Stroke is a medical emergency that requires prompt treatment. It occurs when the blood supply to part of the brain is interrupted or reduced, preventing brain tissue from getting oxygen and nutrients. Brain cells begin to die in minutes. Early action can reduce brain damage and other complications.
Your brain needs a continuous supply of oxygen and nutrients from blood, supplied by your arteries without oxygen or nutrients, your brain cells will die and the affected area can suffer permanent damage.
Types/Causes of stroke
There are two main causes of stroke: a blocked artery (ischemic stroke) or leaking or bursting of a blood vessel (hemorrhagic stroke). Some people may have only a temporary disruption of blood flow to the brain, known as a transient ischemic attack (TIA), that doesn’t cause lasting symptoms.
This is the most common type of stroke. It happens when the brain’s blood vessels become narrowed or blocked, causing severely reduced blood flow (ischemia). Blocked or narrowed blood vessels are caused by fatty deposits that build up in blood vessels or by blood clots or other debris that travel through the bloodstream, most often from the heart, and lodge in the blood vessels in the brain.
Some initial research shows that COVID-19 infection may increase the risk of ischemic stroke, but more study is needed.
Hemorrhagic stroke occurs when a blood vessel in the brain leaks or ruptures. Brain hemorrhages can result from many conditions that affect the blood vessels. Factors related to hemorrhagic stroke include:
• Uncontrolled high blood pressure
• Overtreatment with blood thinners (anticoagulants)
• Bulges at weak spots in your blood vessel walls (aneurysms)
• Trauma (such as a car accident)
• Protein deposits in blood vessel walls that lead to weakness in the vessel wall (cerebral amyloid angiopathy)
• Ischemic stroke leading to hemorrhage
A less common cause of bleeding in the brain is the rupture of an irregular tangle of thin-walled blood vessels (arteriovenous malformation).
Transient ischemic attack (TIA)
A transient ischemic attack (TIA) — sometimes known as a ministroke — is a temporary period of symptoms similar to those in a stroke. A TIA doesn’t cause permanent damage. A TIA is caused by a temporary decrease in blood supply to part of the brain, which may last as little as five minutes.
Like an ischemic stroke, a TIA occurs when a clot or debris reduces or blocks blood flow to part of the nervous system.
Seek emergency care even if you think you’ve had a TIA because your symptoms got better. It’s not possible to tell if you’re having a stroke or TIA based only on the symptoms. If you’ve had a TIA, it means you may have a partially blocked or narrowed artery leading to the brain. Having a TIA increases your risk of having a full-blown stroke later.
Common risk factors that increase your blood pressure or cause your arteries to narrow over time include:
• Smoking — Tobacco smoke deposits toxic chemicals in your bloodstream, making your blood sticky and more likely to form clots.
• Not enough physical activity — Being inactive increases your risk of high blood pressure, type 2 diabetes and other related conditions.
• Unhealthy eating — Too much body fat (obesity) can contribute to high blood pressure and other conditions, while too much salt in your diet increases blood pressure.
• High cholesterol — Excess low-density lipoprotein (‘bad’ cholesterol) in your blood can build up on artery walls.
• Certain medical conditions, such as type 2 diabetes and atrial fibrillation (an irregular heartbeat).
There are also factors you can’t change that increase your risk of a stroke, such as:
• Your age — Most people who have a stroke (7 out of 10) are 65 years or older.
• Your family history — if one of your parents had a stroke before they were 65, your risk of getting one is 3 times greater than average.
• Your gender — Stroke is more common in men, especially between 65 and 84 years of age.
How is a stroke diagnosed?
Your doctor will diagnose a stroke by conducting a physical examination and reviewing images of your brain. In hospital, doctors will carry out tests to check whether you have had a stroke, or have another condition. If it’s a stroke, they will work out what kind of stroke it is, find out which part of your brain is affected and decide how to treat it.
