Strokes occur when blood flow to a part of the brain is interrupted, leading to brain cell damage or death. There are two main categories and several contributing factors: Core causes
- Ischemic stroke: A blockage (usually a blood clot) in a brain artery reduces or stops blood flow. This is the most common type.
- Hemorrhagic stroke: A blood vessel in the brain ruptures and bleeds, causing pressure and damage to surrounding brain tissue.
Common mechanisms behind ischemic strokes
- Atherosclerosis: Plaques narrow or block arteries, especially in the carotid arteries or the Circle of Willis.
- Cardioembolic sources: Blood clots from the heart (e.g., due to atrial fibrillation, recent heart attack, or other heart conditions) travel to the brain.
- Small vessel disease: Narrowing or occlusion of small vessels inside the brain, often related to chronic hypertension or diabetes.
- Vessel dissection or other vascular disorders: Tear or inflammation of a blood vessel can create an obstruction or clot.
Common mechanisms behind hemorrhagic strokes
- Hypertension: Chronic high blood pressure weakens vessels, increasing rupture risk.
- Aneurysm rupture: A weakened arterial wall bulges and may burst.
- Arteriovenous malformations or other vascular abnormalities: Abnormal connections can bleed.
- Anticoagulant or antiplatelet use, trauma, or certain illnesses that affect clotting.
Key risk factors (shared across stroke types)
- High blood pressure (hypertension)
- Diabetes
- High cholesterol
- Smoking
- Obesity and physical inactivity
- Afibrillation and other heart rhythm problems
- Age (risk increases with age; also higher in certain ethnic groups)
- Family history and prior stroke or transient ischemic attack (TIA)
Additional notes
- TIAs, often called “mini-strokes,” involve temporary blockage with symptoms resolving within 24 hours and serve as a warning for potential future stroke.
- Ischemic and hemorrhagic strokes require urgent medical attention; time to treatment is critical for outcomes.
If you’d like, I can tailor this to a specific audience (patients, caregivers, students) or provide a concise comparison table of ischemic vs hemorrhagic stroke with symptoms, typical imaging findings, and treatment priorities.
