healthy weight
- Controlling diabetes
- Preventive medicines: these are blood thinners like aspirin, clopidogrel (under the guidance of your doctor)
Stroke is treated on an emergency basis, as quick restoring of blood supply to the brain drastically changes the prognosis.
- Injecting clot busters in the veins: this is effective in ischemic strokes and should be injected within 3-4 hrs of initiation of stroke symptoms
- Emergency endovascular procedures like removing the clot with a stent retriever, and injecting drugs preventing further formation of clot
- Treatment of increased blood glucose levels
- Other procedures like carotid endarterectomy (removing clot from carotid artery that lies in the neck) and carotid angioplasty
- If you use blood thinners on a regular basis, you may be given blood transfusion products or drugs to counteract their effect.
- Blood pressure lowering drugs are used in cases of uncontrolled hypertension (high BP)
- Bleeding in the brain causes your intracranial pressure (pressure within the skull vault) to rise drastically. This poses a threat of expulsion of brain into the vertebral column, which can be fatal. Hence, drugs are given intravenously to lower this pressure.
- Surgical repair of blood vessels: in cases of arteriovenous wall defects, vascular surgeries like vessel clipping, coiling, stereotactic radiosurgery are performed to strengthen the wall and prevent bleeding in the future.
Physiotherapy also plays an important role in rehabilitation of stroke.
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