Congenital syphilis: No longer just of historical interest

Question 1

How is syphilis acquired?

Answer 1

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

Question 2

When should syphilis be suspected in a pregnant woman?

Answer 2

Always as many infected persons are asymptomatic

Question 3

What is the risk of vertical transmission?

Answer 3

• 70-100% untreated primary or secondary syphilis during pregnancy - 40% early latent syphilis (as risk of re-activation) - <10% if late latent syphilis

Question 4

When should pregnant women be screened?

Answer 4

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

Question 5

When can syphilis be transmitted?

Answer 5

Usually after the 4th month of gestation 9 wk GA to delivery if contact with active genital lesion

Question 6

What should you do if syphilis serology was not performed during pregnancy?

Answer 6

Do not discharge the newborn until maternal serology is drawn and f/u is arranged

Question 7

When should you screen the mother for syphilis postpartum?

Answer 7

if the cause is not known for a hydropic or stillborn newborn

Question 8

What serological tests exist for syphilis?

Answer 8

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

Question 9

How should you interpret serological tests for syphilis if RPR is the initial screen?

Answer 9

• 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

Question 10

Why are RPR titres still required if EIA is used as an initial screen?

Answer 10

Staging of infection

Following the response to treatment

Diagnosing re-infection

Question 11

How should you interpret serological tests for syphilis if EIA is the initial screen?

Answer 11

• 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

Question 12

What is the expected RPR titre decline with adequate therapy during/before pregnancy?

Answer 12

Primary syphilis

• fourfold drop @ 6m
• eightfold drop @ 12m
• 16-fold drop @ 24m

Secondary syphilis

• eightfold drop @ 6m
• 16-fold drop @ 12m

Early latent syphilis

• fourfold drop @ 12m

Question 13

Which infants should be considered to be at risk for congenital syphilis?

Answer 13

• maternal RPR titres did not decline appropriately
• follow-up titres were not obtained
• if maternal reinfection is a possibility

Question 14

What are common features of congenital syphilis?

Answer 14

1. spontaneous abortion/stillbirth/hydrops fetalis
2. necrotizing funisitis
3. rhinitis and/or snuffles
4. rash
5. hepatomegaly/splenomegaly
6. lymphadenopathy
7. neurosyphilis
8. musculoskeletal involvement
9. hematological abnormalities
10. interstitial keratitis
11. Hutchinson’s teeth
12. Mulberry molars
13. Eighth nerve deafness (sensory neurodeafness)

Question 15

What is the expected course of infant RPR titres?

Answer 15

Decline by 3mo and be non-reactive by 6mo in the absence of congenital syphilis

Question 16

What is the expected course of infant treponemal test results (i.e. EIA)?

Answer 16

Passiv antibodies from ohtr infctions usu. clar by 12mo and always clear by 18mo

Question 17

How do you interpret infant CSF results re: congenital syphilis?

Answer 17

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

Question 18

What is the treatment of choice for congenital syphilis?

Answer 18

Crystalline Benazathine Penicillin G 50 000U/kg IV x 10d course

• q12h infants <1wo
• q8h infants 1-4wo
• q6h infants >4wo

Question 19

When should follow-up serology be done post treatment of congenital syphilis?

Answer 19

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