Pathology of Cerebro-Vascular Disease Flashcards
(127 cards)
1
Q
What are the major blood vessels of the brain?
A
Right and left internal carotid arteries
Right and left vertebral arteries
Basilar artery
Right and left anterior cerebral arteries
Right and left middle cerebral arteries
Right and Left posterior cerebral arteries
Anterior communicating artery
Right and left posterior communicating arteries
2
Q
What does the right middle cerebral artery supply?
A
Left body strength
Left body sensation
3
Q
What does the left middle cerebral artery supply?
A
Right body strength
Right body sensation
Language
4
Q
What does the right posterior cerebral artery supply?
A
Perception of the left visual field
5
Q
What does the left posterior cerebral artery supply?
A
Perception of the right visual field
6
Q
What is the cerebellum supplied by (Arteries)?
A
Posterior inferior, anterior inferior and superior cerebellar arteries
7
Q
Presentation of brain aneurysm
A
Severe headache
Vomiting
Extremely sudden presentation
Possible coma
8
Q
Investigation of brain aneurysm
A
Unenhanced CT
LP
9
Q
What does LP stand for?
A
Lumbar puncture
10
Q
Where do most intracranial aneurysms arise from?
A
Branch points of the circle of willis
11
Q
Treatment of ruptured intracranial aneurysm
A
Endovascular coil embolisation
Surgical clipping
12
Q
Prevalence of aneurysms
A
2%
13
Q
Complications of intracranial aneurysm
A
Hydrocephalus
Vasospastic infarcts
Disability
14
Q
Lobes of the brain
A
Frontal
Parietal
Temporal
Occipital
15
Q
Do the veins of the brain accompany the arteries?
A
No
16
Q
Definition of stroke
A
Focal neurological deficit (loss of function affecting a specific region of the CNS) due to disruption of blood supply
17
Q
Pathological mechanism of stroke
A
Interruption of supply of O2 and nutrients, causing damage to brain tissue
18
Q
Causes of interruption to supply of oxygen to brain causing stroke
A
Vessel wall abnormality - atheroma - vasculitis - outside pressure Blood flow - decreased - increased BP Blood constitutents - thrombosis of arteries and rarely veins - bleeding due to anticoagulation, reduced platelets and clotting factors
19
Q
3 main causes of localized interrupted blood supply
A
- ATHEROMA AND THROMBOSIS of the artery causing ischaemia
- THROMBOEMBOLISM causing ischaemia
- RUPTURED ANEURYSM of a cerebral vessel causing haemorrhage
20
Q
Internal carotid artery thrombosis typically causes ischaemia where?
A
Middle cerebral artery territory
21
Q
Definition of ischaemia
A
A relative or absolute lack of blood supply in a tissue or an organ
22
Q
What does TIA stand for?
A
Transient ischaemic attack
23
Q
What is the viability of the tissues in a TIA?
A
Still viable tissues
24
Q
What is the viability of the tissues in a stroke?
A
Infarcted tissue
25
Pathogenesis of ischaeimc stroke
Brain very sensitive to oxygen ischaemia
A few minutes hypoxia or anoxia will cause brain ischaemia
Can lead to infarction
26
What is a localized area of brain death called?
Regional cerebral infarct
27
Histology of infarcted brain tissue
Loss of neurones
Foamy macrophages
Repair process leading to gliosis
28
What is gliosis the CNS equivalent of?
Fibrosis
29
What two factors can cause an aneurysm to form?
Weakening of wall
| HTN
30
2 common sites of ruptured vessels causing haemorrhagic stroke
Basal ganglia
- microaneurysms form in HTN patients
Circle of willis
- berry aneurysms form in HTN patients
31
Causes of generalised problem with blood supply or hypoxia affecting the brain
1. Low O2 in blood
- CO poisoning
- near drowning
- resp arrest e.g. pneumonia
2. Inadequate supply of blood (blood flow not occurring)
- cardiac arrest with immediate resolution
- Hypotension
- brain swelling e.g. trauma due to compressed vessels
3. Inability to use O2 (RARE)
- e.g. cyanide poisoning
32
What are watershed zones?
Areas of the brain that are poorly perfused
33
What % of strokes occur in patients over 65 y/o?
