Stroke Flashcards
Define a neurovascular unit
Relates to the functional and structural interplay between/among neurons, glial cells and endothelial lumens (including the dynamic of the blood brain barrier, a huge part of which is the tight junction of cerebral endothelial cells).
Mechanism of stroke? Reason for its sudden onset?
hypoperfusion in the endothelial lumen
reduction in available oxygen and glucose
reduction in ATP synthesis
impairment of all energy dependent cell processes including membrane transport
impairment of AP generation and therefore reduced neuronal transmission
The binary nature of APs and their relationship to the change in neuronal transmission underlies the SUDDEN evolution of stroke symptoms
Anterior cerebral artery stroke associated effects?
Contralateral hemiparesis and sensory loss, lower extremity > upper
Middle cerebral artery stroke associated effects?
Contralateral hemiparesis and sensory loss, upper extremity > lower
Contralateral homonymous hemianopia
Aphasia
Posterior cerebral artery stroke associated effects?
Contralateral homonymous hemianopia with macular sparing
Visual agnosia
Weber’s Syndrome define? Associated effects?
Stroke affecting branches of the posterior cerebral artery that supply the midbrain
Ipsilateral CN III palsy
Contralateral weakness of upper and lower extremity
Define wallenberg syndrome? Alternative name? Associated effects?
Stroke affecting Posterior inferior cerebellar artery
also called Lateral medullary syndrome
Ipsilateral: facial pain and temperature loss
Contralateral: limb/torso pain and temperature loss
Ataxia, nystagmus
DANVAH - Dysphagia, ataxia (ipsilateral), Nystagmus (ipsilateral), Vertigo, Anaesthesia (ipsilat facial numbness + absent corneal
reflex; Contralateral pain loss)
Horner’s syndrome (ipsilateral)
Lateral pontine syndrome define? Associated effects?
Stroke affecting Anterior inferior cerebellar artery
Symptoms are similar to Wallenberg’s , but also:
Ipsilateral: facial paralysis and deafness
Wallenbergs:
Ipsilateral: facial pain and temperature loss
Contralateral: limb/torso pain and temperature loss
Ataxia, nystagmus
Retinal/ophthalmic artery stroke associated effects?
Amaurosis fugax
Lacunar stroke presentation? Risk factor? Common sites?
• present with either isolated hemiparesis, hemisensory loss or hemiparesis with limb ataxia
Associated with hypertension
common sites include the basal ganglia, thalamus and internal capsule
List the components of the complete stroke service
- Rapid access TIA clinics
- Hyperacute stroke unit with access to neurosurgical and interventional radiology services
- Acute stroke wards
- Inpatient rehabilitation
- Outpatient rehabilitation including Early Supported discharge services
- Outpatient stroke clinics
Differentials, other than stroke, for isolated presentation of dysarthria?
Generalised cerebral impairment: alcohol intoxication, sepsis, post-ictal phase
Peripheral neural dysfunction: impaired peripheral vocal apparatus, facial/tongue/throat muscles
Presentations that reduce chance of being a stroke?
Isolated presentation of dysarthria, double vision or vertigo
Symptoms that evolve in a sequential fashion are difficult to fit into a vascular territory
Define cryptogenic stroke?
when cause of stroke remains unclear after thorough assessment
Features that increase the chance of stroke being the dx?
Sudden onset
focal
predominantly negative
Vascular territory hypoperfusion can explain collection of symptoms
Symptoms do not migrate
Episodes do not typically stereotype (symptoms do not recur in an identical fashion
Stroke mimics that involve sensory and visual neurological disturbances that tend to migrate?
Migraine, seizures
Slow migration applies to migranous sensory and visual aura
Fairly rapid migration can be a feature of focal seizures – so called “Jacksonian march” - a phenomenon where a simple partial seizure spreads from the distal part of the limb toward the ipsilateral face (on same side of body)
Cases of stroke which do exhibit stereotyping symptoms?
Capsular warning syndrome and intracranial stenosis
Capsular warning syndrome define? Mechanism? Presentation? Imaging?
a term used to describe recurrent stereotyped lacunar transient ischemic attacks (TIAs)
Intermittent (and critical) hypoperfusion of lentriculostriate arteries
Recurrent events occur over minutes to hours (non vascular stereotyping where recurrence is over days, weeks or even years) - tend to be LACS type stroke
Diffusion weight imaging tends to be positive - confirming infarcted brain tissue
Intracranial stenosis presentation? Imaging?
