Stroke Flashcards
Describe the common pathology of small vessel disease?
Small Artery Lipohyalinosis
Hypertension causes thickening of small artery walls leading to luminal narrowing
What are borderzone anatomoses? [1]
Anastomoses between peripheral branches of cerebral arteries
Too small to compensate for blocked major arteries
What neglect syndromes result from infarct of non-dominant hemisphere?
- Visual Agnosia (Cant process left side vision)
- Sensory Agnosia
- Anosagnosia (Denial/unawareness of hemiplegia or stroke as a whole)
- Prosopagnosia (Failure to recognise faces)
Which cerebral artery supplies the basal ganglia? [2]
Middle cerebral -> Lenticulostriate arteries
What does the basilar artery supply? [3]
Brainstem, Cerebellum, thalamus
Where does the post cerebral circulation supply? [5]
Brainstem. Cerebellum and thalamus
+ Occipital and medial temporal lobes
What symptoms occur if the brainstem is ischemic? (Such as in post circulation infarcts) [6]
- Coma
- Ataxia, Vertigo, N&V
- Cranial nerve palsies
- Hemiparesis or hemisensory loss
- Crossed sensori/motor deficits (Means ipsilateral cranial nerve signs and contralateral motor/sensory signs)
- Visual field deficits
How do you classify strokes? [4]
Total Anterior Circulation Stroke (TACS)
Partial Anterior Circulation Stroke (PACS)
Lacunar Stroke (LACS)
Posterior Circulation Stroke (POCS)
Order the classes of stroke by prognosis? [4] (Death or dependance at 6m) Difference between (terminology) TACI and TACS?
Death or dependance at 6 months:
- TACS 96%
- PACS 45%
- LACS 39%
- POCS 38%
They are refferred to as **S instead of **I, meaning stroke syndrome instead of infarct prior to imaging as we cant yet be sure it is a stroke and not some other condition causing a stroke like syndrome.
Aims of treatment in stroke [3]
Restores supply
ABCDE
Prevents ischemia & extension
Protect brain tissue
Stroke treatments [4]
- Oyxgen >95%
- NBM until swallow screen, so give IV fluids
- NCCT
Refer to Stroke On-Call - Within 4.5 hour window consider thrombolysis
- Within 6 hour window consider imaging for thrombectomy
- BM 5-15
- Treat hypertension if >185 >110
- Start statins within 48h
Criteria for TPA use [4]
it is administered within 4.5 hours of onset of stroke symptoms (unless as part of a clinical trial)
haemorrhage has been definitively excluded (i.e. Imaging has been performed)
Contraindicaitons for thrombolysis
Relative [5]
Absolute [11]
What sort of treatments can reduce stroke risk after a TIA? [4]
Antiplatelets
Antihypertensives
Statins
Endarterectomy if atheroma
Whats involved in stroke secondary prevention? [4]
- Anti-HTN
- Anti-platelets: 75mg clopidogrel or aspirin + dypiridamole (if contraindicated/not tolerated) lifelong
- Atorvastatin 80mg
- Endarterectomy (mainly carotid)
Differentiating between different classes of stroke: LACS [4]
Where are the infarcts? [4]
At least one of:
- unilateral weakness (and/or sensory deficit) of face and arm, arm and leg or all three.
- pure sensory stroke.
- ataxic hemiparesis
Lacunar strokes are small in infarct in basal ganglia, internal capsule or thalamus and pons
Differentiating between different classes of stroke:
PACS [4]
Source: Oxford stroke classification/Bamford classification
Partial anterior circulation stroke
At least 2 of:
1. Unilateral hemiparesis and/or hemisensory loss of face, arm or leg
2. Homonymous hemianopia
3. Higher cognitive dysfunction (dysphasia)
Differentiating between different classes of stroke: TACS [4]
Source: Oxford stroke classification/Bamford classification
All 3 of:
- Unilateral hemiparesis and/or hemisensory loss of face, arm or leg
- Homonymous hemianopia
- Higher cognitive dysfunction (dysphasia)
Differentiating between different classes of stroke: POCS [4]
Source: Oxford stroke classification/Bamford classification
Posterior circulation syndrome Any of motor, sensory, cerebral deficits [1] \+ 1. cerebellar or brainstem syndromes 2. loss of consciousness 3. isolated homonymous hemianopia
Stroke by anatomy:
Basilar artery infarct
Locked-in syndrome
Stroke by anatomy:
ACA [2]
Contralateral hemiparesis + sensory loss
Lower extremity > upper
Stroke by anatomy:
MCA [4]
Contralateral hemiparesis + sensory loss
Upper extremity > lower
Contralateral homonymous hemianopia
Aphasia
Stroke by anatomy:
PCA [3]
Contralateral homonymous hemianopia with macular sparing [2]
Visual agnosia
Define stroke [3]
A neurological deficit [1] of sudden onset [1] lasting >24 hours of vascular origin [1]
When is the main risk period for further strokes/TIAs following one?
