Understanding Stroke: Risks and Myths

Clinical Sciences: Medical and Neurological Conditions - Cerebral Vascular Accident (CVA) / Stroke A

• Learning Outcomes:
  • Understand the epidemiology of CVA in Hong Kong
  • Identify different types of CVA
  • Recognize the clinical features and pathology of CVA
  • Learn about the general medical management of CVA

Outline of Lecture

• Epidemiology:
  • Definition of CVA
  • Types and Pathology
  • Signs and Symptoms
  • Classifications
  • Clinical Features
  • Medical Managements

What is Stroke?

• Symptoms:
  • Speech problems
  • Tingling or numbness in the body
  • Problems with thinking
  • Loss of balance or coordination problems
  • Severe headache
  • Vision problems

Stroke: It's NOT an "Accident"

• CVA is a poor term
• Stroke is preventable and treatable
• Prevention is better than cure
• Combating stroke decreases medical costs

The Perceptions of Stroke

• Myths:

  • Stroke is not preventable
  • Stroke cannot be treated
  • Stroke only strikes the elderly
  • Stroke happens in the heart
  • Stroke recovery ends after 6 months

• Reality:

  • Up to 80% of strokes are preventable
  • Stroke requires emergency treatment
  • Anyone can have a stroke
  • Stroke is a "Brain Attack"
  • Stroke recovery can last a lifetime

Risk Factors of Stroke

• Family history of stroke
• Age over 55 (risk increases with age)
• High blood pressure
• High cholesterol (atherosclerosis)
• Cigarette smoking
• Diabetes mellitus
• Obesity
• Cardiovascular disease
• Vascular malformation or aneurysm
• Alcohol consumption

Epidemiology

• 12.2 million new strokes annually globally
• One stroke every 3 seconds
• 101 million people globally live with stroke aftermath
• This number doubled over the last 30 years
• In 2019, 63% of strokes occurred in people under 70 years old.
• Stroke is no longer solely a disease of the elderly.

Epidemiology WHO 2016

• Top 10 global causes of deaths:

  • Ischemic heart disease
  • Stroke
  • Chronic obstructive pulmonary disease
  • Lower respiratory infections
  • Alzheimer's disease and other dementias

• Top 10 causes of deaths in low-income, upper-middle, and high-income countries.

Epidemiology in Hong Kong

• Stroke was the fourth leading cause of death in Hong Kong in 2020
• 3,164 registered deaths

How Stroke Survivors Suffer?

• 2/3 experience neurological impairment and disability
• 15% institutionalized within 5 years
• 20% experience recurrent stroke
• 22.5% experience dementia

Definition Of Cerebral Vascular Accident (CVA)

• Rapidly developing clinical signs of focal or global disturbance of cerebral function
• Symptoms last 24 hours or longer or lead to death
• No apparent cause other than vascular origin
• Sudden brain dysfunction due to blood vessel problems
• Transient Ischemic Attack (TIA) is less than 24 hours

Classification of CVA

• Ischemic Stroke (Infarction): ~80%
• Hemorrhagic stroke: ~20%
• Transient Ischemic Attack (TIA)

Pathology - Ischemic Stroke

• Diminished blood supply to focal area of brain
• Mostly thromboembolism

Pathology - Sub-type of Infarction

• Thromboembolism: Blood clot forms in the vascular system
• Thrombotic Infarction: Clot develops in the brain artery itself
• Embolic Infarction: Clot travels from another site (e.g., heart)
• Large blood vessel

Ischemic Stroke Risk Factors (Non-Modifiable)

• Advanced age
• Male gender
• Race (Asian, Black)
• Family history of MI or early stroke

Ischemic Stroke Risk Factors (Modifiable)

• Hypertension (systolic and diastolic)
• Diabetes mellitus
• Hypercholesterolemia
• Cigarette smoking
• Prior stroke or TIA
• Carotid disease, heart disease
• Hypercoagulable states
• Cocaine, excessive alcohol use

Pathology - Hemorrhagic Stroke (Intracerebral Hemorrhage (ICH))

• Blood vessel rupture within the skull (not due to trauma)
• Due to chronic arteriolar hypertensive disease(HT)
• Preventing blood flow to the brain
• Higher incidence in Asian patients (15-30%)
• Higher mortality than ischemic stroke

Pathology - Subarachnoid Hemorrhage (SAH)

• Rupture of aneurysms at the bifurcations of large arteries at the inferior surface of the brain
• Vessel malformation and tumors
• Non-traumatic subarachnoid hemorrhage (Most common in 40-60 year-old people)
• Female: male ratio of 2:1
• Smoking increases risk 3-10 times

Pathology - Brain Arteriovenous Malformation (AVM)

