What is the definition of a stroke?
acute focal neurological deficit resulting from cerebrovascular disease and lasting more than 24hrs or causing earlier death
Describe what a stroke actually is/what happens in the brain.
- brain equivalent of heart attack
- blockage in the local cerebral blood flow (so there is no blood flow)
- get death of brain tissue due to hypoxia (no O2 delivery)
What are the 2 types of strokes? (due to aetiology)
- infarction of tissue
- haemorrhage into the brain tissue and causing pressure which prevents blood flow to other parts of the brain
What should you look out for when suspecting a stroke?
FAST:
- facial drooping
- arm weakness
- speech difficulty
- time
What does TIA stand for and what happens in these?
Transient ischeamic attack
There is temporary ischeamia and localised loss of brain function.
Ischeamia is cleared quickly and there is fully recovery in 24hrs (most in 30mins)
If a patient has has a TIA, what are they at higher risk of?
Higher risk of a ‘proper’ stroke over years (also a 2.4% risk of a myocardial infarction)
What are some risk factors for a stroke?
- hypertension
- smoking
- alcohol
- ischaemic heart disease
- atrial fibrilation
- diabetes mellitus
Strokes account for what perentage of deaths?
12%
What sex are more affected by strokes and how is age influenced?
males and more risk as you get older
What are the 4 causes of strokes?
- ischeamic stroke (unsure why this hapens)
- intercranial bleed (haemorrhage) - aneurysm rupture
- Embolic stroke - embolism from LHS of heart
- Atheroma of cerebral vessels
What are some other, less common causes of strokes?
- venous thrombosis
- ‘borderzone infarction’ - poor brain perfucsion and can lead to brain injury (severe hypotension and cardiac arrest)
- Vasculitis (narrow blood vessels and limit O2 delivery)
What can increase your risk of venous thrombosis? (3)
- oral contraceptive pill use
- polycythaemia (high haem)
- thrombophillia
What are some steps that can be taken to prevent a stroke?
- Reduce risk factors
- Smoking
- Diabetes control
- Control hypertension
- Antiplatelet action (secondary prevention only)
- Aspirin
- Dipyridamol
- Clopidogrel
- Anticoagulants - embolic risk – AF, LV thrombus
- Warfarin, Apixaban
- Surgery
What surgery can be done to try and prevent strokes?
-Carotis endarterectomy (removing plaque from carotid artery)
BUT 7.5% mortality from surgery
-preventative neurosuregry (aneurysm clips, AV malformation correction)
When investigating a potential stroke, what needs to be done?
- need to be able to differentiate the stroke (infarct, bleed, subarachnoid haemorrhage)
- EARLY info needed to assess treatment options
What imaging can be used to investigate strokes? Give a brief description of their use in stroke investigations.
- CT Scan
- rapid, easy access
- poor for ischaemic stroke
- good for haemorrhage strokes
- MRI Scan
- Difficult to obtain quickly
- Better at visualising early changes of damage
- MRA (MR angiography) is the best investigation for visualising the brain circulation
- Digital Subtraction angiography (DSA)
- If MRA not available
When investiagting a stroke, risk factors should be assessed. How is this done?
- Carotid ultrasound
- Cardiac ultrasound (LV thrombus)
- ECG (arrhythmias)
- Blood pressure
- Diabetes screen
- Thrombophilia screen (young patients)
What are the effects of a stroke on the patient?
- Loss of functional brain tissue
- immediate nerve cell death
- Nerve cell ischaemia in penumbra around infarction
- Will die if not protected
- Will vary due to the location of tissue and how large it is
- Gradual or rapid loss of function
- Stroke may ‘evolve’ over minutes or hours
- Gradual inflammation of tissues can lead to a max point
- Inflammation in tissue surrounding the infarct/bleed
- Recovery of some function with time
What are the possible complications of a stroke?
- motor function loss
- dysphonia (difficulty speaking)
- swallowing (aspiration of food and saliva, pneumonia and death)
- sensory loss
- body perception (neglect, phantom limbs)
- cognitive impairment
Describe the cognitive impairments that may occur due to a stroke.
The following canbe impaired:
- Appreciation – special sensation
- Processing
- understanding of information
- Speech and language
- Dysphasia, dyslexia,dysgraphia & dyscalculia
- Memory impairment
- Emotional lability and depression
What are the aims of treatment in the acute and chronic phases of a stroke?
acute phase - limt damage by reducing amount of tissye loss but managing penumbra effectively
Chronic phase - rehabilitation and reduce future risk
Describe the treatment that can be given in the acute phase of a stroke.
- reduce damage to penumbra region using calcium channel blockers
- improve blood flow/oxygenation
- Thrombolysis possible within 3 hrs of stroke
- maintain perfusion pressure to the brain tissue
- Normoglycaemia (glucose levels in brain) - hypo/hyper is harmful as the brain relies on correct amount of glucose to function
- Remove haematoma for subarachnoid haemorrhages
- start to prevent future risk
