Stroke Flashcards
Why is it important to distinguish between ischaemic and haemorrhagic stroke?
Treatment.
Ischaemic stroke is caused by occlusion of cerebral vessels and requires thrombolysis. This could cause further bleeding in a haemorrhagic stroke.
Define stroke
Sudden onset of focal neurological symptoms over 24hrs with a vascular cause (due to haemorrhage or ischaemia, leading to an infarct).
Causes of stroke
haemorrhagic: ruptured berry aneurysm, head trauma, cartoid dissection
ischaemic: thrombus, embolus, artery stenosis, small vessel disease (lacunar infarct)
How do you distinguish a TIA from a stroke
Stroke: focal symptoms last for over 24hrs. Damage within the brain tissue
TIA: severe symptoms for <20 mins, but self resolving and full recovery within 24hrs. Amourois fugax (curtain drop in vision). TIAs are due to carotid or vertebrobasillar insuffiency.
How is risk of stroke after a TIA assessed?
ABCD2 Score>4 is high risk of stroke
Age >60
BP > 140/90
Clinical features - unilateral weakness (2), speech problems
Duration of symptoms >60mins (2)
Diabetes
Common types of CNS syndromes following an infarct
TACS: higher cortical dysfunction, dysphasia, homonymous hemianopia, motor+sensory defects
PACS: partial motor+sensory defects,
LACS: produces distinct symptom complex. e.g. pure motor or pure sensory hemiparesis, clumsy hand, ataxic hemiparesis, mixed sensorimotor stroke
POCS: CN palsy, bilateral motor/sensory deficit, eye movement defects.
Risk factors for stroke
Hypertension
Diabetes mellitus
Cardiac disease e.g. AF, valve disease, atherosclerosis
hyperlipidaemia
Smoking
Family history
Obesit and diet
Common sites of atheroma in the cerebral circulation
Internal carotid arteries
Carotid syphon (curved part of the ICA)
Origin of the vertebral arteries
Signs of middle cerebral artery occlusion
Contralateral hemiplegia (including lower part of the face)
Contralateral hemisensory loss
Ataxia in the contralateral limbs
aphasia (left brain lesion)
apraxia (right brain lesion)
contralateral homonymous hemianopia
Signs of anterior cerebral artery occlusion
ACA is a branch of the internal carotids, jointed by communicating artery. Proximal occlusions are normally well tolerated because of cross-flow
Occlusion distal to anterior communicating artery:
contralateral weakness and sensory loess in the lower limbs
Can cause incontinence.
Stroke normally due to occlusion more proximally in the internal carotid.
Signs of Posterior cerebral artery occlusion
Effect depends on the site.
Proximal: Webers syndrome. 3rd nerve palsy, contralateral hemiplegia, chorea/hemiballismus, hemisensory disturbance
Cortical vessel: homonymous hemianopia with macular sparing
Bilateral occlusion: Cortical blindness. Patient is blind but is unaware of the degree of their visual loss.
Post-stroke pain
Thalamic pain. Numbness on the affected side replaced by burning and tingling. Usually hyperalgesia and allodynia
Occurs 1week-6months after stroke. Can occur anywhere in the spinothalamic system.
Watershed infarcts
Areas where there is an overlap of vascular territory is very susceptible to ischaemia. Infarcts caused by systemic drop in BP
ACA-MCA zone: Loss of motor/sensory function in the trunk. Aphasia
PCA-MCA: loss of visual processing
How is stroke diagnosed
Diagnosed clinically based on presentation.
e.g. FAST
Use CT to distinguish between haemorrhagic and ischaemic
Management of stroke
Ischaemic: thrombolyis rtPA within 3hrs. Give anti-platelets
Haemorrhagic: emergency surgery
Monitor and prevent complications
