Double Bubble Sign

[On antenatal ultrasound  a case with Double Bubble sign  turned out to be  midgut malrotation postnatally]

Appearance-  Two well defined echofree cystic areas seen  in fetal upper abdomen due to fluid distended stomach and proximal duodenum.  Abdominal radiograph of these cases also usually reveals two gaseous/ lucent areas [double bubble] representing air in stomach & duodenum , with gasless rest of the abdomen.

By-

Dr.Subhash Tailor M.D.[ Radiology]

Dr.Gaurav Bahety M Ch [Ped.Surgery ]

Bhilwara [Rajasthan] , INDIA

Possible D/Ds

Intrinsic duodenal obstructions like- duodenal atresia,stenosis and web

Extrinsic causes like – Annular pancreas & Ladd’s band with midgut malrotation

Case details

A 19 yr primi gravida was asked  for antenatal ultrasound in last trimester for fetal well being. She also complained of pain abdomen & slight leaking PV.

At US- Fetal abdomen revealed a Double Bubble Sign [fig. 1 ] . Mild oligohydramnios was also present [due to recent leaking pv]. Fetal gestation was about 35 weeks. No any other abnormality was seen. In keeping  with antenatal sonography findings, a probable diagnosis of Duodenal atresia was made. The patient then delivered  a female child same day.

 Neonatal abdominal radiograph showed  a large single gaseous shadow due to distended stomach , with relatively gasless abdomen [fig. 2 ] . The second bubble was absent , likely the duodenal air was deflated with NG tube or passed distally,which  raised the suspecian of some other pathology or cause .

Again postnatal abdominal ultrasound was asked which  revealed upper abdominal  epigastric whirlpool sign on B-mode  & color Doppler due to mesenteric twist .  There was transposition of superior mesenteric artery & vein with clockwise 360degree rotation of SMV over SMA [fig.3 ] . Rest of abdomen was normal except mildly promiment & fluid filled small bowel loops .So ,on the basis of mesenteric whirlpool sign a possibility of midgut malrotation with volvulus was  suggested.

The neonate was operated in emergency to avoid impending mesenteric ischemia due to suspected volvulus , & the diagnosis of midgut malrotation with volvulus was confirmed  [ fig.4 & 5].

Fig.1 – Fetal upper abdomen shows Double Bubble sign due to fluid distended stomach & prox.duodenum

Fig. 2- Neonatal abdominal radiograph reveals single lucent shadow of stomach with NG tube in situ , & gasless rest of the abdomen

Fig. 3 – Upper abdominal B-mode & color Doppler TS images shows classical Whirlpool sign due to mesenteric twist

Fig.4 – Peroperative photograph of mesenteric twist & midgut malrotation

Fig.5 – Peroperative photograph of mesenteric twist & midgut malrotation after complete exploration