Congenital syphilis confirmed by PCR as a result of treatment failure for syphilis in pregnancy. Case report

Abstract

Introduction: Congenital syphilis is a major public health problem, and early diagnosis and treatment are necessary to prevent it. Penicillin G benzathine is the treatment of choice in pregnant women; however, it may fail to prevent fetal infection, as in the present case. Case presentation: Male newborn, son of an HIV negative mother with gestational syphilis (venereal disease research laboratory (VDRL) 1:4 dilution, positive treponemal test) diagnosed at week 21 of gestation and treated with three doses of 2 400 000 IU of penicillin G benzathine. At delivery, the mother presented VDRL 1:1 dilution. The newborn was diagnosed with congenital syphilis due to VDRL 1:4 dilution, positive treponemal test, elevated aspartate aminotransferases, hyposthenuria, proteinuria, hematuria, and leukocyturia that resolved after treatment with crystalline penicillin for 10 days. The molecular testing in blood showed a high treponemal load. The VDRL test at 3 months was non-reactive. Conclusions: Preventing congenital syphilis with the recommended treatment for gestational syphilis may fail. Moreover, diagnosing this condition in an asymptomatic newborn is difficult. Therefore, clinical and serological tests are recommended to confirm whether maternal treatment was effective in the fetus.

Congenital syphilis. New questions about a neglected but re-emerging condition

“…It is important to keep in mind that, as described in Cifuentes-Cifuentes et al (1), international guidelines do not consider the administration of benzathine penicillin to the mother as effective for the treatment of GS if it is administered 30 days before delivery, which is consistent with what has been reported in the literature (2,3). congenital syphilis.…”

“…In this regard, in the case published by Cifuentes-Cifuentes et al (1), more than explaining reinfection, the mechanism that would explain the success of treatment in the mother but the failure of treatment in the fetus remains unclear.…”

“…According to Workowski et al (2), a single dose of 2 400 000 IU of benzathine penicillin is effective in curing 97% of CS cases if administered more than 30 days before delivery and if there is no reinfection. Therefore, the case of Cifuentes-Cifuentes et al (1) could be among the 3% of patients who do not respond to treatment or could be a case of decreased response of fetal Treponema pallidum to benzathine penicillin administered to the mother. However, this cannot be validated because the evidence supporting the effectiveness of GS treatment in terms of fetal or neonatal outcome is considered to be of low certainty since the majority of the information is derived from observational studies (4).…”

“…Another interesting aspect of the case presented by Cifuentes-Cifuentes et al (1) is that infection in the newborn was confirmed by a polymerase chain reaction (PCR) test to detect T. pallidum, which is one of the most sensitive and specific diagnostic tests to identify this bacterium (2). This is relevant because the diagnosis of syphilis is still based on treponemal and non-treponemal tests, as diagnosis and treatment in a single time have been prioritized for both pregnant women and high-risk populations (5); however, these tests do not perform well in primary syphilis, where microscopy techniques of genital or oral ulcer samples are preferred (2).…”

“…Treatment was started with 150 000 IU of intravenous crystalline penicillin every 12 hours for 10 days, which resulted in improvement of the signs of renal failure and liver disease, as well as a negative VDRL test result at 3 months. This case presents relevant and novel information about the management of CS since Cifuentes-Cifuentes et al (1) concluded that the recommended treatment for GS was insufficient to prevent CS. Consequently, they indicated that clinical and serological follow-up is required to confirm whether maternal treatment was effective in the fetus.…”