Stroke Flashcards
Blood supply to the brain?
- basilar artery
- posterior cerebral artery
- left and right carotid arteries
- middle cerebral artery
> posterior communicating artery - anterior cerebral artery
> anterior communicating artery
What is the blood supply to the brain called?
Circle of Willis
Circle of Willis is famous for what pathology?
berry aneurysms
- main cause of non-traumatic subarachnoid hemorrhage
Middle cerebral artery supplies?
anterior two thirds of the brain
Anterior cerebral artery supplies?
remaining medial 2/3 of the brain
Posterior cerebral artery supplies?
posterior 1/3 of the brain
- occipital lobe
Brainstem and cerebellum are supplied by?
vertebral and basilar arteries
Common sites for stroke?
MCA>ACA>lacunar>PCA
What is a stroke?
- Sudden neurological deficit
- Lasting more than 24 hours/causing death
- With no explanation other than a vascular cause
What is a transient ischaemic attack?
- Sudden neurologic deficit lasting less than 24 hours with full recovery.
- Danger sign for an eminent stroke in the near future
Risk of stroke after TIA?
- Stroke in 30% of the patients within 1 year
- 15% within three months
Aetiological classification of stroke?
- ischaemic - 80%
- haemorrhagic - 20%
Ischemic stroke?
Blockage of the arteries causing ischaemia
1. Thrombosis
- arteriosclerosis, dissection, fibromuscular dysplasia
2. Embolism.
3. Systemic hypoperfusion.
dissection - when blood extrudes into the connective tissue framework of a vessel wall, causing seperation of the natural vessels causing luminal narrowing or occlusion
fibromuscular dysplasia - progressive twisting of the blood vessels throughout the body
Haemorrhagic stroke?
Types?
Rupture of the arteries causing haemorrhage.
1. Parenchymal/intracerebral haemorrhage.
2. Subarachnoid haemorrhage.
Clinical classification of stroke?
- progressing/evolving - Progressive neurological deficits
- completed - Persistent neurological deficits not getting worse
- TIA - Resolved neurological deficits
Cardiac output required by the brain?
Receives 15% of resting cardiac output
Oxygen consumption of the brain?
Accounts for 20% of total body oxygen consumption
Consequences of reduced blood flow?
- If zero leads to death within 4-10mins
- <16-18ml/100g tissue/min causes infarction within 1hr
- <20ml/100g tissue/min causes ischaemia without infarction
- Unless prolonged for several hours or days
Pathogenesis of hemorrhagic stroke?
- hemorrhage
- cytotoxic and vasogenic edema
- swelling of the brain
Pathogenesis of ischemic stroke?
- loss of blood supply
- infarction/necrosis
- cytotoxic and vasogenic edema
- swelling of the brain
Why is Stroke now one of the leading causes of neurological admissions and death in urban hospitals throughout Africa?
Because of increasing urbanization and life style changes
Epidemiological risk factors?
- high income countries
- > 65 years
Risk factors for stroke?
- age - highest
- hypertension
- atrial fibrillation
- previous TIA/stroke
- elicit drugs e.g. marijuana, amphetamines and cocaine
- very high - ischemic heart disease
- lifestyle e.g. diet, high salt, lack of exercise, drinking and smoking
- moderate - obesity
- low
FAST tool for stroke recognition?
- Face droops
- Arm weakness
- Speech difficulty
- Time is critical
History taking in stroke?
- Onset and progression of neurological symptoms
- completed Vs stroke in evolution, other stroke mimics - Exposure to major risk factors.
- Previous stroke like symptoms
- possible TIA - Drug history
- Diabetic medications, anticoagulation therapy - Any hypercoaguable disorders
e.g SCD & polycythemia - HIV status
- History of trauma
- Screen for stroke mimics
- Substance abuse, seizure, migraine etc
Important finding in neuro exam?
Stroke territory: Localization
How do you assess the extent of neurological deficit?
NIHSS - National Institute of Health Stroke Scale
General examination for precipitating causes, risk factors & stroke mimics?
Neck stiffness: CNS infections/SAH
CVS: Pulse rate and rhythm, Blood pressure, Carotid murmurs and Carotid bruits
Respiratory: Signs of pulmonary edema.
Skin: Xanthelasma
Locomotor: injuries sustained during collapse.
ICA localization in stroke?
