Laryngeal atresia: antenatal diagnosis in a twin pregnancy.

Congenital laryngeal atresia is a rare malformation almost always incompatible with life. Prenatal sonographic diagnosis of this condition has been described on five occasions and all occurred in singleton pregnancies. To our knowledge, this is the first reported case of prenatal diagnosis of laryngeal atresia in a twin pregnancy. A monochorionic diamniotic twin gestation was noted at a routine ultrasound examination at 18 weeks' gestation. One twin was found to have changes consistent with laryngeal atresia with bilateral enlarged hyperechogenic lungs and hydrops fetalis. The other twin appeared normal. A Cesarean section was performed for worsening pre-eclampsia at 29 weeks' gestation. The abnormal twin died, despite resuscitative measures and autopsy confirmed the diagnosis of laryngeal atresia. The presence of the anomaly in only one twin of a monozygotic gestation supports the theory of a developmental anomaly within the branchial arches. Prenatal diagnosis of laryngeal atresia allows prenatal planning for resuscitation at birth, but its presence in one twin of a twin gestation poses several management dilemmas.

Acardiac twins.

Three cases of twin pregnancy complicated by an acardiac twin are reported. This is a rare abnormality of twins. A vascular communication exists between the twins and the usually normal twin or so called 'pump' twin may develop cardiac failure as a result of perfusion of the abnormal twin. The acardiac twin is, generally, grossly abnormal with reduction anomalies, particularly of the upper part of the body, and gross oedema. Unless this abnormality is recognized the misdiagnosis of fetal death in utero may be made and the complications of the 'pump' twin may not be predicted. Three cases are presented with only one survivor.

Non-immune hydrops fetalis: rapidity of onset and usefulness of prenatal ultrasonography.

Non-immune hydrops fetalis (NIHF) has become more common than immune hydrops fetalis as a cause of fetal hydrops and its contribution to the total perinatal mortality rate has increased from 0.1% to 3.0% for the 10 years to 1979. A case is reported where an antenatal ultrasonograph performed within 24 hours of delivery showed hydrops was not present, however, at birth the infant was grossly hydropic and died despite intensive management. This case shows the rapidity of onset of NIHF and the devastating effect of this disorder. A review of two large series of NIHF revealed that in only 11.4% and 16.3% respectively, a significant uncorrectible associated major malformation may have been missed by antenatal ultrasonography. Hence, if prenatal ultrasonography fails to reveal a major malformation a viable fetus with NIHF should be regarded as salvageable. Pulmonary hypoplasia occurred in over 90% and is probably due to compression from serous cavity effusions. Thus to improve survival the ultrasonographer needs to watch for the development of serous cavity effusions so that a pregnancy complicated by NIHF can be terminated before the fetus develops pulmonary hypoplasia.

Ureteric obstruction by the gravid uterus.

This paper reports the only 6 cases of ureteric obstruction apparently caused by the gravid uterus diagnosed at the Mercy Maternity Hospital in the past 17 years, during which time there were 82,836 confinements. In 3 of the 6 cases there was clear radiographic evidence that the level of obstruction was at the pelvic brim. The rapid resolution of the ureteric obstruction shortly after delivery strongly suggested that the gravid uterus was the cause of the obstruction. Cases 1-3 were the only patients of 793 with polyhydramnios who developed bilateral ureteric obstruction and acute renal failure. In Cases 4 and 5 there was unilateral ureteric obstruction and pyelonephritis; in Case 4 a ureteric catheter was inserted from below, and in Case 5 a ureteric stent was inserted via a nephrostomy tube. In Case 6 a percutaneous nephrostomy tube was inserted.