Stroke Flashcards
What national screening tool is used to identify stroke Sx?
FAST
Face
Arms
Speech/Smile
Time (is brain)
What are the differential diagnoses for stroke?
- seizures (post-ictal activity)
- Wernicke’s encephalopathy
- Psychiatric disorders: Somatic disorders, conversion disorder)
- Brain tumour
- Trauma
What signs may suggest seizure rather than stroke?
- eye deviation away from lesion (for many types of seizure)
- EEG: seizure activity
- MRI: to rule out strokes or structural abnormalities
What is Wernicke’s encephalopthy?
A type of Beri Beri disease
Caused by thiamine (vit. B1) deficiency
often seen in alcoholics
In acute setting, PABRINEX can be given to resolve the low B1 levels
WERNICKE’S TRIAD:
- confusion
- ophthalmoplegia
- ataxia
How may a brain tumour present?
- picked up by imaging: CT/MRI
- may present with seizure activity
- can increase risk of coagulopathies such as stroke
What are the defining features of a stroke?
Sx must develop over a period of 24hr (officially)
usually Sx are NEGATIVE causing loss of function
e.g. ataxia
however some of the Ddx would present with POSITIVE Sx e.g. migraine with aura
What are the main types of haemorrhagic stroke?
INTRACEREBRAL (66%)
within the brain parenchyma
SUBARACHNOID (10%)
within subarachnoid space
INTRAVENTRICULAR (<5%)
within ventricles
What is a TIA?
= transient ischaemic attack
episodes usually last ~ 10mins (defo less than 24hr unlike full strokes)
cannot visualise TIA on imaging (CT/MRI)
Afro-Caribbean or S. Asian ethnicity carry the biggest risks for TIA
there is a high risk of reoccurrence of TIA
What is the main MODIFIABLE risk factor for strokes?
hypertension
What is the main NON-MODIFIABLE risk factor for strokes?
age
Which drugs (abuse) can elevate risk of strokes?
EtOH abuse
COCP (oestrogen containing)
cocaine
all of these will cause blood to be more thrombophilic or prone to bleeding
What is the MONROE-KELLIE HYPOTHESIS in cerebral perfusion?
Cerebral Perfusion Pressure (CPP) = MAP - ICP
where MAP = mean arterial pressure (i.e. systolic+diastolic/2 pressure)
ICP = intracranial pressure
in order for the brain to be adequately perfused, the systolic BP must always be higher than the ICP
hence, if there is increased ICP due to oedema in the brain, then the relative perfusion of the brain is going to be reduced
(at this level, the MAP < ICP and therefore no auto-regulation of CPP can occur)
What is a ‘cerebral sinus venous thromboembolism’?
when a clot develops in the venous dural sinuses in the brain
What are the biggest risks or causes of EMBOLIC STROKES?
recent MI
Atrial fibrillation
Why do cardiac arrests result in increased stroke risk?
cardiac arrest -> systemic hypoperfusion -> can cause endothelial damage -> stroke (ischaemia)