syhpilis

Question 1

rubella IgM positive

Answer 1

distinguish between primary infection & reinfection with rubella vaccine virus by IgG avidity assay in pregnant women

Question 2

avidity

Answer 2

strength in which a multivalent Ab binds a multivalent Ag

Question 3

ulcerative infections

Answer 3

-syphilis does not hurt
-herpes does hurt
-both genital ulcers

Question 4

frequency of genital ulcer infections

Answer 4

HSV > syphilis > chancroid
-chancroid is rare

Question 5

herpesviruses

Answer 5

large, enveloped DNA viruses

Question 6

HSV

Answer 6

-common cold sores
-can be neonatal or congenital
-risk of transmission is with primary maternal infection at the time of delivery
-risk smaller with recurrent herpes at time of delivery

Question 7

VZV

Answer 7

chickenpox & shingles

Question 8

HHV-6

Answer 8

-primary target of infection is T cells

Question 9

prevention of neonatal herpes

Answer 9

-recognition
-elective section in primary herpes at term of <4 hours after membrane rupture
-elective selection when recurrent genital herpes is present at term

Question 10

syphilis infection

Answer 10

-treponema pallidum (spirochete)
-sexually transmitted
-placental transmission >6 weeks gestation (mostly second half of pregnancy). mom with primary or secondary syphilis more likely to transmit

Question 11

syphilis neonatal clinical manifestations

Answer 11

fetal: still birth, neonatal death, hydrops fetalis
-intrauterine death 25%
-perinatal mortality in 25-30% if untreated

Question 12

early congenital syphilis manifestation

Answer 12

-1st 5 weeks
-cutaneous lesions (palms/soles)
-HSM
-jaundice
-anemia
-snuffles
-periostitis & metaphysical dystrophy (bone abnormality)
-funisitis

Question 13

late congenital syphilis manifestations

Answer 13

-frontal bossing
-short maxilla
-high palatal arch
-hutchinson teeth (sharp)
-8th nerve deafness
-saddle nose
-perioral fissures

Question 14

RPR/VDRL

Answer 14

nontreponemal test
-sensitive but not specific
-quantitative, can follow up to monitor treatment treatment
-all pregnant women get screened early & at term

Question 15

MHA-TP/FTA-ABS

Answer 15

specific treponemal
-confirmatory testing
-qualitative, once positive always positive

Question 16

CDC definition of congenital syphilis

Answer 16

confirmed if T. pallidum identified in skin lesions, placenta, umbilical cord or at autopsy

Question 17

latent syphilis

Answer 17

-seroreactivity without other evidence of primary, secondary or tertiary disease

Question 18

manifestation of primary syphilis

Answer 18

chancre:
-painless, but tender
-indurated
-highly contagious
-rapid dissemination
congenital

Question 19

manifestation of secondary syphilis

Answer 19

-diffuse maculopapular rash: non pruritic, lesions on palms & soles
-mucous membrane lesions/patches
-fever
-jaundice
-scleral icterus

Question 20

stages of syphilis

Answer 20

-primary: painless sores (chancre) at inoculation site
-secondary: rash, fever, lymphadenopathy, malaise
-tertiary/latent: CNS invasion, organ damage

Question 21

syphilis microbiology

Answer 21

-labile spiral bacterium with axial filaments
-non-cultivable: rely on dark field microscopy for diagnosis
-gram neg

Question 22

RIT

Answer 22

rabbit infectivity test:
-high sensitivity & specificity
-long TAT
-limited to research setting

Question 23

dark field microscopy

Answer 23

-primary infection
-expertise required

Question 24

immunostaining

Answer 24

direct fluorescent Ab or silver stain

Question 25

PCR

Answer 25

research only

Question 26

non-treponemal assays (RPR/VDRL)

Answer 26

-t. pallidum infections leads to production of reagin - reagin react with cardiolipin

Question 27

reagin

Answer 27

Abs to substances released from cells damaged by T. pallidum

Question 28

cardiolipin

Answer 28

phospholipid component of certain eukaryotic & prokaryotic membranes

Question 29

non-treponemal advantages

Answer 29

-rapid TAT -inexpensive -no specialized instrumentation needed -usually revert to negative following therapy -monitor response to therapy -successful treatment: 4 fold decrease in RPR titer

Question 30

non-treponemal limitations

Answer 30

-results are subjective -non-specific (false pos) -limited sensitivity in early/late infection -low throughput -prozone effect: high levels of Ab inhibit agglutination, dilute sample

Question 31

treponemal assays

Answer 31

-infection leads to production of specific Abs directed against t. pallidum -detect IgG (or total IgM/IgG) Abs against T. pallidum -multiplex flow immunoassay

Question 32

serologic treponemal assays for syphilis

Answer 32

-MHA -FTA-ABS -TP-PA -EIA -MFI

Question 33

treponemal limitations

Answer 33

-remain positive despite treatment (not used to monitor therapy) -conventional methods (subjective interpretation) -newer methods (expensive)

Question 34

traditional syphilis algorithm

Answer 34

1. RPR NR = neg for syphilis R = treponemal test (FTA) 2. FTA R = syphilis NR = no syphilis

Question 35

traditional algorithm advantages

Answer 35

-good correlation with disease state -rapid & cheap -approved by CDC -good for small labs -refluxed confirmation test leads to clear results

Question 36

traditional algorithm disadvantages

Answer 36

-manual & subjective -non-specific & leads to false + -not good for high volume labs -lower sensitivity in early/late syphilis

Question 37

reverse syphilis algorithm

Answer 37

1. treponemal (EIA) R = step 2 NR = no syphilis 2. RPR R = syphilis NR = step 3 3. second treponemal (TP-PA) R = probable syphilis NR = no syphilis

Question 38

reverse algorithm advantages

Answer 38

-automated treponemal assays -objective interpretation -results from EIA or MFI can be interfaced with LIS -specific screening for T. pallidum Abs -increased detection of early syphilis

Question 39

reverse algorithm disadvantages

Answer 39

-high cost -higher assay complexity -increased detection of patients with + screen, RPR -