Stroke

Question 1

What is a stroke?

Answer 1

Sudden death of brain tissue due to lack of oxygen and glucose delivery arising from an interrupted blood supply (ischaemia)

Question 2

How many deaths per year are caused by strokes in the UK?

Answer 2

152,000

1 every 3.5 minutes

Question 3

How many first time strokes were there worldwide in 2010/

Answer 3

17 million

1 every 2 seconds

Question 4

Whats the difference in men and women and the likelihood of getting a stroke?

Answer 4

Men are 25% higher risk of having stroke compared to women

However, incidence of stroke in women is higher due to longer lifespan

Question 5

How many stroke survivors are there in the UK?

Answer 5

Around 1.2 million

Question 6

How many strokes are fatal within the first 30 days?

Answer 6

1 in 8

Question 7

How many strokes are fatal within the first year?

Answer 7

1 in 4

Question 8

What are modifiable risk factors towards a stroke?

Answer 8

Hypertension- single most important modifiable risk factor
Smoking
Waist to hip ratio
Diet (i.e. obesity)
Physical inactivity
Diabetes
Alcohol intake (>30 drinks per month)
Psychological factors (stress, depression)
Cardiac causes (Atrial fibrillation, Previous transient ischaemic attack)
Apoliopoproteins
o All 10 combined about for 90% of risk of stroke

Question 9

What are non-modifiable risk factors towards a stroke?

Answer 9

Age- most important risk factor
Gender
Ethnicity- Black and south Asian origin

Question 10

What is stroke the leading cause of?

Answer 10

Disability

Question 11

How many stroke survivors are dependent on others?

Answer 11

More than half
42% will be independent
22% have mild disability
14% have moderate disability
10% have severe disability 
12% have very severe disability

Question 12

What are the stroke warning signs?

Answer 12

Face
Arms
Speech
Time

Question 13

What are the stroke subtypes?

Answer 13

15% primary intracerebral haemorrhage
5% subarchanoid haemorrhage
80% ischaemic

Question 14

What are the subtypes of ischaemic stroke?

Answer 14

Thrombotic stroke

Embolic stroke

Question 15

What is a thrombotic stroke caused by?

Answer 15

A blood clot in an artery supplying the brain

Question 16

What is the most common cause of thrombotic stroke?

Answer 16

Atherosclerosis- results in narrowing of arteries

Accounts for half of all strokes

Question 17

How is an embolic stroke caused?

Answer 17

Blood clot forms elsewhere in the body and travels to the brain

Question 18

What is the most common cause of embolic stroke?

Answer 18

Atrial fibriliation- increased risk of clots

Air bubbles, plaque form in an artery wall

Question 19

When does a haemorrhagic stroke occur?

Answer 19

Occurs when a blood vessel within the brain ruptures

Question 20

What can cause a haemorrhagic stroke?

Answer 20

Aneurysm

Arteriovenous malformation

Question 21

What is an aneurysm?

Answer 21

Ballooning of weakened region of blood vessel

Question 22

What is arteriovenous malformation?

Answer 22

Abnormal connection between arteries and veins. Increased risk of bleeding due to increased pressure

Question 23

What happen in a haemorrhagic stroke?

Answer 23

The blood accumulates and causes compression of brain tissue and increased pressure within brain (intracranial pressure)

Question 24

What is there an increased mortality for?

Answer 24

Haemorrhagic stroke than ischaemic stroke

Question 25

What is a Transient Ischaemic Attack (TIA)?

Answer 25

Sometimes referred to as mini-stroke Brief period of symptoms similar to stroke At greater risk of subsequent stroke

Question 26

What is TIA caused by?

Answer 26

Caused by a temporary decrease in blood supply to a particular brain region Caused by a clot or other debris blocks blood flow temporarily

Question 27

What happens to ischaemic core in ischaemic stroke?

Answer 27

Irreversibly damaged and cells are destined to die within 2 mins

Question 28

What happens to ischaemic penumbra in ischaemic stroke?

Answer 28

Tissue does not function normally but is still viable and may recover if blood flow is restored or drugs given to support survival

Question 29

Who introduced the ischaemic penumbra?

Answer 29

Originally by Astrup and Symon 1981

Question 30

What is the the ischaemic penumbra?

