stroke Flashcards
what is stroke?
“acute focal neurological deficit resulting from cerebrovascular disease and lasting more than 24hrs or causing earlier death”
Brain equivalent of heart attack
Death of brain tissue from hypoxia
No local cerebral blood flow
Infarction of tissue
Haemorrhage into the brain tissue -> pressure effects to stop blood into areas
there is ischaemic and hemorrhagic stroke
TEMPORARY ischaemia : TIA (transient ischaemic attack) -> high risk of bigger stroke later on
FAST – Facial Drooping, Arm Weakness, Speech Difficulty, Time
transient ischaemic attack
Incidence 25% that of stroke
Localised loss of brain function
Ischaemic event – not haemorrhage
FULL recovery within 24hrs
Most recover in 30mins
Higher risk of ‘proper’ stroke over 5 years
12% in 1yr
29% in 5yrs
2.4% risk of myocardial infarction
PLATEL EMBOLI THAT GETS REMOVED
risks for stroke
HYPERTENSION
if DIASTOLIC >110mm Hg then a x15 risk compared to diastolic <80mm Hg
Even borderline hypertension has risk
SMOKING
Alcohol
ISCHAEMIC HEART DISEASE
Atrial Fibrillation
Diabetes Mellitus
stroke facts
12% of all deaths
Commonest cause of adult disability
Lifetime risk of 1in 6
Incidence 2 in 1000 pop/year
Male > female
Increasing incidence with age
0.5/1000 pop age 50
15/1000 pop age 80
Infarction 85%
Haemorrhage 10%
Subarachnoid Haemorrhage 5%
Venous thrombosis <1%
causes of stroke
Ischaemic stroke – uncertain
Intracranial Bleed =
Aneurysm rupture
Embolic Stroke =
Embolism from left side of heart
Atrial fibrillation
Heart valve disease
Recent MI
Atheroma of cerebral vessels =
Carotid bifurcation
Internal carotid artery
Vertebral artery
Other less common causes =
Venous thrombosis
OCP use
Polycythaemia
Thrombophillia
‘borderzone’ infarction
Severe hypotension
Cardiac arrest
for infarction strokes
MRI is the best
prevention of stroke
Reduce risk factors
Smoking
Diabetes control
Control hypertension
Antiplatelet action (secondary prevention only)
Aspirin
Dipyridamole
Clopidogrel
occasionally = Anticoagulants - embolic risk – AF, LV thrombus
Warfarin, Apixaban
Carotid Endarterectomy
Severe stenosis
Previous TIAs
<85 years of age
But 7.5% mortality from surgery
Preventative neurosurgery
Aneurysm clips, AV malformation correction
investigation of stroke
Need to differentiate
INFARCT
BLEED
Subarachnoid Haemorrhage
EARLY information needed to assess treatment options
Imaging =
CT Scan
rapid, easy access
poor for ischaemic stroke, but good for haemorragic
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
investigations of stroke
Assess risk factors
Carotid ultrasound
Cardiac ultrasound (LV thrombus) -> check for atherosclerosis in carotid artery
ECG (arrhythmias) -> atrial fib
Blood pressure
Diabetes screen
Thrombophilia screen (young patients)
effect of stroke
Loss of functional brain tissue
immediate nerve cell death
Nerve cell ischaemia in penumbra around infarction
Will die if not protected
Gradual or rapid loss of function
Stroke may ‘evolve’ over minutes or hours
Inflammation in tissue surrounding the infarct/bleed
Recovery of some function with time, as the inflammation settles
complications of stroke
Motor function loss
Cranial nerve or somatic (opposite side!)
Autonomic in brainstem lesions
Dysphonia
Swallowing
Aspiration of food & saliva
Pneumonia and death
Sensory loss
Cranial nerve or somatic (opposite side!)
Body perception
Neglect
Phantom limbs
change of ownership of limbs sometimes
Cognitive impairment
Appreciation – special sensation
Processing
understanding of information
Speech and language
Dysphasia, dyslexia,dysgraphia & dyscalculia
Memory impairment
Emotional lability and depression
management of stroke
Acute phase
Limit damage
Reduce future risk
Chronic Phase
Rehabilitation
Reduce future risk
acute phase treatment in stroke
Reduce damage
Penumbra region – survivable ischaemia
CA+ CHANNEL BLOCKERS
Improve blood flow/oxygenation
Thrombolysis possible within 3hrs (alteplase)
Maintain perfusion pressure to brain tissue
Normoglycaemia - hyper/hypo harmful
WATCH BLOOD SUGARS
Remove haematoma = SUBARANCHOID haemorrhage only
Prevent future risk
Aspirin 300mg daily
Anticoagulation if indicated (delay 2 weeks)
ESP IF Atrial Fibrillation OR Left ventricular thrombus
chronic phase treatment in stroke
Nursing and Rehabilitation
Immobility support
Prevention of bed sores
Physiotherapy to prevent contractures
Speech and language therapy
Communications
Swallowing and eating
Occupational therapy
