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53 Cards in this Set
- Front
- Back
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Ddx of measles?
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Rubella (german measles)
Scarlatina (strep) - less catarrhal, more papular Typhoid (rose spot rash, doesn't last long) Serum sickness Allergic rash (esp ampicillin) |
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What is the gold standard for dx measles?
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Plaque neutralization
Most expensive, time consuming, requires live virus, hood (infect tissue cx with measles...then add antibodies) Elisa: cheap, easy, no reader, sensitive Hemagglutination inhibition - less reliable, expensive |
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How to mangage measles?
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fever reduction
airway mgmt cleanse conjunctivae maintain fluids high protein/calorie diet oval vitamin A 250,000U qd x2 |
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Measles control measures
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Quarantine (stopgap)
Vaccine (immunity starts within a week) Measles Immuge Globulin or Immune serum globulin (may prevent dz if given within 6 d exposure) -- in high risk folks, like immunocompromised |
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Considerations for use of measles vaccine
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Regional variation in maternal antibody
Age of vaccination 6 vs 9 mos Little vaccine virus spread Effect of vaccine strain and dose |
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When to immunize children in a measles outbreak?
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Shift from 9 mos to 6 mos, revaccinate at 12 mos
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What was the probem with the Edmonston-Zagreb measles vaccine?
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Pomoted in 1980s
Better window period Increase antibodies seen BUT more all cause mortality in girls, more potent bad wild measles habits, like immunosuppression in gut |
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What easles vaccine is recommended by WHO
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Shwartz
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How effective are measles vaccines?
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Vaccine induces antibodies in 95%
(outbreaks occur with even 99% coverage) |
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What is active immunity?
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From a person's own immune system
Usually permanent |
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What is passive immunity?
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Transferred from another person or animal as an antibody
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Most common passive immunity?
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Maternal (transplacental) antibodies IgG
Cross placental in 3rd trimester (therefore none in preemees) Degrade over time (6-8 mos) |
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Where are IgG antibodies found?
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In self
From transplacental |
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Where are IgA antibodies found?
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Dimers
In secretions A local antibody response |
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Where are IgM antibodies?
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Early antibodies
Pentomers Less specific -- dirty, rapid |
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Where are IgE antibodies found?
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Allergic reaction
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Sources of passive immunity?
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Blood or blood products
Gamma globulin shot (poled human antibodies against lots of things) Homologous human hyperimmune globulins (from donors who have been immunized) Heterologous hyperimmune serum (antitoxins) from on humans who have been exposed to toxins |
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What is a heterologous hyuperimmune serum
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Antitoin
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What is homologous pooled human antibody?
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Gamma globulin shot
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What does a vaccine do?
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Causes active immunity and immunologic memory similar to natural infection but without risk of dz
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What are the classes of vaccines?
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Live attenuated (weakened to not produce serious dz)
Inactivated (killed, or component vaccines -- were never alive) |
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Types of innactivated vaccines
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Whole virus
Whole baceria Fractional protein based -subunit (e.g hep b vaccine works based on surface antigen) - toxoid (antibodies against a toxoid...protein similar to toxin) Fractional polysacchaide base |
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What's the problem with polysaccharide based fractional vaccines?
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Children under 2 don't make good immune response to them.
By adding polysaccharide to a conjugate, younger kids can respond to vaccine |
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How do live attenuated vaccines work?
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Weakened form of wild virus/bacteria
Must replicate to be effective Usually effective within 1 dose Sometimes give booster (e.g. measles) |
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Problems with live attenuated vaccines?
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Severe reactions possible
Maternal antibodies may inactivate Unstable Harder to manufacture |
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Where do breastmilk antibodies work?
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IgA
Work ony at the gut level Interfere with oral live attenuated |
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What are some live attenuated viral vaccines?
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Measles
Mumps Rubella Vacinia Varicella Yellow fever Oral polio Influenza Rotavirus |
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what are some live attenuated bacterial vaccines?
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BCG
Oral typhoid |
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At what age can you give inactivated vaccines?
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Birth
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How many doses needed for inactiated vaccines to create immunity?
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3-5 doses
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Name some innactivated whole cell viral vaccines
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Influenza
Polio Rabies Hep A |
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Names some inactivated whole cell bacterial vaccines
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Pertussis
Typhoid Cholera Plague |
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Name some fractional inactivated vaccines (subunit vaccines)
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Hep B
Influenza Acellular pertussis Typhoid Vi Lyme |
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Name some fractional inactivated vaccines (toxoid)
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Diptheria
Tetanus |
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What kind of rash with measles?
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Maculpapular
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What virus causes measles?
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Paramyxovirus
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How long does measles virus live in the air?
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Hours
Highly contagious Concern in overcrowded setting |
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Are there non-human measles reservoirs?
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No
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What time of year is measles most common?
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Endemic year round in tropics
Outbreaks every 2-5 years |
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What is the problem with vit A deficiency and measles?
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Increases risk of disease and blindness
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Risk factors for measles?
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Malnutrition
Vit A deficiency Low vaccination coverage Age (loss of maternal antibodies...35% between 6-12 mos in tropics) Low maternal antibody levels due to diarrhea and serum protein loss/less dz Family size |
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Is case fatality rate of measles higher in Africa that US?
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YES
5-10% fatal in Africa 0.01% fatal in USA |
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Clinical features of Measles
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Incubation 10-12 days
Prodrome (contageous) - 3-4d fever, coryza, cough, conjunctivitis, Kopli spots 1-2d pre-rash, pharyngitis, red tip tongue, tracheobronchits/croup Rash - hairline down |
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When are you infectious with measles?
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From prodrome to 2 days into rashDiarrhea
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How does measles rash present?
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Head down
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Complications of measles?
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Hemorrhagic (bleeding into rash with purpura), GI, CNS bleeding, vasculitis, thrombocytopenia
Bacterial superinfection (OM, pneumonia) Hect's giant cell pneumonia (no rash, seen in adults, deadly) Encephalitis |
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What is a diarrheal complication of measles?
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Higher rate of OTHER diarrheal dz in year following measles due to cellular immunosuppression
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What is a bad side effect of killed measle's vaccine?
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Some reciptients get hypersensitivity (not immunity) to measles -- when infected, get severe form
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What percent of patients get measles encephalitis?
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0.5-1%
Occurs 3-5d post rash More common in older pts Renewed fever, vomiting, drowsiness, seizures, coma 10-30% mortality, 40% survivors with sequelae |
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CSF findings in measles encephalititis?
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Lymphocytosis
Normal to high protein/glucose |
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What is a latent measles complication?
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Subacute sclerosing panencephalitis (SSPE)
Years after infection Mental deterioration, myoclonic jerks Abnormal EEG |
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WBC count in measles?
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Lymphocytosis, frequently low (1500)
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CXR of measles
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Patchy pneumonic perihilar pattern
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