STROKE & TIA Flashcards
Definition of stroke
A clinical syndrome of presumed vascular origin characterised by rapidly developing signs of focal or global disturbance of cerebral functions with lasts >24 hours or leads to death
What is a TIA?
a transient (less than 24 hours) neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without evidence of acute infarctio
Most people have complete resolution of Sx and signs within 1 hour
What is a silent stroke?
radiological or pathological evidence of an infarction or haemorrhage not caused by trauma without an attributable history of acute neurological dysfunction attributable to the lesion
Epidemiology of stroke?
100,000 strokes every year in the UK
It’s a leading cause of death and disability - causes around 38,000 deaths a year in the UK
Non-modifiable risk factors for stroke?
Older age
Male
Race
Previous TIA or stroke
FHx - more common in black African or south Asian
Modifiable risk factors for stroke?
Hypertension
Diabetes
AF
CVD - valvular disease, CAD, CHF, MI, structural heart disease
Smoking
Hyperlipidaemia
Obesity
Poor diet and inactivity
Alcohol misuse
Drug abuse -cocaine and amphetamines
Migraines Hx
Other diseases - DM, sickle cell, APS, CKD, haemophilia, PCKD, connective tissue disorders, OSA, vascular malformations
What is the most important risk factor for cerebral haemorrhage?
Hypertension
Who is considered a young patient for a stroke?
<65
Risk factors specific for a “young stroke”?
Infarcts:
Arterial dissection
Heath abnormalities e.g. PFO or infective endocarditis
Vasculitis
Genetic e.g. CADASIL, MELAS
Illicit drug use
Haemorrhage:
AVMs
Aneurysms
Examples of stroke mimics?
Old stroke
Epilepsy
Todds paresis
Bell’s palsy
SOL
Head injuries
Delirium
Migraine
Mass lesion
MS
Encephalitis
Transient loss of consciousness
Hypoglycaemia
Hypoxia
Drug/alcohol use
Functional disorders
What are examples of stroke chameleons?
Acute confusional state e.g. receptive dysphasia
Abnormal movements / seizures
PNS symptoms e.g. pt presents with a wrist drop ans it actually turns out to be a stroke
Acute vestibular syndrome
(This are things commonly missed that are actually a stroke!!)
When does a CT scan have to be done if you suspect a stroke?
Within 1 hour of arrival to ED
Hyperacute findings on Non-contrast CT head after a stroke?
May directly visualise the clot immediately - hyper dense artery (white artery)
You may be able to see early parenchymal signs as early as 1 hour after onset. These may be loss of grey-white matter differentiation or cortical hypodensity with associated parenchymal swelling
Subacute findings on Non-contrast CT head after a stroke?
As time goes on, the swelling starts to subside and small amounts of cortical petechial haemorrhages (not to be confused with haemorrhagic transformation) result in elevation of the attenuation of the cortex. This is known as the CT fogging phenomenon 5. Imaging a stroke at this time can be misleading as the affected cortex will appear near normal.
Chronic findings on Non-contrast CT head after a stroke?
Later still the residual swelling passes, and gliosis sets in eventually appearing as a region of low density with a negative mass effect.
Cortical mineralisation can also sometimes be seen appearing hyperdense
Acute vs chronic CT head for a brain bleed
Acute - hyperdense i..e white
Chronic - hypodense i.e. black
What % of strokes are ischaemic?
85%
What are the 2 types of haemorrhagic strokes?
Remember 15% of all strokes are haemorrhagic…
10% of all strokes are intracerebral
5% are SAH
What causes an intracerebral haemorrhage?
Hypertension usually
What causes an subarachnoid haemorrhage?
Most common cause is head injury
80% of non-traumatic SAH are caused by rupture of an intracranial saccular ‘berry’ aneurysm
20% are due to AVMS, arterial dissections and use of anticoagulants
Conditions associated with berry aneurysms and therefore SAH?
Hypertension
Adult PCKD
Ehlers danlos syndrome
Coarctation of the aorta
Whats the prognosis of a stroke?
1 in 7 pts with acute stroke die in hospital
30 day mortality for ischaemic stroke is 12% and haemorrhagic is 30.5%
Of people with SAH, up to 15% will die before hospital
Disability following stroke is very common - at 6 months after haemorrhagic stroke only up to 30% will live independantly
Falls occur in up to 73% of pts within the first year after severe stroke
Investigations for ?stroke
FBC, ESR
Blood glucose
Choleserteol
U&Es
12 lead ECG to exclude arrhythmias
Non-contrast CT head
Carotid Doppler
Consider: CT angiogram, 24 hour tape for paroxysmal AF, ECHO for IE, thrombophilia screen (protein C, protein S, leiden 5 factor),
What causes an ischaemic stroke?
50% thrombosis and embolism from atherosclerosis
25% intracranial small vessel disease - often related to hypertension and diabetes
20% cardiac source of embolism e.g. AF, IE, atrial myxomas
5% rarer causes e.g. hypercoagulable states, vasculitis, arterial dissection, genetic causes