L16 Ischaemic Stroke Flashcards
Definition of a stroke
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)
Name 6 risk factors for a stroke
gender, age, genetics, diabetes, diet, atherosclerosis, exercise, heart condition
Clinical presentation of a stroke
depends on part of brain
sudden onset
What does diagnosis of stroke depend on
time of onset, history of TIA, pattern, symptoms, physical neurological exam, lab tests
stroke scale score
What type of imagery is used to show stroke? What about TIA?
Stroke = CT scan TIA= MRI
What does the size of a cerebral infarct depend on
availability of collateral circulation
duration of ischaemia
magnitude of reduction in cerebral blood flow
What are red infarcts normally caused by
embolic events
haemorrhagic
What are pale infarcts normally associated with
thrombosis
What is the penumbra
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
What is reperfusion injury
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
What is a TIA
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
Causes of TIA
atherosclerotic plaque
clot formation
temporary vasospasm
What does a TIA mimic
migraine
glucose abnormalities
tumours
demyelinating disease eg MS
Prevention of TIA methods
avoid smoking, decrease cholesterol and fat in diet, limit sodium, reduce BP, maintain normal weight
Ischaemic stroke sub-types
thrombotic and embolic
What is the most common cause of thrombotic stroke and what are the risk factors
cerebral atherosclerosis
atherosclerosis risk factors (hypertension, hyperlipidaemia, smoking, obesity
What is usually involved in an embolic stroke
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
What is a lacunar stroke and where are they normally located
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)
Three lacunar stroke syndromes
pure motor hemiplegia
pure sensory hemiplegia
dysarthria with clumsy hand syndrome
What is haemorrhagic transformation
stroke complication
bleeding into infarct/damaged vessels = blood moves into brain parenchyma
can worsen outcome
Treatment of stroke
depends on type
thrombolysis
removal of clot
stent (rare)
management of complications
anti platelet (aspirin) anti coagulant (warfarin)
rehabilitation
How is tPA used in thrombolysis
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)
