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22 Cards in this Set
- Front
- Back
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What are the types of cerebral ischaemic injury? |
Global ischaemic injury: - Generalised reduction in cerebral perfusion - ischaemic/hypoxic encephalopathy Focal ischaemic injury: - Reduction in blood flow to a localised area Prompt: Describe the patterns of cerebral ischaemic injury |
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What are the causes of focal cerebral infarction? |
Arterial thrombosis: in situ Embolism: cardiac mural thrombi, thromboemboli from carotids Vasculitis: infectious, TB, CMV/non-infectious PAN/temporal arteritis/SLE Arterial dissection Venous infarction: hanging Drugs: amphetamine, cocaine |
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What are the sources of cerebral thromboemboli? |
Majority from heart - cardiac mural thrombus, valvular vegitations Carotid arteries - bifurcation Parodoxical emboli in patent foramen ovale Precipitated by: Afib/DCCV |
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What happens to the thromboemboli |
Most lodge in MCA, or at branch points leads to ischaemia |
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What are the pathological effects of hypertension on the brain? |
Lacunar infarcts arteriosclerosis of the vessels in the lenticular nucleus, thalamus, internal capsule, caudate nucleus + pons Hypertensive encephalopathy Intracerebral hemorrhage |
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What types of intracranial bleeding can be seen in a patient with a head injury? |
Extradural Subdural Subarachnoid Intra-parenchymal |
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What type of vessels are damaged to produce a subdural hematoma? |
Tearing of the bridging veins as they enter into the cerebral sinuses Bleeding between the dural and arachnoid space |
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Which groups of patients are most at risk for SDH and why? |
Elderly pts, due to brain atrophy and increased stretch on the veins Infants: thin walled bridging veins |
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How does an extradural hematoma occur? |
Blunt injury or skull # Rupture of the middle meningeal artery Bleeding between the skull and dural (strips of the dural from the skull) May be a lucid period before LOC |
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Define concussion and what are its clinical features? |
Altered conscious state secondary to head injury Transient neurological dysfunction - transient resp arrest/loss of reflexes Feat: headache, amnesia, nausea/vomiting, poor concentration/memory, irritability, behaviour/personality changes, neuropsychiatric syndromes |
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Define and describe diffuse axonal injury |
Axonal microscopic injury - microscopic damage to deep brain white matter Axonal swelling and focal hemorrhagic lesions Damage the integrity of the axon at the node of ranvier - alteration in axoplasmic flow Commonly found with coma but no cerebral contusions |
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What is the most frequent cause of subarachnoid haemorrhage? |
Rupture of an aneurysm Less common Traumatic HTN intracerebral bleed AVM Bleeding disorders Tumours |
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Where are saccular aneurysms commonly located? |
Major arterial branch points along circle of willis- 90% (40/30/20/4) Ant comm 40% MCA 30% ICA/PCA 20% Basilar A/PCA 4% Can be multiple |
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What factors increase the likelihood of rupture of these aneurysms? |
Increasing size > 10mm, 50% rupture per year May occur at anytime, 1/3rd assoc w/ acute increases in ICP ie. straining |
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What are the genetic risk factors for saccular aneurysms? |
Unknown Polycystic kidney Ehlers danlos Marfans Neurofibromatosis Aortic coarctation |
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What are the pathological sequelae of subarachnoid haemorrhage? |
Acute (hrs-days): Ischaemic injury/stroke from vasospasm + increased ICP Late (healing): Meningeal fibrosis and scarring, may lead to CSF obstruction Death |
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What are the clinical features of Multiple Sclerosis? |
Distinct episodes of neurological deficits separated by time (and presentations separated by space) Unilateral visual impairment - optic neuritis Brainstem + cord lesions |
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What is the pathogenesis of MS? |
Autoimmune, demyelinating disorder to white matter lesions separated in space Genetic triggered viral CD4+ Th1 cells react against myelin Ag, release cytokines, activate macrophages Inflammatory cells create plaques |
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What might be found in CSF of a pt with MS |
Mildly elevated protein pleocytosis Increased proportion gamma globulin Oligoclonal bands |
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Describe the clinical features of parkinsonism |
lead pipe/cogwheel rigidity Stooped posture Shuffling gait Pill rolling tremor Poor co-ordination + slowness of voluntary movement Micrographia Diminished facial expression |
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What are the causes of parkinsonism? |
Conditions that damage the nigrostriatal dopaminergic system - Parkinsons disease - Drugs - dopamine antagonists/toxins - Post-encephalitic - Trauma/injuries - Multiple system atrophy - Familial |
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Outline the possible pathogenesis of Parkinson's disease? |
No underlying mechanism identified Misfolded protein/stress response triggered by alpha synuclein aggregation Genetic Defective proteosomal function |
