Treatment of Infants With Reactive Syphilis Serology, New Jersey: 1992 to 1996
Authors: Finelli Lyn , Crayne Eileen M. , Spitalny Kenneth C. 
Published: August 2004

Background and Rationale. Diagnosis of congenital syphilis is problematic: infants with congenital syphilis are often asymptomatic, and signs in symptomatic infants are frequently subtle and nonspecific. Furthermore, there are no readily available diagnostic tests that provide a definitive diagnosis. Previously, the diagnosis of congenital syphilis was based on a complex set of clinical and laboratory criteria, and only infants with clinically apparent illness or laboratory findings indicating congenital syphilis were classified as cases and reported to health departments and the Centers for Disease Control and Prevention (CDC). To systematize diagnosis and case-reporting, the CDC developed a standardized surveillance case definition in 1988. This case definition includes symptomatic infants as well as asymptomatic infants of mothers with untreated or inadequately treated syphilis during pregnancy. It is intended to be highly sensitive to better estimate the burden of disease in the community. Treatment guidelines for congenital syphilis are intentionally conservative and err on the side of overtreatment so that all potentially infected infants are treated. The congenital syphilis surveillance case definition is compatible with the American Academy of Pediatrics (AAP) and CDC treatment guidelines; thus, the number of infants identified and reported to state health departments and the CDC should reflect the number of infants treated. Hundreds of infants with reactive serologic tests for syphilis (STS) are reported each year to the New Jersey Department of Health and Senior Services (NJDHSS). The majority of these infants do not meet the case definition for congenital syphilis, and most are treated although treatment guidelines indicate that treatment is not necessary.

Objective. To determine whether infants with reactive STS in New Jersey are being treated according to the AAP treatment guidelines.

Methods. Medical records of newborns with reactive STS reported to NJDHSS between July 1, 1992, and June 30, 1996, were reviewed to determine status of infection and compliance with the AAP treatment guidelines. The 1995 NJDHSS Uniform Billing and Hospital Discharge Data was used to estimate the mean cost of hospitalization per day for infants with the diagnosis of congenital syphilis.

Results. During the study period, 1669 newborns with reactive STS were reported to the NJDHSS Sexually Transmitted Disease Program. Medical record review was completed for 1480 infants (88%). Infants were classified by CDC surveillance criteria as follows: 0 confirmed cases; 515 (35%) presumptive cases; 16 (1%) syphilitic stillbirths; and 949 (64%) cases that did not meet the definition for congenital syphilis.

Of the 512 presumptive cases that survived the immediate perinatal period, 478 (93%) were treated with antibiotics and 459 (90%) were treated according to the AAP treatment guidelines. Only 27 infants (6%) were treated with a single intramuscular dose of benzathine penicillin. Thirty-four infants (7%) were not treated; instead, their physicians chose to follow them clinically and serologically. All of those treated were asymptomatic, and most were born to mothers with a history of adequate treatment before or during pregnancy, but who were without serologic follow-up.

Of the 949 infants that did not meet the case definition, 329 infants (35%) were not treated and 620 (65%) were treated with antibiotics. The 508 (82%) infants treated with antibiotics were treated with intravenous or intramuscular antibiotics for ≥10 days; only 62 (10%) were treated with a singular intramuscular dose of benzathine penicillin.

According to NJDHSS Uniform Billing Hospital Discharge Data, 267 infants weighing ≥2500 g were discharged with a diagnosis of congenital syphilis in 1995. The median number of hospital days for these infants was 10, and the mean cost of hospitalization per day was $1010. Sources of payment of hospital charges for most infants were public insurance and self-pay. The estimate cost for 9 excess days of hospitalization for treatment of 231 infants with reactive STS who did not meet the case definition in New Jersey in 1995 was $2 100 330.

Discussion. Nearly half of the infants classified as presumptive cases were born to mothers who had been administered proper treatment for syphilis before or during pregnancy, but who failed to drop their titer fourfold after treatment. Of these infants, 99% were asymptomatic. If the recommended diagnostic testing of infants had been performed, the majority probably could have been treated with a single intramuscular injection. Most of the infants not meeting the case definition were treated for 10 days with intravenous or intramuscular antibiotics. It is unclear why the majority of infants were treated, but it is unlikely that maternal treatment history was unknown to the clinician at the time the treatment decision was made and the infant was managed as if the mother were untreated. However, it is our experience that even when documentation of maternal treatment is readily and conspicuously available in the maternal medical record, most infants are treated for 10 days. Unnecessary and prolonged hospitalization and treatment of infants with reactive serology have significant social, medical, and economic consequences and should be prevented when possible. Hospitalization of uninfected infants for antimicrobial treatment separates newborns from their parents at a critical time for bonding and integration into the family unit. Infants who are hospitalized after birth, even for minor health problems, are at risk of developing a nosocomial infection. The economic burden of treatment falls almost entirely on public programs. In response to this problem, we have developed a set of recommendations to reduce overtreatment of infants with reactive syphilis serology. Clinicians should be trained regarding the interpretation of maternal and infant serology test results and indications for treatment. The recommended diagnostic work-up of infants should be performed including physical examination, a quantitative nontreponemal STS, cerebrospinal fluid analysis, and long-bone radiography when indicated. The antibiotic therapy recommended should be administered after review of maternal history and the results of the infant's examination and testing. Clinicians should be aware that health departments possess and are required to retain information about maternal serology titer history and treatment, which can be used to make clinical decisions about the treatment of infants. Health departments should be able to provide information about maternal titer history and treatment to clinical agencies with 1 to 2 working days of the birth of the infant. Clinical agencies and health departments need to develop strategies for improving the exchange of information. Clinicians should improve the exchange of information between obstetric and pediatric services. Finally, all untreated or inadequately treated mothers should be treated before discharged hospital so that they are treated adequately before their next pregnancy.