2025 New Edition Pediatrics ITE Sample Question

Did you get it right? The correct answer is E.

Answer Explanation

The infant described in the vignette is experiencing bilious emesis within the first day of life, which is highly suspicious for intestinal malrotation with or without midgut volvulus. The best diagnostic modality listed to diagnose malrotation is an upper gastrointestinal series.

Malrotation occurs during embryological development when there is incomplete or absent rotation of the bowel around the superior mesenteric artery (SMA). This leads to duodenal obstruction due to external compression by the displaced cecum, and it predisposes the bowel to twist around the SMA, known as midgut volvulus. A midgut volvulus occurs in over 50% of children with malrotation, and if it is not properly managed it can lead to bowel ischemia, tissue necrosis, shock, and death. Many individuals with malrotation of the gut exhibit clinical signs of bowel obstruction early in infancy. These signs may include abdominal distension, bilious emesis, and bloody stools. Any infant with bilious emesis requires urgent evaluation for malrotation and volvulus, as it is a surgical emergency.

Abdominal radiographs can be normal despite the presence of malrotation. The test of choice to diagnose intestinal malrotation is an upper gastrointestinal (GI) series. The classic finding is a misplaced duodenum (ligament of Treitz is on the right), and, if volvulus is present, it will have a “corkscrew” appearance with a “bird’s beak” sign at the point of obstruction. Definitive treatment for malrotation of the bowel is surgical, using Ladd’s procedure. Further preoperative treatments that must be considered are the placement of a gastric decompression tube, broad-spectrum intravenous (IV) antibiotics to cover gut flora, and any cardiopulmonary resuscitation measures needed to stabilize the child prior to surgical intervention.

Incorrect Answer Explanations

Answer A: Rectal suction biopsies are helpful in the diagnosis of Hirschsprung disease. Hirschsprung disease is a congenital absence of ganglion cells in the rectum leading to distal intestinal obstruction. It can lead to bilious emesis, but intestinal malrotation is more important to rule out prior to further workup.

Answer B: An abdominal radiograph is a quick test to evaluate for abdominal pathology, but it is not the best test to diagnose malrotation with a midgut volvulus. Waiting 24 hours to perform further studies could cause severe bowel ischemia if the diagnosis is not made. Abdominal radiographs may be useful if necrotizing enterocolitis is suspected, but this child is full term, and this diagnosis (though not impossible) is unlikely.

Answer C: Surgery for malrotation will eventually be required. However, the patient described in the vignette is clinically stable and warrants proper evaluation before surgical intervention. If the child were showing signs of shock, then an emergent surgical consult would be necessary.

Answer D: Ultrasound imaging of the abdomen can be used to screen for or diagnose malrotation. However, an ultrasound is not as specific as an upper GI series. Upper GI series remains the test of choice in the diagnosis of malrotation.

Bottom Line

Any newborn child with bilious emesis in the first days of life should be evaluated for intestinal malrotation with/without volvulus. Intestinal malrotation is a surgical emergency and should be diagnosed quickly with an upper gastrointestinal series.