5. Stroke Flashcards
Define stroke
Interruption of the blood supply to a focal part of the brain causing loss of neurological function
Symptoms last >24 hours or lead to death with no apparent cause other than that of vascular origin
Define a TIA (transient ischaemic attack)
Same cause as a stroke i.e. blockage to blood supply to brain leading to loss of neuro function
However, symptoms lasting <24 hours
3 different types of stroke?
- Ischaemic: 80-85%
- Haemorrhagic: 15%
- Subarachnoid haemorrhage: 5%
Causes of haemorrhagic stroke?
Hypertension Tumour Bleeding disorder Vascular malformation Amyloid angiopathy
Causes of ischaemic stroke?
Cardioembolism
Large vessel artherothrombosis
Cardiac course: Small vessel disease, carotid/vertebral dissection, watershed areas
Hypoperfusion
What is the progression of the brain tissue in an ischaemic stroke?
In the CORE zone, which is an area of severe ischemia (blood flow below 10% to 25%), the loss of oxygen and glucose results in rapid depletion of energy stores. Severe ischemia can result in necrosis of neurons and also of supporting cellular elements (glial cells) within the severely ischemic area.
Brain cells within the PENUMBRA, a rim of mild to moderately ischemic tissue lying between tissue that is normally perfused and the area in which infarction is evolving, may remain viable for several hours. That is because the penumbral zone is supplied with blood by collateral arteries anastomosing with branches of the occluded vascular tree (see inset). However, even cells in this region will die if reperfusion is not established during the early hours since collateral circulation is inadequate to maintain the neuronal demand for oxygen and glucose indefinitely.
How many neurones are lost per year due to aging?
30 million neuron loss per year in normal ageing
How can cerebral autoregulation be impacked by bp and age?
In cerebral autoregulation alter diameter in order to maintain cerebral perfusion
- Impeded if bp too high as there is force dilation, increased flow and vadogenic Oedema
- If bp too low leads to impaired dilation, artery collapse and then ischemia
- Older arteries are stiffer which is a problem
What is the anterior circulation supply to the brain?
From the internal carotids. Supply the:
- -> Anterior 3/5 of the cerebrum
- -> Diencephalon
Main branches:
- Middle cerebral artery (MCA)
- Anterior cerebral artery (ACA)
- Striate arteries
What is the posterior circulation supply to the brain?
Via the vertebrobasilar arteries Supplies: -Posterior 2/5 of the cerebrum -Diencephalon -Cerebellum -Brainstem Main branches: -Posterior cerebral arteries -Striate and thalamus -Pontine -Cerebellar
S&S of stroke and TIA?
Diplopia Ataxia Hemianopia (Stroke > TIA) Speech loss (TIA> stroke) Sensory loss (stroke > TIA) Motor loss (Stroke > TIA)
What is diplopia?
Double vision
What is hemianopia?
Blindness over half the field of vision
Key things to look for in examination in vascular neurology?
• BP and pulse measurement in 2 arms
• Conscious level (GCS; document breakdown)
• Cardiac and carotid bruits
• BM/blood glucose value
• Neck stiffness/meningism (Kernig’s/Brudzinski signs)
• Abnormal or involuntary movements
• Any seizure-like activity
• Skin rash/infarcts e.g. vasculitic, papular rash
• Specific neurological
- eye movements (gaze preference,fixed deviation)
- speech, visual fields, inattention, motor & sensory
- gait assessment
Name 3 different ways to classify a stroke?
Oxford Community Stroke Project (OCSP)
- Clinical classification
TOAST classification
-Mechanism classification (e.g. large or small vessel, cardioembolic)
Carotid or vertebrobasilar territory
-Location classification
What are the 4 subtypes in the OCSP classifications of stroke?
- Total Anterior Circulation Syndrome (TACS)
- Partial Anterior Circulation Syndrome (PACS)
- Lacunar Syndrome (LACS)
- Posterior Circulation Syndrome (POCS)
What is seen/affected in LACS in the OCSP classification of strokes?
Pure motor
Pure sensory
Sensorimotor
Ataxic hemiparesis (paralysis on half body)
What is seen/affected in POCS in the OCSP classification of strokes?
Brainstem
Cerebellar
and/or
Isolated homonymous hemianopia
What is seen in TACS in the OCSP classification of strokes?
Triad of hemiparesis (or hemisensory loss)
Dysphasia (or other higher cortical function)
Homonymous hemianopia
What is seen in PACS in the OCSP classification of strokes?
2 features of TACS or Isolated dysphasia or Parietal lobe signs (e.g. inattention, agnosia, apraxia, agraphesthesia, alexia)
What is agnosia
Inability to interpret sensation hence unable to recognise things
What is apraxia
Inability to perform particular purposive actions due to brain damage
What is agraphaesthesia
Agraphesthesia is a disorder of directional cutaneous kinesthesia or a disorientation of the skin’s sensation across its space. It is a difficulty recognizing a written number or letter traced on the skin after parietal damage.
What is alexia?
Inability to recognise or read certain words or letter (often due to brain damage)
What is the ABCD2 assessment in TIA and risk of stroke?
7 points score to predict early stroke risk post TIA
- Age [60 or above;=1]
- Blood pressure [systolic > 140 and/or diastolic =/> 90; =1]
- Clinical features [unilateral weakness = 2; speech disturbance w/o weakness = 1; other = 0]
- Duration of Symptoms in mins [=/> 60 =2; 10-59 =1; < 10 = 0)
- Diabetes = 1
2-day strokes scores/risk: 0-3 (1%), 4-5 (4%), 6-7 (8%)
Name 5 stroke mimics
Hint: S S S S S
- Seizures
- Sepsis
- Syncope
- SpaceOccupyingLesion (e.g. tumour, subdural)
- Somatisation
What is somatisation?