Stroke syndrome episodes are associated with clinical markers of generalised hypoperfusion.
These may include palpitations, dizziness, pallor clamminess, occur on standing in cases of postural hypotension etc.
Targeted imaging with angiography will confirm the stenosis.
What criteria is assessed in the oxford stroke classification?
- unilateral hemiparesis and/or hemisensory loss of the face, arm & leg
- homonymous hemianopia
- higher cognitive dysfunction e.g. dysphasia
TACI involvement? Presentation
Involves proximal MCA or ICA
Hemiparesis AND higher cortical dysfunction AND homonymous hemianopia
PACI involvement? Presentation?
involves smaller arteries of anterior circulation e.g. upper or lower division of middle cerebral artery
Isolated higher cortical dysfunction OR Any two of: hemiparesis, higher cortical dysfunction, hemianopia
POCS involvement? features?
Occlusion of vertibral, basilar, cerebellar or PCA vessels.
Isolated hemianopia or brainstem or cerebellar syndromes
LACS involvement? Features?
Small penetrating artery occlusion - usually in lenticulostriate branches of MCA or supply to brainstem or deep white matter
Pure motor OR pure sensory OR sensorimotor stroke OR ataxic hemiparesis (a combination of cerebellar and pyramidal hemiparesis on the contralateral side of the body) OR Clumsy hand-dysarthria (dysarthria and contralateral ‘clumsiness’ (i.e. weakness) of the hand, which is often most prominent when the patient is writing. )
Signs of spontaneous intracrainial haemorrhage?
- Possible underlying cause
- Reduced level of consciousness at admission
- History of headache
- Seizures
Causes of primary haemorrhage?
Primary - caused by spontaneous rupture of small vessels associated with chronic hypertension or amyloid angiopathy.
Causes of secondary haemorrhage?
(some other lesion complicated by haemorrhage)
- Haemorrhagic transformation infarct- Venous sinus thrombosis and venous infarction
- Tumour –GBM, anaplastic astrocytoma, metastasis
- Vascular –aneurysm, AVM, vasculitis
- Coagulopathy, warfarin, aspirin
- Cocaine, alcohol
Groups of stroke mimics?
Group 1 - readily identifiable with standard imaging: subdural heamatomas, space occupying lesions, multiple sclerosis (MS) etc.
Group 2 - syndromically distinguishable from the stroke syndrome on clinical grounds after general medical assessment: syncope syndrome, benign positional vertigo, vestibular neuronitis, transient global amnesia.
Group 3 - conditions where recognition is also clinical but features can be subtle and justify specialist assessment - migraine with aura, focal seizures, functional syndrome, amyloid spells.
Define transient global amnesia
dysfunction of “episodic” memory with preservation of other kinds of memory e.g. procedural memory (hence patients are able to make a cup of tea or drive during episode), biographical memory etc.
Migraine with aura vs stroke?
Migraine - Therefore typically gradual onset, migratory and sequential onset of migraine aura symptoms. Also mostly positive symptoms
Presentations of migraine affecting different lobes of the brain?
Visual aura - occipital lobe
dysphasia and tinnitus - temporal lobe
pins and needles/transient cognitive disturbance (parietal lobe)
unsteadiness/dizziness/ collapse/hemiparesis (cerebellum, brainstem)
Amyloid spell presentation? Imaging?
Similar to migraine but significantly shorter lived (usually < 10 mins)
typically occur in older people with no previous history of migraine
most importantly the MRI scan here will show features of Cerebral Amyloid Angiopathy
Define apparent neurological deficit
neurological dysfunction in patients with chronic stroke (but seemingly good recovery) and residual areas of scar tissue (gliosis) at the site of previous brain damage
Symptoms become “apparent” due to underperformance of the gliotic tissue in the context of suboptimal physiology eg. infection, low blood pressure, hypoglycaemia, hypoxia, fatigue etc
List stroke chameleons? (ie different presentations of stroke)
Venous infarcts – gradual onset, preponderance for seizure activity
Small cortical strokes – peripheral nerve lesions
Limb shaking TIA – ?seizure
Occipital strokes – predominant presentation with confusion ?delirium (visual field examination should still reveal field loss)
Stroke amnestic syndromes
Stroke mimicking vestibular dysfunction
1st line radiological Ix for ?stroke?
non-contrast CT head scan
Hallmarks of early cerebral ischaemia on CT scan?
