Stroke: clinical diagnosis and classification Flashcards
Define stroke:
neurological deficit:
- sudden onset
- focal
- presumed to be of non-traumatic vascular origin
- lasts for >24 hours
What are the 2 main types of strokes?
Cerebral infarct - 81%
Intracerebral haemorrhage
What are the characteristics of a cerebral infarct?
Occluded blood vessel
- Mean (norm) cerebral blood flow= 50ml/100g/min - electrical failure occurs at 20-10ml/100g/min
- metabolic failure at <10ml/100g/min
Define penumbra
area surrounding an ischaemic event
What are some example mechanisms of cerebral infarcts?
large artery disease cardioembolic stroke small artery disease (lacunar) cryptogenic strokes - cerebral ischaemia of unknown or obscure origin others: endocarditis, vasculitis
What is the commonest cause of young stroke?
carotid dissection
- minor trauma to the neck can cause it
- Classic triad (2 out of 3)
1) unilateral pain (face, neck, head)
2) horner’s syndrome
3) anterior circulation stroke or TIA
What is a cardioembolism?
blood clot forms in the heart and embolises to the brain- can be caused by atrial fibrillation
What are lacunar infarcts?
occlusion of small perforator arteries
involves deep white matter and brainstem
RF: hypertension, diabetes and hyperlipidaemia
What do infarcts look like on CT?
Dark - low attenuation
- loss of grey and white matter differentiation
- sulcal effacement - mass effect on brain parenchyma can push gyri together therefore displacing the csf between sulci
Can be difficult to see the infarct early on but by doing multiple scans it can be useful in timing when the stroke occurred
What are the 2 mechanisms of non traumatic ICH?
Primary- 78-88%
- chronic hypertension
- amyloid angiopathy
Secondary ICH
- vascular abnormalities - ateriovenous malformation, aneurysm
- tumour
- impaired coagulation
- vasculitis
- drug induced - e.g. warfarin
What does an ICH appear like on a CT scan ?
Appears bright - high attenuation - obvious straight away
Becomes isodense after a few days due to Hb breakdown
Often surrounded by low attenuation due to oedema/ischaemic necrosis
When do extradural haemorrhages usually occur?
after head trauma
What are the roles of the frontal lobe?
Consciousness, wakefulness, self-control, language production (Broca’s area), eye movement, body movement (motor cortex)
What are the roles of the parietal lobe?
Sensation, spatial orientation, calculation
What are the roles of the temporal lobe?
speech (language comprehension- Wernicke’s area), smell, hearing, memory
What are the roles of the occipital lobe?
vision
What are the roles of the brainstem?
eye movements, pupil reflexes, swallowing, balance, breathing, consciousness
What are the roles of the cerebellum?
balance, coordination
What are the arteries in the neck that supply the brain?
x2 internal carotid arteries
x2 vertebral arteries (also supply the spinal cord)
Due to the circle of willis, if you lose one/two of these arteries the brain will still be perfused
What are the 3 stroke syndromes?
TACS - total anterior circulation stroke / PACS (partial anterior circulation stroke)
POCS - posterior circulation stroke
LACS - lacunar stroke
What blood vessels are affected in thrombotic occlusion of TACS and what are the common mechanisms?
85% thrombotic occlusion of ACA, MCA or ICA
Mechanisms:
- large vessel disease e.g. atherosclerosis /dissection
- cardioembolic
What blood vessels are affected in a cortical ICH of TACS origin and what are the common mechanisms?
15% cortical ICH ACA or MCA territory
Mechanisms:
- secondary ICH - vascular malformation, tumour
- primary ICH- amyloid angiopathy
What are the clinical features of an anterior circulation stroke?
1) Contralateral UMN hemiparesis and/or hemisensory loss
2) Higher mental function problems - dominant left cortex (dysphasia), non dominant R cortex (apraxia, inattention)
3) Hemianopia - blindness over half of the visual field
TACS = 3/3 PACS = 2/3
What usually causes lacunar syndrome?
95% infarction in pons and basal ganglia - mostly small vessel disease
Affect anterior or posterior circulation
5% deep (subcortical) haemorrhage- mostly PICH due to hypertension
What are the clinical features of lacunar syndrome?
Contralateral UMN hemiplegia
Contralateral hemisensory loss
Contralateral upgoing plantar
NO cortical problems- hemianopia, dysphasia, apraxia, neglect
What are the 2 types of posterior circulation syndromes?
85% vertebrobasilar territory occlusion
-Mechanism : large vessel disease, cardiodembolic
15% brainstem haemorrhage
-Mechanism: primary or secondary ICH but NOT amyloid angiopathy
What are the clinical features of a posterior circulation stroke?
dizziness, vertigo, diplopia, dysphagia, ataxia, cranial nerve palsies, and uni/bilateral limb weakness
HALLMARK: cross neurological deficits- ipsilateral cranial nerve deficits with contralateral motor weakness and upgoing plantar
What are some examples of posterior circulation syndrome?
brainstem stroke syndrome
PCA stroke
Cerebellar stroke
Basilar artery thrombosis
What are the 3 types of midbrain strokes?
1) weber - ipsilateral 3rd contraplegia
2) claude - contra rubral trmor
3) benedikt - ipsilateral contraplehia and rubral tremor
What are the 3 types of pons strokes?
1) marie-fox syndrome - ipsilateral ataxia, contralateral plagia and spinothalamic
2) raymond syndrome - ipsilateral 6th contraplegia
3) milard-gubler syndrome - ipsilateral 6, 7th and contraplegia
What are the 2 types of medulla strokes?
1) dejerine = ipsilateral 12th, contraplegi and dorsal column
2) wallenberg - ipsilateral 5, 8, 9, 10, horner’s, ataxia, contralateral spinothalamic
What types of stroke are often unrecognised by the pt?
PCA infarct or occipital haemorrhage
- contralateral homonymous visual field defect
What are the clinical features of a cerebellar stroke (infarction or haemorrhage)?
nausea, vomiting, loss of balance, vertigo, headaches, ipsilateral ataxia, intention tremor, heel shin incoordination, nystagmus, dysarthia, risk of obstructive hydrocephalus (because cerebellum is close to the 4th ventricle) and coma
What are the clinical features of a basilar artery thrombosis ?
bi/unilateral cranial nerve palsies severe quadraplegia bilateral upgoing plantar coma respiratory arrest locked-in syndrome-complete muscle paralysis except for upward gaze
What is a TIA?
Temp stroke syndrome <24 hours that resolves spontaneously
mainly due to ischaemia
What is a amaurosis fugax?
retinal artery TIA - norm caused by large vessel disease
transient monocular blindness 1-5mins - abrupt or peaking severity <5mins
moves from periphery towards centre- partial or complete
visual disturbance- dark, foggy, gray, white
painless
usually occurs in isolation
What do TIAs almost NEVER cause?
global symptoms - syncope, blackout, general feelings of dizziness
migrainous symptoms - headache or visual disturbance
Burning or painful sensation in the limbs
recurrent falls
seizure like symptoms that develop over mins/horus
daily symptoms
What are the neurological deficits in vascular vs mimic?
Stroke:
- sudden onset
- Negative symptoms - take away functions
- definite focal symptoms or able to lateralise signs
- presence of neurological signs
- OCSP subclassification possible
Mimic:
- gradual onset symptoms
- positive symptoms
- nonfocal/nonspecific symptoms or cognitive impairment
- abnormal signs in non-neurological systems
- prior history of unexplained transient neurologic attack
