L16 Ischaemic Stroke

Question 1

Definition of a stroke

Answer 1

clinical syndrome with a rapid onset of a focal disturbance in cerebral function of a vascular origin of more than 24 hour duration (or leading to death)

Question 2

Name 6 risk factors for a stroke

Answer 2

gender, age, genetics, diabetes, diet, atherosclerosis, exercise, heart condition

Question 3

Clinical presentation of a stroke

Answer 3

depends on part of brain

sudden onset

Question 4

What does diagnosis of stroke depend on

Answer 4

time of onset, history of TIA, pattern, symptoms, physical neurological exam, lab tests
stroke scale score

Question 5

What type of imagery is used to show stroke? What about TIA?

Answer 5

Stroke = CT scan
TIA= MRI

Question 6

What does the size of a cerebral infarct depend on

Answer 6

availability of collateral circulation
duration of ischaemia
magnitude of reduction in cerebral blood flow

Question 7

What are red infarcts normally caused by

Answer 7

embolic events

haemorrhagic

Question 8

What are pale infarcts normally associated with

Answer 8

thrombosis

Question 9

What is the penumbra

Answer 9

potentially salvageable tissue, core of dead tissue is surrounded by penumbra, can’t function but not dead, may survive for hours depending on collateral blood supply

Question 10

What is reperfusion injury

Answer 10

worsening of injury upon restoration of blood flow (bringing blood back into damaged vessels)
generation of free radicals
development of oxidative stress = activation of destructive enzymes

Question 11

What is a TIA

Answer 11

usually indicator of underlying thrombotic disease
warning sign of stroke
same underlying pathology as stroke but different duration
typically lasts less than an hour
like zone of penumbra without a dead core
symptoms resolve

Question 12

Causes of TIA

Answer 12

atherosclerotic plaque
clot formation
temporary vasospasm

Question 13

What does a TIA mimic

Answer 13

migraine
glucose abnormalities
tumours
demyelinating disease eg MS

Question 14

Prevention of TIA methods

Answer 14

avoid smoking, decrease cholesterol and fat in diet, limit sodium, reduce BP, maintain normal weight

Question 15

Ischaemic stroke sub-types

Answer 15

thrombotic and embolic

Question 16

What is the most common cause of thrombotic stroke and what are the risk factors

Answer 16

cerebral atherosclerosis

atherosclerosis risk factors (hypertension, hyperlipidaemia, smoking, obesity

Question 17

What is usually involved in an embolic stroke

Answer 17

thrombo fragments from outside the brain causing occlusions of cerebral vessel
emboli formation predisposed in individuals with AF, recent MI, bacterial endocarditis
sudden onset
usually involves large region of brain

Question 18

What is a lacunar stroke and where are they normally located

Answer 18

small vessel disease in arterioles
located in deep non-cortical structures (internal capsule, basal ganglia, brain stem)
occur in territory of single penetrating vessel
healing leads to small cavities (lacunar which means lakes)

Question 19

Three lacunar stroke syndromes

Answer 19

pure motor hemiplegia
pure sensory hemiplegia
dysarthria with clumsy hand syndrome

Question 20

What is haemorrhagic transformation

Answer 20

stroke complication
bleeding into infarct/damaged vessels = blood moves into brain parenchyma
can worsen outcome

Question 21

Treatment of stroke

Answer 21

depends on type

thrombolysis
removal of clot
stent (rare)

management of complications

anti platelet (aspirin)
anti coagulant (warfarin)

rehabilitation

Question 22

How is tPA used in thrombolysis

Answer 22

dissolve clot, administered within 4.5 hours of symptom onset
ischaemic stroke only
tPA breaks down fibrin (catalyses conversion of plasminogen to plasmin, plasmin breaks down fibrin into FDP’s to dissolve clot)