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22 Cards in this Set
- Front
- Back
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How do you work out cerebral blood flow?
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Perfusion pressure/ resistance
= (MABP - ICP)/ resistance = 50ml/100g/min |
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How is Cerebral blood flow controlled?
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Autoregulation
PaC02 (potent) PaO2 (modest) Blood viscosity |
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If there is an increase in Hct what happens to the CBF?
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causes an increase in PaO2 = decreased CBF
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What is a stroke?
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Syndrome of rapidly developing clinical signs of focal (or global) disturbance of cerebral function with symptoms lasting over 24 hours
Death with no apparent cause other than that of vascular origin |
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What does the definition of a stroke not include?
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Subdural haemorrhage
Extradural haemmorhage Haemorrhage of infarction caused by infection or tumour Silent stroke (small bleed, no symptoms, increased risk of stroke, affects may lead to vascular dementia) |
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What is the definition of a transient ischaemic attack?
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A syndrome characterised by an acute loss of focal cerebral/ monocular function with symptoms lasting less than 24 hours and which is thought to be due to inadequate cerebral/ ocular blood supply as a result of arterial thrombosis/ embolism
Associated with arterial, cardiac or haematological disease |
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What are the 2 different types of Ischaemic (80%) stoke?
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Global - whole brain (blood supply interrupted), watershed regions, selectively vulnerable regions
Focal - large (regional)/ small (lacunar) |
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What are the 2 types of haemorrhagic stroke (15%)?
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Intracerebral haemorrhage (into substance of the brain 10%)
Subarachnoid haemorrhage (on surface 5%) |
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What are the 5 causes of ischaemic stroke?
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1. Thrombosis (underlying atheroma/ hypercoaguability/ heart attack and stroke risk similar)
2. Embolism (from heart e.g with atrial fibrilation) 3. Haemodynamic failure (global effects) 4. Increased ICP 5. Arterial vasospasm |
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What are 4 distributions of an ischaemic stroke?
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1. Total anterior cerebral infarct (17%)
2. Partial anterior cerebral infarct (34%) 3. Posterior cerebral infarct (24%) 4. Lacunar cerebral infarct (25%) |
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Why does a cerebral infarct occur after a road accident?
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Causes an increase in ICP which decreases the CBF
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What does a total anterior cerebral infarct cause?
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Hemiplegia/ hemianopia on contralateral side to lesion
New disturbance of higher function (e.g language, speech, vision) |
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What does a partial anterior cerebral infarct cause?
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Motor/ sensory deficit plus hemianopia OR new higher cerebral dysfunction
New higher cerebral dysfunction and hemianopia Pure motor/ sensory deficit New higher cerebral dysfunction alone |
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What does a posterior cerebral infarct cause?
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Unequivocal brainstem features
Isolated hemianopia or cortical blindness Ipsilateral CN palsy with contralateral motor and/ or sensory deficits Bilateral motor and/ or sensory deficit Disorder of conjugate eye movements Without cerebellar dysfunction |
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What does a lacunar cerebral infarct cause?
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Pure motor/ sensory stroke
Semimotor stroke Ataxic hemiparesis Deep within brain e.g thalamus |
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What causes the local vessel abnormalities that cause intracerebral haemorrhages?
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Hypertension
Vascular malformation Infarction (especially venous) Vasculitis Amyloid angiopathy (amyloid deposits = brittle BV) |
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What are the systemic factors associated with an intracerebral haemorrhage?
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Blood dyscrasias (sickle)
drugs (anticoagulants) trauma Tumours Miscellaneous |
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What are the concequences of a intracerebral haemorrhage?
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Sudden
Damage to brain tissue Increased ICP (headache, nausea, vom, coma, death) |
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What are the causes of a subarachnoid haemorrhage?
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Traumatic
Saccular (berry) anneurysm: Dilation of arteries at base of brain Arterial branch point on the circle of willis Congenital/ acquired Silent/ compressive/ haemorrhagic Complications = vasospasm/ hydrocephalus |
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What are the 5 other causes of Subarachnoid haemorrhages?
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Extension of intracerebral haemorrhage
Infarction (meningitis) Neoplasm (pituitary) Vasculitis Blood dyscrasias |
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Stroke management?
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Antiplatelets/ thrombolysis
CT scan Damage limitation: BP, hydratiom, correction of anaemia, hyperglycaemia, prevention of DVT |
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Rehabilitation?
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Early mobilisation
Active therapy Specialised stroke unit - multidisciplinary |
