Congenital high airway obstruction syndrome is a rare but life-threatening condition. Therefore, prenatal diagnosis is important. The obstruction can be due to laryngeal/tracheal atresia or external compression. While a differential diagnosis with congenital cystic adenomatoid malformation (CCAM) type III may be difficult, it is still possible with ultrasonography. In this study, we report a case of bilateral echogenic lungs with hydrops fetalis. After the prenatal diagnosis of laryngeal atresia, the couple opted to have an elective termination of pregnancy performed at 20 weeks of gestation. The diagnosis was confirmed by a complete pathological examination.
Congenital atresia of the larynx is a rare abnormality of upper airway obstruction. For such a condition, prenatal diagnosis is difficult. Nevertheless, the diagnosis is crucial because affected fetuses face a high risk of demise. Sonographic findings showed increased lung echogenicity and size coexisting with fetal ascites. However, the findings may not always be typical. We reported a 20-week-old male fetus with congenital laryngeal atresia diagnosed prenatally by the findings of fetal hydrops, hyperechogenic lungs and other abnormalities without the fluid-filled trachea. After the elective termination of pregnancy, the diagnosis was confirmed by a complete pathological examination.
A 29-years-old, gravida 1, woman was referred to our perinatal unit at 20 weeks of gestation on suspicion of fetal anomaly. Her family history was noncontributory. Physical examination revealed a 20-week-sized uterus with audible fetal heart sound. Transabdominal ultrasound showed oligohydramnios and fetal hydrops with marked ascites, generalized skin edema and placentomegaly. The fetal chest circumference was larger than 95th percentile of 20 weeks gestation. Both lungs became severely enlarged and highly hyperechoic (Figure
Coronal scan through the fetal chest and abdomen revealed bilateral echogenic lungs and ascites.
Sagittal view: note the inversion of the diaphragm.
Axial scan of the fetal chest: the heart was squeezed by the hyperechoic lungs.
The aborted fetus weighed 450 g and had a distended thorax and abdomen and deformation both ear lobules. Postmortem examination revealed generalized edema and markedly distended abdomen compatible with hydrops fetalis (Figure
Postabortion: generalized edema with markedly distended abdomen.
Gross appearance of thorax and abdomen show enlarged both lungs with costal impression on the external surface.
(a) Bisection of the neck block demonstrates complete obstruction of the larynx (arrow). (b) Sagittal view of the larynx and trachea demonstrates atresia at subglottic level (arrow).
Congenital high airway obstruction syndrome (CHAOS) is a rare and usually lethal abnormality. Three possible presentations include (1) complete laryngeal atresia without an esophageal fistula, (2) complete laryngeal atresia with a trachea-esophageal fistula, and (3) near-complete high upper airway obstruction [
Laryngeal atresia may be associated with other structural and genetic abnormalities [
Although laryngeal atresia is usually lethal, it has recently become possible to bypass the airway obstruction and establish adequate ventilation by the EXIT procedure (Ex Utero Intrapartum Treatment) or fetoscopic laser decompression, while the fetus is still connected to the placenta. Several successful cases have been reported [
In this case, we observed enlarged bilateral echogenic lung masses, inversion of the diaphragm with nonimmune hydrops fetalis. Oligohydramnios can be present in the context of hydrops due to the impairment of renal function. The findings were difficult to differential with congenital cystic adenomatoid malformation (CCAM) type III. However, bilateral CCAM was very rare; therefore, the diagnosis of CHAOS was considered. Moreover, our case had distinct abnormalities, including deformed ears, a single lobe in the left lung, and intestinal malrotation. Lastly, our case did not have an enlarged fluid-filled trachea, a unique sonographic feature, although the laryngeal stenosis without fistula was confirmed by the pathological examination.