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  • Writer's pictureFarhad Nassiri Afshar

Understanding Stroke: Mechanisms, Risk Factors, Common Causes, and Prevention

Stroke is a serious medical condition that occurs when blood flow to the brain is disrupted, leading to brain cell death. It is a leading cause of disability and death worldwide. In this article, we will explore the mechanisms, risk factors, and most common causes of stroke, as well as ways to prevent them.

A neurologist in a surgical gown intently studies a series of MRI brain scans illuminated on a monitor, possibly evaluating for signs of a stroke

Mechanisms of Stroke:

There are two main types of stroke: ischemic and hemorrhagic. Ischemic stroke, which accounts for about 87% of all strokes, occurs when a blood clot blocks an artery supplying blood to the brain. Hemorrhagic stroke, on the other hand, happens when a weakened blood vessel in the brain ruptures, causing bleeding into the brain tissue.

Risk Factors for Stroke:

Several factors can increase the risk of stroke, including:

1. High blood pressure: This is the number one risk factor for both ischemic and hemorrhagic strokes.

2. Smoking: Cigarette smoking doubles the risk of stroke by damaging blood vessels and increasing the risk of blood clots.

3. Diabetes: High blood sugar levels can damage blood vessels and nerves, increasing the risk of stroke.

4. High cholesterol: Excess cholesterol can build up in the arteries, leading to narrowing and increased risk of blood clots.

5. Atrial fibrillation: This heart rhythm disorder can cause blood to pool in the heart, increasing the risk of clot formation.

6. Age: The risk of stroke increases with age, particularly after 55.

7. Family history: Having a family member who has had a stroke increases your risk.

Common Causes of Stroke:

1. Atherosclerosis: The buildup of fatty deposits (plaque) in the arteries can lead to narrowing and blockage, causing ischemic stroke. This is the most common common cause of ischemic strokes. large artery atherosclerosis is cause of 50-70% of ischemic strokes

2. Cardioembolism: Blood clots that form in the heart, often due to atrial fibrillation, can travel to the brain and cause 20-30% of ischemic strokes.

3. Small vessel disease: Damage to the small blood vessels in the brain can lead to lacunar strokes, a type of ischemic stroke and this compromises 25% of them.

4. Aneurysms and arteriovenous malformations (AVMs): Weakened or abnormal blood vessels in the brain can rupture, causing hemorrhagic stroke.

5. Other causes (e.g., arterial dissection, vasculitis, hypercoagulable states): 5-10% of ischemic strokes

Illustrative comparison of ischemic and hemorrhagic strokes, displaying the brain in cross-sections. On the left, ischemic stroke types are depicted, including thrombosis with a clot in the carotid artery, an embolism showing a clot fragment from the heart, and hypoxia with areas of infarct due to poor blood flow. On the right, hemorrhagic stroke is illustrated with a subarachnoid hemorrhage at the top showing a ruptured aneurysm, and below, an intracerebral hemorrhage due to high blood pressure with localized bleeding in the brain tissue.

Preventing Stroke:

Many risk factors for stroke are modifiable, meaning you can take steps to reduce your risk:

1. Manage high blood pressure through medication, diet, and lifestyle changes.

2. Quit smoking and avoid exposure to secondhand smoke.

3. Control diabetes through proper diet, exercise, and medication.

4. Maintain healthy cholesterol levels through diet, exercise, and medication if necessary.

5. Treat atrial fibrillation with medications or procedures to prevent blood clots.

6. Eat a healthy diet rich in fruits, vegetables, whole grains, and lean proteins, while limiting saturated and trans fats, salt, and added sugars.

7. Exercise regularly, aiming for at least 150 minutes of moderate-intensity activity per week.

8. Maintain a healthy weight.

9. Limit alcohol consumption.

Time is Brain:

The timing interval from the onset of stroke symptoms to intervention is crucial in determining the effectiveness of treatment and the patient's overall outcome. The two main types of interventions for acute ischemic stroke are thrombolysis with tissue plasminogen activator (tPA) and mechanical thrombectomy (extraction of the clot using a device). It is essential to note that "time is brain" in acute stroke care. The longer the brain tissue remains without adequate blood flow, the more extensive and irreversible the damage becomes. Rapid recognition of stroke symptoms, prompt medical attention, and swift intervention are critical in minimizing brain damage and improving patient outcomes. The timing interval for tPA is within 4.5 hours of symptom onset, while mechanical thrombectomy can be performed within 6-24 hours in selected patients. However, in both cases, the earlier the intervention, the better the chances of a favorable.

A series of axial CT brain scans displayed in two rows show cross-sectional images of a patient's brain at different levels. The scans are characterized by varying shades of gray, indicating different tissue densities. Some images highlight areas of abnormal radiolucency or radiodensity, suggesting possible pathological findings such as an ischemic area, which are indicative of a stroke.


In summary, understanding the mechanisms, risk factors, and common causes of stroke is crucial for prevention. By adopting a healthy lifestyle and managing underlying medical conditions, you can significantly reduce your risk of stroke. If you experience any signs or symptoms of stroke, such as sudden weakness, numbness, or confusion, seek immediate medical attention, as prompt treatment is essential for the best possible outcome.

Medical Disclaimer

This article is for educational purposes only and should not replace professional medical advice. Always consult your doctor for medical concerns or before acting on any information in this article. If you suspect a medical emergency, seek immediate medical attention.

Book an Appointment at Irys Medical Clinic


If you're concerned about stroke or related symptoms, we invite you to book an appointment at Irys Medical Clinic. Our team of healthcare professionals specializes in stroke prevention, diagnosis, and treatment. Early intervention is crucial for managing stroke risk factors and outcomes. Visit our website or contact us directly to schedule your appointment. Your health is our top priority, and we're here to provide the care and support you need.

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