[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.
Dr.Subhash Tailor M.D.[ Radiology]
Dr.Gaurav Bahety M Ch [Ped.Surgery ]
Bhilwara [Rajasthan] , INDIA
Intrinsic duodenal obstructions like- duodenal atresia,stenosis and web
Extrinsic causes like – Annular pancreas & Ladd’s band with midgut malrotation
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