Congenital Syphilis-An Illustrative Review

Abstract

Congenital syphilis is caused by the spirochete, Treponema pallidum, which can be transmitted from an infected mother to her fetus during pregnancy or by contact with a maternal lesion at the time of delivery. The incidence of congenital syphilis is rapidly increasing all over world with 700,000 to 1.5 million cases reported annually between 2016 and 2023. Despite the widespread availability of Penicillin, 2677 cases were reported in 2021 in the US. Clinical manifestations at birth can vary widely ranging from asymptomatic infection to stillbirth or neonatal death. Low birth weight, rash, hepatosplenomegaly, osteolytic bone lesions, pseudoparalysis, central nervous system infection, and long-term disabilities have been reported in newborns with congenital syphilis. Prevention of congenital syphilis is multifaceted and involves routine antenatal screening, timely treatment of perinatal syphilis with penicillin, partner tracing and treatment, and health education programs emphasizing safe sex practices and strategies to curb illicit drug use. Neonatal management includes risk stratification based on maternal syphilis history, evaluation (nontreponemal testing, complete blood counts, cerebrospinal fluid, and long-bone analysis), treatment with penicillin, and followup treponemal testing. Public health measures that enhance early detection during pregnancy and treatment with penicillin, especially in high-risk mothers, are urgently needed to prevent future cases of congenital syphilis.

Keywords: congenital syphilis; hydrops; syphilis; treponema pallidum; vertical transmission.

Figure 3

Screening and management algorithm for infants with possible congenital syphilis. CSF, cerebrospinal fluid. RPR, rapid plasma reagin. CBC, complete blood counts. LFT, liver function tests. ABR, auditory brainstem response for hearing test. Infographic based on CDC and AAP guidelines for screening and management of congenital syphilis. Copyright: Satyan Lakshminrusimha.

Figure 1

Clinical features of perinatal syphilis and risk of maternal-to-fetal transmission. Primary syphilis (painless skin lesions/chancre or regional lymphadenopathy) and secondary syphilis (flu-like syndrome, maculopapular rash, and skin lesions known as condyloma lata) are associated with 60–100% transmission of infection to the fetus. Latent syphilis with disappearance of symptoms is associated with <8% to 40% risk of transplacental transmission of syphilis infection to the fetus. Neurosyphilis can develop at any stage of infection and present as seizures, meningitis, dementia, or tabes dorsalis. Copyright: Satyan Lakshminrusimha.

Figure 2

Clinical features of congenital syphilis. A newborn with congenital syphilis may remain asymptomatic in up to 70% of cases, and may be born preterm. Clinical symptoms and signs include snuffles (nasal congestion), maculopapular, peeling, desquamating rash especially involving the palms and soles, lymphadenopathy, jaundice, hepatosplenomegaly, and osteochondritis or periostitis (“pseudoparalysis” due to limited range of movement of affected extremity). Severely infected fetuses may have hydrops fetalis or result in stillbirth (in up to 40% of untreated pregnancies). Copyright: Satyan Lakshminrusimha.

Figure 4

Risk factors for perinatal syphilis and congenital syphilis. System-level factors such as decreases in funding for prevention and treatment of sexually transmitted infections and poverty, community-level factors such as poor access to prenatal healthcare and individual level factors such as unstable housing, domestic violence, poor socioeconomic status, substance abuse (especially heroin and methamphetamine), and high-risk sexual behavior. Inset: dark-field microscopic view of Treponema pallidum subspecies pallidum. Copyright: Satyan Lakshminrusimha.