Answer 30

A region of reduced CBF with impaired electrical activity but still maintained ionic homeostasis and transmembrane electrical potentials. This definition further evolved to include preserved energy metabolism and increased oxygen extraction faction (OEF)

Question 31

Where do most ischaemic strokes occur?

Answer 31

Forebrain

Question 32

What is the composition of the forebrain?

Answer 32

22 billion neurones 84,500 miles of myelinated fibres 157 trillion synapses

Question 33

What is the timeframe of brain damage associated with occlusive stroke/

Answer 33

Occurs roughly a 10 hour time frame

Question 34

What happens if the patient is left untreated?

Answer 34

Patient will lose 1.9 million neurones (every minute) 13.8 billion synapses (every minute) 7 miles of axonal fibres (every minute)

Question 35

What is infarction dependent on?

Answer 35

Severity and duration of ischaemia

Question 36

What is acute ischaemic stroke treatment?

Answer 36

Thrombolysis (clot buster) (recombination tissue plasminogen activator; Alteplase) Can only be used in specialist stroke units

Question 37

What is a CT scan essential to exclude?

Answer 37

Haemorrhagic stroke

Question 38

In thrombolysis how long before treatment?

Answer 38

Treatment within 4.5 hours of stroke onset

Question 39

What are the side effects of thrombolysis?

Answer 39

Bleeding- must not be used in haemorrhagic stroke

Question 40

How many patients are eligible for thrombolysis?

Answer 40

5-10%

Question 41

What happens in Thrombolysis?

Answer 41

Tissue plasminogen activator (t-PA) binds to fibrin on clot surface t-PA (Alteplase) activates Plasminogen → Plasmin Plasmin is a proteolytic enzyme Plasmin breaks down fibrin molecules and results in clot dissolving t-PA preferentially binds fibrin bound plasminogen

Question 42

What is a thrombectomy?

Answer 42

Used for acute stroke treatment? Stent retriever into cerebral vessel Five different clinical trials have shown efficacy of mechanical thrombectomy in acute stroke (MRCLEAN, ESCAPE, EXTEND-IA, SWIFT PRIME, REVASCAT)

Question 43

What is the efficacy of thrombectomy?

Answer 43

Up to 6 hours post stroke

Question 44

What is thrombectomy often used in combination with?

Answer 44

rt-PA

Question 45

What does Ischaemic penumbra contain?

Answer 45

Salvageable tissue

Question 46

What is acute treatment of ischaemic penumbra?

Answer 46

Selection of patients for acute treatment Acute treatment futile in patients without salvageable tissue Patients with penumbra most likely to benefit from “clotbuster” therapy

Question 47

What is penumbra the main target tissue for?

Answer 47

Acute neuroprotection

Question 48

What does Computerised Tomography (CT) scans use?

Answer 48

X-rays

Question 49

What does Magnetic Resonance Imaging (MRI) scans use?

Answer 49

Signals are generated by nuclei with a positive charge (i.e. H, P) MRI most commonly uses the signal from hydrogen atoms Hydrogen most abundant atom in body (approx. 70-90% of body) Non-invasive

Question 50

What are the purposes of imagining a stroke?

Answer 50

Exclude haemorrhage To discriminate between irreversibly damaged brain tissue and tissue at risk of infarction To identify location of stroke To identify patients that will benefit from thrombolysis

Question 51

What are the benefits of CT scans?

Answer 51

Very good at detecting haemorrhage Quicker than MRI Cheaper and more widely available

Question 52

What are the disadvantages of CT scans?

Answer 52

CT scanning not very sensitive for detecting early ischaemic damage following stroke

Question 53

What are the advantages of MRI?

Answer 53

More detail than CT MRI sequences can be used to detect very early brain damage due to stroke Diffusion weighted imaging (DWI) an MR sequence which is sensitive to motion of water molecules can detect ischaemic damage within minutes of stroke Perfusion weighted MRI can be used to assess the tissue at risk

Question 54

What is perfusion?

Answer 54

Delivery of blood to capillary bed for supply of nutrients and oxygen

Question 55

What information can be obtained by MRI?

Answer 55

Information about the perfusion status of the brain can be obtained (blood flow)

Question 56

What can Perfusion Weighted Imaging (PWI) combined with diffusion weighted imaging (DWI) be used to clinically determine?

Answer 56

Which patient will benefit from thrombolysis