Tracheal diphtheria mimicking bacterial tracheitis

Prenatal diagnosis of fetal primary cytomegalovirus infection

OBJECTIVE

To determine the reliability of prenatal diagnosis for congenital cytomegalovirus in women with primary infection.

DESIGN

Retrospective analysis of case records between 1992 and 1997.

SETTING

Fetal medicine unit of a large teaching hospital.

POPULATION

Forty-two pregnant women with primary cytomegalovirus infection.

METHODS

Fetal diagnosis was made by amniocentesis for viral culture and amplification of cytomegalovirus DNA by polymerase chain reaction (n = 37), or by cordocentesis for the detection of cytomegalovirus-specific IgM antibodies (n = 13). All patients had serial ultrasonographic scans in order to detect those fetuses with abnormalities that could be associated with cytomegalovirus infection.

RESULTS

Fourteen pregnancies (33 x 3%) had evidence of vertical transmission. Nine out of 14 (64 x 3%) had positive amniotic fluid culture, while 11 (78 x 6%) had positive polymerase chain reaction results. The combination of both tests allowed antenatal diagnosis in 12 of the 14 infected fetuses (sensitivity 85 x 7%). All women who underwent cordocentesis for the detection of cytomegalovirus-specific IgM antibodies had negative results, but in two cases cytomegalovirus infection was detected by amniotic fluid studies. In five of the infected fetuses there were abnormal ultrasonographic findings. All pregnancies with evidence of vertical transmission were terminated and the remainder proceeded normally to term.

CONCLUSIONS

Our data showed that amniotic fluid studies, preferably polymerase chain reaction amplification of viral DNA, are the best diagnostic tools for the detection of vertical transmission in pregnancies with primary cytomegalovirus infection. For women with positive amniotic fluid studies who elect to continue their pregnancies, cordocentesis and serial ultrasound scans may be useful for assessment of fetal status.

Evaluation of virological procedures to detect fetal human cytomegalovirus infection: avidity of IgG antibodies, virus detection in amniotic fluid and maternal serum

Human cytomegalovirus (HCMV) is the most common cause of viral intrauterine infection and fetal damage largely due to maternal primary infection. Virological procedures which are able to detect HCMV fetal infection were evaluated. HCMV IgG antibodies were detected in 62.5% of the pregnant women and 1.47% had a primary infection. From March, 1992 to August, 1995, 29 seroconversions were observed, and in 64 other cases. HCMV IgM antibodies were detected in the first serological test. The mean IgG antibody avidity test (AI) was 31% for the 11 seroconversions tested and 74% in 32 cases where IgG and IgM HCMV antibodies were detected in the first serum. In the 29 HCMV seroconversions, 19 amniocentesis were carried out and 12 fetuses (41.4%) were infected in utero. In four amniotic fluids positive in culture and PCR, the fetus or newborns were infected and in one out of the two cordocentesis undertaken, hepatitis, anemia, and thrombocytopenia were noted. In four other cases, investigations seeking HCMV in amniotic fluid were negative whereas infants were infected at birth. Among the 64 cases with positive HCMV IgM and IgG antibodies detected in the first serological test, three fetuses were infected in utero, but no amniotic fluid was available in these cases. Amniotic fluids were studied in 39 cases, and HCMV detection by culture and PCR-hybridization was negative. HCMV DNA was detected in the maternal sera of five out of 21 pairs of seroconversions and in two cases on the first negative serum. The assay was also carried out on 50 of the 64 HCMV IgM positive sera. Two had detectable HCMV DNA.