Stroke: A Medical Emergency Affecting the Brain

A stroke, sometimes called a “brain attack” or cerebrovascular accident (CVA), is a serious medical condition that occurs when the blood supply to part of the brain is interrupted or reduced. This deprives brain tissue of oxygen and nutrients, causing brain cells to begin to die within minutes. Prompt medical attention is crucial to minimize brain damage and potential long-term complications.

Causes and Risk Factors

Strokes are broadly caused by either a blockage of blood flow or bleeding in the brain. Numerous factors can increase an individual’s risk of having a stroke. These can be categorized as:

Medical Conditions:

• High Blood Pressure (Hypertension): This is the leading cause of stroke.
• High Cholesterol: Can lead to the buildup of plaque in arteries (atherosclerosis), narrowing them.
• Diabetes: Increases stroke risk, partly due to its association with high blood pressure and atherosclerosis.
• Heart Disease: Conditions like coronary artery disease, atrial fibrillation (irregular heartbeat), heart valve defects, and enlarged heart chambers can lead to blood clots that may travel to the brain.
• Obesity: Linked to higher rates of high blood pressure, high cholesterol, and diabetes.
• Sickle Cell Disease: Can cause blockages in blood vessels.
• Previous Stroke or Transient Ischemic Attack (TIA): Having had a stroke or TIA significantly increases the risk of another stroke.
• Aneurysms and Arteriovenous Malformations (AVMs): These are weaknesses or tangles in blood vessels that can rupture and cause bleeding in the brain.
• Sleep Apnea: Can increase stroke risk.
• Kidney Disease: Also a contributing factor.
• Migraine Headaches: Some studies suggest a link.
• Inflammatory Conditions: Chronic inflammation from conditions like lupus or rheumatoid arthritis can damage blood vessels.

Lifestyle Factors:

• Smoking (Tobacco Use): Damages blood vessels and raises blood pressure. Exposure to secondhand smoke also increases risk.
• Poor Diet: Diets high in saturated fats, trans fats, cholesterol, and sodium can contribute to high cholesterol and high blood pressure.
• Physical Inactivity: Contributes to obesity, high blood pressure, high cholesterol, and diabetes.
• Excessive Alcohol Consumption: Can raise blood pressure and triglyceride levels.
• Illegal Drug Use: Drugs like cocaine can increase stroke risk.
• Getting Too Much Sleep (More than 9 hours): Some studies indicate a possible link.

Other Unmodifiable or Partially Modifiable Factors:

• Age: The risk of stroke increases with age, particularly after 55, though strokes can occur at any age, including in children and young adults.
• Family History and Genetics: A family history of stroke can increase risk. Certain genetic factors, including blood type (e.g., type AB), may play a role.
• Race and Ethnicity: In the United States, stroke occurs more often in Black, Alaska Native, American Indian, and Hispanic adults compared to white adults. Non-Hispanic Black adults and Pacific Islander adults have the highest stroke death rates.
• Sex: At younger ages, men are more likely to have a stroke. However, women have a higher lifetime risk of stroke as they tend to live longer. Factors specific to women, such as birth control pills, hormone replacement therapy, pregnancy, and preeclampsia, can also increase risk.
• Environmental Factors: Living or working in areas with air pollution can contribute to stroke risk.
• Socioeconomic Factors: Stress, working long hours, and lack of social contact may also elevate risk.

