Stroke Flashcards
Ischemic Stroke
- This is the most common type and occurs when a blood clot blocks or narrows an artery leading to the brain. This type can further be divided into:
- Thrombotic Stroke: Caused by a blood clot that forms in one of the arteries supplying blood to the brain.
- Embolic Stroke: Occurs when a blood clot or other debris forms away from the brain, commonly in the heart, and is swept through the bloodstream to lodge in narrower brain arteries.
Hemorrhagic Stroke
- This occurs when a blood vessel in the brain bursts, leading to bleeding in or around the brain. There are two types of hemorrhagic strokes:
- Intracerebral Hemorrhage: The most common type of hemorrhagic stroke, occurs when an artery in the brain bursts, flooding the surrounding tissue with blood.
- Subarachnoid Hemorrhage: Bleeding in the area between the brain and the thin tissues covering it.
Transient Ischemic Attack (TIA)
often called a mini-stroke. A TIA is a temporary period of symptoms similar to those of a stroke. A TIA doesn’t cause permanent damage and is often a warning sign for a future stroke.
* major risk factor for disabling stroke
* 13 fold icnreased risk of CVA in a year
* symptoms may only last few mins
Symptoms of Stroke
- Sudden numbness or weakness in the face, arm, or leg, especially on one side of the body.
- Sudden confusion, trouble speaking, or difficulty 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.
What is the penumbra?
Region of the brain that is between areas that are dying & areas that receive enough blood to communicate.
* Made up of ischemic brain tissue that has enough energy to survive for a shoft time but not enough to function or communicate
* it is unstable in both time and space
* Can be reversible or irreversible
It is important because:
* early recsue is key for treating ischemic stroke
* can be salvageable if perfusions is improved rapidly
Risk Factors (Ischemic)
- Cardiac disease
- history of hypertension
- diabetes
- hypercholesterolaemia
- TIA
- Smoking
- Mitral stenosis
- Obesity & low PA
- Age, gender, hereditary, race, geographic location
Risk Factors (Hemorrhagic)
- Anticoagulation
- hypertension
- heavy drinking
- illegal drug use (coke and meth)
- thrombolytic therapy
- age, race, amyloid angiopathy
Pathology of Stroke
- Brain requires constant supply of O2 & glucose via cerebral arteries to function
- Stroke interrupts normal cerebral blood flow, can lead to brain cell damage or death
- If blood flow drops below critical level, affected neurones will die and be unable to regenerate
- Brain tissue ischemia, nerve cell function ceases after 1 min. after 4 mins, irreversible cell death occurs
Frontal lobe function & dysfunction
Function
* motor, personality/mood, intellect, working memory & recall, speech
Dysfunction
* muscle weakness, altered muscle tone, decreased voluntary control, personality/mood changes, memory issues, expressive dysphasia, issues with higher executive function, dyspraxia
Occipital Lobe function & dysfunction
Function:
* Vision
* Whole object integration/imaging
Dysfunction:
* Issues with visuospatial awareness, diplopia
Temporal lobe function & dysfunction
Function:
* Auditory ability, naming of objects, formation & management of memory, visual recognition
Dysfunction:
* Deafness, agnosia, prosopagnosia, inability to form new memories, receptive dysphasia
Parietal lobe function & dysfunction
Function:
* sensation, speech, understanding & concentration
Dysfunction:
* altered sensation, neglect, issues with understanding & concentration
Cerebellum function & dysfunction
Function:
* coordination of voluntary movement such as posture, balance, coordination & speech, resulting in smooth & balanced muscular activity
* important for learning motor behaviours
Dysfunction:
* ataxia
Brainstem function & dysfunction
Function:
* conduction of info to/from body to cerebrum & cerebellum
* emergence of cranial nerves that supply the face, head, viscera
* cardiovascular system control
* respiratory control
* alertness
* pain sensitivity control
* awareness
* consciousness
Dysfunction:
* alteration to function of cranial nerves: visual disturbances, pupil abnormalities, changes in sensation, muscle weakness, hearing issues, vertigo, swallowing & speech issue, voice change, coordination issue, locked in syndrome, death
Basal ganglia function & dysfunction
Function:
* selection processor
* filters info & selects appropriate response in relation to novel & well learned movements
* involved in planning, initiating, execution of movement
Dysfunction:
* Involuntary movements, bradykinesia, increased muscle tone, muscle rigidity, tremor, memory loss, problem finding words, uncontrollable repeated movements/speech/tics
Broca’s area function & dysfunction
Function:
* Left hemisphere: expression of speech
* Right hemisphere: non-verbal communcation
Dysfunction:
* Expressive dysphasia
Wernicke’s area function & dysfunction
Function:
* Recognition of spoken words & interprets meaning of speech
Dysfunction:
* Receptive dysphasia
Stroke Classification
TACS
* all of the following: motor or sensory deficit, higher cortical dysfunction, homonomous hemianopia
PACS
* two of the following: motor or sensory deficit, higher cortical dysfunction, homonomous hemianopia
LACS
* Motor or sensory deficit only
POCS
* Isolated hemianopia, brain stem signs, cerebellar ataxia
TACS
- Poor prognosis, high mortality 30%
- presents with:
- Unilateral hemiplegia (motor and/or sensory deficit in at least 2 areas, face, UL, LL)
- Contralateral/unilateral hemianopia
- higher cerebral dysfunction, eg. dysphasia** OR** visuospatial disorder/inattention/neglect
- usually caused by thrombosis or embolism
PACS
- Low mortality 5%
- good prognosis, 55% indepedent
- high percentage of subsequent stroke
- presents with 2 out of 3 components:
- Unilateral weakness and/or sensory deficit
- homonymous hemianopia (partial loss of vision in same half of visual field in both eyes)
- higher cortical dysfunction (includes expressive or receptive aphasia, issues with spatial awareness)
- usually caused by thrombosis or embolism
Causes of Neglect
usually caused by damage to the parietal lobe of the brain, especially the right parietal lobe, which is responsible for spatial awareness and attention.
LACS
- Good prognosis, 65% independent
- low risk of recurrence
- deficit from single vascular event must involve 2 of face, UL, LL
- no visual field deficit, no higher cortical dysfunction, no brainstem disturbances
- pure motor and/or sensory stroke
POCS
- High mortality rate
- good prognosis, 65% independent
- presents with:
- ipsilateral cranial nerve palsy + contralateraly motor and/or sensory deficit
- bilateral motor and/or sensory deficit
- disordered conjugate eye movement
- cerebellar dysfunction
- isolated hemianopia
Medical Management of Stroke
-
Ischemic Stroke:
- Thrombolytics: Medications like tissue plasminogen activator (tPA) can dissolve blood clots if administered within a few hours of symptom onset.
- Antiplatelets and Anticoagulants: Aspirin or other blood thinners may be used to prevent further clot formation.
-
Hemorrhagic Stroke:
- Blood Pressure Control: Medications to lower blood pressure and reduce bleeding.
- Surgical Intervention: Procedures to repair ruptured blood vessels or relieve pressure on the brain.
Secondary Prevention
- Antihypertensives: To manage high blood pressure.
- Statins: To lower cholesterol levels.
- Antidiabetic Medications: To control blood sugar levels.
- Lifestyle Modifications: Diet, exercise, smoking cessation.
