Flashcards in Neuro Deck (229)
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31
Perinatal Brain Injury
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non-aggressive motor deficits from pre- and perinatal neurologic insults.
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risk factor: prematurity.
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can have brain injury without reactive gliosis.
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intraparenchymal hemorrhage, periventricular leukomalacia, multicystic encephalopathy, ulegyria, status marmoratus.
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presentation: depends on location but includes dystonia, spasticity, ataxia/athetosis, and/or paresis
32
Perinatal Intraparenchymal Hemorrhage
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in germinal matrix btw thalamus and caudate nucleus. can extend to ventricular system.
33
Periventricular Leukomalacia
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ischemic infarcts in periventricular white matter.
34
Multicystic Encephalopathy
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ischemic infarcts within the hemispheres.
35
Ulegyria
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thin, gliotic gyri from perinatal cortical ischemia.
36
Status Marmoratus
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ischemic neuronal loss and gliosis in basal ganglia and thalamus with aberrant and irregular myelin formation.
37
Skull Fractures
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fracture resistance varies with skull bone thickness.
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displaced fracture = bone shifts into cranial vault by more than its thickness.
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accidental falls = occiput. 2° basal skull involved with lower CN or cervicomedullary symptoms, CSF discharge, and/or meningitis.
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syncope ⇒ frontal skull.
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diastatic fractures = transverse sutures.
38
Concussion
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transient trauma-related clinical syndrome with loss of consciousness, temporary respiratory arrest, loss of reflexes, amnesia of event.
39
Direct Parenchymal Injury (Brain)
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lacerations = penetrating injury causes tissue tearing.
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contusions = CNS bruises.
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gyral crest very susceptible.
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coup contusion = at site of impact
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contrecoup = on opposite side of cranium from impact
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brain hemorrhage and edema resolves ⇒ depressed, yellow-brown glial scar going to pial surface = plaque jaune
- gyral crest very susceptible.
- coup contusion = at site of impact
- contrecoup = on opposite side of cranium from impact
40
Diffuse Axonal Injury
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when mechanical forces (acceleration) disrupt axonal integrity and axoplasmic flow.
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widespread axonal swelling and focal hemorrhage ⇒ degenerated fibers and gliosis.
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1/2 pts comatose after trauma have diffuse axonal injury even without contusions.
41
Epidural Hematoma
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rupture of dural arteries (middle meningeal artery) ⇒ blood btw dura and skull ⇒ compress brain.
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can have lucid period several hours after trauma
42
Subdural Hemorrhage
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tearing of veins that stretch from cortical surface through subarachnoid and subdural spaces into draining veins (superior sagittal sinus).
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after traumatic shifting of brain.
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geriatric pts with cerebral atrophy susceptible.
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presentation: non-localizing headache, confusion within 48hrs of injury.
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chronic subdural hematoma = recurrent episodes of bleeding from hemorrhage of thin-walled vessels of granulation tissue.
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tx: surgical drainage and remove granulation tissue.
43
Sequelae of Brain Trauma
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epilepsy, meningiomas, infectious disease, psychiatric disorders.
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post-traumatic hydrocephalus = hemorrhage into subarachnoid space obstructs CSF resorption
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post-traumatic dementia = dementia pugilistica. repeated head trauma ⇒ hydrocephalus, corpus callosum thinning, diffuse axonal injury, amyloid plaques, and neurofibrillary tangles.
44
Spinal Cord Trauma
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displacement of spinal column.
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injury level:
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thoracic vertebrae or below ⇒ paraplegia.
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cervical vertebrae ⇒ quadriplegia.
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C4 and above ⇒ respiratory compromise from diaphragm paralysis.
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acute = hemorrhage, necrosis, white matter axonal swellings
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later = cystic and gliotic. ascending and descending white matter tracts do 2° degeneration.
- thoracic vertebrae or below ⇒ paraplegia.
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cervical vertebrae ⇒ quadriplegia.
- C4 and above ⇒ respiratory compromise from diaphragm paralysis.
45
Global Cerebral Ischemia
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hypoxia from reduced blood flow or hypotension.
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neurons more sensitive to hypoxia.