Types of Stroke

There are two main categories of stroke, with further subdivisions:

1. Ischemic Stroke (Clot-Caused): This is the most common type, accounting for about 87% of all strokes. It occurs when a blood vessel supplying the brain becomes blocked by a blood clot or plaque.
   • Thrombotic Stroke: A blood clot (thrombus) forms in an artery that supplies blood to the brain. This often happens in arteries already narrowed by atherosclerosis. These strokes can sometimes be preceded by one or more TIAs.
   • Embolic Stroke: A blood clot or other debris (embolus) forms elsewhere in the body (often the heart) and travels through the bloodstream to lodge in a narrower brain artery. Atrial fibrillation is a common cause of embolic strokes.
   • Lacunar Infarct: A type of thrombotic stroke that occurs in the small blood vessels deep within the brain. Often associated with diabetes or high blood pressure.
2. Hemorrhagic Stroke (Bleeding): This type occurs when a blood vessel in or on the surface of the brain ruptures and bleeds into the surrounding brain tissue or the spaces around the brain. This accounts for about 13% of strokes.
   • Intracerebral Hemorrhage: Bleeding occurs directly within the brain tissue. High blood pressure is a common cause.
   • Subarachnoid Hemorrhage: Bleeding occurs in the subarachnoid space (the area between the brain and the thin tissues that cover it). Often caused by a ruptured aneurysm or an AVM, and can also be caused by trauma.

Other Related Conditions:

• Transient Ischemic Attack (TIA): Often called a “mini-stroke.” It involves a temporary blockage of blood flow to the brain, causing stroke-like symptoms that usually last for a few minutes to 24 hours and do not cause permanent brain damage. However, a TIA is a serious warning sign of a future stroke and requires immediate medical attention.
• Cryptogenic Stroke: A stroke where the exact cause cannot be identified despite thorough investigation.
• Brain Stem Stroke: Describes the location of the stroke rather than the cause. Strokes in the brainstem can be particularly severe as this area controls vital functions like breathing and heartbeat.
• Recurrent Stroke: Refers to having more than one stroke. Having had a stroke significantly increases the risk of subsequent strokes.

Symptoms of Stroke: Act F.A.S.T.

Recognizing the signs of a stroke and seeking immediate medical help is critical. The F.A.S.T. acronym is a helpful way to remember the common symptoms:

• F – Face Drooping: Ask the person to smile. Does one side of their face droop?
• A – Arm Weakness: Ask the person to raise both arms. Does one arm drift downward?
• S – Speech Difficulty: Ask the person to repeat a simple sentence. Is their speech slurred or strange? Are they unable to speak or hard to understand?
• T – Time to call emergency services (e.g., 911 in the US, 999 in Bangladesh): If you observe any of these signs, even if they go away, call for emergency medical help immediately. Note the time when symptoms first appeared.

Other potential stroke symptoms include:

• Sudden Numbness or Weakness: Especially on one side of the body (face, arm, or leg).
• Sudden Confusion or Trouble Understanding Speech.
• Sudden Trouble Seeing: In one or both eyes.
• Sudden Trouble Walking, Dizziness, Loss of Balance, or Lack of Coordination.
• Sudden Severe Headache: With no known cause, especially for hemorrhagic strokes.

Symptoms can develop rapidly or over hours or days, particularly if a TIA progresses to a full stroke. The specific symptoms depend on the type of stroke and the area of the brain affected.

Diagnosis of Stroke

Prompt diagnosis is essential to determine the type of stroke and guide treatment. When a stroke is suspected, medical professionals will:

1. Perform a Physical and Neurological Examination: Assess symptoms, medical history, and check for changes in alertness, coordination, sensation, reflexes, and speech.
2. Brain Imaging Tests: These are crucial for determining if the stroke is ischemic or hemorrhagic.
   • Computed Tomography (CT) Scan: Often the first imaging test performed. It uses X-rays to create detailed images of the brain and can quickly show bleeding or significant brain damage.
   • Magnetic Resonance Imaging (MRI) Scan: Can provide more detailed images of brain tissue and detect changes earlier than a CT scan in some cases.
3. Other Tests May Include:
   • Blood Tests: To check blood sugar levels, clotting factors, and look for infections.
   • Carotid Ultrasound: To look for narrowing or blockages in the carotid arteries in the neck.
   • Echocardiogram: To check for heart problems that could be a source of clots.
   • Cerebral Angiogram: Involves injecting dye into blood vessels to get a detailed view of blood flow in the brain,