Importance of Serological Tests in the Diagnosis of Asymptomatic Congenital Syphilis in Neonates: A Case Report

Abstract

Introduction: Congenital Syphilis (CS) is caused by the vertical transmission of Treponema pallidum during pregnancy. Here, we describe a case of CS, diagnosed solely by serological tests. Case Presentation: The patient was a newborn with CS, whose mother was infected with Treponema pallidum at the gestational age of 16 - 20 weeks. However, the patient had no signs of early CS, such as low birth weight, nasal congestion, maculopapular rash, or hepatosplenomegaly. The histopathological features in both mother and neonate suggested syphilitic placentitis. Regarding the serological tests, a non-reactive Venereal Disease Research Laboratory (VDRL) test result and a reactive Treponema pallidum haemagglutination (TPHA) test result were reported. After establishing the diagnosis of CS, we initiated treatment with procaine penicillin G (50,000 U/kg body weight), which was injected intramuscularly once a day for 10 days. Six months after discharge, physical examinations showed normal findings and non-reactive results of VDRL and TPHA tests. Conclusions: It can be concluded that detailed history-taking and serological tests play a vital role in establishing the diagnosis of CS, particularly in patients with asymptomatic congenital syphilis. An early diagnosis of CS can guide clinicians to initiate a standardized treatment and improve patient outcomes.