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severe ⇒ widespread neuronal cell death, pt vegetative state or brain dead.
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brain dead = flat EEG, absent reflexes/respiratory drive/cerebral perfusion
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kept on ventilator ⇒ brain autolyzes.
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watershed/border zone infarcts = oxygenation incompletely compromised. interface between major vessels.
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btw anterior and middle cerebral arteries most vulnerable.
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morphology: edematous with widened gyri and narrowed sulci. poor gray/white demarcation.
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red neurons 12-24hrs post injury. pyramidal neurons in hippocampus CA1 (Sommer sector), cerebellar Purkinje cells, cortical pyramidal neurons most susceptible.
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then neutrophil infiltration ⇒ macrophage influx, neovascularization, reactive gliosis.
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pseudolaminar necrosis = uneven cortical neuronal loss and gliosis alternating with preserved zones.
- brain dead = flat EEG, absent reflexes/respiratory drive/cerebral perfusion
- kept on ventilator ⇒ brain autolyzes.
- btw anterior and middle cerebral arteries most vulnerable.
- red neurons 12-24hrs post injury. pyramidal neurons in hippocampus CA1 (Sommer sector), cerebellar Purkinje cells, cortical pyramidal neurons most susceptible.
- then neutrophil infiltration ⇒ macrophage influx, neovascularization, reactive gliosis.
- pseudolaminar necrosis = uneven cortical neuronal loss and gliosis alternating with preserved zones.
46
Stroke
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brain oxygen deprivation from global or focal ischemic necrosis.
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outcome depends on collateral circulation, duration of ischemia, magnitude and rapidity of flow reduction.
47
Focal Cerebral Ischemia
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infarction from obstruction of local blood supply ⇒ thrombotic or embolic arterial occlusion.
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thrombosis = from atherosclerosis. affects extracerebral carotid system and basilar artery.
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embolism = involves intracerebral arteries (middle cerebral). comes from atheromatous cerebrovascular plaques, cardiac mural trhombi, valvular lesions, or paradoxical embolisms.
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inflammatory lesions can ⇒ lumenal narrowing and cerebral infarct.
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venous infarcts after occlusion of superior sagittal sinus or deep cerebral veins. are hemorrhagic.
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morphology: nonhemorrhagic infarcts = bland/anemic infarcts. see at 48hrs as pale, soft regions of edematous brain with neutrophils. then liquefies ⇒ fluid-filled cavity with macrophages lined by reactive glia.
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hemorrhagic infarcts = embolic occlusion with reperfusion injury, have blood extravasation.
- hemorrhagic infarcts = embolic occlusion with reperfusion injury, have blood extravasation.
48
Lacunar Infarcts
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small cystic infarcts from cerebral arteriolar sclerosis and occlusion.
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lipid-laden macrophages and surrounding gliosis.
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affects: lenticular nucleus, thalamus, internal capsule, deep white matter, caudate nucleus, and pons.
49
Slit Hemorrhages
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when HTN causes small vessel rupture.
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they resorb leaving hemosiderin-laden macrophages and gliosis.
50
Acute Hypertensive Encephalopathy
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↑ ICP ⇒ diffuse cerebral dysfunction (headaches, confusion, vomiting, convulsions, coma).
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need rapid intervention.
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post mortem shows edematous brain with petechiae and arteriolar fibrinoid necrosis. somtimes see herniation.
51
Chronic Hypertensive Injury
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recurrent small infarcts ⇒ vascular (multi-infarct) dementia
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dementia, gait abnormalities, pseudobulbar signs, focal neuro deficits.
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Binswanger disease = pattern of recurrent ischemic injury involves subcortical white matter with myelin and axonal loss.
- dementia, gait abnormalities, pseudobulbar signs, focal neuro deficits.
52
Intracerebral Hemorrhage
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spontaneous rupture of small intraparenchymal vessel.
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age >60yrs.
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causes:
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HTN in 50%. ⇒ hyaline arteriosclerosis and vessel weakening, focal vessel necrosis, Charcot-Bouchard aneurysms. in putamen (50-60%), thalamus, pons, cerebellar hemispheres.
