Stroke part 2 Flashcards
what does ischaemic vs haemorrhagic stroke look like on CT?
- infarct = dark
- fresh blood = white
what are lacunes?
small infarcts caused by occlusion of small penetrating aterial branches
How could a bone fracture cause a stroke?
a fat emboli after a long bone fracture could cause vessel occlusion —> infarct
What accounts for 1 in 5 strokes below the age of 40?
dissection of carotid or vertebral artery.
can follow trivial neck trauma or hyperextension e.g. whiplash, exercise
Apart from trivial neck trauma or hyperextension, what could be the cause of artery dissection in patient s under the age of 40 leading to stroke?
connective tissue disorders e.g. marfan’s syndrome
how does carotid or vertebral artery dissection lead to stroke?
- blood penetrates the subintimal vessal wall
- forms a false lumen
- THROMBOSIS within the TRUE lumen due to thromboplastin release —–> EMBOLUS from site of dissection —–> stroke
What symptoms / signs could indicate carotid / vertebral artery dissection as cause of stroke?
- pain in neck / face
1% of strokes are venous. What increased the risk of thrombosis in the intracranial venous sinuses?
- pregnancy
- dehydration
- malignancy
- hypercoagulable state
What is the result of thrombosis in the intracranial venous sinuses?
- cortical infarction
- seizures
- raised ICP
TIAs are usually caused by microemboli - what are the sources for these emboli?
1) Cardiac (AF, MI, Valve disease)
2) Thrombi - aortic arch, carotid, vertebral
What could be the cause of a fall in cerebral perfusion leading to TIA?
- Cardia dysarrhythmias
- postural hypotension
- decreased flow through atheromatous arteries
What are the major risk factors for stroke/
1) hypertension **
2) smoking **
3) alcohol
4) high cholesterol **
5) Atrial fibrillation ***
6) Obesity
7) diabetes
8) severe carotid stenosis **
What intervention results in the greatest stroke risk reduction ?
Anticoagulation for Atrial fibrillation
hypertension control
what are the most common clinical features of TIAs?
- Hemiparesis (weakness on one side of the body)
- Aphasia
inability to comprehend and formulate language
What is often the first sign of internal carotid artery stenosis?
TIA causing Amaurosis Fugax
(sudden transient loss of vision in one eye)
True or false :
-consciousness is preserved in TIA
True
How would you distinguish focal epilepsy from TIA?
Positive features of epilepsy:
- limb shaking
- loss of consciousness
- tongue biting
- urinary incontinence
What is limb shaking TIA a sign of?
Severe carotid stenosis causing transient focal cerebral hypoperfusion.
How can you differentiate between a migraine aura and a TIA in elderly people?
Migraine aura can occur on its own causing:
- speech, visual disturbances and ataxia.
- Headache is common in migraine but rare in TIA.
- postive visual phenomena such as shimmering are typical of migraine but not seen in TIA.
- onset of symptoms slower in migraine aura than TIA
- limb weakness is rarely due to migraine
What is used to stratify stroke risk in the first 2 days of a TIA?
ABCD2 score
- Age >60
- BP >140 / 90
- Clinical features (unilateral weakness, isolated speech disturbance, other)
- Duration of symptoms > 60mins, 10-9 mins or less than 10 mins.
- Diabetes?
***score of <4 is minimal risk, score of >6 is high risk within 7 days of TIA
What investigations are done for TIA?
- Doppler of internal carotid arteries
- Cardiac Echo
- ECG + 24tape
- MRI brain
- MR or CT angiography
What is the treatment for TIA?
- if CT excludes haemorrhage give immediate thrombolytic therapy. e.g. Tissue Plasminogen Activator
- surgery - stenting of high grade carotid stenosis.
What does complete MCA occlusion result in?
- contralateral hemiplegia
- contralateral facial weakness
- hemisensory loss
- eye deviated to affected side
- aphasia
- hemianopia
What is the consequence of occlusion of lenticulostriate perforating arteries?
infarction of deep sub-cortical structures e.g internal capsule —> hemiplegia and hemisensory loss
