Obstetrics and Gynecology I - HASSAN II University Hospital – Fez- Morocco

Introduction
On antenatal , esophageal atresia is usually suspected when there is polyhydramnios and an absent or small stomach. This, however, is not definitive,The presence of a blind-ending anechoic pouch in the fetal neck or mediastinum, the upper neck pouch sign, which is best visualized during fetal swallowing is an additional sign for the antenatal diagnosis of esophageal atresia.

Case Report
A 29-year-old multiparous (gravida 2) woman at 37 weeks′ gestation was referred for a fetal well-being examination. There was no history of consanguinity and the family history was unremarkable. Her previous pregnancy had been uneventful.Ultrasonography examination revealed polyhydramnios (amniotic fluid index: 25 cm) and a very small stomach. In view of these findings, the fetal neck and chest were examined in detail. An anechoic, dilated, blind-ending proximal esophageal pouch was seen in the neck. It could be seen to be filling and emptying repeatedly on real-time examination . Based upon this finding, a diagnosis of esophageal atresia was made. In view of the very small stomach, the presence of a distal tracheoesophageal fistula was suspected. Patient delivered a male baby vaginally. The baby, however, died immediately after birth.

Discussion
Esophageal atresia is a condition in which the proximal and distal portions of the esophagus do not communicate. The reported incidence is 1 in 3590 pregnancies.Prenatal diagnosis is particularly interesting allowing search for associated malformations related to worse prognosis forms (reference ultrasound, MRI and amniocentesis) and planning the birth in an adapted medico-surgical center. Diagnosis of EA is usually suspected because of indirect and non-specific signs: association of polyhydramnios and absent or small stomach bubble. The visualization in ultrasound or MRI of cervical or thoracic fluid image corresponding to the expansion of the bottom of upper esophageal ("pouch sign") increases the specificity of diagnosis. If EA is confirmed at birth, surgical management consists in a primary end-to-end anastomosis in first days of life, or in two-steps surgery if the defect is too large. Although current prognosis of EA is good, frequency of surgical complications and esophageal lesions secondary to gastroesophageal reflux justify a systematic and multidisciplinary extended follow-up.

Conclusion
To conclude, the presence of the upper neck pouch sign on USG is an additional sign that helps in the diagnosis of esophageal atresia; this sign is seen regardless of the presence or absence of a tracheoesophageal fistula.When seen, the pouch is specific for this diagnosis, but is not appreciated in up to 57% of proved cases of esophageal atresia.Therefore, in the presence of polyhydramnios, the radiologist should look for the pouch sign in the neck, irrespective of whether the stomach is present or absent.

Reference

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