Stroke & TIA Flashcards
What is the definition of stroke?
a sudden onset, focal neurological deficit of presumed vascular origin that lasts for more than 24 hours
What is the definition of a TIA?
a sudden onset, focal neurological deficit of presumed vascular origin that resolves within 24 hours
What are the 2 different types of stroke?
haemorrhagic:
caused by vascular rupture
ischaemic:
caused by vascular occlusion or stenosis
vascular rupture causes blood to leak into the brain tissue
How can ischaemic strokes be further subdivided?
thrombotic:
due to atherosclerotic plaque formation
embolic:
due to a blood clot that has originated from elsewhere (e.g. AF)
What are the 6 major risk factors for stroke?
- smoking
- obesity
- hypertension
- diabetes
- high cholesterol
- old age
What are some less common risk factors for stroke?
- polycythaemia
- AF
- excessive alcohol consumption
- heart valve disease
- clotting disorders
- peripheral arterial disease
What are the general signs and symptoms of stroke?
Why does this vary?
stroke has an ACUTE onset
- limb weakness / numbness
- facial drooping
- speech difficulty
- dizziness
- loss of coordination / balance
- visual changes
presentation is influenced by which area of the brain is affected
What are the roles of the frontal and temporal lobes?
frontal lobe:
* personality / behaviour
* planning / decision making
* concentration
* primary motor cortex (precentral gyrus)
temporal lobe:
* understanding speech
* interpreting auditory + olfactory sensations
What are the roles of the parietal and occipital lobes?
parietal lobe:
* comprehension / language
* primary somatosensory cortex (postcentral gyrus)
* sensory functions
occipital lobe:
* vision
* processing visual information + storing visual memories
What are the roles of the brainstem and cerebellum?
brainstem:
* breathing / heart rate
* swallowing
* arousal / wakefulness
cerebellum:
* coordination + movement
* balance
Why does the affected artery produce different symptoms of stroke?
it depends on the vascular territory supplied by that artery and the function of that area
What key regions are supplied by the anterior cerebral artery (ACA)?
- medial + superior parts of frontal lobe
- anterior parietal lobe
What are the symptoms of anterior cerebral artery stroke?
- contralateral hemiparesis that tends to affect the lower limbs > upper limbs / face
- behavioural changes
What are the regions supplied by the middle cerebral artery (MCA)?
lateral parts of the frontal, parietal and temporal lobes
What are the associated signs of MCA stroke?
- contralateral hemiparesis affecting upper limbs / face > lower limbs
- contralateral hemisensory loss
- apraxia
- aphasia
- quandrantopias
What are the roles of Broca’s and Wernicke’s area?
Broca’s area:
* responsible for the production of speech
* damage to this area results in expressive aphasia
Wernicke’s area:
* responsible for the comprehension of speech
* damage to this area results in receptive aphasia
remember B for “buccal” - meaning mouth - where speech is produced
remember W for “what do you mean”
What regions are supplied by the posterior cerebral artery?
- occipital lobe
- inferior part of temporal lobe
What are the consequences of a posterior cerebral artery stroke?
- contralateral homonymous hemianopia
- visual agnosia (difficulty recognising familar faces / objects)
What parts of the brain are supplied by the posterior circulation?
- brainstem
- cerebellum
- occipital lobes
What is the result of a posterior circulation stroke?
- isolated hemianopia
- signs related to the brainstem and cerebellum
this includes:
* vertigo / imbalance
* slurred speech
* unilateral limb weakness
* double vision
What mnemonic can be used to remember signs of cerebellar damage?
What is significant about signs of cerebellar damage?
DANISH
D - dysdiadochokinesia
A - ataxia (gait + posture)
N - nystagmus
I - intention tremor
S - slurred, staccato speech
H - hypotonia / heel-shin test
- there is also decreased consciousness
cerebellar lesions produce IPSILATERAL SIGNS
What is meant by a lacunar stroke?
a subcortical stroke that occurs secondary to small vessel disease affecting the deep parts of the brain
there is no loss of higher cerebral functions
What is the most common classification system for ischaemic stroke?
Bamford classification
categorises strokes based on initial symptoms / clinical signs
this classification system is based on clinical findings alone and not imaging
What are the 4 different types of stroke according to the Bamford classification?
- total anterior circulation stroke (TACS)
- partial anterior circulation stroke (PACS)
- posterior circulation syndrome (POCS)
- lacunar stroke (LACS)
What is a total anterior circulation stroke (TACS)?
What criteria must be present for diagnosis?
a large cortical stroke affecting areas of the brain supplied by both the middle and anterior cerebral arteries
ALL 3 MUST BE PRESENT:
* unilateral weakness of the face, arm AND leg
* homonymous hemianopia
* higher cerebral dysfunction (dysphasia / visuospatial disorder)
What is required for diagnosis of a partial anterior circulation stroke (PACS)?
this is a less severe form of TACS, in which only part of the anterior circulation has been compromised
TWO must be present:
* unilateral weakness and/or sensory deficit of the face, arm and leg
* homonymous hemianopia
* higher cerebral dysfunction (dysphasia / visuospatial disorder)
higher cerebral dysfunction ALONE is classified as PACS
What is meant by posterior circulation syndrome (POCS)?
damage to an area of the brain supplied by the posterior circulation (e.g. cerebellum / brainstem)
What is the diagnostic criteria for POCS?
