A practical guide to the diagnosis of congenital infections in the newborn infant

Common complaints in the first 30 days of life

Visits to the emergency department (ED) by neonates and their parents can cause anxiety for parents and the ED staff. Many of the presenting complaints are unique to the neonatal population, and an understanding of both common problems and true medical emergencies is paramount. This article discusses the complaints the EDs have seen more frequently as a result of earlier newborn discharges from hospitals.

[Diagnostic of congenital syphilis: a comparison between serological tests in mothers and their newborns]

For the purpose of establishing the incidence of maternal and congenital syphilis among pregnant women at delivery and their respective newborns, a study was carried out to determine treponemic and non-treponemic serology in one thousand (1,000) parturient women and their children at Santa Marcelina Hospital - São Paulo, between June 95 and July 96. All blood samples (maternal venous, umbilical cord and newborn venous) were VDRL-tested, treponemic tests (TPHA, ELISA IgG, ELISA IgM) being applied whenever one of the samples from mother or newborn proved positive. Further, an anti-HIV search was run through ELISA among VDRL-positive mothers. Among the 1,000 parturients, 24 (2.4%) were found to be VDRL-reactive; 18 (1.8%) newborn children of these 24 mothers presented positive serology in their umbilical cord blood and 19 (1.9%) in venous blood. No positive newborns were found for negative mothers. From the high occurrence of maternal and congenital syphilis in this group of patients, we propose a VDRL maternal test as a way of selecting gestational and congenital syphilis cases, since this test appeared to be sufficiently capable of such diagnoses. Of the treponemic tests, the ELISA test did not enhance diagnostic sensitivity.

Timely diagnosis of congenital infections

The acronym TORCH has served to increase awareness of congenital infections; however, this collective term suggests that the clinical manifestations of congenital infections are not distinguishable by pathogen. Although some clinical features may be common to several of these infections, a congenital infection caused by one pathogen generally can be distinguished from infection caused by another pathogen on a clinical basis. Pediatricians need to be aware of the prominent features of each congenital infection rather than to consider them collectively. This article focuses on the prominent features of the more common congenital infections, suggests a specific diagnostic approach, and reviews the available therapeutic strategies.

Problems with serum IgM as a screening test for congenital infection

The purpose of this study was to determine the usefulness of the total serum IgM level as a screening test for congenital infection in asymptomatic or mildly symptomatic infants. A retrospective medical record review was performed on 168 infants in whom the serum IgM was measured as a screen for congenital infection. The indications for testing, the yield of testing, and the adequacy of follow-up of abnormal values were examined. Only one infant was diagnosed with a congenital infection which was not specifically suspected prior to screening; this was a case of congenital cytomegalovirus (CMV). Inappropriate screening was frequently performed in infants in whom indications for specific evaluation were present. Appropriate follow-up testing was performed in only 30% (seven of 23) of the infants with elevated serum IgM who received their pediatric care at our institution. Because of the low yield (< 1%) and lack of follow-up shown in this study, as well as poor sensitivity, serum IgM was not a useful screening test for congenital infection in our institution.

Laboratory diagnosis of congenital syphilis by immunoglobulin M (IgM) and IgA immunoblotting

We screened cord blood or serum samples from 101 infants at risk for congenital syphilis and serum samples from their mothers for immunoglobulin G (IgG), IgM, and IgA antibodies to Treponema pallidum by western blotting (immunoblotting). Clinical evaluation showed that six infants had signs and/or symptoms consistent with congenital syphilis. The sera from five of these infants were IgM blot positive, and four were IgA blot positive. Four asymptomatic infants had serologic evidence of congenital syphilis. The sera from three of these infants were IgM blot positive, and two were IgA blot positive. However, the IgM reactivity of the serum from one asymptomatic infant, which was also IgA positive, was abolished by protein G treatment. An IgM capture enzyme-linked immunosorbent assay corroborated the presence of IgM antibodies in six of seven IgM blot-reactive sera. Overall, for detection of symptomatic congenital syphilis, a sensitivity of 83% for IgM blotting and 67% for IgA blotting was obtained. The significance of positive IgM or IgA Western blots for asymptomatic infants requires further study to confirm infection in these infants.

Congenital syphilis: the diagnostic value of the rheumatoid factor in symptomatic patients

The rheumatoid factor (RF) latex test was used as a side-room investigation for congenital syphilis. Thirty-four infants aged 0-4 months with suggestive clinical signs and unknown serological tests for syphilis were studied. Nineteen were subsequently diagnosed as having congenital syphilis on the basis of positive serology, while 15 infants had other conditions. The sensitivity of the RF latex test was 95% with a specificity of 80%. Reactive tests were seen only in neonates with congenital infections (p < 0.001). The total IgM test had a similar sensitivity in the diagnosis of congenital syphilis but its specificity (14%) was significantly less (p < 0.001). In areas where the prevalence of congenital syphilis is high, the RF latex test is useful for rapid diagnosis of the condition while confirmatory tests are awaited.

Neonatal and post-neonatal onset of early congenital syphilis: a report from Mozambique

Congenital syphilis (CS) has been and continues to be a principal public health problem in developing countries. Despite the wide experience acquired, physicians still have problems in diagnostic evaluation. We report 145 cases of CS at the Central Hospital, Maputo, emphasizing the differences in clinical features and in the results of serological and X-ray examinations between the neonatal and post-neonatal age groups. In the post-neonatal age group, the clinical expression of CS is mostly overt. It is commonly recognized that manifestations of CS in the neonatal age group are often poor or negative, yet a relevant percentage of CS that we report were fully symptomatic. In the neonatal age, the Venereal Disease Research Laboratory (VDRL) test in the mother and characteristic osteochondritic lesions on X-ray examination of the long bones help to make the diagnosis; in the post-neonatal age group, the VDRL test in the child is more often positive than in the mother and X-ray examination shows most periostitic lesions.

Cholestatic disorders of infancy

We no longer view the infant with persistent cholestasis with a "wait and see" strategy. Identification of the cause of "neonatal hepatitis" may allow specific treatment. Improved surgical techniques for portoenterostomy have provided early hope for patients with biliary atresia. Rapidly advancing nutritional strategies allow many portoenterostomy failures an additional further option, that is, hepatic transplantation. I express my thanks to the many investigators who have contributed and are continuing to advance the progress recounted in this review. Perusal of the references cited in this review makes clear the identity of these investigators.