Stroke Flashcards
stroke pathophysiology
Cerebrovascular accidents are either:
Ischaemia or infarction of brain tissue secondary to inadequate blood supply
- Intracranial haemorrhage
Disruption of blood supply can be caused by:
Thrombus formation or embolus, for example in patients with atrial fibrillation
Atherosclerosis
Shock
Vasculitis
TIA
symptoms of a stroke that resolve within 24 hours. It has been updated based on advanced imaging to now be defined as transient neurological dysfunction secondary to ischaemia without infarction.
Transient ischaemic attacks often precede a full stroke. A crescendo TIA is where there are two or more TIAs within a week. This carries a high risk of developing in to a stroke.
presentation of a stroke
sudden onset of neurological symptoms
Sudden weakness of limbs
Sudden facial weakness
Sudden onset dysphasia (speech disturbance)
Sudden onset visual or sensory loss
stroke RF
Cardiovascular disease such as angina, myocardial infarction and peripheral vascular disease Previous stroke or TIA Atrial fibrillation Carotid artery disease Hypertension Diabetes Smoking Vasculitis Thrombophilia Combined contraceptive pill
FAST tool in the community
F – Face
A – Arm
S – Speech
T – Time (act fast and call 999)
management of stroke
Admit patients to a specialist stroke centre
A-E assessment
neurological examination
Exclude hypoglycaemia
Immediate CT brain to exclude primary intracerebral haemorrhage (and CT angiogram to look at neck and intracranial vessels if there is any blockade)
Aspirin 300mg stat (after the CT) and continued for 2 weeks
Thrombolysis with alteplase can be used after the CT brain scan has excluded an intracranial haemorrhage.
- (Alteplase: tissue plasminogen activator. rapidly breaksdown clots. needs to be given within a defined window of opportunity, for example 4.5 hours.)
(wouldn’t see anything on an ischaemic stroke- it will look normal)
2 minute bouts (first 10%)
the remaining 90% in an hour? infusion
- monitor for post-thrombolysis complications (intracranial or systemic haemorrhage. repeated CT scans of the brain.)
Thrombectomy (mechanical removal of the clot) may be offered if an occlusion is confirmed on imaging, depending on the location and the time since the symptoms started. It is not used after 24 hours since the onset of symptoms.
ensure BP is not lowered- risks reducing the perfusion to the brain.
TIA management
Start aspirin 300mg daily. Start secondary prevention measures for cardiovascular disease. They should be referred and seen within 24 hours by a stroke specialist.
stroke specialist imaigng
Diffusion-weighted MRI is the gold standard imaging technique. CT is an alternative.
Carotid ultrasound can be used to assess for carotid stenosis. Endarterectomy to remove plaques or carotid stenting to widen the lumen should be considered if there is carotid stenosis.
secondary prevention of stroke
Clopidogrel 75mg once daily (alternatively dipyridamole 200mg twice daily)
Atorvastatin 80mg should be started but not immediately
Carotid endarterectomy or stenting in patients with carotid artery disease
Treat modifiable risk factors such as hypertension and diabetes
rehab stroke
Nurses Speech and language (SALT) Nutrition and dietetics Physiotherapy Occupational therapy Social services Optometry and ophthalmology Psychology Orthotics
types of stroke
ischaemic stroke
hemorrhagic stroke
subarchnoid hemorrhage
in every minute that passes, the patient looses 2 million neurones.
core and penumbra (can survive if reperfused)
stroke mechanism and causes
ischaemic stoke
cardio-embolism: AF, other causes PFO, VSD, infective endocarditis, embolism from aortic arch
large vessel (carotid artery disease caused by atheroma or dissection)
small vessel- lacunar stroke (the area of stroke is <1.5cm) due to progressive narrowing overtime ‘lipohyalinosis’ associated with HTN or diabetes
hypo-perfusion: severe hypotension during preoperative period or during cardiac arrest. ‘watershed / border zone infarction’
haemorrhage stroke causes
HTN tumor bleeding disorder vascular malformation amyloid antipathy
cerebral virus sinus thrombosis not uncommonly presents with cerebral haemorrhage.
(treat with LMWH)
immune mediated astrezenica of thrombosis- IV immunoglobulin (does not respond to LMWH)
hemorrhagic stroke management
control BP- in first 6 hours the more aggressive you are in normalising the BP the better the long term outcomes
target 150mmHg systolic
anticoagulant
neurosurgery
stroke other causes
infective endocarditis antiphospholipid syndrome vasculitis drugs - cocaine, heroine commonest- <50 years: cardioembolism and carotid/vertebral dissection