You might need different tests. Some common ones include:
• a computer tomography (CT) scan
• a magnetic resonance imaging (MRI) scan
• an angiogram or ultrasound to pinpoint a potential blood clot and assess blood flow
• an electrocardiogram (ECG) to check for unusual heart rhythms
• blood tests to rule out other medical conditions
Some illnesses that are unrelated to stroke may show stroke-like symptoms and require different treatments. These include migraine, seizures, and low blood sugar, fainting and heart arrhythmias.
Ways to prevent stroke
More than 4 in 5 strokes are preventable. If you have high blood pressure, type-2 diabetes, high cholesterol or an irregular heartbeat (atrial fibrillation), see your doctor for ways to manage these stroke risk factors using medication.
You can also reduce your risk by maintaining a healthy lifestyle, including by staying active, eating well, quitting smoking and drinking alcohol in moderation.
If you’ve already had a stroke or TIA, it’s even more important to make the following lifestyle changes:
• Improve your diet — A diet that’s varied, high in fibre, fruit, nuts, vegetables and healthy fats, but low in saturated fat and salt, can help prevent stroke.
• Avoid smoking — Smoking cigarettes doubles your risk of having a stroke.
• Regular exercise — this helps you maintain a healthy weight and improve blood circulation.
If you or someone you’re with may be having a stroke, pay particular attention to the time the symptoms began. Some treatment options are most effective when given soon after a stroke begins.
Signs and symptoms of stroke include:
• Trouble speaking and understanding what others are saying. You may experience confusion, slur words or have difficulty understanding speech.
• Paralysis or numbness of the face, arm or leg. You may develop sudden numbness, weakness or paralysis in the face, arm or leg. This often affects just one side of the 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.
• Problems seeing in one or both eyes. You may suddenly have blurred or blackened vision in one or both eyes, and you may see double.
• Headache. A sudden, severe headache, which may be accompanied by vomiting, dizziness or altered consciousness, may indicate that you’re having a stroke.
• Trouble walking. You may stumble or lose your balance. You may also have sudden dizziness or a loss of coordination.
Many factors can increase the risk of stroke. Potentially treatable stroke risk factors include:
Lifestyle risk factors
• Being overweight or obese
• Physical inactivity
• Heavy or binge drinking
• Use of illegal drugs such as cocaine and methamphetamine
Medical risk factors
• High blood pressure
• Cigarette smoking or secondhand smoke exposure
• High cholesterol
• Obstructive sleep apnea
• Cardiovascular disease, including heart failure, heart defects, heart infection or irregular heart rhythm, such as atrial fibrillation
• Personal or family history of stroke, heart attack or transient ischemic attack
• COVID-19 infection
Other factors associated with a higher risk of stroke include:
• Age — People age 55 or older have a higher risk of stroke than do younger people.
• Race or ethnicity — African Americans and Hispanics have a higher risk of stroke than do people of other races or ethnicities.
• Sex — Men have a higher risk of stroke than do women. Women are usually older when they have strokes, and they’re more likely to die of strokes than are men.
• Hormones — Use of birth control pills or hormone therapies that include estrogen increases risk.
A stroke can sometimes cause temporary or permanent disabilities, depending on how long the brain lacks blood flow and which part is affected. Complications may include:
• Paralysis or loss of muscle movement. You may become paralyzed on one side of the body, or lose control of certain muscles, such as those on one side of the face or one arm.
• Difficulty talking or swallowing. A stroke might affect control of the muscles in the mouth and throat, making it difficult for you to talk clearly, swallow or eat. You also may have difficulty with language, including speaking or understanding speech, reading, or writing.
• Memory loss or thinking difficulties. Many people who have had strokes experience some memory loss. Others may have difficulty thinking, reasoning, making judgments and understanding concepts.
• Emotional problems. People who have had strokes may have more difficulty controlling their emotions, or they may develop depression.
• Pain. Pain, numbness or other unusual sensations may occur in the parts of the body affected by stroke. For example, if a stroke causes you to lose feeling in the left arm, you may develop an uncomfortable tingling sensation in that arm.
