A stroke is the condition that occurs when blood supply to an area of the brain is interrupted or cut off due to blood vessel blockage or rupture. This results in brain tissue damage and brain cell death, thus disrupting and/or causing loss of certain brain functions.
Stroke Classifications
There are 2 main types of stroke:
- Ischemic stroke is the most common type of stroke, accounting for about 80% of all stroke cases. This can be an obstruction caused by a blood clot or piece of debris that forms in another area and travels along the bloodstream until it causes a blockage of an artery in the brain. An ischemic stroke can also be the result of the accumulation of fatty deposits and cholesterol in the arterial wall, which causes narrowing of the blood vessels and loss of flexibility, resulting in an inefficient transport of oxygen-rich blood to the brain.
- Hemorrhagic stroke accounts for about 20% of stroke cases. The most common causes of hemorrhagic stroke are high blood pressure and brain aneurysms, as the weak or bulging area in the arterial wall balloons and eventually ruptures. It can also be caused by artery weakening or loss of flexibility due to accumulation of fat in the arteries, making them susceptible to breakage and rupture. This is very dangerous as it causes a sudden drop in blood supply to the brain, as well as bleeding within the brain, which can result in death in a very short period of time.
Risk Factors
There are a variety of factors which can increase the risk of a stroke. These are divided into uncontrollable risk factors and controllable risk factors.
- Uncontrollable Risk Factors
- Age — as a person gets older, their blood vessels weaken and deteriorate, whereby the inner layer of the artery walls thicken and harden due to plaque buildup, causing a gradual narrowing of the arteries.
- Gender — men have a higher risk of stroke than women.
- Hypercoagulable States — this condition causes blood platelets to stick together and clot more easily than normal.
- Controllable Risk Factors
- High blood pressure is the most important risk factor for stroke. People who have high blood pressure are at much greater risk of stroke.
- Diabetes causes hardening of the arteries throughout the body. If this occurs in the brain, it increases the chance of stroke by 2-3 times.
- High cholesterol is just as a risk factor for stroke as it is for coronary artery disease. The accumulation of fatty deposits in the arterial wall results in narrowing of lumen, making it difficult for an efficient amount of blood to flow through.
- Heart disease, such as atrial fibrillation and arrhythmia, causes blood clots. If a blood clot forms in an artery that supplies blood to the brain, it could result in a blood deficiency in the brain.
- Smoking is a risk factor, as nicotine and carbon monoxide lower the oxygen levels in the blood, damage the arterial walls, and causes hardening of the arteries.
- Oral contraceptives are a risk factor, as the chance of a stroke is higher in women using birth control pills with high doses of estrogen.
- Syphilis can cause inflammation of cerebral blood vessels and hardening of the arteries.
- Physical inactivity and lack of exercise raises the risk of stroke.
Symptoms
Insufficient blood supply to the brain results in the inability of the brain to function normally. Symptoms will be more or less serious depending on the size of the brain damage and the location or part of the brain affected.
Symptoms of stroke include:
- Sudden numbness or weakness of the face and/or limbs, especially on one side of the body
- Slurred speech, crooked smile or drooping mouth corner, drooling and difficulty swallowing
- Headache, sudden dizziness
- Blurred vision, double or blackened vision, or sudden loss of vision on one side of the visual field
- Trouble with walking, loss of balance or coordination
The onset of these symptoms always occurs suddenly.
Some patients may experience transient ischemic attacks (TIAs), also known as mini-strokes, which may occur a few times before an actual stroke. Signs and symptoms appear temporarily, disappearing within 24 hours.
TIAs are a warning sign that a full-blown stroke can occur within one week, especially within the first 24 hours after the initial TIA. These warnings occur in only about 10% of cases; the other 90% have no warning.
If any of these abnormal symptoms occur, it is vital that patients seek immediate medical attention. As a stroke can be severe and potentially life-threatening, the outcome depends on how soon treatment starts.
Diagnosis
Current diagnostic methods are highly effective and are able to identify the location of the damage or abnormalities in the brain or blood vessels, as well as any conditions and causes that could be risk factors for stroke.
Methods include:
- Blood tests to determine complete blood count (CBC)
- Tests to determine blood glucose and cholesterol levels
- Electrocardiogram to check for irregularities in heart rate and rhythm
- Computerized tomography (CT) scan to identify blood deficiencies or hemorrhaging in the brain
- Carotid duplex scan , an ultrasound test using high-frequency sound waves to measure blood flow in the carotid arteries; the carotid arteries are located in the neck and supply blood to the brain
- Magnetic resonance imaging (MRI) to examine the brain, cerebral arteries, and carotid arteries
Treatment
The preferred method of stroke treatment depends on whether the stroke is ischemic or hemorrhagic, each with a different treatment approach, as follows:
- Ischemic Stroke - Treatment focuses on restoring blood flow to the brain – in which there are a variety of procedures available. In some cases, doctors may prescribe medications to dissolve blood clots. This has been found to be effective in patients who are treated within 4.5 hours of stroke symptoms manifesting themselves.
- Hemorrhagic Stroke - Treatment focuses on controlling bleeding by reducing blood pressure in the brain. In cases of extreme bleeding, the doctor may consider surgery in order to prevent brain damage from occurring as a result of the change in blood pressure.
Prevention of Stroke Recurrence
Prevention is always the best treatment, and prevention of stroke includes controlling risk factors.
Tips for stroke prevention:
- Have annual health check-ups in order to check for risk factors. If any are found, patients should quickly begin treatment and have regular doctor visits.
- In cases where risk factors are found that could cause artery stenosis, blockage, or rupture, patients can take anti-coagulant and/or anti-platelet medication – following their doctor’s treatment plan. Medications should not be discontinued on one’s own; patients should seek immediate medical attention if any unusual symptoms develop.
- Control high blood pressure, cholesterol, and blood sugar levels – remaining within a normal range.
- Have a well-balanced diet; avoid salty, sweet, and greasy foods.
- Exercise regularly, at least 30 minutes a day, 3 times per week, and maintaining a healthy weight.
- Quit smoking and avoid alcohol.
- If there are any symptoms indicating inadequate blood supply to the brain, seek immediate medical attention.
- For patients who have already experienced an ischemic stroke, the doctor will prescribe medications to prevent a stroke recurrence. Use of these medications must be monitored and taken strictly in line with the doctor’s orders, as incorrect usage could result in potentially serious or even life-threatening complications.