Fetal 'Double Bubble' Sign
· Duodenal atresia-This lesion is usually associated with PH and a ‘double bubble’ sign as a result of a dilated stomach and proximal duodenum. The appearances are those of two communicating cystic masses in the upper abdomen. Thirty percent association with trisomy 21.
· Duodenal stenosis-Signs in duodenal stenosis are variable and may not be present in utero.
· Jejunal atresia- PH is a feature of most upper bowel obstruction, whatever the cause. In common with other upper GI obstructions the presence of dilated loops of bowel may be seen. Jejunal atresia may give rise to a ‘triple bubble’ sign.
· Annular pancreas- This is a rare congenital anomaly that may give rise to upper GI obstruction and potentially give rise to a ‘double bubble’ sign.
· Other causes of upper GIT obstruction- These include congenital bands, internal hernias, volvulus, cystic fibrosis and meconium ileus.
· Normal variant- A normal stomach divided by a prominent wave of peristalsis may superficially resemble a ‘double bubble’ but this is likely to be a transient phenomenon. Meconium may acquire an anechoic state and thus meconium in the transverse colon close to the stomach may mimic a ‘double bubble’ when scanning in the transverse plane. Care should be taken not to misinterpret a normal gallbladder adjacent to the stomach as ‘double bubble’.
· Normal stomach with adjacent fluid filled structure-A normal fluid filled stomach with an adjacent fluid filled cystic mass may resemble a ‘double bubble’. These cystic lesions include renal, choledochal, hepatic, adrenal, mesenteric, duplication and retroperitoneal cysts and hydronephrosis.
Congenital duplication of stomach- Duplication cysts may occur at any point in the GIT and may be multiple. The stomach is less frequently affected than other regions. A cystic mass in the right upper quadrant has been reported: it proved to be a gastric duplication cyst.
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