Stroke Flashcards
what is stroke?
- a rapidly developing acute neurological deficit of vascular origin that lasts >24hours or causes death
- stroke follows heart disease and cancer as the third leading cause of death in developed countries
- accounts for 10% overall mortality in UK
what are the two types of stroke?
- ischaemic (85%) - reduced blood flow to particular part of brain followed by occlusion of cerebral artery
- haemorrhagic (15%) - due to ruptured blood vessel, commonly associated with high BP and diseases that weaken the arterial wall
- primary intracerebral haemorrhage 10%
- subarachnoid haemorrhage 5% - 1/3 of ICH
what is TIA?
- NICE: a stroke that recovers within 24hrs from the onset of symptoms
- a brief period of cerebral ischaemia may cause a reversible neurological deficit that resolves when the blood flow is restored
- stroke symptoms lasts less than 24hrs, majority <30mins
- involvement of retinal blood supply causes temporary blindness in one eye - amaurosis fugax
what are the causes of TIA?
caused by inadequate cerebral or ocular blood supply like
- arterial thrombosis
- low flow
- embolism (arterial/cardiac/haematological)
why are TIA’s important?
- 20% of patients with stroke report a preceding TIA
- to identify and treat if possible high risk individuals (risk factors like hypertension, cholesterol, diabetes etc) to prevent a subsequent more serious event
- symptoms usually resolves within mins (never lasts >24hrs, by definition) but neuroimaging evidence suggests that permanent damage occurs in 10-20% cases
- TIA are associated with increased risk of both stroke and heart attacks
what is the ABCD² score and why is it used?
- Prognostic scores to identify people at high risk of stroke after a transient ischaemic attack (TIA) - NICE 2012
- used for training HR patients and target rapid intervention to HR patients like crescendo TIA (2 or more TIAs in a week) or HR factors like high BP, cholesterol, diabetes, smoking etc.
what does the ABCD score of <4 and >4 signify?
- ABCD < 4 – low risk
Seen in TIA clinic within 1 week - ACBD > 4 – high risk
Seen in TIA clinic next 24 hrs
what are the treatment options for TIA?
- Asipirin and ER Dipyridamole - NICE 2012
- Clopidogrel monotherapy - RCP 2012
- early secondary prevention - BP, DM, cholesterol, smoking, alcohol, weight, exercise
what are the different types of ischaemic stroke?
- classification derived from a multi centre trial of acute stroke treatment (TOAST) 1990 and is widely used in UK stroke trials
- classified into five group based in the cause
1. large artery disease/ atherothromboembolism: 25%
2. small vessel disease: 25%
3. cardioembolic: 20%
4. other defined or uncertain cause (like abnormalities if blood coagulation, infectious diseases, arterial damage and inflammatory disorders) : 25%
5. other: 5%
what is large vessel disease and who is commonly affected?
- ischaemic stroke caused by coagulation of blood within a cerebral vessel termed ins its thrombosis or large artery occlusive disease
- more common in people of asian and African origin but is increasingly recognised in caucasians
- artherosclerosis of medium and large arteries(e.g. neck vessels, aorta, coronary arteries) universal in developed countries, as result of lifestyle factors
- vasculopaths - plaque formation -> inflammation -> thrombosis/ embolism
what are the various mechanisms resulting in large vessel disease?
- thrombus on lesion causing local occlusion
- embolisation of plaque debris or thrombus in distal vessel
- small vessel origin occlusion by growth of plaque
- severe reduction in diameter of vessel lumen leads to hypoperfusion and infarction of distal “watershed” areas
what are small vessel disease, its two types and its pathology?
- small penetrating arteries of brain affected
- common cause: arterial hypertension
- High BP damages arterial walls and its smooth muscle is gradually replaced by collagen termed hyaline arteriosclerosis
- some cases: necrosis of vessel wall + accumulation of lipid laden foam cells - lipohyalinosis
- both types of pathology cause arteriosclerosis or hardening of arteries
- sclerotic vessels are unable to dilation in repose to reduced flow leading to lacunar infarcts
- often BG or internal capsule damaged
- important cause of vascular cognitive impairment and dementia
what is cardioembolism?
- cerebral blood vessels may be occluded by an embolus
- embolus is a small piece of coagulated blood (sometimes, fat) that travels in the circulation and lodges in the vascular tree of brain
- emboli often originate from from heart in association w valve disease or abnormal heart rhythm (called atrial fibrillation)
what are the causes of cardioembolsim?