• Changes in behavior and self-care ability. People who have had strokes may become more withdrawn. They may need help with grooming and daily chores.
Knowing your stroke risk factors, following your health care provider’s recommendations and adopting a healthy lifestyle are the best steps you can take to prevent a stroke. If you’ve had a stroke or a transient ischemic attack (TIA), these measures might help prevent another stroke. The follow-up care you receive in the hospital and afterward also may play a role.
Many stroke prevention strategies are the same as strategies to prevent heart disease. In general, healthy lifestyle recommendations include:
• Controlling high blood pressure (hypertension). This is one of the most important things you can do to reduce your stroke risk. If you’ve had a stroke, lowering your blood pressure can help prevent a subsequent TIA or stroke. Healthy lifestyle changes and medications are often used to treat high blood pressure.
• Lowering the amount of cholesterol and saturated fat in your diet. Eating less cholesterol and fat, especially saturated fat and Trans fats, may reduce build-up in the arteries. If you can’t control your cholesterol through dietary changes alone, your doctor may prescribe a cholesterol-lowering medication.
• Quitting tobacco use. Smoking raises the risk of stroke for smokers and non-smokers exposed to second-hand smoke. Quitting tobacco use reduces the risk of stroke.
• Managing diabetes. Diet, exercise and losing weight can help you keep your blood sugar in a healthy range. If lifestyle factors don’t seem to be enough to control your diabetes, your doctor may prescribe diabetes medication.
• Maintaining a healthy weight. Being overweight contributes to other stroke risk factors, such as high blood pressure, cardiovascular disease and diabetes.
• Eating a diet rich in fruits and vegetables. A diet containing five or more daily servings of fruits or vegetables may reduce the risk of stroke. The Mediterranean diet, which emphasizes olive oil, fruit, nuts, vegetables and whole grains, may be helpful.
• Exercising regularly. Aerobic exercise reduces the risk of stroke in many ways. Exercise can lower blood pressure, increase the levels of good cholesterol, and improve the overall health of the blood vessels and heart. It also helps you lose weight, control diabetes and reduce stress. Gradually work up to at least 30 minutes of moderate physical activity — such as walking, jogging, swimming or bicycling — on most, if not all, days of the week.
• Drinking alcohol in moderation, if at all. Heavy alcohol consumption increases the risk of high blood pressure, ischemic strokes and hemorrhagic strokes. Alcohol may also interact with other drugs you’re taking. However, drinking small to moderate amounts of alcohol, such as one drink a day, may help prevent ischemic stroke and decrease the blood’s clotting tendency. Talk to your doctor about what’s appropriate for you.
• Treating obstructive sleep apnea (OSA). Your doctor may recommend a sleep study if you have symptoms of OSA — a sleep disorder that causes you to stop breathing for short periods repeatedly during sleep. Treatment for OSA includes a device that delivers positive airway pressure through a mask to keep the airway open while you sleep.
• Avoiding illegal drugs. Certain street drugs, such as cocaine and methamphetamine, are established risk factors for a TIA or a stroke.
Can stroke be managed?
The exact treatment depends on what caused your stroke, but generally involves both immediate and long-term measures.
Immediate stroke treatment
For ischaemic strokes, the blood clot needs to be dissolved using medication, or removed. Small blood clots may be dissolved with medication. Large clots usually require brain surgery such as endovascular clot retrieval (mechanical thrombectomy), where a catheter is threaded up your blood vessels to find and remove the clot.
For haemorrhagic strokes, immediate treatment involves intensive blood pressure control and surgery to relieve swelling from bleeding in the brain, or to repair the ruptured blood vessel.
Long-term stroke treatment
Treatments to prevent another stroke or TIA include: medication, to lower blood pressure and cholesterol or to thin your blood, surgery to increase the flow in your carotid artery (in the front of your neck). Lifestyle improvements, such as good nutrition, regular exercise and quitting smoking