The first two weeks, this is why its mportant to give DAPT
Hemorrhagic stroke mx [5]
Reverse anticoagulation
Systolic BP between 130-139 mmHg within one hour
Hydrocephalus should consider extraventricular drain
Acute drop in GCS necessitates neurosurgical opinion for consideration of decompressive craniectomy
TIA initial mx [3]
Ix [6]
Immediate anti-platelet therapy Aspirin 300mg
clopidogrel (initial dose 300 mg followed by 75 mg od) + aspirin (initial dose 300 mg followed by 75 mg od for 21 days) followed by monotherapy with clopidogrel 75 mg od
ticagrelor + clopidogrel is an alternative
Ix:
- Bloods
- CXR
- ECG
- ECHO
- Carotid doppler
- Brain imaging
TIA subsequent management [4]
o Further anti-platelet: CLOPIDOGREL
o Anti-coagulant: if in AF
o Modifiable cardiac RFs: BP control, statin, DM, stop smoking
o Carotid endarectomy: >70% stenosis
When would you offer thrombectomy?
Eligibility considerations
Offer thrombectomy as soon as possible and within 6 hours of symptom onset, together with intravenous thrombolysis (if within 4.5 hours), to people who have:
* acute ischaemic stroke and
* confirmed occlusion of the proximal anterior circulation [1]
* that has been demonstrated by computed tomographic angiography (CTA) or magnetic resonance angiography (MRA)
* NICE recommend a pre-stroke functional status of less than 3 on the modified Rankin scale and a score of more than 5 on the National Institutes of Health Stroke Scale (NIHSS)
Patterns of stroke: Lateral medullary syndrome (posterior inferior cerebellar artery) [3]
- aka Wallenberg’s syndrome
- Cerebellar features:
Vertigo
Dysarthria
Dysphagia
Ipsilateral facial numbness and contralateral sensory loss in other areas
Ipsilateral Horner’s syndrome
Weber’s syndrome [2]
ipsilateral III palsy
contralateral weakness
Patient presenting within 6-24 hour window including wake-up strokes - which circumstances would you consider thrombectomy?
Offer thrombectomy as soon as possible to people who were last known to be well between 6 hours and 24 hours previously (including wake-up strokes):
* confirmed occlusion of the proximal anterior circulation demonstrated by CTA or MRA and
* if there is the potential to salvage brain tissue, as shown by imaging such as CT perfusion or diffusion-weighted MRI sequences showing limited infarct core volume
When would you consider thrombectomy together thrombolysis?
Consider thrombectomy together with intravenous thrombolysis (if within 4.5 hours) as soon as possible for people last known to be well up to 24 hours previously (including wake-up strokes):
* who have acute ischaemic stroke and confirmed occlusion of the proximal posterior circulation (that is, basilar or posterior cerebral artery) demonstrated by CTA or MRA and
* if there is the potential to salvage brain tissue, as shown by imaging such as CT perfusion or diffusion-weighted MRI sequences showing limited infarct core volume
Cerebrovascular disease comes in two forms [2]
- Localised interruption of blood or oxygen supply (Stroke)
- Generalised interruption of blood or oxygen supply
What could cause a stroke? Outline 3 main mechanisms: vessel wall [4], blood constituents [2], blood flow [2]
Vessel Wall:
- Aneurysm
- Atheroma
- Vasculitis
- Strangulation
Blood Constituents
- Thrombosis
- Bleeding due to anticoags or reduced platelet/clotting factors
Blood flow:
- Hypotension
- Hypertension -> Bursting
So what are the 3 main causes of localised interrupted blood supply to the brain (Stroke)?
Ischaemic:
- Embolic eg Afib
- Thrombotic (atherosclerosis)
- Lacunar strokes
Haemorrhagic:
- Intracerebral haemorrhage - HTN, vascular malformations
- SAH (bleeding into subarachnoid space)
Watershed strokes
Whats the difference between a TIA [3] & Stroke [3]?