- Atrial Fibrillation (LA thrombus) – 80%
- Myocardial Infarction (anterior wall) with hypokinetic wall segment/ LV aneurysm
- Infective endocarditis
- Non-bacterial thrombotic endocarditis
- Prosthetic heart valves (mitral)
- Paradoxical embolus - PFO, ASD, VSD
what are the obscure (uncertain) causes of ischemic stroke?
- Arterial dissection and trauma e.g. coughing
- Inflammatory vascular disease (GCA, SLE, antiphospholipid syndrome, RhA)
- Haematological (thrombophilias, leukaemia, lymphoma, polycythaemia, sickle cell, TTP, DIC)
- Peri-operative
- Recreational drugs (cocaine, amphetamines)
why is stroke considered as a global and national burden?
Global burden cause
- stroke: 2nd most common cause of death WW (after IHD)
- 15 million/ year suffer a stroke
- 5 million die
- 5 million people ;eft permanently disabled;ed
- absolute number of strokes increasing because of increase in ageing population
national burden cause
- approx 150,000 strokes each year in UK
- 3rd leading cause of death in UK
- leading cause of disability
- 20% mortality within 30day
- 1 in 4 < 65 years
- high costs: at least £7 billion per year
what are the major modifiable risk factors of stroke?
- Hypertension
- Smoking
- Diabetes
- High cholesterol
- AF (atrial fibrillation)
- IHD (ischemic heart disease)
- PVD (peripheral vascular disease, blood circulation disorder that causes the blood vessels outside of your heart and brain to narrow, block, or spasm)
- Previous TIA
- Obesity
- Unhealthy diet
- Low socioeconomic status
- Psychosocial stress
- Excess alcohol use
- 80% stroke causing factors are modifiable
what are the non-modifiable risk factors of stroke?
- age
- stroke uncommon in <40s but does happens even in children
- risk of stroke doubles each decade after 55
- 85 years (if lived to): 1/4men, 1/5men - family history - increased risk if 1st degree relative has had
- IHD or
- stroke <55yrs (men), <65yrs (women)
- race - people of African and carribean ethnicity - 2x likely to suffer stroke due to high prevalence of high BP and diabetes but is increasingly being recognised in caucasians
what is the effect if BP on stroke risk?
- for every 10 deaths from stroke - 4 preventable if stroke is treated
- risk of stroke increases with increase in mean BP
what are the stroke prevention techniques from a population based approach?
- Education regarding healthy life style including:
1. Increased exercise
2. Lower salt intake
3. Better diet - more fruit & vegetables
4. Reduced cholesterol intake
5. Reduced alcohol intake
6. Stop smoking
what is the effect of smoking of stroke?
- smoking doubles the risk of stroke in both men and women
- stopping smoking reduces the risk of CVD close to a non-smoker
how does smoking result in stroke?
- damages endothelial lining
- promotes atheroma
- enhances clotting
- raises LDL and lowers HDL
- raises BP
why is diabetes a significant factor for stroke?
- 170m people affected with diabetes WW and the numbers are increasing
- diabetes doubles the risk of stroke
- diabetics have a HR of dying from stroke
what is the effect of cholesterol on stroke?
- high LDL and low HDL - risk factors for IHD
- causation fro stroke not clear yet
- pooled data suggests high levels of cholesterol - risk factor for ischaemic stroke but not ICH
- nevertheless, clinical trials have shown lowering cholesterol in patients w IHD, PVD or prion stroke - prevents further stroke
how is statins beneficial in stroke?
- reduce cholesterol and have effectsoin platelets and vascular endothelium
- reduce the risk of MI, stroke
- improves revascularisation by 1/3
- according to the heart protection study in 2001, 5yrs of statin use prevents major vascular events in
- 100/1000 previous MI
- 80/1000 other CHD
- 70/1000 for diabetes (40+), previous stroke and other PVD
what is the effect of obesity on stroke?
- obesity is associated with metabolic syndrome like hypertension, diabetes, reduced physical activity, high cholesterol levels and reduced insulin sensitivity
- therefore, is associated with increased risk of stroke
- waist to hip ratio of >1.0 in men and >0.85 in women associated with 3 fold increase in IHD
- > 60% adults in USA overweight or obese (BMI >25 overweight, >30 obese)
what is impact of social deprivation on stroke?
- people living in deprived areas 3 times more likely to die from stroke than least deprived
- this is tribute to high rates of smoking, poor diet, obesity, lack of exercise in socially deprived communities
what is the impact of AF on stroke?
