Review Question - QID 218739

This young patient with bilious vomiting, tachycardia, and an upper gastrointestinal series showing a right-sided duodenum and small bowel most likely has malrotation.

In normal development, the intestines rotate 270 degrees around the superior mesenteric artery (SMA). Arrest of this rotation leads to malrotation. The majority of these cases present before 1 year of age and are associated with another anomaly such as a congenital diaphragmatic hernia, heart disease, or omphalocele. Clinically, patients with malrotation present with bilious vomiting and abdominal distention. Hemodynamic instability, peritonitis, and hematochezia can also occur in some patients due to bowel necrosis or perforation from volvulus. In patients who are hemodynamically unstable or with suspected perforation, emergent surgery should be performed. Otherwise, evaluation should consist of a plain film abdominal radiograph, followed by ultrasonography. If ultrasound is nondiagnostic, the gold standard for diagnosis of malrotation is an upper gastrointestinal series. Fluid resuscitation followed by operative management with the Ladd procedure (division of peritoneal bands, reduction of volvulus, appendectomy, and functional positioning of the intestine) is the treatment of choice.

Sizemore et al. discussed the diagnostic performance of upper gastrointestinal series in evaluating children with suspected malrotation. The authors found that an upper gastrointestinal series when compared to surgically verified malrotation had a sensitivity of 96%. The authors also found that the majority of false-negative cases typically had normal jejunal positioning. The authors recommend careful interpretation of upper gastrointestinal series, especially in patients with normal jejunal positioning, to avoid false negatives.

Figure/Illustration A shows a representative image from an upper gastrointestinal series of a patient with malrotation. The duodenum fails to cross the midline (red circle), and the duodenal-jejunal flexure is located to the right of the midline (blue arrow).

Incorrect Answers:
Answer 1: Distal intestinal obstruction syndrome (DIOS) is an obstruction of the colon in patients with cystic fibrosis and presents with abdominal pain and distention. Imaging in patients with DIOS will typically show inspissated stool in the right colon.

Answer 2: Gastroparesis is delayed gastric emptying and can be found in patients with longstanding diabetes. Patients often present with nausea, abdominal pain, postprandial fullness, and vomiting. The vomitus often contains remnants of food ingested several hours prior. Abdominal radiographs in patients with gastroparesis would not be expected to show an abnormal location of the duodenum.

Answer 3: Intussusception can clinically mimic malrotation with volvulus and present with bilious vomiting, abdominal distention, and hematochezia. Ultrasonography would show the “target sign” typical of intussusception. Upper gastrointestinal series would not show abnormal positioning of the intestines.

Answer 5: Necrotizing enterocolitis (NEC) can mimic malrotation in premature infants. However, NEC is less likely in this 2-month-old patient born at term. In addition, patients with NEC will typically show dilated bowel loops, bowel wall edema with thumbprinting, and pneumatosis intestinalis on abdominal radiography.

Bullet Summary:
Sudden onset bilious vomiting in infants in conjunction with an upper gastrointestinal series that shows abnormal positioning of the ligament of Treitz is highly suggestive of malrotation.