Both are ischaemia to a localised section of brain tissue
TIA:
- Reversible Ischaemia
- Tissue still viable
Stroke:
- Irreversible ischaemia
- Localised brain death (i.e. infarct)
What happens to the brain tissue during a regional cerebral infarct? [5]
The region is classically wedge shaped reflecting the in->out arterial supply. [1]
The tissue becomes soft, yellowy discoloured and begins to disintegrate [1] typically in a cystic appearance [1]
There may be visible congested vessels [1] and swelling around the area [1]
How does infarcted brain tissue appear histologically? [2]
Visibly lost neurons [1]
Foamy macrophages - Part of the repair process prior to gliosis (Scar tissue formation) [1]
Why are cerebral arteries so likely to have aneurysms? [3]
They are very thin walled due to their lack of muscle. [1]
This is so that there’s no way cerebral blood can be diminished [1]
This when coupled with hypertension leads to aneurysms which can burst [1]
How does a ruptured aneurysm cause localised interruption of blood flow? [2]
The haemorrhage means blood doesnt get through and compresses the brain [1]
Can also get distal ischaemia due to arterial spasm [1]
Where do cerebral aneurysms most often form? [2]
- Microaneurysms in the Basal Ganglia
- Berry Aneurysms in the Circle of Willis
What are the main causes of a generalised interrupted blood supply or hypoxia? [3]
- Low O2 in the blood (Hypoxic Hypoxia) e.g. CO poisoning or resp arrest
- Inadequate supply of blood e.g. Cardiac arrest, swollen brain or hypotension
- Rarely an inability to use the O2 such as cyanide posioning
What are the main types of Generalised interrupted blood supply? [3]
- Hypotension
- Cardiac Arrest
- Complex Case (Combines various types of ischaemia form multiple causes)
What pattern of infarction could be caused during an Operation in which there is a prolonged period of hypotension? [3]
Generalised interrupted blood flow [1]
- -> poor perfusion to the borders between arterial territories in the brain [1]
- -> So you get a pattern of ischaemia and infarction [1] at the interfaces between these area (watershed infarcts) [1]
If someone goes into cardiac arrest and is resuscitated after several minutes, describe their pattern of ischaemia?
They go several minutes with no supply of blood so Generalised interruption
Causes infarction all over the brain
They get Laminar (lined) cortical necrosis [1] i.e. large areas of grey matter thin and necrose [1]
Lets say a woman comes in with a known Coronary artery disease, bouts of pneumonia and suffers a cardiac arrest, describe her pattern of ischaemia? [3]
This is known as a Complex Case [1], she has multiple different sources of ischaemia causing different patterns in her brain:
- Watershed infarcts from her time poorly ventilated due to pneumonia [1]
- Regional infarcts related to localised loss of blood flow from atheromatous disease [1]
- Laminar Cortical infarcts due to complete cessation of blood flow during cardiac arrest [1]
Prognosis strokes - what % ability to lead independent lifestyle? Mortality within 1y?
50% of survivors become dependant on others for daily activities
& roughly 1/3rd die within a yr
What is the ischaemic penumbra? [3]
Region around the edge of the ischaemic core [1] because blood & O2 supply is reduced locally after an ischaemic event [1]
The tissue may remain viable for several hours due to collateral circulation. [1]
Radiological imaging stroke [4]
Non-contrast CT scan
- First option
- MRI with DWI
- Carotid ultrasound scanning
- CT angiography
Compare CT and MRI CT pros [2] CT cons [2] MRI pros [2] MRI cons [2]
CT pro: infarcts show up clearer + darker; can exclude hemorrhagic stroke
CT cons: <6h not as sensitive, poor visualization for POCs
MRI pros: better for POCs, increased sensitivity to acute ischemia and smaller infarcts
MRI cons: $$$, longer scanning time
Diabetes and stroke risk [1]
Smoking and stroke risk [2]
Diabetes causes an increases risk up to 3fold.
Smoking doubles risk of stroke and triples risk of SAH
Alcohol and stroke risk [2]
Small amounts actually decrease risk but heavy drinking more than doubles it
Alcohol and stroke risk [2]
Small amounts actually decrease risk but heavy drinking more than doubles it
What 3 other investigations must you carry out to identify underlying cause of stroke?
