Stroke - definitions, management and key concepts Flashcards
What are the FOUR sub-types of stroke
- Intrinsic vessel abnormality (e.g. atherosclerosis, inflammation, lipohyalinosis*, amyloid deposiiton, artierial disection, venous thrombosis)
- Embolism - embolus from the heart (most common) OR extracranial circulation lodges in an intracranial vessel
- Inadequate blood flow - the process may result from inadequate cerebral blood flow due to decreased perfusion pressure or increased blood viscosity.
- Vessel rupture – The process may result from rupture of a vessel in the subarachnoid space or intracerebral tissue.
List the sub-types of stroke that cause ischaemic strokes
vessel abnormality (e.g. atheroma), embolus, systemic hypoperfusion
List the sub-types of stroke that cause intracranial haemorrhages OR SAH
vessel rupture
How can thrombotic strokes be classified
1) large vessel disease
2) small vessel disease (smaller branches from arteries such as the basilar)
What are lacunes/lacunar strokes?
these are thrombosis in small arteries that can result in small deep infarcts
What is the sequale of an intracerebral haemorrhage?
bleeding directly into brain -> localised haematoma that gradually enlarges (like a snowball rolling downhill and accumulating snow).
where do intracerebral haemorrhages usually occur?
arterioles or small arteries
List the common causes of an intracerebral haemorrhage
Hypertension, trauma, bleeding diatheses, amyloid angiopathy, illicit drug use (mostly amphetamines and cocaine), and vascular malformations.
List 2 uncommon causes of intracerebral haemorrhage
- bleeding into tumours
- anerurysmal rupture
- vasculitis
In an intracerebral haemorrhage, what is the onset of neurological symptoms
usually GRADUAL - minutes to hours
What is the major cause of a SAH?
rupture of an arterial aneurysm
Describe the mechanism of a SAH if there is rupture of an aneursym
rupture of aneurysm into CSF under pressure > rapid spreading of blood > raised ICP
- HIGH risk of death if bleeding continues
- bleeding takes a few seconds but re-bleeding is common!
List 3 causes of a SAH that are not due to an aneurysm rupture
- vascular malformations
- bleeding diatheses
- trauma
- amyloid angiopathy
- illicit drug use
*of note bleeding less abrupt compared to aneurysmal bleeidng
What are the key symptoms/clinical presentation associated with a SAH?
- abrupt onset
- sudden, severe (worst) headache
- usually lateralised to the side of the aneurysm
- brief associated Sx of nausea, vomiting, seizure, brief LOC
*usually NO focal neurology unless there is bleeding into the CSF and brain at the same time
List 4 risk factors associated with cerebral venous thrombosis
- Prothrombotic conditions, either genetic or acquired
- Obesity
- Oral contraceptives
- Pregnancy and the puerperium
- Malignancy
- Infection
- Head injury and mechanical precipitants
What are the vessels involved in an ANTERIOR circulation stroke?
- anterior cerebral artery
- middle cerebral artery
Which cerebral artery territory do 2/3rds of ischaemic strokes occur?
middle cerebral artery
What is the dominant hemisphere in the brain?
LEFT - dominant
RIGHT - non-dominant
What does the term ‘apraxia’ mean?
inability to perform particular purposive actions, as a result of brain damage.
“dressing apraxia”
Describe the MCA stroke syndrome if the dominant (left) hemisphere was affected
- Right hemiparesis - Variable involvement of face and upper and lower extremity (if arm > leg likely MCA)
- Right-sided sensory loss in a pattern similar to that of the motor deficit -
- Right homonymous hemianopia
- Dysarthria
- Aphasia, fluent and nonfluent
- Alexia, Agraphia, Acalculia, Apraxia
Describe the MCA stroke syndrome if the non-dominant (right) hemisphere was affected
- Left hemiparesis - Same pattern as on right
- Left-sided sensory loss - Similar pattern that of the motor deficit
- Left homonymous hemianopia - Same pattern as on right
- Dysarthria
- Neglect of the left side of environment
- Anosognosia (unaware of condition)
- Asomatognosia (loss of awareness of a limb)
- Loss of prosody of speech
- Flat affect
Describe an ACA stroke syndrome
- hemiparesis - leg>arm
- abulia (unable to act decesively)
- disinhibition
- executive dysfunction
Describe a PCA stroke syndrome that would affect the medial temporal lobe
- deficits in long and short term memory
- behaviour alteration (agitation, anger, paranoia)
Describe a PCA stroke syndrome that affects the thalamus
– Contralateral sensory loss
– Aphasia (if dominant side involvement)
– Executive dysfunction
– Decreased level of consciousness
– Memory impairment
List two key features and two other features of a brainstem stroke syndrome
–Crossed sensory findings (e.g. ipsilateral face and contralateral body numbness) - KEY FEATURE
– Crossed motor findings (ipsilateral face, contralateral body) - KEY FEATURE
– Gaze-evoked nystagmus
– Ataxia and vertigo, limb dysmetria
– Diplopia and eye movement abnormalities
– Dysarthria, dysphagia
– Tongue deviation
– Deafness (very rare)
– Locked-in syndrome (can’t move any limb, can’t speak, can sometimes blink)
List two examples of a lacunar stroke syndrome
- pure motor
- pure sensory
- pure sensorimotor (i.e. no visual field deficit, no apraxia, no neglect etc)
List 3 features for how a cerebellar stroke may present
- ataxia
- nystagmus
- vertigo
- nausea
- headache
- rapid deterioration in consciousness
List 3 differential diagnoses for a stroke
- migrane with aura
- seizure with Todd’s paresis (seizure with hemiparesis post)
- functional
- metabolic/sepsis
What is the most important investigation for a stroke?