- NVAF (non-valvular AF) associated w x6 fold increase in stroke
- Individual’s risk is compounded by other risk factors e.g. CHF (chronic heart failure), PVD, high BP, elderly, diabetes, female
- Treatment options include Aspirin, Warfarin or one of the NAOCs (non-vitamin K antagonist oral anti-coagulant, drug used for NVAF)
- CHA2DS2VASc score predicts risk of stroke
- HASBLED score predicts individual risk of haemorrhage on treatment
what are the primary prevention techniques for stroke?
- identify HR population
- regular BP checks of adult population
- well clinics
- considering diabetes/high cholesterol/AF
- asses overall cardiovascular risk prior to treatment
what are the secondary prevention techniques for stroke?
- Rapid assessment of patients with TIA
- address cardiovascular risk factors
- BP < 130/80, < 120/80 in diabetics
- Statin for all patients
- Antiplatelet – reduces risk by ~ 20% annually -> Clopidogrel or aspirin and dipyridamole combination
- Warfarin/DOAC (direct oral anti-coagulant, sam as NOAC) for patients in AF
- Carotid endarterectomy (surgery to correct stenosis in common carotid artery and ICA) for patients with tight symptomatic stenosis - within 7days of symptoms
what are the different types of stroke syndrome?
according to the Oxford classification
type with morbidity rates associated
1. Total anterior circulation syndrome (TACS)
2. partial anterior circulation syndrome (PACS)
3. posterior circulation syndrome (POCS)
4. lacunar syndrome (LACS)
what are the morbidity rates associated with different stroke syndrome and
- proportion of patients dying within the first year:
TACS - 60%
PACS and POCS - 20%
LACS - 10% - most common cause of death is raised ICP due to brain swelling (cerebral oedema) -> causes herniation of tonsils of cerebellar tonsils compressing the brainstem, referred to as coning
what are the symptoms of TACS, PACS, POCS and LACS?
TACS
- new higher cortical dysfunction (e.g. aphasia)
- AND homonymous hemianopia
- AND sensorimotor deficit (affecting 2/3 of face, arm,leg)
PACS
- 2/3 elements of TACS
- OR higher cortical disfunction alone
- OR limited sensorimotor deficit (affecting fewer than 2 of face, arm,leg)
POCS
- CN + crossed sensorimotor deficit
- OR bilateral sensory/motor deficit
- OR disordering of conjugate eye movement
- OR isolated cerebellar dysfunction/field defect
LACS
- pure motor deficit
- OR pure sensory deficit
- OR sensorimotor deficit
- OR ataxic hemiparesis
what are the various causes of rupture of vessels in haemorrhagic stroke?
- excessive pressure - hypertension
- friable/da,aged vessels: vasculitis, CAA, vascular malformations, moyamoya
- trauma e.g. trauma SAH
- malignant tumour
what is the eligibility criteria for thrombolysis?
- treatment is started as early as possible within 4.5 hrs of stroke symptoms onset
- ICH has been excluded by appropriate imaging techniques
what are the exclusive criteria for thrombolysis?
- Low NIHSS
- Uncertain time of onset
- Improving NIHSS at time of review
- Haemorrhage on CT
- Uncontrolled hypertension
- Recent head trauma, neurosurgery or stroke within 3 months
- Presentation suggests SAH
- History of ICH
- known AVM, tumour or aneurysm
- Active bleeding
- Possible SBE
- Surgery in last 14 days (relative to type of surgery)
- Recent UGI, urinary haemorrhage
- Arterial puncture in a non-compressible site
- Pregnancy
- Recent lumbar puncture
- Actively anticoagulated
what are the immediate symptoms of a stroke? (FAST)
Face: one side drooping
Arms: weakness
Speech: difficulty
Time: to call 999
what is NIHSS and why is it used?
- Grade and track the severity
- Monitor response to acute treatments
what are the pros and cons of CT in acute stroke?
Pros - Quick - Readily available 24/7 - Sensitive for haemorrhage - May see a ‘hyperdense vessel’ Cons - Cannot usually diagnose an infarct in the acute phase - Less sensitive than MRI for picking up other abnormalities (demyelination, mass lesions, microhaemorrhages) and for lacunar and posterior circulation infarcts.
what are the key steps in management of stroke?
- Investigate the cause (history, examination, bloods, imaging)
- Screen and prevent complications (dehydration, aspiration, VTEs, pressure sores, infection, depression)
- Establish Secondary Prevention (lifestyle, medical, surgical)
- Rehabilitation (physiotherapy, occupational therapy, speech and language therapy
what are the keys steps involved in treatment of stroke?
- MDT
- Lifestyle
- medical
- surgical