- Routine bloods
- ECG (LVH or AF)
- Echocardiogram (Valves, ASD/VSD)
Case study: O/E can move eyes up and down Breathing spontaneously No other movements She has CV risk factors
Diagnosis: locked in syndrome secondary to pontine infarction
Locked in syndrome
What are causes [2]
Why are vertical eye movements preserved?
Damage to ventral pons
Pontine infarct
Basilar artery obstruction
Can be precipitated by neck trauma causing vertebral artery dissection
Horizontal eye movements coordinated in Pons but Midbrain and vertical eye movements preserved
In what patients would a carotid endarterectomy definitely be indicated?
- recommend if patient has suffered stroke or TIA in the carotid territory and are not severely disabled
- should only be considered if carotid stenosis > 70% according ECST** criteria or > 50% according to NASCET*** criteria
What are the complications of Carotid Endarterectomy [4]
Infection
- Bleeds
- Nerve Damage
- Perioperative Stroke (due to rupturing plaque or the vessel clamping causing hypoperfusion of the brain)
Agnosia definition
Types of agnosia [4]
inability to interpret sensations and hence to recognize things
- Visual agnosia
- Sensory agnosia
- Anosagnosia
- Prosopagnosia
Describe prevalence of hemorrhagic vs ischemic strokes
Haemorrhagic (Around 15%)
Ischaemic (Around 85%)
Fluid management in stroke patients
- manage fluids in this immediate post-event period as hypovolaemia can worsen the ischaemic penumbra, as well as increase risk of other complications such as infection, deep vein thrombosis, constipation and delirium
- over-hydration can also complicate matters by leading to cerebral oedema, cardiac failure and hyponatraemia, therefore it is important to regularly review fluid status in these patients
- encourage oral hydration when able
The NICE guidelines recommend maintaining a blood sugar level between ———– in people with acute stroke
The NICE guidelines recommend maintaining a blood sugar level between 4 and 11 mmol/L in people with acute stroke
* hyperglycaemia leads to worse outcomes, leaky BBB
Use of anti-hypertensive medications should only be used for blood pressure control in patients post ischaemic stroke if there is a hypertensive emergency with one or more of the following serious concomitant medical issues (according to the NICE guidelines): [5]
Hypertensive encephalopathy Hypertensive nephropathy Hypertensive cardiac failure/myocardial infarction Aortic dissection Pre-eclampsia/eclampsia
Consequences of lowering BP too much post-ischemic stroke
This is because lowering blood pressure too much can potentially compromise collateral blood flow to the affected region, and possibly hasten the time to complete and irreversible tissue infarction
What are the recommendations on how fast you should lower BP?
Which anti-HTN drugs would you be able to use? [3]
If if treatment is indicated, UptoDate recommend cautious lowering of blood pressure by approximately 15% in the first 24-hours after stroke onset
Rx: intravenous labetalol, nicardipine and clevidipine
Management of BP for patients who are candidates for thrombolytic therapy for acute stroke is different
- blood pressure should be reduced to 185/110mmHg or lower as elevated BP can affect thrombolytic eligibility and delay treatment
Feeding assessment and management of any concerns regarding swallow [2]
All patients presenting with acute stroke must be SCREENED for safe swallowing function prior to further oral intake, as dysphagia is common after stroke
Specialist input for any concerns regarding swallow within 24h of admission and no more than 72h after admission, remain NBM until assessed
Recommendations for patients deemed unsafe for oral intake [2]
Patients should receive nasogastric tube feeding, ideally within 24 hours of admission, unless they have had thrombolytic therapy
2nd line:
- Nasal bridle tube or gastrostomy
FAST screening tool (for general public)
ROSIER score is used by medical professionals [8]
- Exclude hypoglycaemia first, then assess the following:
- LOC or syncope -1
- Seizure activity -1
- New acute onset of: (all +1 pt)
- Asymmetric facial weakness
• asymmetric arm weakness
• asymmetric leg weakness
• speech disturbance
• visual field defect
ROSIER score clinical significance?
A stroke is likely if > 0.
Atrial fibrillation post stroke [3]
- following a stroke or TIA, WARFARIN or a direct thrombin or factor Xa inhibitor (APIXABAN 5MG BD)
- Antiplatelets should only be given if needed for the treatment of other comorbidities
- Start 14d after stroke
- If imaging shows a very large cerebral infarction then the initiation of anticoagulation should be delayed
