A stroke occurs when the blood supply to part of your brain is interrupted or severely reduced, depriving brain tissue of oxygen and nutrients. Brain cells can begin to die within minutes. A stroke is a medical emergency, and prompt treatment is crucial to minimize brain damage and potential complications. Early action can reduce brain damage and other complications. Strokes are often categorized into two main types: ischemic stroke (due to a blocked artery) and hemorrhagic stroke (due to bleeding in the brain).
Causes:
The causes of stroke depend on whether it is an ischemic stroke (blockage) or a hemorrhagic stroke (bleeding).
- Ischemic Stroke (Most Common, ~87% of strokes):
- Occurs when the blood vessels supplying the brain become narrowed or blocked, leading to severely reduced blood flow (ischemia).
- Thrombotic Stroke: A blood clot (thrombus) forms in an artery that supplies blood to the brain. Often occurs in arteries damaged by atherosclerosis (fatty deposits).
- Embolic Stroke: A blood clot or other debris forms away from the brain, typically in the heart, and travels through the bloodstream to lodge in narrower brain arteries. A common cause is atrial fibrillation (an irregular heartbeat).
- Risk Factors for Ischemic Stroke: High blood pressure, high cholesterol, diabetes, obesity, smoking, heart disease (e.g., atrial fibrillation, heart failure), carotid artery disease, sickle cell anemia, sedentary lifestyle, excessive alcohol consumption.
- Hemorrhagic Stroke (Less Common, but often more severe):
- Occurs when a blood vessel in the brain leaks or ruptures. Blood spills into or around the brain, creating pressure and damaging brain cells.
- Intracerebral Hemorrhage: The most common type of hemorrhagic stroke, where a blood vessel bursts within the brain tissue. High blood pressure is a primary cause.
- Subarachnoid Hemorrhage: Bleeding occurs in the space between the brain and the membranes covering the brain (subarachnoid space). Often caused by a ruptured aneurysm (a balloon-like bulge in a blood vessel).
- Risk Factors for Hemorrhagic Stroke: High blood pressure, ruptured brain aneurysm, arteriovenous malformation (AVM – abnormal tangle of blood vessels), anticoagulant medications, trauma, smoking, drug abuse (e.g., cocaine).
- Transient Ischemic Attack (TIA – “Mini-stroke”):
- Caused by a temporary disruption of blood flow to part of the brain, spinal cord, or retina, causing stroke-like symptoms that last only a few minutes to an hour and cause no permanent damage.
- A TIA is a warning sign of a future stroke and requires immediate medical attention.
Symptoms:
Stroke symptoms appear suddenly and require immediate medical attention. Remember the acronym FAST to recognize signs of a stroke:
- F – Face Drooping: One side of the face droops or is numb. Ask the person to smile. Is the smile uneven?
- A – Arm Weakness: One arm is weak or numb. Ask the person to raise both arms. Does one arm drift downward?
- S – Speech Difficulty: Speech is slurred, or the person is unable to speak or is hard to understand. Ask the person to repeat a simple sentence. Is it correct?
- T – Time to call emergency services: If anyone shows any of these symptoms, even if the symptoms go away, call emergency services immediately.
- Other Sudden Symptoms May Include:
- Sudden numbness or weakness of the leg, arm, or face.
- Sudden confusion or trouble understanding speech.
- Sudden trouble seeing in one or both eyes.
- Sudden trouble walking, dizziness, loss of balance, or coordination.
- Sudden severe headache with no known cause.
Diagnosis:
Prompt diagnosis of a stroke is critical to determine the type of stroke and initiate appropriate treatment. It involves a rapid assessment and imaging of the brain.
- Physical Exam and Neurological Assessment: Doctors will check symptoms, reflexes, vision, speech, and strength.
- Blood Tests: To check blood clotting time, blood sugar levels, and other factors that could contribute to stroke or mimic its symptoms.
- Imaging Tests:
- CT Scan (Computed Tomography): Often the first imaging test. It can quickly show bleeding in the brain (distinguishing hemorrhagic from ischemic stroke) and can identify large ischemic strokes later.
- MRI (Magnetic Resonance Imaging): Provides more detailed images of brain tissue and can detect ischemic strokes earlier than CT.
- CT Angiography (CTA) or MR Angiography (MRA): Use dye and imaging to look at the blood vessels in the brain and neck to identify blockages or aneurysms.
- Carotid Ultrasound: Uses sound waves to check for narrowing or blockages in the carotid arteries (major arteries in the neck supplying the brain).
- Echocardiogram: To check for blood clots in the heart that could travel to the brain.
Treatment:
Stroke treatment varies greatly depending on whether it’s an ischemic or hemorrhagic stroke. Time is of the essence for both types.
- For Ischemic Stroke (to restore blood flow):
- Emergency IV Medication (tPA – Tissue Plasminogen Activator): Administered within 3-4.5 hours of symptom onset for eligible patients. This “clot-busting” drug can dissolve the clot and restore blood flow.
- Endovascular Procedures (Mechanical Thrombectomy): For large vessel occlusions, a catheter is threaded through an artery, usually in the groin, to the brain to physically remove the clot. This can be done up to 6-24 hours after symptom onset in select cases.
- Medications: Antiplatelet drugs (e.g., aspirin, clopidogrel) or anticoagulants (e.g., warfarin, direct oral anticoagulants) to prevent future clots.
- For Hemorrhagic Stroke (to control bleeding and reduce pressure):
- Emergency Measures: Control bleeding, reduce pressure in the brain, manage blood pressure.
- Medications: To lower blood pressure, reduce brain swelling, or reverse the effects of blood thinners.
- Surgery:
- Surgical Clipping: A tiny clamp is placed at the base of a brain aneurysm to stop blood flow to it.
- Endovascular Coiling: Coils are threaded into an aneurysm to block blood flow.
- Craniotomy: To relieve pressure on the brain or remove a large blood clot.
- Post-Stroke Rehabilitation:
- Crucial for recovery and often begins in the hospital.
- Physical Therapy: To regain strength, balance, and coordination.
- Occupational Therapy: To improve ability to perform daily activities (dressing, eating).
- Speech and Language Therapy: For problems with speaking, understanding, reading, or swallowing.
- Cognitive Therapy: For issues with memory, problem-solving, and judgment.
- Psychological Counseling: To address depression, anxiety, or emotional changes.
- Prevention of Recurrence:
- Long-term management of risk factors: controlling blood pressure, diabetes, cholesterol; quitting smoking; maintaining a healthy weight; regular exercise; healthy diet.
- Medications to prevent future strokes (e.g., antiplatelets, anticoagulants).
- Surgical procedures (e.g., carotid endarterectomy or angioplasty and stenting) to clear blocked neck arteries.
Recognizing the signs of stroke and seeking immediate medical help is paramount for the best possible outcome.