- Effacement – when CSF is displaced from the sulci due to mass effect pushing adjacent gyri together
- Loss of grey/white matter distinction
- Increased density of relevant blood vessel
Hallmark of intracerebral haemorrhage on CT?
Increased attenuation
How to describe cerebral bleeds?
location, size, age, presence or absence of mass effect or complications e.g. hydrocephalus.
What are the four P’s if stroke imaging?
Pipes - refers to exploration of the blood vessels - CT angiography or less usually MR angiography
Parenchyma - refers to exploration of tissue compromise in terms of cell death - non-contrast CT or MRI
Perfusion - CT angiography (measure of collateral circulation)
What is the ASPECTS score?
a 10-point quantitative topographic CT scan score used in patients with middle cerebral artery (MCA) stroke
2 CT slices used: One at the level of the basal ganglia and the other at the level of body of the lateral ventricles.
Used in revascularisation therapies for patient selection and outcome prediction
ASPECTs score < or equal to 5 - unlikely a patient will be accepted for thrombectomy
Poor ASPECTS - signifies a high likelihood of haemorrhagic complications.
What measures are used for perfusion scans?
cerebral blood flow - amount of blood perfusing a volume of brain tissue per unit time
mean transit time - the time it takes a volume of blood to traverse a region – increased due to vasodilatation in all hypoperfused/acutely ischaemic regions reflecting cerebral autoregulation.
Limitations of perfusion scanning?
- poor availability of the relevant hardware
- radiographer expertise to generate the images
- the longer time it takes to get images (eating away your “time to bolus/groin”)
List the assessment tools used in stroke
ABCD2 CHA2D2CASc HASBLED NIHSS OCSP classification ASPECTS Modified Rankin Scale ROSIER scale FAST test TOAST classification Barthel index
ABCD2 tool use?
Estimates the risk of stroke after a suspected transient ischemic attack (TIA).
High risk groups (ABCD2>4, multiple TIAs [>2 in previous 7 days], patients in AF or on anticoagulants) will require urgent review, i.e. within 24 hrs
CHA2DS2VASc use?
calculates stroke risk for patients with atrial fibrillation
0 -no treatment
1 - Male (consider anticoag). Female (No Tx)
2 or more - (offer anti coag
HASBLED tool use?
assess 1-year risk of major bleeding in patients taking anticoagulants with atrial fibrillation
score of >= 3 indicates a ‘high risk’ of bleeding, defined as intracranial haemorrhage, hospitalisation, haemoglobin decrease >2 g/L, and/or transfusion.
NIHSS use?
provides a quantitative measure of stroke-related neurological deficit
Used in assessing stroke severity, patient selection for various acute therapies, estimating prognosis and charting stroke recovery
Modified Rankin Scale use?
measure of global disability used to assess baseline function and evaluate outcomes and treatment impact after interventions
The rosier scale use?
Aim is to differentiate between stroke and stroke mimics
Need to exclude hypoglycaemia first
TOAST classification use?
Describes five sub types of ischaemic stroke.
large-artery atherosclerosis (embolus / thrombosis)*
cardioembolism (high-risk / medium-risk)*
small-vessel occlusion (lacunar)*
stroke of other determined aetiology *
stroke of undetermined aetiology
Barthel Index use?
used to measure disability
When to suspect vasculitis as cause of stroke?
the elderly lady
a few months of headache, weight loss, lethargy, pallor
with or without absent temporal pulses (temporal arteritis)
or the patient with past medical history of systemic lupus erythematosus (SLE)
When to suspect thrombophilia as cause of stroke?
the pregnant stroke patient
or the patient with a history of venous thromboembolism (VTE), multiple miscarriages or active cancer.
Causes of deep and lobar bleeds. How to clarify cause?
Deep - due to hypertension
Lobar - tend to be secondary - Causes include underlying vascular anomalies, mass lesions, and cerebral amyloid angiopathy
Interval imaging can be required to clarify cause of haemorrhage
Clinical and radiological signs of large artery atherosclerosis cause of stroke?
