Congenital cystic adenomatoid malformation: accuracy of prenatal diagnosis, prevalence and outcome in a general population.

OBJECTIVES: Most available data regarding accuracy of prenatal diagnosis, prevalence and outcome of congenital cystic adenomatoid malformation (CCAM) are derived largely from tertiary referral centres and may not reflect general population rates. We aimed to describe the accuracy of prenatal diagnosis, ascertain the population prevalence and post-natal outcome for cases of suspected CCAM. METHODS: Retrospective collection of prenatal and paediatric data for cases of suspected CCAM notified to the Trent Congenital Anomalies Register 1997 to 2001. RESULTS: Thirty-seven cases of CCAM were suspected prenatally. Twenty-one cases were confirmed post-natally as having a CCAM (positive predictive value 57%). Eighteen of the 21 cases were delivered at term as live births, 15 of which have undergone successful surgery to date. Thirteen of the 37 cases had apparently resolved by delivery. Three further cases were subsequently found to be cases of lung sequestration or lobar emphysema. Five cases of CCAM were detected after delivery (sensitivity of prenatal detection 81%). The population prevalence at delivery was 9.0 per 1,00,000 total births. Five confirmed cases of CCAM developed hydrops, three required in utero intervention and delivered as live births at term, one was terminated and one died in utero. The overall mortality in the confirmed cases of CCAM was 23% of which the majority were terminations of pregnancy. CONCLUSIONS: Problems of diagnostic accuracy and apparent resolution of CCAM render counselling difficult, although our data suggest that the prognosis is better than others have reported. Confirmation of the diagnosis in the neonatal period is vital in order to obtain the true population prevalence figures and to interpret outcome data.

Trisomy 13 and trisomy 18 in a defined population: epidemiological, genetic and prenatal observations.

OBJECTIVES: To establish precise incidence figures for trisomy 13 and trisomy 18 in the former Trent region, to identify current prenatal diagnostic practice, and to assess the potential impact of the introduction of recently devised prenatal diagnostic practices. METHODS: An audit of all cases of trisomy 13 and trisomy 18 ascertained through the records of the Trent Congenital Anomalies Register and the Trent Regional Cytogenetic Laboratories. RESULTS: Forty-four cases of trisomy 13 and 88 cases of trisomy 18 were ascertained. Advanced maternal age effects were observed. Of all cases, 64% were first detected through chromosomal analysis initiated because of abnormalities noted on fetal anomaly scanning in the second trimester, whereas only 3% of cases were detected through the serum-screening programme currently offered for Down syndrome. In 11% of cases, the diagnosis was first suspected after birth. Twelve percent of couples chose to continue pregnancy following chromosomal confirmation of a suspected diagnosis. CONCLUSION: The introduction of a highly sensitive prenatal diagnostic screening programme would have a major impact on the timing and proportions of all trisomy 13 and 18 cases diagnosed in pregnancy as gauged by current practice. It is important that health professionals involved in prenatal counselling be aware that, as with Down syndrome and anencephaly, around 12% of prospective parents of a child with trisomy 13 or 18 choose to continue rather than terminate the pregnancy.

Relapsing post-transfusion purpura. A preventable disease.

Post-transfusion purpura is an isoimmune disorder that can recur if unrecognized. A 56-year-old woman is described who had her third episode of post-transfusion purpura 17 years after her last exposure to the inciting antigen. Clinical and immunologic features are reviewed, and specific preventive measures are proposed.