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
What infarct leads to hemiparesis affecting the leg more than the arm and frontal lobe deficits such as apathy (loss of interest) and apraxia (inability to perform planned actions)
Anterior cerebral artery infarct
What are the features of brainstem infarcts?
- hemiparesis or tetraparesis
- sensory loss
- diplopia
- facial numbness
- facial weakness
- nystagmus, vertigo
- dysphagia (difficulty swallowing)
- dysarthria (difficulty speaking)
- ataxia, hiccups and vomiting
- horner syndrome
- coma, altered consciousness
Infarct in what region leads to
- right sided weakness
- involving face and arms more than legs?
- Left middle cerebral artery
Infarct of what region leads to left sided weakness involving face and arms more than legs.
- visual and/or sensory neglect
- denial of disability?
Right middle cerebral artery
- Homonymous hemianopia
- confudion
- memory impairment
Posterial cerebral artery
When should a CT scan be done within 1 hour for a stroke patient?
- if considering thrombolysis or patient is on anticaogulants or has a reduced conscious level.
What are the immediate invx for stroke?
- CT brain scan
- FBC
- Glucose
- clotting
What investiagtions are done within 24hrs for stroke?
- Routine blood tests e.g. FBC, ESR, glucose, clotting, lipids
- ECG and 24hr ECG (Atrial fibrillation)
- carotid doppler studies to identify high grade carotid stenosis that requires stenting (in anterior circulation stroke ie. ACA, MCA)
- CT / MRI to identify stenosis in posterior circulation.
What imaging is more sensitive for early changes of infarction?
- MRI (infarct)
- CT (haemorrhage)
Paramedics and members of the public are encouraged to make diagnosis of stroke using FAST - what does this stand for?
Face - sudden weakness of the face.
Arms - sudden weakness of one or both arms.
Speech - difficulty speaking, slurred speech.
Time - sooner the treament can be started the better.
When seeing to a stroke patient - what are the first steps you take ? hint RAAPID style
1) Airways : ensure pantency
2) Breathing : RR, O2 Sats —> Oxygen
3) Circulation: PR, BP, Cap refil —-> monitor BP
Why is thrombolysis of stroke patients important?
Thrombolysis within 4.5 hour time window significantly improves outcome - sifnificantly reduces chance of disability.
Thrombolysis in acute non haemorrhagic stroke?
- IV Recombinant tissue plasminogen activator
( ALTEPLASE 0.9mg/Kg over 1 h)
OR
- 300g/day aspirin if thrombolytic therapy contraindicated.
When is anticoagulation started for stroke?
Once haemorrhage excluded :
- 24hr after thrombolysis start 300mg aspririn for 2 weeks then switch to clopidogrel.
- atrial fibrillation
- sinus venous thrombosis
