Double bubble. . . double trouble! Duodenal obstruction

Case presentation

A 4-day-old patient presents to the emergency department with forceful emesis associated with every feed. The emesis is described as nonbloody, slightly green in color. The child has decreased feeding and activity over the past 24 hours. There has been no fever, diarrhea, cough, or congestion. There is no report of trauma. The child was the product of an uncomplicated term spontaneous vaginal delivery and the mother had good prenatal care. The parents state that the child has had emesis since 12 hours of life but were told that this was due to “formula allergy” and the child was switched to a soy formula. The emesis has continued.

The patient’s physical examination reveals a quiet child in no apparent distress. There is no fever; the patient has a heart rate of 190 beats per minute, respiratory rate of 35 breaths per minute, blood pressure of 80/40 mm Hg, and pulse oximetry of 100% on room air. The child has had a 20% weight loss compared to the documented birth weight. The anterior fontanel is slightly sunken and the mucous membranes are dry. There is no heart murmur and the lungs are clear. The abdomen is nondistended and there is no hepatosplenomegaly. There does not appear to be any obvious tenderness.

You decide to ask the mother to feed the child. She does so, and several minutes later, there is obvious bilious emesis.

Imaging considerations

Plain radiography

Plain radiography is a typical first-line imaging modality in neonates with emesis, particularly if the emesis is bilious, although over the age of 2 days, upper gastrointestinal series (UGI) is also a first-line imaging study in order to evaluate for malrotation ( Table 7.1 ). On plain radiography, the bowel gas pattern may be assessed for evidence of obstruction as well as the presence of free air. However, plain radiography may be nonspecific or unrevealing. ^, The “double bubble” sign may be present and indicates duodenal obstruction, classically duodenal atresia, but it is not entirely specific for this entity. A double bubble sign may also be associated with malrotation, duodenal web, duodenal stenosis, and annular pancreas, and these entities may coexist. ^, The true or classic “double bubble” appearance is produced by air-filled dilated proximal duodenum and stomach, usually associated with lack of bowel gas more distally. ^, Visualizing a “double bubble” on plain radiography and a lack of distal bowel gas suggests duodenal obstruction, and further investigation and/or pediatric surgical consultation is indicated.

Table 7.1

American College of Radiology Appropriateness Criteria:® Vomiting in Infants *

Adapted from the Expert Panel on Pediatric Imaging. Alazraki AL, Rigsby CK, Iyer RS, et al. American College of Radiology ACR Appropriateness Criteria® vomiting in infants. https://acsearch.acr.org/docs/69445/Narrative/

Procedure	Appropriateness Category	Relative Radiation Level
Variant 1	Vomiting within the first 2 days after birth. Poor feeding or no passage of meconium. Initial imaging.
Radiography abdomen	Usually appropriate
US abdomen (UGI tract)	Usually not appropriate
Fluoroscopy contrast enema	Usually not appropriate
Fluoroscopy upper GI series	Usually not appropriate
Nuclear medicine gastroesophageal reflux scan	Usually not appropriate
Variant 2	Vomiting within the first 2 days after birth. Radiographs show classic double bubble or triple bubble with little or no gas distally (suspected proximal bowel obstruction or atresia). Next imaging study.
Fluoroscopy upper GI series	May be appropriate
US abdomen (UGI tract)	Usually not appropriate
Fluoroscopy contrast enema	Usually not appropriate
Nuclear medicine gastroesophageal reflux scan	Usually not appropriate
Variant 4	Bilious vomiting within the first 2 days after birth. Radiographs show a nonclassic double bubble with gas in the distal small bowel, or few distended bowel loops, or a normal bowel gas pattern. Next imaging study.
Fluoroscopy upper GI series	Usually appropriate
US abdomen (UGI tract)	May be appropriate
Fluoroscopy contrast enema	Usually not appropriate
Nuclear medicine gastroesophageal reflux scan	Usually not appropriate
Variant 5	Bilious vomiting in an infant older than 2 days (suspected malrotation). Initial imaging.
Fluoroscopy upper GI series	Usually appropriate
US abdomen (UGI tract)	May be appropriate
Radiography abdomen	May be appropriate (disagreement)
Fluoroscopy contrast enema	Usually not appropriate
Nuclear medicine gastroesophageal reflux scan	Usually not appropriate

GI , Gastrointestinal; UGI , upper gastrointestinal series; US , ultrasound.

* ACR Appropriateness Criteria® content is updated regularly and users should go to the website ( https://www.acr.org/Clinical-Resources/ACR-Appropriateness-Criteria ) to access the most current and complete version of the Appropriateness Criteria®.