• Abnormal blood vessels connecting arteries and veins in the brain
• Usually congenital(at birth) in origin and onset in the 20s - 30s

Pathology - TIA (Transient Ischemic Attack)

• Transient blockage of a cerebral artery
• Decreasing blood flow to the brain
• Many strokes result from complete blockage leading to brain cell death and permanent loss of function

How to Investigate & Make Diagnosis for Stroke

• Computerized Tomography (CT Scan): Differentiate stroke (lack of blood supply) from hemorrhagic stroke (bleeding).
• Magnetic Resonance Imaging (MRI): Shows the status of brain tissue and the patency/narrowing of blood vessels.
• Ultrasonic Imaging of Cervical Blood Vessels: Detects narrowing or blockage in the neck's blood vessels
• Transcranial Doppler (TCD): Detects narrowing or blockages in the brain's blood vessels

CT Scan

• Infarction: Hypodense (darker) areas.
• Hemorrhage: Hyperdense (lighter) areas

Magnetic Resonance Image (MRI)

• Different sequences (e.g., T1, T2, FLAIR) provide additional information
• Helps in evaluating the severity and location of stroke-related issues like hematomas.

Magnetic Resonance Angiography (MRA)

• Specialized MRI to visualize blood vessels and identify abnormalities.

Review of Brain Vessels

• Diagram of the major arteries supplying blood to the brain and surrounding areas

Blood supply to Different Areas

• Diagram illustrating the branches of the major arteries supplying different brain regions

Review of Brain Structure & Function

• Diagram of the brain with labeled functional areas.

Classification of CVA - By Types

• Cerebral ischemic stroke: Acute focal neurological dysfunction from a single or multiple brain/retina infarcts, lasting more than 24 hours.
• Intracerebral hemorrhage: Hemorrhage within the brain parenchyma or ventricular system, causing neurological dysfunction.
• Subarachnoid hemorrhage: Hemorrhage in the subarachnoid space, primarily due to aneurysm rupture.
• Stroke of unknown type: When a stroke has occurred but determining if ischemic vs. hemorrhagic has not been accomplished through diagnostic testing

Clinical Features

• Hemorrhagic Stroke (general):

  • Sudden onset & dramatic headache (worst of their life)
  • Visual Disturbances
  • Nausea and Vomiting
  • Neck and back pain
  • Sensitivity to light
  • Weakness on one side

• Ischemic Stroke (general):

  • Hard to detect as a first sign, gradual or subtle development
  • Weakness in one side of the body
  • Facial drooping
  • Numbness and tingling
  • Language disturbances
  • Visual disturbances

• Left Brain Stroke:

  • Right side paralysis
  • Speech and language disturbances
  • Behavioral changes
  • Swallowing issues

• Right Brain Stroke:

  • Left side paralysis
  • Spatial perception issues
  • Coordination problems
  • Perception & recognition of familiar objects

• Neurological Complications:

  • Brain edema
  • Hemorrhagic transformation
  • Seizures/epilepsy
  • Recurrent stroke
  • Delirium/vascular dementia

Medical Assessment

• Initial Assessment:

  • General impression
  • Airway management
  • High-flow O2
  • Circulation check
  • High-priority transport

• Further Medical Assessment (AED):

  • Focused history and physical exam, Including a thorough neurologic exam
  • History of seizures, headaches, nausea/vomiting, neck pain
  • Obtain baseline vitals
  • Recheck vitals frequently

• Priorities of Care:

  • Trauma assessment (recent or within the last month)
  • Assess for recent seizures or subdural hematoma
  • Cardiovascular status: cardiac medications, atrial fibrillation, blood thinners (e.g., Warfarin)
  • Pulse oximetry (>94% SpO2)
  • Blood sugar control
  • Pupil assessment

Stroke Prevention Guidelines

• Awareness of blood pressure:

  • Normal BP
  • Elevated BP (pre-hypertension)
  • High Blood Pressure (Hypertension) - Stage1
  • High Blood Pressure (Hypertension) - Stage 2
  • Hypertensive Crisis - consult a doctor immediately

• Prevention Considerations:

  • Recognizing and managing atrial fibrillation
  • Avoiding excessive alcohol intake
  • Managing cholesterol if affected
  • Controlling diabetes carefully
  • Exercise regularly
  • Maintaining a low-sodium and low-fat diet
  • Seeking medical attention for any circulation issues
  • Contacting emergency services (911 or 999 in HK) for immediate Stroke symptoms

Stroke Team

• Stroke Physician
• Neurologist
• Nurses
• Physiotherapist
• Occupational therapist
• Speech therapist
• Pharmacist
• Dietitian
• Social worker
• Clinical psychologist

Useful Web Sources (Local & International)

• Provides links to various stroke-related organizations and resources in Hong Kong and internationally