How is syphilis acquired?
1. Vaginal, anal or oral sex within the preceding year 2. kissing 3. blood transfusions 4. sharing of needles 5. accidental inoculation or direct contact with an infected lesions
When should syphilis be suspected in a pregnant woman?
Always as many infected persons are asymptomatic
What is the risk of vertical transmission?
- 70-100% untreated primary or secondary syphilis during pregnancy - 40% early latent syphilis (as risk of re-activation) - <10% if late latent syphilis
When should pregnant women be screened?
1. at first prenatal visit routinely 2. 28-32 wks GA if high risk 3. at delivery if high risk High risk = women from countries with high prevalence of syphilis or in areas experiencing outbreaks of heterosexual syphilia
When can syphilis be transmitted?
Usually after the 4th month of gestation 9 wk GA to delivery if contact with active genital lesion
What should you do if syphilis serology was not performed during pregnancy?
Do not discharge the newborn until maternal serology is drawn and f/u is arranged
When should you screen the mother for syphilis postpartum?
if the cause is not known for a hydropic or stillborn newborn
What serological tests exist for syphilis?
Non-treponemal tests: 1. Rapid plasmin reagin (RPR) 2. Venereal research laboratory (VDRL) test Treponemal-specific antibody tests: 3. Fluorescent trepenomal antibody absorption (FTA_ABS) 4. Treponema pallidum particle agglutination 5. microhemagglutination for T pallidum 6. enzyme immunoassay (EIA) 7. Line blot immunoassay e.g. INNO-LIA
How should you interpret serological tests for syphilis if RPR is the initial screen?
- primary syphilis --> RPR NR, TPPA NR, FTA-ABS R
- syphilis any stage --> RPR R, TPPA R, FTA-ABS R
- treated syphilis OR early infection OR late latent/tertiary syphilia OR in persons from endemic countries OR Lyme disease --> RPR NR, TPPA R, FTA-ABS R
- False positive --> RPR R, TPPA NR, FTA-ABS NR
Why are RPR titres still required if EIA is used as an initial screen?
Staging of infection
Following the response to treatment
How should you interpret serological tests for syphilis if EIA is the initial screen?
- Not a case --> EIA -ve, RPR & confirmatory test not performed
- repeat serology because there may be early seroconversion but if serology remains unchanged, not a case --> EIA borderline/indeterminate, RPR NR, Confirmatory test -ve or indeterminate
- early primary syphilis OR late latent/tertiary syphilis OR previously treated syphilis OR in persons from endemic countries, or Lyme disease --> EIA borderline/indeterminate, RPR NR, confirmatory test reactive/positive
- false positive --> EIA +ve, RPR R or NR, confirmatory test negative
- repeat serology to determine stage or false positve --> EIA +ve, RPR reactive, confirmatory test indeterminate
- repeat serology to determine stage or false positive --> EIA +ve, RPR NR, Confirmatory test indeterminate
- early primary syphilis OR late latent/tertiary syphilis OR prev. tx syphilis OR in persons from endemic countries, OR Lyme disease --> EIA +ve, RPR NR, confirmatory test R
- syphilis any stage --> EIA +ve, RPR reactive, confirmatory tests R/+ve
What is the expected RPR titre decline with adequate therapy during/before pregnancy?
- fourfold drop @ 6m
- eightfold drop @ 12m
- 16-fold drop @ 24m
- eightfold drop @ 6m
- 16-fold drop @ 12m
Early latent syphilis
- fourfold drop @ 12m
Which infants should be considered to be at risk for congenital syphilis?
- maternal RPR titres did not decline appropriately
- follow-up titres were not obtained
- if maternal reinfection is a possibility
What are common features of congenital syphilis?
- spontaneous abortion/stillbirth/hydrops fetalis
- necrotizing funisitis
- rhinitis and/or snuffles
- musculoskeletal involvement
- hematological abnormalities
- interstitial keratitis
- Hutchinson's teeth
- Mulberry molars
- Eighth nerve deafness (sensory neurodeafness)
What is the expected course of infant RPR titres?
Decline by 3mo and be non-reactive by 6mo in the absence of congenital syphilis
What is the expected course of infant treponemal test results (i.e. EIA)?
Passiv antibodies from ohtr infctions usu. clar by 12mo and always clear by 18mo
How do you interpret infant CSF results re: congenital syphilis?
CSF VDRL lacks sensitivity but reactive CSF VDRL is diagnostic of neurosyphilis
CSF FTA-ABS lacks specificity and should not be routinely performed, negative FTA-ABS r/o diagnosis of neurosyphilis
What is the treatment of choice for congenital syphilis?
Crystalline Benazathine Penicillin G 50 000U/kg IV x 10d course
- q12h infants <1wo
- q8h infants 1-4wo
- q6h infants >4wo
When should follow-up serology be done post treatment of congenital syphilis?
Loss of treponemal antibodies by 18mo in infants:
- infants who did not have congenital infection
- infants who had treatment very early after congenital infection
Sustained > fourfold drop in RPR in all other infants treated for congenital syphilis
If CSF was initial abnormal --> CSF q6m until normal
May require second course of treatment