stroke/case 5 Flashcards
What does the brain use for respiration? what type of respiration?
O2 and glucose
aerobic respiration: no lactate build up
What happens with occlusion of the anterior cerebral artery?
- contralateral hemiparesis
- sensory loss of contralateral leg and perineum
What parts of the brain does the middle cerebral artery supply?
- lateral sulcus and travels along lateral surface of frontal, temporal and parietal lobes
- subcortical areas including internal capsule and neostratium
What happens with occlusion of the middle cerebral artery?
- contralateral hemiparesis
- sensory loss of contralateral upper limb
- contralateral homonymous hemianopia
- aphasia
What happens with occlusion of the posterior cerebral artery?
-contralateral homonymous hemianopia with macular sparing
-visual agnosia
(-Weber’s syndrome: branches of the PCA that supply midbrain: ipsilateral CN3 palsy + contralateral weakness of upper and lower extremity)
What parts of the brain does the posterior cerebral artery supply?
curves around midbrain to reach medial surface of cerebral hemisphere
–> inferior surface of temporal lobe + occipital lobe
What happens with occlusion of the basilar artery?
- ‘locked-in’ syndrome
- respiratory failure: death
What is a lacunar stroke?
type of ischemic stroke that occurs when blood flow to one of the small arteries deep within the brain
What are symptoms of lacunar strokes?
What are the risk factors?
Common sites?
- isolated hemiparesis, hemisensory loss or hemiparesis with limb ataxia
- strong association with hypertension
- common sites: basal ganglia, thalamus and internal capsule
What are functional consequences of damage to motor cortex?
movement
What are functional consequences of damage to frontal lobe?
-Broca’s aphasia
-disinhibition
-perseveration
-anosmia
-inability to generate a list
(judgement, foresight, voluntary movement, smell)
What are functional consequences of damage to temporal lobe?
- Wernicke’s aphasia
- superior homonymous quadrantonopia
- auditory agnosia
- prosopagnosia
What are functional consequences of damage to brainstem?
swallowing, breathing, heartbeat, wakefulness centre (+other involuntary functions)
What are functional consequences of damage to cerebellum?
- midline lesions: gait and truncal ataxia
- hemisphere lesions: intention tremor, past pointing, dysdiadokinesis, nystagmus
What are functional consequences of damage to parietal lobe?
- sensory inattention
- apraxias
- astereognosis (tactile agnosia)
- inferior homonymous quadrantanopia
- Gerstmann’s syndrome (lesion of dominant parietal): alexia, acalculia, finger agnosia and rich/left disorientation)
What are functional consequences of damage to occipital lobe?
- homonymous hemianopia (with macular sparing)
- cortical blindness
- visual agnosia
What brain areas do the anterior cerebral artery supply?
superior and medial surfaces of frontal and parietal lobes
What is the WHO definition of stroke?
-sudden onset of acute focal ‘occasionally global) neurological deficit probably due to a pathological process in blood vessels
What are stroke risk factors?
- BP (especially in haemorrhage strokes)
- cholesterol
- blood sugar/diabetes
- atrial fibrillation
- obesity
- smoking
What is the FAST test?
Face
Arms
Speech
Time
What is the percentage of ischemic strokes compared to haemorrhage strokes
85%
15%
What are causes of ischemic strokes?
- blood clot causing occlusion: carotid atherosclerosis (carotid bifurcation), embolism of plate rich clot further i cerebral vessel
- atrial fibrillation
What must be looked at in terms of blood diffusion:perfusion for treatment via thrombolysis?
it mismatch (perfusion loss but not much diffusion loss) then brain tissue can be salvaged
What is the neurovascular unit and what does it consist of?
- close interaction of brain cells with the brain endothelium and the extracellular matrix contributes to the maintenance of brain homeostasis and functions
- consists of :
- ->astrocytes, microglia, neurones
- -> endothelial cells and pericytes
- -> extracellular matrix
What are the different post stroke complications?
- paralysis/motor control
- sensory disturbances
- dysphagia
- language problems
- memory impairments
- depression/anxiety
- fatigue
What is the initial damage in stroke? When does it take place?
energy failure, excitatoxicity, depolarisation, necrosis, oxidative stress (causing mitochondrial damage)
-within minutes to hours
What happens in secondary damage in stroke? When does it happen?
inflammation, programmed cell death
hours to days
What is excitotoxicity?
over activation of NMDA receptors by glutamate allowing excess calcium into cell causing it to swell and rupture
(inhibitory cells die quite quickly)
How would you describe progression of injury between the tissue and the MRI scan?
- upon presentation: no perfusion of tissue (doesn’t show in brain tissue but it shows in MRI scan)
- one day after presentation: loss of brain tissue
- 6 days after presentation: not much difference n MRI but more tissue loss
What do you measure stroke severity with?
-National Institute of stroke scale
the higher the scale, the more severe the stroke
What is the initial treatment of ischemic stroke? What are the complications
- -thrombolysis: tissue plasminogen activator (alteplase) by IV bolus (10%) plus 1 hour infusion (90%) with 4.5h
- complications: haemorrhage, anaphylaxis - endovascular thrombectomy: removal of clot
BUT time dependent benefit: within 6 hours of onset
What treatment do you give if the patient presents with haemorrhagic stroke?
- PCC (prothrombin complex concentrates) to reverse bleeding
- management of BP
- lower blood pressure: beta blockers and GTN
- sometimes minimally invasive surgery
What is secondary treatment for stroke?
- blood pressure
- aspirin 300 mg 14days then clopidogrel 75mg
- exclude AF (if have AF: anticoagulants)
- statins
- exclude DM
- exclude carotid stenosis (if have stenosis more than 50% can get carotid endarterectomy)
- speech and language therapy (dysarthria + swallowing)
- physiotherapy
- occupational therapy
- pschomotor
How do you diagnose stroke?
MRI
CT
signs (ROSIER and National Institute of Stroke scale, FAST)
What are the different types of aphasia?
- Wernicke’s (receptive) aphasia
- Broca’s (expressive) aphasia
- conductive aphasia
- global aphasia
What happens in Wernicke’s (receptive) aphasia?
- due to lesion of superior temporal gyrus
- comprehension is impaired
- sentences that make no sense, word substitution and neologisms but speech remains fluent
What happens in Broca’s (expressive) aphasia?
- due to lesion of the inferior frontal gyrus
- speech is non-fluent, laboured, and halting
- comprehension is normal
What happens in conductive aphasia?
- ususally due to stroke affecting arcuate fasciculus (connection between Wernicke’s and Broca’s area)
- speech fluent but repetition is poor
- aware of errors they are making
- comprehension is normal
What happens in global aphasia?
large lesion affecting all 3 of the areas (Wernicke’s, Broca’s and arcuate fascicles)
–> severe expressive and receptive aphasia