75%
34
Two types of stroke
Ischaemic
| Haemorrhagic
35
Causes of ischaemic stroke
```
Large artery atherosclerosis (35%)
Cardioembolic e.g. AF (25%)
Small artery occlusion e.g. lacune (25%)
Undetermined/cryptogenic (10-15%)
Rare causes (<5%)
- arterial dissection
- venous sinus thrombosis
```
36
What % of strokes are ischaemic?
85%
37
What % of strokes are haemorrhagic?
15%
38
Types of haemorrhagic stroke
Primary intracerebral haemorrhage 70%
Secondary haemorrhage 30%
- SAH
- AV malformation
39
Stoke risk increases with what?
Age
40
What is the public awareness campaign for stroke?
FAST
- Facial weakness
- Arm weakness
- Speech problems
- Time to call 999
41
Risk factors for stroke
```
HTN
Smoking
DM
Cholesterol
Diet
Activity
High BMI / Sedentary lifestyle
Alcohol
Previous stroke
Older
Male
Family history
Impaired cardiac function
- recent heart attack
- AF
Oral contraceptives (with oestrogen)
HRT
Hypercoagulable states
- malignancy
- genetic
```
42
What is the most important modifiable risk factor for stroke?
HTN
43
Where does HTN tend to cause the damage in stroke?
Small end arteries in the basal ganglia and brain stem
44
Why does increased serum lipid levels lead to increased risk of stroke?
Blood vessel wall atheroma
| Increased plasma level of low density lipoprotein (LDL) results in excessive amounts of LDL within the arterial wall
45
What contributes to LDL-C deposition in arterial walls?
HTN
Smoking
DM
46
What colour is brain tissue on CT?
Black
47
What colour is CSF on CT?
Black
48
What colour on bone on CT?
White
49
Which of MRI and CT is easier to pick up smaller strokes?
MRI
50
What arteries make up the anterior circulation to the brain?
2 internal carotid arteries
- 2X ACA
- 2 MCA
51
What arteries make up the posterior circulation to the brain?
2 vertebral arteries - 1 basilar
- 3 pairs of cerebellar arteries
- 2 posterior cerebral arteries
52
Symptoms of ACA occlusion
Contralateral
Paralysis of foot and leg
Sensory loss over foot and leg
Impairment of gait and stance
53
Symptoms of MCA occlusion
Contralateral
- paralysis of face/arm/leg
- sensory loss of face/arm/leg
Homonymous hemianopia
Gaze paralysis to opposite side
Loose visual fields on same side as the paralysis
Aphasia if stroke on dominant (left) side
Unilateral neglect and agnosia for half of external space if non dominant stroke (usually right side)
54
Symptoms of damage to the left hemisphere
Hemiplegia
Homonymous hemianopia
Dysphagia
55
Symptoms of damage to the right hemisphere
Left hemiplegia
Homonymous heminaopia
Neglect syndromes (agnosia)
56
Types of neglect syndromes (agnosia)
Visual
Sensory
Anosagnosia
Prosphanosia
57
What is anosagnosia?
Denial of hemiplegia - unawareness that have had stroke
58
What is prosophanosia?
Failure to recognise faces
59
What is a feature of main lacunar stroke syndromes?
Devoid of 'cortical signs
| Affects deep pathways in the brain so dont cause cortical syndromes e.g. no dysphagia, neglect, hemianopia
60
What does a lacunar stroke syndrome usually present as?
Weakness
Clumsiness
Numbness
Ataxic hemiparesis
61
Symptoms of posterior circulation damage to the brain
Depends on where affected
- brain stem
- cerebellum
- thalamus
- occipital and medical temporal lobes
62
Symptoms of brainstem dysfunction
```
Coma
Vertigo
Nausea and vomiting
CN palsies
Ataxia
Hemiparesis
Hemisensory loss
Crossed sensorimotor deficits
Visual deficits
```
63
Types of stroke
Total anterior circulation stroke (TACS)
Partial anterior circulation stroke (PACS)
Lacunar stroke (LACS)
Posterior circulation stroke (POCS)
64
Which of the types of stroke has the worst prognosis?
TACS
65
Which of the types of stroke has the best prognosis?