Signs of lesion in cortex (Aphasia, apraxia and neglect), subcortex, cerebellum or brainstem
Radiological: CT/MRI - >1.5cm lesion in cortex, subcortex, cerebellum or brainstem compatible with symptoms
CT scan negative when performed shortly after onset
Colour duplex images of precerebral arteries shows stenosis > or equal to in symptomatic major intra/extracranial arteries
Clinical and radiological signs of cardioembolic cause of stroke?
Signs of lesion in cortex (Aphasia, apraxia and neglect), subcortex, cerebellum or brainstem
Radiological: CT/MRI - >1.5cm lesion in cortex, subcortex, cerebellum or brainstem compatible with symptoms
CT scan negative when performed shortly after onset
ECG/TOE confirm high-medium risk of Cardio-embolic source
Clinical and radiological signs of small-vessel disease cause of stroke?
Signs of a lacunar syndrome
CT/MRI shows lacunar infarction (lesion <1.5cm)
CT scan negative when performed shortly after onset
Rare causes of stroke?
Watershed stroke: sudden ↓ in BP (e.g. in sepsis)
Carotid artery dissection
Vasculitis: PAN, HIV
Cerebral vasospasm 2O to SAH
Venous sinus thrombosis
Anti-phospholipid syndrome, thrombophilia
Cardiac causes of stroke?
AF: 4.5% /yr External cardioversion: 1-3% Prosthetic valves Acute MI: esp. large anterior Paradoxical systemic emboli Cardiac surgery Valve vegetations
Causes of hyperviscosity?
Polycythaemia
SCD
Myeloma
Brainstem infarcts presentations? Hemi- / quadr-paresis Conjugate gaze palsy Horner’s syndrome Facial weakness (LMN) Nystagmus, vertigo Dysphagia, dysarthria Dysarthria, ataxia ↓ GCS
Hemi- / quadr-paresis - Corticospinal tracts
Conjugate gaze palsy Oculomotor system
Horner’s syndrome Sympathetic fibres
Facial weakness (LMN) CN7 nucleus
Nystagmus, vertigo CN8 nucleus
Dysphagia, dysarthria CN9 and CN10 nuclei
Dysarthria, ataxia Cerebellar connections
↓ GCS Reticular activating syndrome
Brainstem infarcts presentations? Corticospinal tracts Oculomotor system Sympathetic fibres CN7 nucleus CN8 nucleus CN9 and CN10 nuclei Cerebellar connections Reticular activating syndrome
Corticospinal tracts Conjugate gaze palsy Oculomotor system Horner’s syndrome Sympathetic fibres Facial weakness (LMN) CN7 nucleus Nystagmus, vertigo CN8 nucleus Dysphagia, dysarthria CN9 and CN10 nuclei Dysarthria, ataxia Cerebellar connections ↓ GCS Reticular activating syndrome
Stroke differential’s?
Head injury ± haemorrhage ↑↓ glucose SOL Hemiplegic migraine Todd’s palsy Infections: encephalitis, abscesses, Toxo, HIV, HTLV Drugs: e.g. opiate overdose
Millard-Gubler Syndrome involvement? Presentation?
Pontine infarct
6th and 7th CN nuclei + corticospinal tracts - Diplopia LMN facial palsy + loss of corneal reflex Contralateral hemiplegia
Define locked in syndrome? Causes?
Pt. is aware and cognitively intact but completely
paralysed except for the eye muscles.
Causes: Ventral pons infarction: basilar artery
Central pontine myelinolysis: rapid correction of
hyponatraemia
Define TACS features
Contralateral hemiparesis/sensory loss AND homonymous hemianopia AND higher cortical dysfunction
Define PACS features
Contralateral hemiparesis/sensory loss of EITHER face, arm or legs
OR
Contralateral hemiparesis/sensory loss of >1 of face, arm or legs AND homonymous hemianopia OR cortical dysfunction
Define LACS features?
pure motor (>1 somatic area) OR pure sensory OR sensorimotor OR clumsy hand dysarthria OR ataxic hemiparesis
Define POCS features?
Isolated hemianopia, cerebellar or brainstem syndrome.
