Lecture 16- Stroke 1/2 Flashcards
1
Q
Stroke
A
“a neurological deficit attributed to an acute focal injury of the central nervous system (CNS) by a vascular cause, including cerebral infarction, intracerebral hemorrage (ICH), and subarachnoid hemorrhage (SAH)”
2
Q
TIA
A
“a transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction.”
3
Q
Types of stroke
A
- Ischaemic (85%)
- thromboembolic
- Haemorrhagic (10%)
- Intracerebral
- Subarachnoid
- Other (5%)
- Dissection
- Venous sinus thrombosis
- Hypoxic brain injury
4
Q
Causes of stroke
In the young…
A
- Vasculitis
- Thrombophilia
- Subarachnoid haemorrhage
- Venous sinus thrombosis
- Carotid artery dissection e.g. via near strangling or fibromuscular dysplasia
5
Q
causes of stroke in
In the old…
A
- Thrombosis in situ
- Athero-thromboembolism e.g. from carotid arteries
- Heart emboli (e.g. atrial fibrillation, infective endocarditis or MI)
- CNS bleed associated with hypertension, head injury, aneurysm rupture)
- Sudden blood pressure drop by more than 40 mmHg
- Vasculitis e.g. giant cell arteritis
- Venous sinus thrombosis
6
Q
Risk factors
A
7
Q
Classic stroke syndrome
A
a list of “classical” stroke syndromes arranged by arterial territory e.g. cerebral artery perfusion territorirs
8
Q
label this circle of willis
A
9
Q
Anterior cerebral artery
A
- Arises as one of the branches of the internal carotid
- Doesn’t supply many anterior structures
- Supplies medial areas of the brain
- grey and white matter distribution
10
Q
grey matter dist of ACA
A
- Grey matter distribution: ACA loops back all over the superior surface of the corpus callosum and sends multiple branches to the medial aspect of the cerebral hemisphere (mostly frontal and parietal lobes)
11
Q
white matter distribution of the ACA
A
- White matter distribution: as the ACA loops around the CC it will send lots of branches into the white matter of the CC
12
Q
example of areas affected in a stroke affecting the ACA
A
- Medial areas of the sensory and motor homunculus affected
- Paracentral lobules
- Corpus callosum
- Frontal lobe
13
Q
ACA stroke sensory and motor deficits
A
-
Medial areas of the sensory and motor homunculus affected
- Contralateral lower limb more affected
14
Q
ACA stroke and paracentral lobules
A
-
Paracentral lobules containing M centre- found in the medial portion of the frontal lobe
- Incontinence
15
Q
ACA stroke and corpus callosum
A
-
Corpus callosum
- Split brain syndrome- Both hemispheres cant communicate meaning limbs wont work together
16
Q
ACA stroke and frontal lobe
A
-
Frontal lobe
- Personality changes
- Apraxia changes- coordinating motor plans e.g. doing laces up
17
Q
Middle cerebral artery
A
- Arise as continuations of the internal carotids
- Run laterally and go over the insular cortex and energy through sylvian fissure onto the surface of the cerebral hemisphere
- Branches of the MCA = lenticular striate arteries which supplies the basal ganglia
- Supplies more lateral aspects of the cerebral hemispheres
- Frontal
- Parietal
- Temporal
18
Q
Proximal MCA occlusion
A
- Will affect everything downstream too e.g. lenticulate striate arteries, inferior and superior arteries of the MCA
- Common –> internal carotid directly supplies the MCA
- Usually more common on right side because left parietal region has dual bilateral blood supply
19
Q
signs of a proximal occlusion
A
face and arms–> lateral part of homonculus affwcted
aphasia if left sided (only found in left hemisphere) due to problem with either brocas, wernickes or arcuate fasiculus
20
Q
Examples of affected areas with proximal MCA occlusion
A
- Problems with the lateral motor homunculus
- Problems with the lateral sensory homunculus
- Problems with vision
- Problems with speech
- Neglect-like symptoms
21
Q
proximal MCA occlusion and problems with the lateral motor homunculus
A
Contralateral upper limb and face motor problems
22
Q
with proximal MCA occlusion we predict contraltateral and upper limb and face motor problems but usually see
A
- a complete hemiparesis à flaccid à spastic hemiparesis
- Why? Because the MCA also supplies the internal capsule (lenticulate striate arteries) which carries fibres from the face, arm and leg
23
Q
proximal MCA occlusion and problems with the lateral sensory homunculus