LACS / POCS
66
What % of patients with a TIA have stroke recurrence within the 1st 2 weeks?
10%
67
Treatment of TIA
Antiplatelets
Anti HTNs
Statins
Endarterectomy
68
Causes of TIA
```
Athersclerotic narrowing
Embolic-cardiac source (AF, recent MI)
Hypercoagulable state
Arterial dissection
Venous sinus thrombosis
```
69
What should acute ischaemic stroke therapies do?
Restore blood supply
Prevent extension of ischaemic damage
Protect vulnerable brain tissue
70
What does TPA stand for?
Tissue plasminogen activator
71
What does TPA do?
It is involved in the breakdown of blood clots
72
What is the strict criteria for TPA use?
< 4.5 hours from symptom onset
Disabling neurological deficit
Symptoms present > 60 mins
Consent obtained
73
Exclusion criteria for IV TPA
```
Anything that increases the possibility of haemorrhage
- blood on CT scan
- recent surgery
- recent episodes of bleeding
- coagulation problems
BP > 125 systolic or > 110 diastolic
Glucose < 2.8 or > 22 mmol/L
```
74
What does the benefit of TPA decline with?
Time
75
What is the effective treatment in symptomatic internal carotid artery stenosis?
Carotid endarterectomy
76
What can be used in secondary prevention of stroke?
```
Anti HTNs
Anti platelets
Lipid lowering agents
Warfarin for AF
Carotid endarectomy
```
77
After the acute phase has settled, what is the management of acute stroke?
Prevention of stroke recurrence
Prevention of complications related to stroke
Rehabilitation
Re-integration into the community
78
What are the objectives of stroke care?
Reduce mortality
Reduce residual disability amongst survivors
Improve psychological status of patients and care givers
Improve patient/care giver knowledge
Maximize quality of life
79
Investigations for stroke
```
Routine blood tests
- FBC
- glucose
- lipids
- ESR
CT or MRI
ECG
Carotid doppler USS
Cerebral angiogram/venogram
Hypercoagulable blood screen
```
80
Definition of stroke
Is the sudden onset of focal or global neurological symptoms caused by ischemia or haemorrhage and lasting more than 24 hours
81
What % of strokes are ischaemic?
85%
82
Definition of TIA
Sudden onset of focal or global neurological symptoms if the symptoms resolve within 24 hours
83
How quickly do most TIAs resolve?
1 - 60 mins
84
Definition of ischaemia
Failure of the cerebral blood flow to a part of the brain, caused by an interruption of the blood supply to the brain
85
How much of the metabolic rate does the brain use at rest?
20%
86
Pathology of stroke
Varying degrees of hypoxia (decreased O2)
Hypoxia stresses the brains metabolism - this is especially important in ischaemic pneumbra
If prolonged the hypoxia leads to anoxia
Anoxia leads to infarction (complete cell death leading to necrosis)
87
Definition of anoxia
No oxygen
88
What further damage can occur after necrosis in stroke?
Oedema
| Secondary haemorrhage
89
What arteries do lacunar infarcts involve?
Perforating arteries around the internal capsule, thalamus and basal ganglia
90
A stroke of the anterior cerebral artery will cause what?
Contralateral hemiparesis and sensory loss
| LL > UL
91
A stroke of the middle cerebral artery will cause what?
Contralateral hemiparesis and sensory loss, UL > LL
Contralateral homonymous hemianopia
Aphasia
92
A stroke of the posterior cerebral artery will cause what?
Contralateral homonymous hemianopia with macular sparing
| Visual agnosia
93
A stroke of the basillar artery causes what?
Locked in syndrome
94
What is webers syndrome and what does it result in?
Stroke of the branches of the posterior cerebral artery that supply the midbrain
Ipsilateral CN III palsy
Contralateral weakness of upper and lower extremity
95
What does a stroke of the posterior inferior cerebellar artery?
Ipsilateral facial pain and temp loss
Contralateral limb/torso pain and temp loss
Ataxia
Nystagmus
96
What does a stroke of the anterior inferior cerebellar artery cause?
Symptoms similar to posterior inferior cerebellar artery stroke but also
ipsilateral facial paralysis and deafness
97
What does a stroke of the retinal / ophthalmic artery result in?
