Stroke

Question 1

What proportion of patients diagnosed with a ischemic stroke will statistically be alive in 5 years?

Answer 1

Approximately 50%

Question 2

What proportion of patients diagnosed with a TIA will go on to:
a) have a ischemic infarct within 3 months,
b) have another TIA,
c) have passed away, had an ischemic infarct or another TIA?

Answer 2

a) Approx 15%
b) Approx 9%
c) Approx 25%

Question 3

What is the most commonly used scale to rank disability from stroke?
Which categories are considered a good outcome from stroke? (0-6 scale).

Answer 3

Question 4

Total Anterior cerebral strokes include which main vessel?

Answer 4

Middle cerebral a.

Question 5

Embolic causes consitute approx 80% of all Total anterior cerebral strokes (TACS) and Partial anterior cerebral stroks (PACS) what are the two most common causes of the emboli?

Answer 5

1. Carotid stenosis / atherosclerosis.
2. Cardiac causes…. most commonly atrial fibrilation

Question 6

What is a tell tale sign of a posterior cerbral arterial stroke?

Answer 6

Mixed side involvement ie. CN involvement of the Left and motor / sensory deficit on the other side or other mixed side combinations ie cerebella dysfunction on one side without controlateral accompanying sensory / motor deficit (remember cerebella input is ipsilateral).

Question 7

What scale is more commonly used for measuring stroke nowdays? What consitutes a moderate stroke?

Answer 7

NIH Stroke Scale - a score 11 or above is considered a moderate stroke

Question 8

How do you divide stroke presentations into acute treatment groups were:
Group 1 may receive tPA +/- endovascular clot retrieval and
Group 2 receives only 300mg of Asprin.

Answer 8

Large vessel anterior strokes would be assessed for appropriateness for Group 1 acute treatment options.

Small vessel / posterior strokes would be provided with Group 2 treatment.

Question 9

Is a loss of consciousness (ALOC) common in stroke & TIA?

Answer 9

No - a significant occlusion is required to cause ALOC therefore a patient reporting ‘funny turn’ including ALOC is not a TIA.

Question 10

What are the TIA Commandments / what constitutes a TIA?

Answer 10

See image

Question 11

It is important to be able to localise / determine which vessel is implicated in stroke, why?
(2 reasons)

Answer 11

Large v small vessel - effects treatment (rapid intervention + secondary prevention vs only secondary prevention).
It is also important because if a vascular territory cannot be determined and deficits are more generalised / over many vascular territories then diagnositic mimics are more likely.

Question 12

What are Lucuna Strokes?

Answer 12

Small vessel strokes located deep within the cerebral hemispheres.
Signs of Lucuna strokes include at least 2/3 of:
1. Face, arm or leg without cortical or brainstem signs
2. RV in literature lecture provided minimal information

Question 13

What is Capsular Warning Syndrome?

Question 14

Pronator drift is a sign of Upper or Lower motor neuron damage?

Answer 14

Upper motor neuron damage causes pronator drift of the UL and extension of the LL - which over time sits in spastic contraction. Think evolution - paralyised arm gets tucked up across the chest & leg extends so it can still be walked on.

Question 15

How do you differentiate between central and peripheral vertigo? in an acute presentation and non-fluctuating and non-positional.

Answer 15

HINTS
1. Head impulse test (assesses occulomotor reflex) - over correction observed when patient is asked to keep focus on your nose and then you rapidly move their head to one side. The overcorrection is observed when the head is moved to the side of the lesion.
*Negative test - central nastagmus. Positive test - peripheral nastagmus.

2. Nastagmus
   *Nastagmus with changing directions (central vertigo).
   Peripheral nastagmus has fast beating (thats the side it is named after L / R) that continues to only have its fast beating face for either the L or Right only.
3. Skew deviation (vertical realignment of the eyes when one is covered and the other is fixated on an object when you uncover the covered eye to test the other eye you notice the covered eye realign vertically with the tested eye - central vertigo / central lesion).
   *Positive test - central vertigo.
   *Negative test - periperal vertigo.

Question 16

30% of stroke presentations are mimics. What are possible mimics of stroke?

Answer 16

Question 17

What are the most common stroke mimics (approximately 2/3rds of all mimics)?

Answer 17

Seizure
Sepsis
Toxic / metabolic (medication / drugs / electrolyte imbalances / glucose).
Space occupying lesion
Syncope / presyncope
Acute confusional state

Question 18

Signs that a stroke mimic may be more likely than a stroke include:

Answer 18

1. Unable to identify an onset,
2. Symptoms are not localisable to a vascular region,
3. Cognitive impairement,
4. Another system (ie resp) abnormalities observed,
5. Normal vascular exam ie. no AF, no hypertension, normal puses, no vascular disease).

