stroke Flashcards
Define stroke?
Rapid permanent neuro deficit from cerebrovascular insult lasting >24hrs
what are the 2 types of stroke and what are the proportions of each one?
85% infarction/ischaemia
15% haemorrhagic
what are the causes of an ischaemic stroke?
- Thrombosis
- Can occur in small vessels (lacunar infarcts)
- Can occur in larger vessels (e.g. middle cerebral artery)
- Can arise in prothrombotic states (e.g. dehydration, thrombophilia)
- Emboli- majority of strokes
- From carotid dissection, carotid atherosclerosis, atrial fibrillation
- they can arise from venous blood clots that pass through a septal defect (e.g. VSD) and get lodged in the cerebral circulation
- Hypotension
If the blood pressure is below the autoregulatory range required to maintain cerebral blood flow, you can get infarction in the watershed zones between different cerebral artery territories
- Vasculitis
- Cocaine (arterial spasm)
- Smoking
- DM
- cholersterol
what are the causes of a haemorrhagic stroke?
HTN, Charcot-Bouchard microaneurysms, AVM
what are the risk factors for ischaemic and haemorrhagic stroke?
Older age
FH
HT - MOST IMPORTANT
Hypercholesterolemia
DM
Smoking
what are the pointers to a haemorrhagic stroke?
meningism, severe headache and coma within hrs
what are the pointers for an ischaemic stroke?>
carotid bruit, AF, past TIA, IHD
which underlying cause is important to investigate in a patient with stroke?
AF
what are the signs of a stroke affecting the anterior cerebral artery?
ACA: -> Frontal Lobe + Medial part of motor cortex
Contralateral hemiparesis
Lower > Upper Limbs
Disturbance of intellect, executive function, judgement and appropriate social behaviour
what are the signs of a stroke affecting the middle cerebral artery?
classic stroke
Facial weakness – contralateral side
Contralateral hemiparesis - arms> legs
Hemisensory loss (sensory cortex) - contralateral
Apraxia- If you think about it it makes sense to have this in lesions where the parietal lobe is affected, bc the parietal lobe is involved in bringing together and combining information needed to perform skillfull actions.
Hemineglect (parietal lobe)
If left sided will also cause aphasia - Receptive or expressive dysphasia (due to involvement of Wernicke’s and Broca’s areas)
Quadrantanopia (if superior or inferior optic radiations are affected)
what is the function and position of Wernicke’s area?
superior left temporal lobe
comprehension
What is the function and position of broca’s area?
left frontal lobe (inferior frontal gyrus)
speech productioin and articulation
what are the signs of a stroke affecting the posterior circulation?
homonymous contralateral hemianopia ( macular sparing)
visual agnosia (unable to recognise things)
prosopagnosia (inability to recognise faces)
why is damage to the visual cortex often macula sparing?
This is bc macular representation, found at the posterior pole of the occipital lobe, is disproportionately large. Because of the large macular representation, as well as the dual blood supply to the posterior occipital lobe (both PCA and MCA), sparing of the centre of the visual field is commonly found with occipital lobe lesions. (Macular sparring can also occur with lesions of the optic radiations or optic tracts. Even without macular sparing, an HH itself does not generally affect visual acuity. If visual acuity is reduced, an accompanying lesion involving the anterior visual pathway should be suspected).
what are the signs of a stroke affecting the cerebellum?
Ipsilateral signs = DANISH
Dysdiadochokinesia
Ataxia
Nystagmus – vertical
Intension tremor
Slurred, staccato speech
Hypotonia, Heel-shin test fail
what are the signs of lacunar infarcts?
Affecting the internal capsule or pons: pure sensory or motor deficit (or both)
Affecting the thalamus: loss of consciousness, hemisensory deficit
Affecting the basal ganglia: hemichorea, hemiballismus, parkinsonism
what are the investigations for a stroke?
URGENT CT HEAD (within 1hr), ECG, glucose
what is the management of a stroke?
<4.5hrs -> IV alteplase
>4.5 (or tPA CI) -> 300mg aspirin
A 70yo male with a PMH of HTN is brought in to A&E by ambulance, he is slurring his speech and cannot raise his left arm and hold it there, he has been like this for about 60 mins. What is the most important thing to do first?
300mg Aspirin
IV alteplase
CT Head
MRI Head
ECG
300mg aspirin
what are lacunar infarcts?
small infarcts (2–20 mm in diameter) in the deep cerebral white matter, basal ganglia, or pons, presumed to result from the occlusion of a single small perforating artery supplying the subcortical areas of the brain
A 70-year-old right-handed man is discovered by a family member to have difficulty speaking and comprehending spoken language, and an inability to raise his right arm. On examination, power is 2/5 in his right arm, 4/5 in his right leg and 5/5 in his left arm and leg.A CT head scan is performedand an ischaemic stroke is diagnosed.
What type of stroke is it?
A.Left total anterior circulation stroke
B.Right anterior cerebral artery stroke
C.Left middle cerebral artery stroke
D.Right middle cerebral artery stroke
E.Left brainstem stroke
A.Left middle cerebral artery stroke
what are the features of a total anterior circulation stroke?
All 3 of:
- Contralateral motor or sensory deficit
- Homonymous hemianopia
- Higher cortical dysfunction
what are the features of partial anterior circulation stroke?
Any 2 of:
- Contralateral motor or sensory deficit
- Homonymous hemianopia
- Higher cortical dysfunction
what are the features of a posterior circulation stroke?
Any of:
- Isolated homonymous hemianopia
- Brainstem signs
- Cerebellar ataxia
