Congenital syphilis

From IDWiki

Background

Epidemiology

  • Rare, with about 20 per 100,000 live births in the US
  • Greatest risk to child is with untreated primary maternal syphilis, and almost exclusively to those mothers with an RPR titre of 1:8 or greater

Pathophysiology

  • Transplacental transmission while bacteremic
  • Can be transmitted during delivery, as well

Clinical Manifestations

Hutchison Triad

Diagnosis

  • Darkfield microscopy and/or PCR on body fluids, including nasal discharge or CSF
  • Serology
    • RPR on infant blood (not cord blood), paired with maternal RPR
    • May need CSF analysis
  • Also check HIV serology, skeletal survey, chest x-ray, ophthalmology, audiology, and cranial ultrasound

Management

  • Treat syphilis in pregnancy with penicillin to prevent congenital syphilis
  • For infants that require treatment, the treatment of choice is crystalline penicillin G
    • Age 1 to 7 days: 50,000 U/kg IV q12h
    • Age 1-4 weeks: 50,000 U/kg q8h
    • Age >4 weeks: 50,000 U/kg q6h
  • Duration is typically 10 days
    • Don't forget to dose adjust from q12h to q8h after the first 7 days
  • Can treat lower-risk infants with benzathine penicillin G 50,000 U/kg IM once

Canadian Guidelines

  • Treat infants at birth if:
    • Symptomatic
    • Infant's RPR at least four-fold higher than mother's
    • Maternal treatment inadequate, did not contain penicillin, is unknown or occurred in the last month of pregnancy, or if the maternal serologic response is inadequate
    • Adequate follow-up can't be ensured
  • Specific scenarios are described in the table below
Maternal treatment Neonatal assessment Recommendations
Type Timing Outcome Monthly exam for 3 months Serology CBC/CSF/x-rays Treatment
any before pregnancy adequate, with no RPR rise and no risk factors for reinfection normal exam no no no none
primary, secondary, or early latent >4 weeks before delivery adequate normal exam, RPR < 4-fold maternal yes 0, 3, 6, and 18 months no none
≤4 weeks before delivery normal exam, RPR < 4-fold maternal yes 0, 3, 6, and 18 months; if not treated, also at 1, 2, and 12 months yes usually
not penicillin normal exam, RPR < 4-fold maternal yes 0, 3, 6, and 18 months; if not treated, also at 1, 2, and 12 months yes usually
before or during pregnancy RPR not decline as expected normal exam, RPR < 4-fold maternal yes 0, 3, 6, and 18 months; if not treated, also at 1, 2, and 12 months yes usually
before pregnancy inadequate, or reinfection normal exam, RPR < 4-fold maternal yes 0, 3, 6, and 18 months; if not treated, also at 1, 2, and 12 months consider depends on risk and results of assessments
during pregnancy unknown normal exam, RPR < 4-fold maternal yes 0, 3, 6, and 18 months; if not treated, also at 1, 2, and 12 months consider depends on risk and results of assessments
primary or secondary syphilis during pregnancy inadequate normal exam, RPR < 4-fold maternal yes 0, 3, 6, and 18 months; if not treated, also at 1, 2, and 12 months yes 10 days
late latent during or after pregnancy adequate normal exam, RPR < 4-fold maternal no 0, 6, and 18 months no none
any during pregnancy normal exam, RPR < 4-fold maternal follow-up unlikely yes 0, 3, 6, and 18 months; if not treated, also at 1, 2, and 12 months consider depends on risk and results of assessments
any any treponemes on tissue examination yes 0, 3, 6, and 18 months; if not treated, also at 1, 2, and 12 months yes 10 days
infant's RPR four-fold or greater than the mother's at birth yes 0, 3, 6, and 18 months; if not treated, also at 1, 2, and 12 months yes 10 days
four-fold rise in infant's titre yes 0, 3, 6, and 18 months; if not treated, also at 1, 2, and 12 months yes 10 days
signs of congenital syphilis at any age yes 0, 3, 6, and 18 months; if not treated, also at 1, 2, and 12 months yes 10 days
RPR & TT reactive at 6 months yes usually
reactive RPR & TT at 12 months yes 0, 3, 6, and 18 months; if not treated, also at 1, 2, and 12 months yes 10 days
reactive TT at 18 months yes 0, 3, 6, and 18 months; if not treated, also at 1, 2, and 12 months yes 10 days
  • Serology includes RPR and treponemal tests
    • In the absence of congenital syphilis, RPR declines by about three months and is usually non-reactive by 6 months, and treponemal tests usually clear by 12 months and always by 18 months
  • Investigations include long-bone x-rays, CBC, and CSF (for glucose, protein, and VDRL), ± ophthalmological and audiological tests
  • Skin lesions, nasal discharge, placental lesions, and the umbilical cord can be sent for darkfield microscopy or DFA testing

US Guidelines

Initial neonatal assessment Maternal treatment Recommendations
RPR/VDRL Evaluation Timing Type Evaluation Treatment
any physical exam suggests congenital syphilis any any LP and CBC 10 days
spirochete in a clinical specimen
≥ fourfold maternal titre any any any LP and CBC 10 days
less than fourfold maternal titre normal before pregnancy adequate none none (or one dose)
reinfection or relapse (≥4-fold increase in titre) LP and CBC one dose (unless exam at all abnormal)
during pregnancy adequate none one dose (or none)
inadequate or suboptimal LP and CBC one dose (unless exam at all abnormal)
nonreactive normal during pregnancy adequate none none (or one dose)
inadequate or suboptimal none one dose
  • LP should be sent for VDRL, cell count, protein
  • CBC with differential for platelet count

Further Reading