The manifestation of psychological distress by the presentation of bodily symptoms
What are the red flags when dealing with a stroke stroke for a more sinister diagnosis?
No history No risk factors No imaging abnormality Young age Seizers Unusual headache
When doing the clinical assessment for a stroke what are your 3 initial questions?
Localisation of the lesions
Likely vascular or non-vascular aetiology
Mechanism of vascular event e.g. small vessel disease, cardioembolism, hypoperfusion
Name the 6 investigations that should be done after a stroke?
GOOD history and exam ECH/Holter (24hr ECG) and Echo Cholesterol/autoimmune and thrombophilia screen Carotid dippler CT brain / MRI brain Cerebral angiography
Indications for urgent head imaging
- Depressed level of consciousness
- Unexplained progressive or fluctuating symptoms
- Papilloedema, neck stiffness or fever
- Severe headache at onset
- History of trauma prior to onset
- Indication for thrombolysis or anticoagulation
- History of anticoagulant treatment or known bleeding tendency
In a CT what feature of the sulci suggests stroke?
If they are NOT VISIBLE
As a stroke progresses how does the CT presentation look?
Loss of normal grey/white differentiation
Difference between DWI and ADC MRI imaging?
DWI is mixture of T2 and diffusion weighting
ADC is pure diffusion of water
DWI/ADC MRI image changes after stroke?
Initially:
High signal- DWI
Low signal- ADC
After 1-2 weeks:
- DWI stays high
- ADC signal increases to normal
After 2 weeks +
- DWI becomes lower
- ADC becomes high and stays high
Advantages and disadvantages of CT scanning in a stroke?
Advantages:
- Can detect bleed
- Available 24/7
- Quick
Disadvantages:
- Lacks sensitivity
Advantages and disadvantages of MRI scanning in a stroke?
Advantages:
- Sensitive
- Diagnostic
- Management
- Prognostic
Disadvantages:
- Limited availability
- Precautions
- Slow
management of an acute stroke?
- Aspirin (300 mg/d) in ischaemic stroke
- Thrombolytic treatment with IV r-tPA if onset < 4.5 hrs, haemorrhage excluded by imaging, considered suitable for treatment, administered in a specialist centre
- Endovascular treatment/ mechanical thrombectomy with clot-retrieval device in selected patients
- Aggressive early BP Rx in ICH; SBP < 140
- Neurosurgical opinion for secondary hydrocephalus especially in cerebellar stroke
- Anticoagulation in atrial fibrillation- oncebleed excluded and usually after 10-14 days of stroke
- In ischaemic stroke, avoid antihypertensive medications unless MAP* (mean arterial pressure) > 130 mm Hg. In haemorrhagic stroke, aim for SBP < 140 mm Hg especially in the first 6 hours.
- If BP persistently elevated, treat with IV Labetolol. Important: avoid abrupt falls in BP
- In raised ICP: hyperventilate mechanically (PC02:25-30 mm Hg/20 breath per min), mannitol, decompressive hemicraniectomy
Management of SAH?
• CT brain/ lumbar puncture if CT normal looking for bilirubin & xanthochromia. Cerebral angiogram
• Management:
- airway: intubate if severe hypoxaemia
- fluid: 3L of 0.9% NaCl per 24 hrs
- BP: keep MAP < 130 mm Hg. If higher: IV labetolol or esmolol or enalapril
- Nimodipine 60 mg 6X/day (for 3 weeks)
- Codeine or tramadol for pain (Avoid NSAID) - Phenytoin if seizures have occurred
In secondary prevention of stroke, what is the drug treatment used?
- Anti-thombotics: Clopidogrel or Aspirin + Dipyridamole. In atrial fibrillation: Warfarin or NOAC (dabigatran, rixaroxaban, apixaban)
- Blood Pressure: Target BP < 130/80 with calcium channel blocker, thiazide diuretic (e.g. bendroflumethiazide or indapamide), ACE inhibitor (e.g. Perindopril)
- Anti-lipids: If total cholesterol > 4.0 mmol/l (or LDL-C > 2.5mmol/l [100 mg/dl], treat with statin e.g. Simvastatin (but caution in ICH or history of cerebral haemorrhage)
What is the MRS assessment?
Modified Rankin Scale (MRS) from 0-6. O= No symptoms, 6= Dead
Measures disability level
When should carotid surgery be considered in secondary prevention of stroke?
• Carotid endarterectomy (CEA) should be
considered for all symptomatic stroke/TIA
patients (without severe disability; MRS<3) and with
50-99% stenosis (by NASCET method) or 70-99% (by ECST method)
• CEA should be performed as soon as patient is stable and fit for surgery, ideally within 1 week
• CEA reasonable for asymptomatic stenosis > 60% provided > 5 yr life-expectancy & peri- operative stroke/death rate < 3%
What is the long term management of strokes?
Potential issues?
6 mths after stroke, over 50% survivors need some help with their ADL; 15% communication impairment and 53% motor weakness
• Psychosocial and support needs reviewed on regular basis
Potential issues: Communication, mobility, driving, depression, pressure sores, sepsis, nutrition, post-stroke seizure, shoulder pain, cognitive impairment & behavioural problem
What is a watershed area?
Name the 3 of the brain?
Areas with dual blood supply, key in limiting damage during an ischaemic stroke
3 watershed areas:
- Cortical border zone: ACA + MCA
- Internal border zone: LCA + MCA
- Cortical border zone: MCA + PCA
