Stroke 2

Question 1

what is TOAST system?

Answer 1

aetiological classification in ischaemic strokes and TIA (not for bleeds)
guesses what has causes the stroke/TIA

Question 2

what are the 5 classifications in TOAST?

Answer 2

1. cardioembolic (usually AF)
2. large vessel atheroembolic (due to atherosclerosis in large vessels usually at bifurcations or areas of turbulance)
3. small vessel (usually thrombotic)
4. infarcts due to other determined causes (dissection, hypoperfusion, vasospasm etc)
5. cryptogenic (unknown cause)

Question 3

cortical symptoms means its been a large or small vessel stroke/TIA?

Answer 3

large

Question 4

what are the dominant hemisphere cortical signs?

Answer 4

mainly communication related (dysphasia etc)
agraphia
acalcula 
finger agnosia 
right/left orientation

Question 5

non-dominant (right) hemispheric cortical signs?

Answer 5

hemispatial neglect
changes in personality
sensory inattention (cant identify simultaneous sensory stimuli - can be sensory or visual)
spatial disorientation
constructional apraxia
dressing apraxia

Question 6

what causes small vessel stroke?

Answer 6

thrombosis

aka lacunar stroke

Question 7

what happens in dissection?

Answer 7

tear in innermost layer of artery wall, blood gets underneath and is forced into artery wall
the pressure causes the tear to get bigger and a flap of tunica intima forms which flaps around in vessel lumen causing turbulent blood flow and increased risk of clot formation

Question 8

what is a watershed infarct?

Answer 8

where the patient has a long term stenosis in an artery but this usually overcome by higher BP so blood still gets through and doesnt cause any problems
watershed infarcts happen when something happens causing a drop in BP (haemorrhage, acute AF etc) so the pressure is no longer enough to give sufficient flow through the stenosed vessel meaning only a small amount of blood can get through
this results in the centre of the area supplied by the artery being fine but the periphery being infarcted

Question 9

common clinical scenario for watershed infarct?

Answer 9

post-surgery where they might have went into AF or had large blood loss etc

Question 10

embolic stroke is usually wedge shaped, is a watershed stroke the same?

Answer 10

no

usually get a line of infarct between 2 arterial territories

Question 11

brain venous system?

Answer 11

veins and venous sinuses

Question 12

venous sinus thrombosis?

Answer 12

thrombosis in venous sinuses in brain

can cause damage to brain due to pressure and can cause infarcts as pressure affects perfusion of tissues

Question 13

ischaemic vs venous stroke on imaging?

Answer 13

both are ischaemic
classical ischaemic stroke shows no blood on imaging
venous stroke shows some haemorrhagic changes due to high pressure which causes some blood to seep out of vessels into tissues

Question 14

what is a paradoxical embolism?

Answer 14

embolism from venous clot passes through patent foramen ovale, into arterial circulation and into the brain causing a stroke

Question 15

how is a venous clot managed?

Answer 15

anti-coagulation

Question 16

what 3 settings are anti-coagulants used in ischaemic stroke disease?

Answer 16

cardio-embolism (AF)
paradoxical embolic stroke
venous stroke

Question 17

left sided heart pressure (Pressure in aorta)?

Answer 17

systemic BP

Question 18

right sided pressure (pulmonary artery pressure)?

Answer 18

8-15

Question 19

why is paradoxical embolic stroke so rare?

Answer 19

bc the pressure in the left atrium is so much higher than the right atrium so it would be very difficult for a clot to pass from low pressure to high pressure

Question 20

when might a paradoxical embolic stroke happen?

Answer 20

if the pressure in the right atrium gets higher to exceed left pressure (even if only for a few seconds)
acute rise in right atrial pressure ie PE or valsalva manoeuvre (remodelling happens to compensate in chronic pulmonary hypertension)

Question 21

what daily activities are basically valsalva manoeuvres so can increase right heart pressure?

Answer 21

weight lifting
vomiting
sneezing
straining when constipated
child birth

Question 22

classic picture of paradoxical embolic stroke?

Answer 22

young person with no vascular risk factors

Question 23

how is paradoxical embolic stroke managed?

Answer 23

close the patent foramen ovale

manage PE if thats the primary cause of the stroke

Question 24

what is a TIA?

Answer 24

transient neurological symptoms without any brain damage
true TIAs only really last a few mins, if symptoms last a few hrs then theyve probably had a stroke and just recovered due to neuroplasticity (area of brain is dead and wont recover but other areas of the brain take over function of that part)

Question 25

important first investigation in TIA/stroke?

Answer 25

CT
must work out if haemorrhage or infarct
also want to work out if embolic or thrombotic (history + imaging)