Amaurosis fugax
98
What does a lacunar stroke present with?
Isolated hemiparesis, hemisensory loss or hemiparesis with limb ataxia
99
What do lacunar strokes have a strong association with?
HTN
100
What is conduction aphasia?
Speech is fluent but repetition is poor
Aware of the errors they are making
Comprehension is normal
101
What causes conduction aphasia?
Stroke affecting the arcuate fasiculus (the connection between wernickes and brocas)
102
What % of patients with intracranial venous thrombosis have sagittal sinus thrombosis?
50%
103
Features of intracranial venous thrombosis
Headache (may be sudden onset)
| Nausea and vomiting
104
Presentation of sagittal sinus thrombosis
Seizures
Hemiplegia
Headache
N and V
105
Causes of cavernous sinus syndrome
Cavernous sinus thrombosis
Local infection (e.g. sinusitis)
Neoplasia
Trauma
106
Presentation of cavernous sinus thrombosis
Headache
N and V
Periorbital oedema
Ophthalmoplegia (6th nerve damage occurs before 3rd and 4th)
If trigeminal nerve involvement - hyperaesthesia of upper face and eye pain
Central retinal vein thrombosis
107
What does lateral sinus thrombosis typically cause?
6th and 7th CN palsies
108
Treatment of ischaemic stroke due to occlusion of anterior circulation presenting < 4.5 hours ago
Thrombolysis AND thrombolectomy
109
What is the tool to assess patients with stroke symptoms in an acute setting and what does this stand for?
ROSIER
| Recognition of stroke in the emergency room
110
Patients following an ischaemic stroke should receive what?
Aspirin 300mg once daily for 14 days before considering anticoagulant treatment
111
If have had TIA or a stroke, how long can you not drive for?
4 weeks
112
Secondary prevention of stroke
1st line - clopidogrel
| 2nd line - aspirin in combination with modified release dipyridamole
113
Criteria for thrombectomy
1. 6 - 24 hours. If potential to salvage brain tissue - as shown by CT perfusion or diffusion weighted MRI sequences showing limited infarct core volume AND confirmed occlusion of proximal anterior circulation
2. ASAP and within 6 hours. If confirmed proximal anterior circulation stroke demonstrated by CTA or MRA
114
What does an anterior cerebral artery stroke cause and NOT cause?
Would CAUSE - leg weakness
| Would NOT CAUSE - Face weakness or speech impairment
115
Criteria for carotid endarectomy
Suffered stroke or TIA in the carotid territory and are not severely disabled
Who have carotid stenosis > 70% (ECST criteria) or > 50% (NASCET criteria)
116
What is the first line radiological investigation for suspected stroke and what does it rule out?
Non contrast CT head
| Rules out haemorrhagic event
117
What tests must be done if < 55 y/o with no obvious cause of the stroke?
Autoimmune and thrombophilia screening
118
What is the scale tool used to measure disability or dependence in activities of daily living in stroke patients?
Barthel index
119
What is characteristic of brain stem infarcts?
'Crossed findings' - with cranial findings IPSILATERAL to the lesion and motor or sensory findings on the CONTRALATERAL side of the body
120
What is webers syndrome?
Midbrain stroke syndrome
- involves fascicles of the oculomotor nerve resulting in an ipsilateral CN III palsy and contralateral hemiplegia or hemiparesis
121
What is the most commonly survived stroke which affects the brainstem? What is this syndrome called?
Stroke affecting the posterior inferior cerebellar artery (PICA) - called lateral medullary syndrome
122
Presentation of lateral medullary syndrome
Facial and contralateral body loss of sensation along with nystagmus and ataxia
123
What is a feature of lacunar infarct?
Isolated hemisensory loss
124
What does pontine haemorrhage commonly occur secondary to?
Chronic HTN
125
Presentation of pontine haemorrhage
```
Life threatning
Reduced GCS
Quadraplegia
Miosis
Absent horizontal eye movements
```
126
A stroke of where can cause aphasia?
Dominant hemisphere middle cerebral artery strokes
127
What does a cerebellar stroke present similarly to?
Vestibular neuritis