A
- Upper limbs and face sensory problems
- Like likely to be full body sensory problems
- Because the posterior parts of the internal capsule are supplies by the PCA- therefore mismatch between sensory and motor deficits
24
Q
proximal MCA occlusion and problems with vision
A
- Contralateral homonomous hemianopia
- Destruction of both superior and inferior optic radiations as they run through the temporal and parietal lobes
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proximal MCA occlusion and problems with speech
* Broca’s aphasia (frontal)
* Reduction in speech fluidity
* Wernicke’s aphasia (temporal/parietal)
* Problems with understanding language
* If proximal occlusion= both Broca’s and Wernicke’s
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brocas aphasia
frontal lobe
reduction in speech fluidity
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Wernicke’s aphasia
(temporal/parietal)
Problems with understanding language
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**proximal MCA occlusion and Neglect-like symptoms**
* Lesions which affect the **right** parietal lobe
* Pt has issue with acknowledging what is going on, on the LHS
* E.g. may only eat half of the meal
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**Lenticulostriate arteries occlusion**
* Due to small emboli coming up from the internal carotid
* Cause lacunar stroke (\<15ml) cause destruction of small areas in the internal capsule and basal ganglia
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**Examples of affected areas with _lenticulate artery occlusion_**
* **_U_**sually smaller deficits
* Deficits depends where the lacunar stroke occurs
* **In the thalamus**= sensory deficits
* In the **internal capsule**
* E.g. could occur on the posterior arm of the internal capsule and cause motor problems with the leg, trunk or arm
* E.g. At the genu= face motor problems
* If in both thalamus and internal capsule= **mixed sensory and motor deficits**
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if lenticulate artery occlusion in the thalamus
sensory deficit
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if lenticulate artery occlusion is in the internal capsule
* E.g. could occur on the posterior arm of the internal capsule and cause motor problems with the leg, trunk or arm
* E.g. At the genu= face motor problems
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distal MCA occlusions
think in terms of superior division and inferior division problems
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distal MCA occlusion: **Superior division problems**
* Supplies the lateral frontal lobe e.g. primary motor cortex and the Broca’s area
* Examples of superior division problems
* Contralateral face and arm weakness
* Broca’s (Expressive) aphasia
* Only if occurs on the LHS
36
distal MCA occlusion: Inferior division problems
* Examples of inferior division problems e.g. **primary sensory cortex and Wernicke’s area**
* Contralateral face and arm loss of sensation
* Wernicke’s aphasia
* Homonomous hemianopia if both optic radiations are damaged or a quadrantanopia if just one radiation is affect
* Without macula sparing
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Posterior cerebral artery
* Posterior areas of the brain, thalamus and midbrain supply
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**Examples of affected areas with _PCA occlusions_**
* **Contralateral Homonomous hemianopia with macula sparing**
* If MCA damaged- everything will be destroyed (doesn’t matter if we have a contralateral supply by the PCA to the macula)- the damage is done
* If PCA occlusion causes damage to the optic radiations, you still have contralateral supply to macula from the MCA therefore macula sparing
* **Contralateral sensory loss due to thalamic involvement**
* More likely to be PCA which supplies the oxygen to the thalamus where the sensory (and motor) pathways go through
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why is homonomous hemianopia with PCA occlusion macula sparing
* If PCA occlusion causes damage to the optic radiations, you still have contralateral supply to macula from the MCA therefore macula sparing
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