Stroke

Question 1

Explain what two types of stroke are [2]

Answer 1

Ischaemic Stroke: occlusion of an intracranial or neck vessel leading to ischaemia and subsequent infarction of brain tissue.

Haemorrhagic Stroke: Bleeding into or around the brain. Classically due to a burst aneurysm. Sub divided into
- intracerebral haemorrhage
- Subarachnoid haemorrhage

Question 2

What are the two main mechanisms that cause ischaemic stroke? [2]

Answer 2

1. Thrombosis: The formation of a blood clot in an artery normally at the site of an atheroma or atherosclerosis.
2. Embolism: An embolus blocks a downstream artery after originating from somewhere else in the body, usually having broken off from a thrombus.

Question 3

Explain how atherosclerosis causes ischaemic stroke

Answer 3

Endothelial damage allows lipoproteins and monocytes to adhere to the vessel wall and enter the intima.

Monocytes differentiate into macrophages and engulf the lipoprotein and become known as foam cells.

Further accumulation of cholesterol and foam cells forms a fatty streak.

Foam cells release pro-inflammatory cytokines which leads to smooth muscle cell proliferation. and connective tissue to deposition in the fatty streak.

These changes form a fibrous cap over the lipid core.

A necrotic core can form due to the lack of capillaries.

Plaque rupture removes the endothelium which exposes the fibrous cap leading to thrombosis and occlusion of the artery

Question 4

What is a watershed ischaemic stroke? [1]

Answer 4

Sudden BP drop by more than 40mmHg, then there is low cerebral blood flow = global ischaemia leading to ‘watershed infarcts’ in vulnerable areas of cortex between boundaries of different arterial territories

brain ischemia that is localized to the vulnerable border zones between the tissues supplied by the anterior, posterior and middle cerebral arteries

Question 5

When is common to see watershed stroke?

Answer 5

Sepsis patients

Question 6

What is the most important risk factor for Haemorrhagic stroke? [1]

Answer 6

Hypertension !

Question 7

Which type of haemorrhagic stroke are the following CTs?

Answer 7

Question 8

Whats the difference between Intracerebral haemorrhage vs Subarachnoid haemorrhage (SAH)?

Which causes a thunderclap headache?

Answer 8

Intracerebral haemorrhage is bleeding into the brain parenchyma: basal ganglia particularly effected

SAH is bleeding into the subarachnoid space. thunderclap headache

Question 9

S & S for stroke?

Question 10

Label A-C

Answer 10

A: anterior cerebral artery
B: middle cererbral artery
C: internal carotid artery

Question 11

draw the circle of willis xxx

Answer 11

Question 12

label A-D [4]

Answer 12

A: vertebral artery
B: superior cerebellar artery
C: posterior cerebral artery
D: basilar artery

Question 13

S&S of stroke?

Answer 13

F – Face
A – Arm
S – Speech
T – Time (act fast and call 999)

Confusion
Aphasia (Expressive vs Receptive)
Dizziness and loss of balance
Visual disturbance

Question 14

Which artery is most common to have a stroke in? [1]

Answer 14

Middle cerebral artery

Question 15

Risk factors for stroke?

Answer 15

Risk factors:
- Male
- Black or Asian
- Hypertension
- Past TIA
- Smoking
- Diabetes mellitus
- Increasing age
- Heart disease (valvular, ischaemic)
- Alcohol
- Polycythaemia, thrombophilia
- AF - stasis of blood in poorly contracting atria = thrombus formation

Question 16

Primary prevention for stroke? [4]

Answer 16

Primary prevention:

• Cholesterol: statin
• AF: anticoagulation
• Good diabetic control
• BP: antihypertensives

Question 17

What are the 3 overlying causes of cellular death in stroke? [3]

Answer 17

Mechanical compression
Cerebral Oedema
Excitotoxicity

Question 18

How does mechanical compression cause cellular damage in stroke?

Answer 18

Raised ICP causes cerebellar tonsils through the foramen magnum = cerebellar herniation and results in compression of brainstem and upper cervical spinal cord

Question 19

How does cerebral oedema cause cerebral cellular death?

Answer 19

Reduced ATP limits the function of Na pumps which usually remove Na from neurons.

An increased Na concentration in the neurons leads to more water entering and the generation of cerebral oedema. Raises intracerebral pressure

Question 20

Excitotoxicity

Question 21

What is penumbra?

Answer 21

The term used for the reversibly injured brain tissue around ischemic core; which is the pharmacological target for acute ischemic stroke treatment. The goal to treat ischemic stroke is to salvage the penumbra as much and early as possible

Question 22

What is first thing you do when suspect stroke patient? [1]

Answer 22

Get them to have a non-contrast CT scan: rule out haemorrhage stroke

Question 23

How would you treat acute stroke? [2]

Answer 23

Thromboylsis:
- using drug - Alteplase
- Must occur within 4.5 hours of onset
- haemorrhage has to be excluded

Mechanical thrombectomy:
- endovascular removal of a thrombus from a large artery.

Question 24

What drug would you initially give to non-haem stroke? [1]

Answer 24

Aspirin !

Question 25

What is the definition of a TIA?

Answer 25

A sudden loss of function, usually only lasting minutes, with complete recovery. No time limit for how long a TIA as long as as symptoms recover.

Question 26

What would clinical features be of a TIA in:

i) Anterior circulation?
ii) Posterior circulation?

Answer 26

Anterior circulation
(Carotid System)
* Amaurosis Fugax (transient loss of vision in one eye (curtain coming down over eye))
* Aphasia
* Unilateral weakness
* Hemisensory loss
* Hemianopic visual loss

Posterior Circulation
* (Vertebrobasilar system)
* Diplopia, vertigo, vomiting
* Choking and dysarthria
* Ataxia
* Hemisensory loss
* Bilateral visual loss

Question 27

How would you manange an acute TIA?

Answer 27

300mg Aspirin
Refer urgently to TIA clinic (to be seen within 24 hours). In clinic: work out if was stroke or not.
Might do ECG to see if have AF