Strokes are a serious medical condition that are becoming increasingly common. Our modern lifestyles are partly responsible, but what exactly happens during a stroke?
Understanding Strokes
A stroke occurs when blood flow to the brain is interrupted. This disrupts the delivery of oxygen and glucose, vital nutrients carried by blood, to brain cells. When this happens, brain cells die, leading to stroke symptoms. These symptoms can vary depending on the location and severity of the stroke, but can include sudden weakness or numbness on one side of the body, difficulty speaking or understanding speech, vision problems, dizziness, and severe headache.
Two Main Types of Stroke
There are two main categories of stroke, each with its own causes and treatments:
- Ischemic Stroke (most common): This type happens due to a blockage in an artery supplying blood to the brain. This blockage limits blood flow, causing a lack of oxygen and nutrients. Common causes of ischemic stroke include:
- Atherosclerosis: This is the buildup of fatty deposits (plaque) in the arteries that can narrow the passage and increase the risk of clots forming on the plaque’s surface. High blood pressure, cholesterol, diabetes, and smoking are all major risk factors for atherosclerosis.
- Blood Clots: These can form in already narrowed arteries in the brain, further reducing blood flow.
- Embolic Stroke: A subtype of ischemic stroke, this occurs when a blood clot or debris, like bits of cholesterol, breaks free from elsewhere in the body and travels through the bloodstream until it lodges in a narrow artery in the brain, blocking blood flow. The source of the clot can be the heart, especially in cases of atrial fibrillation, or from arteries in the neck (carotid arteries).
- Hemorrhagic Stroke: This type occurs when a blood vessel in the brain bursts, causing bleeding within the skull. This bleeding puts too much pressure on the brain and disrupts normal function. Hemorrhagic strokes are less common than ischemic strokes, but are often more deadly. Here are two main causes:
- Subarachnoid Hemorrhage: This type of bleeding occurs on the surface of the brain or in the space between the skull and the brain’s lining. Aneurysms, weakened areas in blood vessel walls, are a common cause of this type of hemorrhage. Aneurysms can be inherited or develop over time due to high blood pressure or injury. Symptoms of subarachnoid hemorrhage often include severe headache and a stiff neck, along with nausea and vomiting.
- Cerebral Hemorrhage: This type of stroke results from a ruptured blood vessel deep within the brain tissue. The bleeding damages surrounding brain tissue and disrupts blood flow. Risk factors for cerebral hemorrhage include uncontrolled high blood pressure, use of blood thinners, and certain vascular malformations in the brain.
Importance of Early Intervention
Understanding the different causes of stroke can help individuals take steps to reduce their risk. This includes managing blood pressure, cholesterol, and diabetes, quitting smoking, maintaining a healthy weight, and eating a balanced diet. If you think you or someone you know may be experiencing a stroke, it’s crucial to seek immediate medical attention. Early intervention can significantly improve stroke outcomes. Strokes are time-sensitive emergencies, and administering clot-busting medications or performing surgery to stop bleeding and minimize brain damage is most effective within a few hours of stroke onset.
Remember, recognizing the signs of stroke and acting FAST (Face drooping, Arm weakness, Speech difficulty, Time to call emergency services) is essential. By understanding the causes of stroke and taking preventive measures, we can all work towards reducing the risk of this devastating condition.