- hemiplegia - arm, face and leg
- hemisensory deficit
- hemianopia
ACA localization in stroke?
hemiplegia - leg>arm
MCA localization in stroke?
- hemiplegia and numbness - face = arm > leg
- aphasia - dominant hemisphere
- hemianopia
- sensory inattention - non dominant hemisphere
PCA localization in stroke?
hemianopia
Lacunar localization in stroke?
- hemiplegia - face = arm = leg
- hemisensory - face = arm = leg
Vertebro-basilar artery localization in stroke?
- dysphagia + dysarthria
- hemiplegia/quadriplegia
- cranial nerve pulsies
- ataxia
Investigations?
- CT/MRI
- Gold standard investigation – anterior and posterior circulation angiography
- stroke vs stroke mimic
- ischaemic vs hemorrhagic - LP
- r/o subarachnoid hemorrhage - cardiac echo
- ECG
- r/o cardiac source of embolism - Duplex USS of carotids
- Magnetic Resonance Angiography
- r/o underlying vascular disease - HIV
- VDRL
Investigations to rule out risk factors?
- Full blood count
- Cholesterol
- Blood glucose
- ESR
- clotting time
- PBF
- Protein C
- Protein S
- Factor V Leiden
- Lupus anticoagulant profile
Management objectives?
- Minimize volume of brain irreversibly damaged
- Prevent complications
- Rehabilitation
- Reduce risk of recurrence
Management of stroke?
- Manage seizures as necessary
- Urgent CT/MRI
- Thrombolysis
- Antiplatelet agents
- Anticoagulants
- Explain what has happened.
- Admission to stroke unit
Airway management?
- Patency
- swallowing ability
- Nil by mouth
- NGT
Breathing management?
- Oxygen saturation
- respiratory rate
- breath sounds
- Oxygen therapy where necessary
Circulation management?
- IV access + get blood samples
- Pulse rate, blood pressure, heart sounds.
- Fluid resuscitation where necessary to maintain euvolemia
- Blood pressure control where necessary
- If Bp > 220/120 mmHg, otherwise delayed up to first 5 days
Exceptions for BP control in circulation management of stroke?
- Intracerebral hemorrhage on CT (<160/90)
- Recanalization therapy(<185/110)
- Subarachnoid hemorrhage based on CT/LP
Disability management?
- GCS ≤ 8: Intubation.
- Focal neurological signs
- Never forget to check glucose
Observation during and after treatment?
- Assess neurological condition daily
- Check for bedsores and contractures daily
- Check for signs of:
- Aspiration Pneumonia
- UTIs due to long term catheterization
- DVT due to immobility - Early physiotherapy preferably from day 1
- Assess for ability to eat, talk, walk, dress and toilet prior to discharge.
- Necessary for post discharge care
Acute complications of stroke?
- aspiration pneumonia
- main cause of death
- associated with poor prognosis - pulmonary embolism
- pressure sores
- urinary tract infections
Chronic long term complications of stroke?
- depression
- dementia
- late onset seizures
- spasticity
- contractures
- pain
Stroke prognosis?
- Outcome for stroke patients is poor.
- Mortality within the first year is over 30%.
- Majority of deaths occur within first month after the stroke and continue throughout the first year.
- The risk of recurrence continues over time.
- Over half of all stroke survivors die within 5 years.
- Long term prognosis is worse in Africa because of the lack of secondary and tertiary care.
Stroke mimics?
Diseases which present like stroke = Stroke mimics
- Incorrect stroke diagnosis
Stroke chameleons?
Stroke presenting like other diseases = Stroke chameleons
- Missed stroke diagnosis
- Account for up to 30% of acute stroke admissions
Importance of proper stroke diagnosis?
- Delays in treatment
- Potentially harmful medication prescriptions
- Unnecessary longer hospital stays
- Leading to increased costs for the patient/public hospital
Minimizing stroke mimics?
- Be thorough. NO short-cuts OR spot diagnoses
- History taking (risk factors + comorbidities)
- Physical examination
- Plus investigations (including brain imaging)
- FABS score
FABS score?
FABS = proposed scale used in discriminating SM from true strokes.
Consists of six parameters
Parameters of FABS score?
- abscence of facial drooping
- negative history of atrial fibrillation
- age less < 50 years
- Systolic blood pressure <150mmHg
- history of seizure
- isolated sensory deficits
Scoring of FABS?
Score ≥ 3 suggestive of SM
- Sensitivity: 90%
- Specificity: 91%