Stroke: Ischaemic Stroke Flashcards
Definition
Rapid onset of neurological deficit
- lasting for more than 24 hours
- poor blood flow to brain causes cell death
Epidemiology
Older people
Males
Risk factors
Hypertension: the single greatest risk factor
Age: the average age for a stroke is 68 to 75 years old
Smoking
Diabetes
Hypercholesterolaemia
Atrial fibrillation
Family history
Haematological disease: such as polycythaemia
Medication: such as hormone replacement therapy or the combined oral contraceptive pill
Aetiology
Reduction in cerebral blood flow due to arterial occlusion or stenosis.
- Cardiac:
=Atherosclerotic disease: smoking, hypertension , diabetes , high cholesterol
= Atrial fibrillation
= Paradoxical embolism due to septal abnormality, such as a patent foramen ovale
- Vascular
= Aortic dissection
=Vertebral dissection
= Vasculitides
- Haematological
= Hypercoagulability, such as antiphospholipid syndrome
= Sickle cell disease
= Polycythaemia
Pathophysiology
Reduction in cerebral blood flow due to arterial occlusion or stenosis. Typically divided into thrombotic, embolic and lacunar.
Blood vessel to/in brain occluded by a clot
Ischaemia + infarction follow
- Infarcted areas dies, resulting in focal neurological symptoms
- Infarcted area is surrounded by a swollen area (oedema) which can regain function with neurological recovery
ACA Signs
If ACA:
- Contralateral Hemiparesis + sensory loss (lower limbs more than upper limbs)
- Akinetic Mutism (will not speak or move, no motivation to do so)
MCA Signs
- Contralateral hemiparesis and sensory loss with upper limbs > lower limbs
- Homonymous hemianopia
- DOMINANT SIDE = APHASIA
Wernicke’s Aphasia (aka receptive aphasia) = cannot understand speech
Broca’s Aphasia (aka Expressive Aphasia) = cannot produce speech - NON DOMINANT = APRAXIA AND HEMINEGLECT SYNDROME
Apraxia = patient can move muscles to do stuff, but don’t know how to
Hemineglect syndrome = all visual and sensory sensations on the contralateral side is neglected
E.g. if the left MCA is affected, the left optic radiations will be affected so the right visual field will be lost = right homonymous hemianopia.
PCA signs
Visual problems
- Homonymous hemianopia with macula sparring (as the MCA can still supply the region of the occipital lobe which is responsible for the macular)
- Visual agnosia (patient can see but not interpret symbols e.g. letters)
Vertebrobasilar
Cerebellar signs
Reduced consciousness
Quadriplegia (paralysis of all 4 limbs - arms and legs) or hemiplegia
Lacunar stroke
Affects the small perforating branches to subcortical structures (e.g. internal capsule, basal ganglia, thalamus, pons)
- Unilateral weakness
- Pure sensory loss
- Ataxic Hemiparesis (cerebella and motor symptoms)
Retinal/ophthalmic artery
Amaurosis fugax
Lateral medullary syndrome (posterior inferior cerebellar artery occlusion)
Ipsilateral facial loss of pain and temperature
Ipsilateral Horner’s syndrome
Ipsilateral cerebellar signs
Contralateral loss of pain and temperature
Basilar artery
Locked in syndrome
Weber’s syndrome (midbrain infarct; branches of posterior cerebral artery)
Oculomotor palsy and contralateral hemiplegia
Investigations
FIRST LINE = Non-contrast CT head
- Exclude haemorrhage
- Low density in gray + white matter
- Hyperdense artery sign
ECG = atrial fibrillation
Bloods tests =
- Glucose to rule out hypoglycaemia
CT angiogram (CTA): identifies arterial occlusion and should be performed in all patients who are appropriate for thrombectomy
MRI head: higher sensitivity for infarction than CT