CT Brain non-contrast
What are the key findings on a CTB non-contrast for an ischaemic stroke?
- hyperdense artery (acute thrombus)
- clear hypodensity (likely it has been >4.5 hours)
- subtle loss of grey-white matter differentiation
With reference to an ischaemic stroke, what is the ischaemic penumbra?
Ischemic penumbra denotes the part of an acute ischemic stroke that is at risk of progressing to infarction but is still salvageable if reperfused. It is usually located around an infarct core which represents the tissue which has already infarcted or is going to infarct regardless of reperfusion.
Describe the utility of a CT perfusion scan
- used in ischaemic strokes (allows identification of viable tissue)
- Generally, it should be conceptually thought of as “the area of the brain with reduced perfusion” minus the “infarct core”
- improves diagnostic accuracy, helps answer the question of giving thrombolytics >4.5 hours +/- thrombectomy >6 hours
Describe the utility of CTA in an ischaemic stroke
- identifies the vessel occlusion or stenosis (i.e. atieology)
- helps target intervention
- can determine collateral
Describe the utility of a CTA in a haemorrhagic stroke
- identify an AVM
- ‘spot sign’ - marker of growth
What is the gold standard scan for diagnosing a stroke
MRI - in ischaemic stroke (within seconds!)
What is the definition of a TIA
NO lesion on brain imaging (diffusion MRI scan)
- often patient can recall the symptoms very clearly
What is the risk of stroke after a TIA?
~10% risk of stroke within the first week
What is the average duration of a TIA?
10 minutes
Outline the investigations for an ischaemic stroke
- arterial pathology - CT angiography (goes until cerebral vertex) and therefore better that carotid doppler
- Cardiac source
- ECG, Holter monitor, TTE, - Delayed MRI (~8 weeks post) - looking for things such as underlying mass lesion, AVM
Describe the evidenced based therapies for ischaemic stroke
- <4.5 hours - thrombolysis
- 4.5-9 hours - thrombolysis; CTP selected
- <6 hours - Thrombectomy
- 6-24 hours - thrombectomy; CTP selected
- Aspirin
- Hemicraniectomy *large infarct
Describe the evidenced based therapies for ischaemic stroke
BP control - SBP<140 mmHg
What are the key indications (2) for IV thrombolysis?
1) <4.5 hours (of note require definitive evidence of an ischaemic stroke
2) disabling defect
What are the absolute contraindications for IV thrombolysis
- intracranial haemorrhage
- extensive hypodensity on CT brain > re-take history (likely to be >4.5 hours)
- active non-compressible systemic bleeding
What are some relative contraindications for IV thrombolysis?
- recent GI/GU bleeding
- recent surgery
- recent trauma
*in these scenarios important to weigh risk vs. benefit - also consider - ?reversing DOACs, INR>1.7, plt>100
What should be BP and BSL be prior to giving thrombolytics?
- BP <185/105
- BSL>2.7
What is the main risk factor associated with thrombolytics?
symptomatic intracranial haemorrhage - of note in large infarcts, haemorrhagic transformation regardless is unavoidable
What is a side effect of thrombolytics outside of bleeding?
- orolingual oedema - usually contralateral to lesion
- onset within 15-105 mins
- treat with hydrocortisone
List two successful sites where a thrombectomy is likely to be beneficial
- ICA
- M1
- basilar
- ?proximal M2
What are the immediate management goals in an intracerebral haemorrhage?
- BP target of 140 (not lower)
- reverse anticoagulants ASAP
> warfarin - give prothrombinex + vitamin K
> dabigatran (idracurizinmab)
*avoid platelet transfusions
A migrane with aura is a common mimic of a TIA. What would rule in a migrane over a TIA
- prescence of a headache
- recurrence of symptoms i.e. parasthesia for example, instead of full resolution
If a patient post ischaemic stroke is NOT for thrombolytics or thrombectomy, what should be the appropriate treatment?
Anti-platelet agents - clopidogrel + aspirin
Describe blood pressure reduction of acute stroke specifically 1) BP target 2) rate of reduction
- All acute stroke patients should have their blood pressure closely monitored in the first 48 hours after stroke onset.
- patients with acute ischaemic stroke eligible for treatment with intravenous thrombolysis should have their blood pressure reduced to below 185/110 mmHg before treatment and in the first 24 hours after treatment.
- patients with acute ischaemic stroke with blood pressure > 220/120 mmHg should have their blood pressure cautiously reduced (e.g. by no more than 20%) over the first 24 hours
What are the key features of a TIA
- relatively sudden and maximal on impact
- can be attributed to a vessel or vascular territory
- focal in nature
What is the definition of a TIA?
Transient symptoms WITHOUT MRI evidence of a stroke
