Multisystem infectious disease caused by Treponema pallidum and transmitted from mother to fetus via the placenta or by contact with an active maternal lesion during delivery. The overall risk of transplacental infection is around 60-80 %, and is increased during the 2nd half of pregnancy. Without treatment, the risk is much higher in cases of primary or secondary maternal syphilis, and lower in the latent or tertiary stages. Untreated syphilis during pregnancy is also associated with a significant risk of late fetal death and stillbirth. The incidence of congenital syphilis in the United States has risen sharply, with a more than 500 % increase in cases since 2010.

In adults, in the absence of treatment, there are 4 successive phases:

-        primary syphilis: painless chancre and adenopathies close to the site of inoculation (10-90 days after infectious contact)

-        secondary syphilis: flu-like episode with myalgias, arthralgias, multiple adenopathies, maculopapular rash on the palmoplantar area, condylomata (perineal, axillary)

-        latent syphilis: the signs of infection disappear. Early syphilis is defined as infection < 1 year before, and late syphilis as infection > 1 year before.

-        tertiary syphilis: progressive destruction of certain tissues (bones) by "gums" or lesion of the aorta.

Neurosyphilis can occur at any stage: meningitis, convulsions, progressive dementia, tabes. Sometimes: hearing loss, keratitis, optic atrophy.

The diagnosis is clinical, confirmed by microscopic identification or serology.

Regarding serology, a distinction is made between :

-        treponemal tests (FTA-ABS, fluorescent treponemal antibody absorption test): they detect antitreponemal antibodies; they remain positive in 80% of patients after recovery; a negative test indicates an absence of infection

-        non-treponemal tests (VDRL [Venereal Disease Research Laboratory], RPR [Rapid Plasma Reagin]): detect antibodies developed against biomarkers released during cellular destruction due to infection; there are many causes of a false positive response (tuberculosis, malaria, Ebstein-Barr infection, hepatitis, HIV), but they are useful for the therapeutic follow-up of congenital forms. The child is considered cured if the titre falls by > 4x over 12 months.

Treatment is IM or IV penicillin.

In infected newborns, syphilis manifestations are classified as early congenital (i.e., from birth to 2 years of age) or late congenital (i.e., after 2 years of age).

Early congenital syphilis

It is asymptomatic in 70 % of cases: only the serological tests are positive. It can also present as hydrops or death in utero.

The usual clinical signs are :

-        nasal congestion ('snuffles', bloody discharge)

-        necrotizing inflammation of the umbilical cord (funisitis)

-        desquamating maculopapular rash (often limited to the palmoplantar areas)

-        perioral fissures

-        adenopathies

-        hepatosplenomegaly with jaundice

-        perforation of the palate

-        osteochondritis, fractures

-        diffuse or localized osteitis: "mitted" appearance of the diaphysis

-        periostitis with pseudoparalysis of the affected limb (Parrot's atrophy of the newborn)

-        metaphysitis: often appears as light or dense bands which may alternate to give the appearance of a sandwich rod or celery stick. Wimberger's sign corresponds to symmetrical erosions of the upper part of the tibia, but may also consist of erosions in the metaphysis of other long bones.

-        excessive callus formation at the ends of long bones.

The search for syphilis is part of the SCORTCH acronym (Syphilis, Cytomegalovirus, Others, Rubella, Toxoplasmosis, Chickenpox, Herpes simplex), which summarizes the possible causes of ante- and perinatal infection.

The diagnosis of early congenital syphilis is usually established by maternal serological tests, routinely performed in early pregnancy, and often repeated in the 3rd trimester and at birth. Newborns whose mothers have serological evidence of syphilis should have a complete clinical examination, dark-field microscopy or immunofluorescence staining of any skin or mucous membrane lesions, and a quantitative non-treponemal serum test. The placenta or umbilical cord should be analyzed, using direct dark-field microscopy or direct immunofluorescence.  Lumbar puncture with cerebrospinal fluid analysis for cell count, VDRL and protein assay; liver work-up; and long-bone X-ray; and other tests as clinically indicated (ophthalmological evaluation, chest X-ray, neuroimaging, and brainstem evoked potentials).

Late congenital syphilis

The Hutchinson triad of interstitial keratitis, Hutchinson teeth and deafness due to damage to the VIII nerve is diagnostic. Sometimes, standard non-treponemal syphilis serological tests are negative, but the treponemal test is positive. Other findings include saber-sharp deformity of the tibia ('saber shin'), painless swelling of the knee joints, molar abnormalities and a saddle nose. The diagnosis should be considered in cases of unexplained deafness, progressive intellectual deterioration or keratitis. More rarely: glomerulonephritis, nephrotic syndrome.

Follow-up

All seropositive infants, and those whose mothers were seropositive at birth, should be tested for VDRL or RPR every 2 to 3 months until the test is negative or the titre has decreased 4-fold. In uninfected or successfully treated infants, non-treponemal antibody titres are usually negative by 6 months of age. Treponemal antibodies acquired passively by transplacental transfer may be present for up to 15 months.

If VDRL or RPR remain positive beyond 6 to 12 months, or if their titres increase, the infant should be reassessed (lumbar puncture for cerebrospinal fluid analysis, CBC with platelet count, long-bone X-ray and other tests, depending on clinical signs).

Anesthetic implications:

risk of contamination (wound, puncture) in case of primary or secondary forms.

References : 

-        Oswal S, Lyons G.
Syphilis in pregnancy.
Continuing Education in Anaesthesia, Critical Care & Pain, 2008 ; 8 : 224-7

-        Sankaran D, Partridge E, Lakshminrusimha S.
Congenital Syphilis- an illustrative review.
Children 2023, 10, 1310. doi.org/10.3390/children10081310

Updated: September 2023