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cerebral amyloid angiopathy (CAA): 2nd most common. amyloidogenic peptides deposited in vessel walls ⇒ weakening. lesions have stiff amyloid deposits in leptomeningeal and cerebral cortical vessels.
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cerebral autosomal dominanty arteriopathy with subcortical infarcts (CADASIL): mutation in Notch3 receptor. vessels have concentric medial and adventitial thickening with basophilic granular depostis and smooth muscle drop-out
- HTN in 50%. ⇒ hyaline arteriosclerosis and vessel weakening, focal vessel necrosis, Charcot-Bouchard aneurysms. in putamen (50-60%), thalamus, pons, cerebellar hemispheres.
- cerebral amyloid angiopathy (CAA): 2nd most common. amyloidogenic peptides deposited in vessel walls ⇒ weakening. lesions have stiff amyloid deposits in leptomeningeal and cerebral cortical vessels.
- cerebral autosomal dominanty arteriopathy with subcortical infarcts (CADASIL): mutation in Notch3 receptor. vessels have concentric medial and adventitial thickening with basophilic granular depostis and smooth muscle drop-out
53
Subarachnoid Hemorrhage
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usually from berry (saccular) aneurysm rupture, traumatic hematomas, vascular malformations, HTN intracerebral hemorrhage, tumors, hematologic disturbances.
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pathogenesis: 90% berry aneurysms in anterior circulation near arterial branch points.
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can be with polycystic kidney disease (autosomal dominant), HTN, aortic coarctation, collagen disorders, neurofibromatosis type I, and fibromuscular dysplasia
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morphology: small with red shiny translucent wall. at aneurysm neck, the muscular wall and intimal elastic lamina are absent. sac wall is only thickened hyalinized intima.
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presentation: rupture from ↑ ICP. excruciating headache, rapid loss of consciousness. re-bleeding common with worse episode each time the aneurysm bleeds.
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blood in subarachnoid ⇒ arterial vasospasm.
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blood resorption ⇒ meningeal fibrosis and hydrocephalus
- can be with polycystic kidney disease (autosomal dominant), HTN, aortic coarctation, collagen disorders, neurofibromatosis type I, and fibromuscular dysplasia
- blood in subarachnoid ⇒ arterial vasospasm.
- blood resorption ⇒ meningeal fibrosis and hydrocephalus
54
Arteriovenous Malformation
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tangles of abnormalled tortuous and misshapen vessels, shunting arterial blood into venous circulation.
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usually MCA.
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2:1 m:f
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presentation: btw ages 10-30yrs as seizure disorder, intracerebral hemorrhage, or subarachnoid hemorrhage
- usually MCA.
55
Cavernous Hemangiomas
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distended, loosely organized vascular channels with thin, collagenized walls.
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usually cerebellum, pons, and subcortical regions.
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low flow without arteriovenous shunting.
56
Capillary Telangiectasias
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microscopic foci of dilated, thin-walled vascular channels separated by normal brain parenchyma.
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in pons.
57
Venous Angiomas
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aka varices
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aggregates of ecstatic veins.
58
Foix-Alajouanine Disease
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venous angiomatous malformation in lumbosacral region.
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slowly progressive ischemia and neuro symptoms.
59
Acute Bacterial Meningitis
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neonates = E. coli and group B strep
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infants & kids = S. pneumoniae
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adolescents & young adults = N. meningitidis
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elderly = S. pneumoniae and L. monocytogenes
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morphology: meningeal vessels engorged, purulent exudate.
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neutrophils in subarachnoid space. may have cerebritis.
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phlebitis ⇒ venous thrombosis and hemorrhagic infarction.
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resolution ⇒ leptomeningeal fibrosis and hydrocephalus
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presentation: fever, headache, photophobia, irritability, clouded sensorium, neck stiffness.
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CSF purulent with neutrophils and organisms, ↑ protein, and ↓ glucose.
- neutrophils in subarachnoid space. may have cerebritis.
- phlebitis ⇒ venous thrombosis and hemorrhagic infarction.
- resolution ⇒ leptomeningeal fibrosis and hydrocephalus
- CSF purulent with neutrophils and organisms, ↑ protein, and ↓ glucose.
60
Acute Viral Meningitis