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23 Cards in this Set
- Front
- Back
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What causes polio?
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Enterovirus (small RNA virus)
Highly selective for motor fibers of the CNS (esp spinal cord and medulla) |
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What does polio mean?
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Grey....therefore a disease of the greay matter of the CNS
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How is polio acquired?
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Fecal oral transmission (excreted in stool for 5 weeks!)
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What are the reservoirs for polio?
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Human
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What is the seasonality of polio?
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Summer fall of enterovirus, year round in tropics
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What is the dromedary curve of polio?
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1-2% of patients...get minor illness, feel ok, then struck with major illness
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Where is virus in the first stage of dromedary curve?
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In blood
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Where is virus in second stage of dromedary curve?
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In feces and saliva
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What are the different presentations of polio infection?
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Incubation 7-14d
Asymptomatic Infection Abortive polio (fever, malaise, H/A, Nausea, done) Nonparalytic polio (stiffness/pain in neck, aseptic meningitis, can resolve or progress) Paralytic polio (assymetrical acute flacid paralysis, brainstem/incoordination, painful muscle spasms) |
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What is the mortality of polio?
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2-20% (40% with brain stem dz)
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What is Progressive Post Polio Muscle Atrophy?
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Recrudescence of paralysis and wasting decades after initial dz
RARE |
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DDX polio
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Guillan Barre Syndreom (paralysis symmetrical, slower, high CSF protein)
Transverse myelitis (alterend motor and sensorium -- from bacterial infection spinal cord) |
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How to confirm a case of polio
(for monitoring purposes) |
Lab confirmation
Epi link to another case Paralysis remaining 60d (as GBS resolves) Death Loss to f/u |
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What percentage of polio develops paralysis?
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only 2%
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How to dx polio?
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Stool/rectal swab for culture
Paired sera for serology (complement fixation titres, neutralizing antibody titires) At autopsy, nerve adn GI sections for cx |
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What vaccines are available to prevent polio?
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OPV
IPV |
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OPV advantages?
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Stored frozen indefinitely
Cheap Produces rapid local immnue response Produces secondary vacccine spread in stool |
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OPV problems?
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Reduced vaccine response in tropics due to viral interference (non-polio enterovirus), antibodies, breast milk IgA
Needs cold chain Can get vaccine-associated paralytic polio (1:20,000 1st dose, 1:12 million later doses) |
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Who were the last to get polio in the us?
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Omish
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How common is vaccine-associated paralytic polio?
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5-10 cases per year if use only OPV
No predictors of who is at risk Risk drops if first dose is IPV |
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How much herd immunity is requred to protect from polio?
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70% (unlike measles, 98%)
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What polio vaccine is used in the US?
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IPV, because we're rich and lucky
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OPV schedule?
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2-3 doses monthly, at age 2-3 mos (sometimes at birth)
Booster at 18 mos and 4 y/o Pregnancy vaccine is controversial |
