Stroke Flashcards
Stroke
Types, classifications, rf, sx, ix, mx
Types:
- Ischaemia (inadequate blood supply) or infarction (tissue death due to ischaemia) of the brain tissue secondary to a disrupted blood supply (ischaemic stroke). Supply can be disrupted by A thrombus or embolus, atherosclerosis, shock or vasculitis
- Intracranial haemorrhage, with bleeding in or around the brain (haemorrhagic stroke)
Classification:
- bamford/oxford stroke classification
A total anterior circulation infarct (TACI) is defined by:
• Contralateral hemiplegia or hemiparesis, AND
• Contralateral homonymous hemianopia, AND
• Higher cerebral dysfunction (e.g. aphasia, neglect)
• A TACI involves the anterior AND middle cerebral arteries on the affected side.
A partial anterior circulation infarct (PACI) is defined by:
• 2 of the above, OR
• Higher cerebral dysfunction alone.
• A PACI involves the anterior OR middle cerebral artery on the affected side.
A lacunar infarct (LACI) is defined by: a pure motor stroke, pure sensory stroke, sensorimotor stroke, ataxic hemiparesis or dysarthria-clumsy hand syndrome.
A LACI affects small deep perforating arteries, typically supplying internal capsule or thalamus.
A posterior circulation infarct (POCI) is defined by:
• Cerebellar dysfunction, OR
• Conjugate eye movement disorder, OR
• Bilateral motor/sensory deficit, OR
• Ipsilateral cranial nerve palsy with contralateral motor/sensory deficit, OR
• Cortical blindness/isolated hemianopia.
A POCI involves the vertebrobasilar arteries and associated branches (supplying the cerebellum, brainstem, and occipital lobe).
Posterior strokes:
• Basilar artery occlusion is more likely to present with locked in syndrome (quadriparesis with preserved consciousness and ocular movements), loss of consciousness, or sudden death.
• Anterior inferior cerebellar artery results in lateral pontine syndrome, a condition similar to the lateral medullary syndrome but with additional involvement of pontine cranial nerve nuclei. It leads to cerebellar ataxia, vertigo, hearing loss as well as ipsilateral facial weakness
• Wallenberg’s syndrome (lateral medullary syndrome) causes ipsilateral
Horner’s syndrome, ipsilateral loss of pain and temperature sensation on the face, and contralateral loss of pain and temperature sensation over the contralateral body.
• Weber’s syndrome/medial midbrain syndrome (paramedian branches of the upper basilar and proximal posterior cerebral arteries): causes an ipsilateral oculomotor nerve palsy and contralateral hemiparesis.
Rf:
Previous stroke or TIA
Atrial fibrillation
Carotid artery stenosis
Hypertension
Diabetes
Raised cholesterol
Family history
Smoking
Obesity
Vasculitis
Thrombophilia
Combined contraceptive pill
Sx:
A sudden onset of neurological symptoms suggests a vascular cause (e.g., stroke). Stroke symptoms are typically asymmetrical. Common symptoms are:
- Limb weakness
- Facial weakness
- Dysphasia (speech disturbance)
- Visual field defects
- Sensory loss
- Ataxia and vertigo (posterior circulation infarction)
Ix:
- non-contrast head CT is main ix for haemorrhagic
Mx:
- Exclude hypoglycaemia
- Immediate CT brain to exclude haemorrhage
- Aspirin 300mg daily for two weeks (started after haemorrhage is excluded with a CT)
- Admission to a specialist stroke centre
- Thrombolysis with alteplase is considered once haemorrhage is excluded (after the CT scan). Alteplase is a tissue plasminogen activator that rapidly breaks down clots. It may be given within 4.5 hours of the symptom onset, based on local protocols and by an appropriately trained team.
- Thrombectomy is considered in patients with a confirmed blockage of the proximal anterior circulation or proximal posterior circulation. It may be considered within 24 hours of the symptom onset and alongside IV thrombolysis.
- Clopidogrel 75mg once daily (alternatively aspirin plus dipyridamole)
- Atorvastatin 20-80mg (not started immediately – usually delayed at least 48 hours)
- Blood pressure and diabetes control
- Addressing modifiable risk factors (e.g., smoking, obesity and exercise)
Transcient ischaemic attack (TIA)
Def, sx, mx
Transient ischaemic attack (TIA) involves temporary neurological dysfunction (lasting less than 24 hours) caused by ischaemia but without infarction. Symptoms have a rapid onset and often resolve before the patient is seen. TIAs may precede a stroke. Crescendo TIAs are two or more TIAs within a week and indicate a high risk of stroke
Sx:
Stroke sx
Mx:
- Aspirin 300mg daily (started immediately)
- Referral for specialist assessment within 24 hours (within 7 days if more than 7 days since the episode)
- Diffusion-weighted MRI scan is the imaging investigation of choice.
