Stroke Flashcards
What is ICP?
A measurement of the pressure of brain tissue and the cerebrospinal fluid that surrounds the brain and spinal cord
What is Monro-Kellie hypothesis?
Intracranial volume is fixed due to non-compliant skull
Change in volume of non- compressible contents or addition of a space occupying lesion (SPOL) increases pressure
What is the pathology of raised ICP?
Reduced blood flow -> ischaemia
Reduced energy production
Pump failure on cell membrane
Cellular dysfunction
Interstitial microenvironment changes (toxic metabolites)
Membrane damage and cell death
What is MAP?
Mean arterial pressure
Difference between systolic and diastolic
What is CPP?
Central perfusion pressure
Difference between MAP and ICP
What is CVR?
Cerebro Vascular Resistance
Resistance offered by cerebral vasculature to flowing blood
What is autoregulation?
Ability of brain to maintain constant blood flow over wide range of pressures
What does cerebral blood flow depend on?
MAP
ICP
Vascular resistance
Autoregulation
What is stroke?
Sudden onset of focal or global neurological symptoms caused by ischaemia or haemorrhage and lasting more than 24 hours
What % of strokes are ischaemic?
85%
What % of strokes are haemorrhagic?
15%
What are the causes of an ischaemic stroke?
- Large artery atherosclerosis
- Cardioembolic
- Small artery occlusion
- Undetermined/Cryptogenic
- Rare causes
- Arterial dissection
- Venous sinus thrombosis
What are the causes of a haemorrhagic stroke?
- Primary intracerebral haemorrhage
- Secondary haemorrhage
- Subarachnoid haemorrhage
- Arteriovenous malformation
What are some modifiable risk factors for stroke?
Hypertension
Smoking
Drugs
Diet
Exercise
Diabetes
Alcohol
Obesity
High lipid intake
Atrial fibrillation
What are some non-modifiable risk factors for stroke?
Previous stroke
Age
Male
FH
Hypercoagulable states- malignancy, genetics
What are the frontal lobe functions?
- High level cognitive functions
- Memory
- Voluntary eye movement
- Motor control of speech- Broca’s area
- Motor cortex
- Urinary continence
- Emotion and personality
What are the parietal lobe functions?
- Sensory cortex
- Sensation
- Awareness
- Spatial orientation and visuospatial information- non dominant right hemisphere
- Performing learned motor tasks- dominant left hemisphere
What are the temporal lobe functions?
- Primary auditory
- Comprehension of speech- Wernicke’s
- Visual, auditory and olfactory perception
- Learning, memory and emotional affect
What are the occipital lobe functions?
- Primary visual cortex
- Visual perception
- Involuntary smooth eye movement
What are the cerebellar functions?
Maintaining balance
Coordinating movement
Motor learning
What are the signs of cerebellar damage?
Vertigo
Ataxia
Nystagmus
Intentional tremor
Slurred speech
Hypotonia
Exaggerated broad based gait
Dysdiadochokinesia
VANISHED
What does blockage of the anterior cerebral artery cause?
Leg> arm weakness
What does blockage of middle cerebral artery cause?
Face and arm> leg weakness
What is the clinical presentation of stroke?
Motor- clumsy/weak limb
Sensory- loss of feelings
Speech- dysarthria/dysphasia
Neglect/visuospatial problems
Vision- loss in one eye, hemianopia
Gaze palsy
Ataxia/vertigo/incoordination/nystagmus
What are the subtypes of stroke?
Total Anterior Circulation Stroke (TACS)
Partial Anterior Circulation Stroke (PACS)
Lacunar Stroke (LACS)
Posterior Circulation Stroke (POCS)
What is the criteria for TACS?
Hemianopia
Complete hemiparesis/numbness
Neglect (RHS) or Dysphasia (LHS)
What is the criteria for PACS?
2 of the 3 TACS criteria
What is the criteria for LACS?
Weakness
Numbness
No damage to cortex- no dysphasia, neglect or hemianopia
What is the criteria for POCS?
Weakness
Numbness
Hemianopia/Dysphasia (LHS)/Neglect (RHS)
Brainstem + cerebellar signs
What is basilar artery occlusion stroke?
Affects brainstem
Ischaemia in pons
One of the worst strokes
What are stroke mimics?
- Seizures
- Syncope
- Sugar
- Sepsis
- Severe migraine
- Space occupying lesions
- Psychological
- Vestibular disorders
- Demyelination
- Transient global amnesia
- Mononeuropathy
What are negative symptoms suggesting stroke?
Loss or reduction of CNS neuron function
Loss of vision
Loss of sensation
Loss of limb power
What investigations are done for stroke?
Bloods- FBC, glucose, lipids, ESR
CT/MRI- infarct vs haemorrhage
ECG + Holter
Carotid doppler ultrasounds
What is acute treatment for stroke?
- IV TPA (thrombolysis) <3 hours
- IV TPA 3-4.5 hours
- Stoke units
- Aspirin <48 hours
- Thrombectomy <6 hours
What is the criteria for thrombolysis?
<4.5 hours from onset of symptoms
Disabling neurological deficits
Symptoms present >60 minutes
Consent obtained
What is the exclusion criteria for thrombolysis?
Blood on CT
Recent surgery
Recent bleeding episodes
Coagulation problems
BP>185 systolic or >110 diastolic
Glucose<2.8mmol/L
Glucose>22mmol/L
What is acute treatment for TIA?
Antiplatelets
Antihypertensives
Statins and endarterectomy
What measures are there for primary prevention of stroke?
Control risk factors: HTN, DM, High lipid content, Cardiac disease, Smoking
Lifelong coagulation: AF and prosthetic heart valves
What measures are there for secondary prevention of stroke?
Antihypertensives
Antiplatelets
Lipid lowering agents
Warfarin for AF
Carotid endarterectomy
