Stroke and Vascular Disorders Flashcards
What are the criteria for stroke diagnosis?
> Focal Neurological Deficit
Symptoms >24 hrs
Sudden onset
If symptoms last less that 24 hrs (still have focal neurological deficit and sudden onset) what is the diagnosis?
Transient Ischaemic Attack
What is the pathophysiology of an Acute Ischaemic stroke?
Reduction in cerebral blood flow –> causes cellular necrosis.
What is cerebral blood flow dependant on and regulated by?
CBF = CPP/ CBR
Cerebral Perfusion pressure
Cerebrovascular Resistance
If you reduce the blood flow to the brain what happens to the Oxygen Extraction Fraction?
It increases
What substrate does the brain use for energy metabolism?
Glucose
What do neurones need a constant supply of to maintain integrity?
ATP
What is a penumbra?
Area of the brain with less flow which compromises electrical function - salvageable if you restore blood flow.
What are capacitance and resistance vessels?
Capacitance = Like pipes Resistance = Can constrict and dilate to physiological changes.
Why does a patient initially get no symptoms in artery occlusion?
Auto-regulation by resistance vessels distal to the occlusion
Why does the pt get no symptoms when CBF is reduced?
OEF increases to compensate
When does the pt get Ischaemic symptoms?
When max oxygen has been extracted.
What causes Ischaemic stroke?
Thrombosis and Embolism
What are the cardiac sources of embolism?
> LV thrombus
Tumour
Endocarditis
What occlusion accounts for 25% of all ischaemic stroke?
Proximal anterior circulation large vessel. (ICA)
