Definition: A stroke, also known as a cerebrovascular accident (CVA), occurs when there's an interruption of blood supply to the brain.
Importance: Knowledge of stroke is crucial as it is extremely common and affects a significant number of people annually.
Statistics
Frequency:
Every 40 seconds a person in the US has a stroke.
Every 4 minutes, someone in the US dies from a stroke.
Approximately 800,000 people experience a stroke each year in the US.
Risk Factors:
Risk of stroke doubles for individuals over the age of 55.
Higher incidence in men, but women have a higher mortality rate due to different symptom presentation.
Geographic and Lifestyle Correlation
Discussion of CDC maps showing correlation between stroke rates and regions with high rates of COPD and heart disease, particularly in the South.
Noted that some regions had insufficient data due to lack of reporting.
Lifestyle factors contribute to increased risk, including poor access to healthcare.
Types of Strokes
Ischemic Stroke
Description:
Most common type, accounting for about 85% of strokes.
Caused by clots blocking blood supply.
Types of Ischemic Strokes:
Embolic Stroke: A clot that forms elsewhere (e.g., in the calf) and travels to the brain.
Thrombotic Stroke: A clot that forms directly in the brain.
Key Term: Ischemia - refers to the interruption of blood supply caused by a clot.
Hemorrhagic Stroke
Description:
Accounts for about 15% of strokes but are generally more deadly.
Occurs when a blood vessel ruptures, often due to an aneurysm.
Treatment Challenges:
Requires locating and stopping the bleed, making it harder to treat than ischemic strokes.
Terminology of Strokes
Complete Stroke: Abrupt onset of neurologic deficits, typically associated with an ischemic stroke.
Stroke in Evolution: Symptoms develop slowly over days, often linked with hemorrhagic strokes.
Transient Ischemic Attack (TIA): A "mini-stroke" resulting in temporary neurologic deficits that resolve within 24 hours. Indicates a high risk for future strokes.
Risk Factors for Stroke
Modifiable Risk Factors
Smoking.
High blood pressure.
Cardiovascular diseases (e.g., heart disease).
Diabetes.
Heavy alcohol use.
High LDL cholesterol.
Illicit drug use.
Obesity.
Non-Modifiable Risk Factors
Increasing age.
Ethnic background (e.g., African Americans at a higher risk).
Gender differences in risk until about age 55 due to protective effects of estrogen.
Genetics plays a minor role (about 6% of cases).
Warning Signs of Stroke
FAST Acronym: Face drooping, Arm weakness, Speech difficulties, Time to call for help.
Sudden weakness or numbness, especially on one side of the body.
Sudden dizziness or loss of balance.
Sudden severe headache (often indicative of a hemorrhagic stroke).
Changes in vision.
Treatment Options
Ischemic Strokes
TPA (tissue plasminogen activator): A medication administered within three hours post-stroke onset that can dissolve clots.
Critical to differentiate between ischemic and hemorrhagic strokes before administration.
Hemorrhagic Strokes
Limited treatment options compared to ischemic strokes.
Possible surgery to locate and correct the source of the bleeding (e.g., decompressive craniectomy).
Diuretics may be used to manage symptoms like high blood pressure.
Patient Presentation Based on Affected Brain Lobes
Frontal Lobe (supplied by ACA and MCA)
Controls voluntary movement and higher cognitive functions.
Symptoms of a frontal lobe stroke:
Impulsive behavior and lack of control.
Poor speech control leading to choppy speech patterns (Broca's area for language production found here).
Parietal Lobe (primarily supplied by MCA)
Processes sensory information.
Symptoms include:
Hemispatial neglect: Unawareness of one side of the body.
Difficulty in perception and executive functioning (planning and coordination).
Temporal Lobe (supplied by MCA)
Involved in auditory processing and language comprehension (Wernicke's area).