Neurology: Stroke + TIA Flashcards
What are the clinical features of a transient ischaemic attack (TIA)?
1) Sudden onset focal neurological deficit of vascular aetiology
2) Symptoms last < 1 hour
3) No evidence of acute infarct on imaging
What are risk factors for TIA?
1) Diabetes
2) Hypercholesterolaemia
3) Hypertension
4) Smoking
5) FH of cardiovascular disease/stroke
6) AF - risk for cardioembolic TIAs
How do patients present with a TIA?
1) Focal neurological deficit e.g. speech difficulty, arm/leg weakness or sensory changes
2) TIA is transient and most symptoms resolve within 1 hour
3) Absence of positive symptoms suggestive of differentials e.g. shaking preceding weakness suggesting focal motor seizure
4) Absence of headache - would suggest a differential e.g. migraine or intracranial bleeding
What are differentials for TIA?
Focal motor seizure, migraine, intracranial bleed
What would suggest a focal motor seizure over a TIA?
Shaking preceding weakness
What would suggest a migraine or intracranial bleed over a TIA?
Presence of headache
How do you manage a patient presenting with a TIA or recent history of TIA?
1) Refer patients who have had a suspected TIA immediately for assessment, to be seen within 24h of onset of symptoms
What is a TIA called when it affects the eye?
Amaurosis fugax
What are the clinical features of amaurosis fugax (TIA affecting the eye)?
1) Sudden painless monocular visual loss which suddenly resolves < 1 hour (then all findings are normal)
2) May be preceded by sudden blurring of vision
3) Normal examination findings once resolved
4) Vascular risk factors present
What is a stroke?
Sudden onset focal neurological deficit of vascular aetiology, with symptoms lasting > 24h or with evidence of infarction on imaging
What % of strokes are ischaemic?
85% (15% haemorrhagic)
What causes ischaemic stroke?
When blood supply in a cerebral vascular territory is reduced secondary to stenosis or complete occlusion of a cerebral artery
What is the ischaemic penumbra?
The cerebral area surrounding the ischaemic event where there is ischaemia without necrosis - this area is amenable to recovery with thrombolysis
What are the main causes of ischaemic stroke?
1) Intracranial small vessel atherosclerosis (25%)
2) Large vessel atherosclerosis (50%) e.g. carotid artery stenosis
3) Cardio-embolic e.g. in AF (20%)
How does large vessel atherosclerosis e.g. carotid artery stenosis typically cause ischaemic stroke?
Thrombus formation on the atherosclerotic plaque and subsequent embolism of the thrombus to a smaller cerebral artery
How do cardio-embolic ischaemic strokes occur?
In AF there is stasis of blood flow in the left atrium, predisposing to thrombus formation in the left atrium and subsequent embolisation to the brain
What are rare causes of ischaemic stroke?
1) Primary vascular causes e.g. vasculitis, arterial dissection
2) Haematological causes - prothrombotic states
What are strong risk factors for ischaemic stroke?
1) Age
2) Male sex
3) FH of ischaemic stroke
4) Hypertension
5) Smoking
6) Diabetes
7) AF
What are weaker risk factors for ischaemic stroke?
1) Hypercholesterolaemia
2) Obesity
3) Poor diet
4) Oestrogen-containing therapy
5) Migraine
What causes haemorrhagic stroke?
Rupture of a cerebrospinal artery
What classification is used to classify stroke?
Bamford/Oxford classification
What are the clinical features of a total anterior circulation infarct (TACI)?
Three features need to be present to be classified as a TACI:
1) Contralateral hemiplegia or hemiparesis
2) Contralateral homonymous hemianopia
3) Higher cerebral dysfunction e.g. aphasia, neglect
Which arteries does a total anterior circulation infarct (TACI) involve?
Anterior and middle cerebral arteries on the affected side
What are the clinical features of a partial anterior circulation infarct (PACI)?
Two of:
1) Contralateral hemiplegia or hemiparesis
2) Contralateral homonymous hemianopia
3) Higher cerebral dysfunction e.g. aphasia, neglect
OR
Higher cerebral dysfunction alone
Which arteries does a partial anterior circulation infarct (PACI) involve?
The anterior OR middle cerebral artery on the affected side
What kind of strokes can be classified as a lacunar infarct (LACI)?
1) Pure motor stroke
2) Pure sensory stroke
3) Sensorimotor stroke
4) Ataxic hemiparesis
5) Dysarthria-clumsy hand syndrome
Which arteries does a lacunar infarct (LACI) affect?
Small deep perforating arteries, typically suppling the internal capsule or thalamus
Any of which clinical features define a posterior circulation infarct (POCI)?
1) Cerebellar dysfunction
2) Conjugate eye movement disorder
3) Bilateral motor/sensory deficit
4) Ipsilateral cranial nervy palsy with contralateral motor/sensory deficit
5) Cortical blindness/isolated hemianopia
Which arteries does a posterior circulation infarct (POCI) involve?
Vertebrobasilar arteries and associated branches supplying the cerebellum, brainstem and occipital lobe