- cranial nerve palsy and contralateral motor/sensory deficit
- bilateral motor/sensory deficit
- conjugate eye movement disorder
- cerebellar dysfunction
- isolated homonymous hemianopia
only ONE of these signs needs to be present for diagnosis
What is the diagnostic criteria for lacunar stroke?
- pure sensory stroke
- pure motor stroke
- sensori-motor stroke
- ataxic hemiparesis
only ONE is needed for diagnosis
If someone is having a suspected stroke, what is the immediate investigation?
What should be calculated in the meantime?
urgent non-contrast CT head within 1 hour to rule out haemorrhage
(a normal CT does NOT rule out ischaemic stroke)
while CT is being arranged, the ROSIER score is calculated (risk of stroke in emergency room)
How can a haemorrhagic stroke be identified on CT?
the blood appears bright white (dense) on CT
the longer it is present, the darker it becomes
What blood tests would you want to do in a stroke patient?
Serum glucose:
hypoglycaemia can mimic stroke
U&Es:
to exclude hyponatraemia
Cardiac enzymes (troponin):
to exclude concomitant MI
FBC:
to exclude anaemia or thrombocytopenia prior to possible initiation of thrombolysis or anticoagulants
What other investigations would be performed in suspected stroke?
- ECG
- monitor vital signs for deterioration
Once haemorrhage is excluded, what does the management for ischaemic stroke depend on?
the time from symptom onset
thrombolysis is contraindicated after 4.5 hours
What is the treatment for ischaemic stroke if it has been < 4.5 hours since symptom onset?
thrombolysis with IV alteplase
followed by aspirin (300mg oral)
this is a recombinant tissue plasminogen activator, (r-TPA)
endovascular interventions can be beneficial in large vessel occlusions
What is the management for ischaemic stroke if it has been > 4.5 hours since symptom onset?
aspirin 300mg, oral
this is also used when thrombolysis is contraindicated
What are the contraindications for thrombolysis?
- symptom onset > 4.5 hours
- CT reveals acute trauma / haemorrhage
- symptoms suggestive of SAH
- high INR, APPT, PT
When might thrombectomy be performed in acute ischaemic stroke?
- confirmed occlusion of the proximal anterior circulation
- potential to salvage brain tissue as shown by CT perfusion
- taking into account pre-stroke functional status
After initial treatment for a stroke, where should they be referred to and why?
all patients should be referred to the stroke unit MDT
- swallowing assessment - to avoid aspiration pneumonia / choking
- VTE prophylaxis
- GCS monitoring
- early mobilisation / rehabilitation
- MDT approach
When might CT angiogram be performed in a stroke patient?
it should be performed in ALL patients with acute ischaemic stroke and suspicion of a large vessel occlusion who would be candidates for endovascular thrombectomy
Why might a carotid doppler be performed in an acute stroke patient?
to look for signs of carotid artery stenosis
carotid endarterectomy recommended if >70% occlusion
What is involved in the secondary prevention of stroke?
antiplatelet therapy
- patients with AF are offered warfarin prophylaxis
- non-AF patients continue 75mg aspirin for 2 weeks
- then switch to lifelong 75mg clopidogrel
What lifestyle changes are advised as part of secondary prevention?
- avoid heavy drinking
- tight glycaemic control
- maintenance of a healthy BMI
- reduce salt intake
- aerobic activity
What is the management for haemorrhagic stroke?
- immediate referral for neurosurgical evaluation
- patients either go straight to surgery
- or to ICU for monitoring / support
Why is it important to review medications in haemorrhagic stroke patients?
- anticoagulants / antithrombotic drugs can make bleeding worse
- they must be discontinued or reversed
DO NOT adminster thrombolysis / aspirin in suspected haemorragic stroke
How does a TIA differ from a stroke?
- it has the same aetiology and presentation as a stroke
- BUT the symptoms resolve within 24 hours
What scoring system is used for TIA and why?
ABCD2 score
used to estimate the stroke risk in a TIA patient
if the patient scores 4 or more - referral to stroke specialist
What is the immediate management for a suspected TIA?
300mg aspirin STAT
if presenting within 7 days of episode:
* specialist review within 24 hours
if presenting after 7 days of episode
* specialist review within 7 days
What is involved in secondary prevention after someone has a TIA?
- clopidogrel 75mg orally once daily
- high intensity statin (e.g. atorvastatin orally once daily)
- BP control with antihypertensive if necessary
What are the investigations for TIA?
Bloods:
* FBC, U&Es, clotting profile, glucose, cholesterol
ECG:
* may reveal AF or MI
Urgent non-contrast CT head:
* ONLY if patient is known to be taking anticoagulants or has a bleeding disorder to exclude haemorrhage
CT is NOT first line, unlike in stroke
