Blood supply to the brain and Strokes Flashcards
stroke
is a clinical syndrome characterised by sudden onset of rapidly developing focal or global neurological disturbance which lasts more than 24 hours or leads to death.
Transient ischaemic attack (TIA)
transient (less than 24 hours) neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without evidence of acute infarction.
- 24hours historically chosen arbitrarily, most <15mins.
THINK FAST
ischaemic attack - this accounts for around 80’% of strokes
- Thrombosis
- Embolism
- Hypoperfusion
Carotid stenosis secondary to plaque could lead to
emboli
what are the areas first effects by hypo perfusion
watershed areas, these are the areas of the brain that are the most distal to the blood supply
what is the penumbra
this is the ‘halo’ that surrounds an area of the brain that has died due to a stroke, it is the area of the brain that is considered to still be saveable
LACS
pure motor, pure sensory, sensorimotor, ataxic hemiparesis
POCS
Brainstem, cerebellar and/or isolated homonymous hemianopia
TACS
triad of hemiparesis (or hemisensory loss), dysphasia (or other higher cortical functions) and homonymous hemianopia
PACS
2 of the fractures of TACS or isolated dysphasia or parietal lobe signs ( e.g. inattention, agnosia, apraxia, agraphaesthesia and Alexia)
Anterior cerebral artery ischaemic stroke-
- Often occur in conjunction with MCA infarction in the setting of a proximal occlusion
- Contralateral leg weakness and/or sensory loss (may be present and mild in the contralateral leg)
- Typically, there is leg > arm weakness
Middle Cerebral Artery stroke
- Contralateral hemiplegia (upper extremity > lower extremity)
- Contralateral Hemisensory loss
- Conjugate eye deviation (looking toward the side of the lesion)
- Contralateral hemianopia
Middle Cerebral Artery Stroke- Language
If entire hemisphere- Global aphasia- can’t speak or understand speech
• Inferior division of MCA supplies the lateral surface of the temporal lobe and inferior parietal lobe
Middle Cerebral Artery Stroke- Language if Brocas area is effects
Broca’s aphasia- ‘non fluent aphasia’- Broken speech understands speech, struggles to get words out.
Middle Cerebral Artery Stroke- Language if Wernikes area is effects
Wernikes aphasia- ‘fluent aphasia’- Word salad- normal sounding speech that doesn’t make sense, doesn’t
comprehend speech.
Middle Cerebral Artery stroke- Hemineglect
Inattention/neglect of the contralateral side of space. The right hemisphere attends to both left and right-sided stimuli, but more strongly to stimuli on the left, the left hemisphere only attends to stimuli on the right side.
• Anosognosia- lack of insight into the neurological deficits
Posterior cerebral artery stroke-
• Hemianopia- potentially macula sparing
• Dominant hemisphere:
-Alexia without agraphia- patients can write but cannot read -Visual agnosia- difficulty naming objects
• Non-dominant hemisphere:
-Prosopagnosia (difficulty recognizing familiar faces; even their own face in a mirror)
• Bilateral:
-Cortical blindness (termed Anton syndrome). Patients can confabulate
Basilar Artery Occlusion
• Coma/hypersomnolence
• Quadriplegia
• Diplopia (gaze palsies/internuclear ophthalmoplegia)
• Sometimes “locked-in” state -awake but quadriplegic, unable to
speak, sometimes able to blink/move eyes
• Bulbar symptoms- facial weakness, dysphagia, dysarthria, or
First described in literature Darolles 1875
dysphonia
Lacunar Stroke
Small infarct, typically defined as less than 1.5 cm occlusion of a small penetrating branch artery
• These syndromes lack cortical signs such as aphasia, agnosia, neglect etc
• Examples of affected arteries: Lenticulostriate branches MCA, thalamoperforators from PCA
• Pure motor- contralateral hand/arm weakness: -E.g damage to Internal capsule/corona radiata
• Pure sensory- contralateral arm/leg sensory loss -E.g damage to thalamus
Brainstem syndromes
- Caused most often by occlusion of the branches of veterbral/basilar artery for example aneterior inferior cerebellar
- There are many eponymously named brainstem syndromes- you do not need to learn them- just be aware they exist
- If mixed signs- think brainstem lesion
Lateral Medullary syndrome
Ipsilateral ataxia, vertigo, nystagmus, and nausea. This results from the involvement of the inferior cerebellar peduncle and vestibular nuclei. This is often the most disabling clinical feature of this condition.
scale used for strokes
National Institutes of Health Stroke Scale (NIHSS)
Stroke Mimics
The 5 ‘S’s
- Seizures
- Sepsis
- Syncope
- SOL (tumour, subdural) • Somatisation
CT perfusion imaging
• assessment of patients presenting in the late time windows, eg 6 to 24 h, or when there is an unknown/unwitnessed time of stroke onset such as a wake-up stroke
Secondary Prevention
Anti-thrombotics:ClopidogrelorAspirin+Dipyridamole • ✓ In atrial fibrillation: Warfarin or NOAC (dabigatran,
rixaroxaban, apixaban)
Carotid endarterectomy (CEA)
Considered for all symptomatic stroke/TIA patients (without severe disability; MRS 60% provided > 5 yr life-expectancy & peri-operative stroke/death rate < 3%
Subarachnoid Hemorrhage
• ‘Like being hit in the back of the head’, ‘worst headache of
life’, sudden LOC, occasionally almost immediate death • 1/3 die 1/3 severely disabled 1/3 recover well
Subarachnoid Hemorrhage- most often caused by
aneurysm
