Bilious emesis in a newborn should be considered a surgical emergency until proven otherwise. In a previously healthy neonate, this finding should raise suspicion for midgut volvulus, which was the ultimate diagnosis in this infant.
During the fourth week of embryonic life, the developing small intestine moves outside the abdominal cavity and into the umbilical cord. After the intestine enlarges and matures, it returns to the abdominal cavity during the 10th week of gestation. Rotation and final placement of the intestinal loops is completed by the eleventh week of pregnancy. This movement comprises a 270° counterclockwise turn that leaves the duodenojejunal junction at the ligament of Treitz fixed to the left of midline and the cecum fixed in the right lower quadrant.
Under normal circumstances, the base of the mesentery is both wide and immobile from the left upper to the right lower quadrant, creating a broad attachment that is unlikely to twist. When this movement is not completed in the usual fashion or does not happen at all, the small bowel is fixed and supported only by a narrow base of the mesentery. It can twist in a clockwise direction, causing a bowel obstruction and simultaneously compromising perfusion to the entire midgut, giving it a dark, dusky appearance when viewed surgically (Figure 1).[2,3] This anatomical condition, known as malrotation, is found in 0.5%-2% of asymptomatic patients at autopsy or during an upper gastrointestinal evaluation done for another reason. Malrotation is twice as common in boys as it is in girls.
Midgut volvulus is the most common and catastrophic complication of a preexisting malrotation. Thirty percent of cases occur during the first week of life, and more than 50% of cases occur before 1 month of age. Bilious emesis is the hallmark feature of the diagnosis, and more than 95% of patients with volvulus present with this symptom. Initially, the infant may have a flat abdomen because the obstruction occurs fairly proximal at the duodenum; however, if the bowel becomes ischemic (and eventually necrotic), severe distension may result, and the infant may become tachycardic, tachypneic, pale, and diaphoretic. Fluid third-spacing and sequestration into the ischemic bowel produce dehydration and acidosis resulting from generalized hypoperfusion. Intestinal mucosal sloughing may eventually cause abdominal wall discoloration and hematochezia.
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Cite this: Jaime Shalkow. A 3-Day-Old Boy With Bilious Emesis - Medscape - Apr 14, 2016.