Congenital Syphilis

Congenital syphilis results from transplacental transmission of Treponema pallidum from an infected mother to her fetus (or by contact with genital lesions at birth). Infection can occur at any stage of pregnancy and at any stage of maternal disease, with the highest risk (70 to 100%) with primary and secondary syphilis, falling to about 40% with early latent syphilis and under 10% with late latent disease.

Consequences include stillbirth (up to 40% of untreated cases), neonatal death, prematurity, and congenital disease. There has been a resurgence in many countries, driven by missed antenatal screening and treatment failures.

Early congenital syphilis presents before 2 years; late congenital syphilis presents after 2 years (typically in childhood or adolescence).

• Early (first weeks of life to 2 years): most are asymptomatic at birth; features include hepatosplenomegaly, jaundice, hepatitis, snuffles (persistent rhinitis with blood stained discharge), mucocutaneous lesions (vesiculobullous rash with palmar and plantar involvement, maculopapular rash, desquamation, condylomata lata, perioral fissures), lymphadenopathy, pseudoparalysis of Parrot (painful osteochondritis and periostitis), anaemia, thrombocytopenia, nephrotic syndrome, pneumonia alba, meningitis, chorioretinitis, and hydrops fetalis
• Late (after 2 years): Hutchinson triad (Hutchinson teeth: notched, peg shaped upper central incisors; interstitial keratitis; sensorineural deafness of the eighth cranial nerve), mulberry molars, saddle nose, frontal bossing (olympian brow), saber shins (anterior bowing of the tibia), Clutton joints (painless knee effusions), higoumenakia sign (thickening of the sternoclavicular joint), rhagades (perioral linear scars), high arched palate, and neurosyphilis with intellectual disability and hydrocephalus

1. Maternal screening: treponemal (EIA, chemiluminescence immunoassay, TPPA, or FTA-ABS) and non-treponemal (RPR or VDRL) tests at the first antenatal visit, at 28 to 32 weeks, and at delivery in high risk settings.
2. Infant evaluation: infants born to mothers with reactive serology need clinical examination, quantitative non-treponemal test on infant serum (not cord blood; a fourfold or greater titre than the mother's confirms infection), and treponemal IgM (limited availability).
3. Direct detection: darkfield microscopy or direct fluorescent antibody of lesion exudate or nasal discharge, PCR, and histopathology of placenta or umbilical cord (necrotising funisitis).
4. Additional evaluation: CSF examination (VDRL, cell count, protein), full blood count, liver function tests, long bone radiographs (metaphyseal lucency, periostitis, Wimberger sign), chest radiograph, cranial ultrasound, ophthalmological and audiological testing.
5. Case classification: proven or highly probable disease (abnormal examination, serological titre fourfold above maternal, positive darkfield or PCR), possible disease (normal exam and infant titre equal or less than fourfold, but mother not or inadequately treated), less likely, and unlikely.

• Proven, highly probable or possible congenital syphilis (including abnormal CSF): aqueous crystalline penicillin G 50,000 units/kg IV every 12 hours during the first 7 days of life, then every 8 hours for a total of 10 days; or procaine penicillin G 50,000 units/kg IM once daily for 10 days. If more than 1 day of therapy is missed, restart the full course. Ampicillin is not an adequate substitute. Penicillin allergic infants must be desensitised.
• Infants with normal exam and titre equal to or less than fourfold maternal, whose mothers were treated inadequately (less than 4 weeks before delivery, non-penicillin regimen, or inadequate documentation): benzathine penicillin G 50,000 units/kg IM in a single dose (alternatively, the 10-day course); infants with a mother adequately treated (at least 4 weeks before delivery, appropriate regimen, with expected serological decline) may be observed with serology follow up or given a single dose.
• Older infants and children with late congenital syphilis: aqueous penicillin G 200,000 to 300,000 units/kg/day IV in divided doses every 4 to 6 hours for 10 days; test for HIV.
• Follow up: clinical and serological assessment (non-treponemal titres) at 2, 4, 6 and 12 months until non-reactive or fourfold decline; repeat CSF at 6 months if initially abnormal; ophthalmology and audiology as indicated. Treat sexual partners of the mother.
• Prevention: universal antenatal screening and benzathine penicillin G 2.4 million units IM weekly (for 1 to 3 doses depending on stage) for infected mothers at least 30 days before delivery; the Jarisch-Herxheimer reaction can precipitate preterm labour and fetal distress, so monitor.
• Test for other sexually transmitted infections, including HIV, hepatitis B, hepatitis C, gonorrhoea and chlamydia.