Question 19

Acute treatment of Stroke includes (large vessel vs small vessel):

Answer 19

1. Large vessel (ie Anterior strokes TACS or PACS) Thrombolysis tPA or
   Clot retrieval.
2. Small vessel (ie Posterior stroke POCS)
   Asprin 300mg.

Question 20

What important non-pharmacological treatment requirements for acute stroke?
(5)

Answer 20

• Panadol for fever
• Manage blood glucose levels
• Manage hypertension gently - witholding antihypertensives or agressive antihypertensive managment is associated with poorer outcomes
• Avoid IDC unless absolutely necessary
• Continue normal medications.

Question 21

Secondary prevention in stroke includes (4 medication classes):

Answer 21

1. Antiplatelets - Asprin being first line; combined with Clopridogrel in the first 3 weeks post stroke only.
2. Anticoagulate if AF is a cause - after haemorrhage risk has past
3. Statins (highest dose tolerated).
4. Antihypertensives even if the patient is normally normo-tensive. ie Perindorpril

Question 22

What investigations should you use in suspected Anterior Stroke?

Answer 22

1. CTA - CT angiography from aortic arch to head increasingly used for acute presentations.
2. US - Carotids ok to ascertain surgical / further imaging candidates.
3. Ecocardiogram - Dilated L atrium may indicated AF even if holter is normal; PFO (patent foramen ovale) - closure can prevent further strokes esp in young candidates.
4. Holter monitoring very low yield - however provides documented evidence to justify anticoagulation. Required prior to anticoag therapy commencement.
5. MRI - can confirm diagnosis; can add information about mechanism of stroke; clarify stroke v’s mimic ie. multiple mini strokes v’s amyloid angiopathy.

Question 23

What investigations should you use in suspected posterior Stroke?

Answer 23

1. CTA - CT angiography from aortic arch to head increasingly used for acute presentations - required for small vessel imaging.
2. Cardioembolic work up is still important as constitutes the cause for approx 20% of POCS (echo & holter).
3. Rare anatomical varients can be cause.

Question 24

If a patient presents withsymptoms and has a stenosis of greater than 70% in a carotid a what is required?

Answer 24

Urgent operation -endarterectomy with the greatest benifit in the first 2 weeks. Not useful post 3 months.

Question 25

In terms of stroke, what does the Penumbra mean?

Answer 25

The salvagable tissue following a stroke - not the infarcted region.

Question 26

What is this image an example of?

Answer 26

This is a CTP (CT perfustion scan) it shows areas of the brain that are infarcted and areas at risk (the penumbra).

Question 27

How is a CTP scan useful in guiding treatment.

Answer 27

If a patient has a large penumbra / salvagable brain area tPA (thrombolysis) or clot retrieval is more likely to be performed = increased benifit vs risk.

Question 28

What are two common examples of tPA (thrombolysis medications) used in the acute treatment of anterior strokes?

Answer 28

Alteplase Tenectaplase

Question 29

What is the role of tPA medications in the treatment of acute anterior strokes.

Answer 29

Treatment does not alter death rates following large strokes (not better or worse); it does however reduce the Modfied Rankin scale of disability. Therefore it increases the survival of penumbra (salvagable tissue) thus reducing the affected tissue = functional deficits associated with the stroke.

Question 30

What is the number to treat for endovascular clot retrieval

Answer 30

4-6 individuals within 6 hours

Question 31

Does the performance of endovascular clot retrieval prevent the use of tPA?

Answer 31

No, currently thrombolysis is still used prior to the performance of endovascular clot retrieval.

Question 32

Which UL muscle groups are weak in upper motor neuron lesions?

Answer 32

Think: what happens to the UL with upper motor neuron lesions (arm pronates and sits across the chest)... therefore all the muscles that are weak in the UL with upper motor neuron lesions are those that fail to oppose this action... the extensors and abductors. Typical progression of muscle weakness: Finger extension > shoulder abduction (distal first then proximal) > elbow extensors / distal > proximal > middle. + strong flexors + Pronator drift = likely upper motor neuron

Question 33

Which LL muscle groups are weak in upper motor neuron lesions?

Answer 33

Flexor muscle weakenss of the lower limb with a pattern of proximal > distal > middle muscle groups.