pediatrics
Malrotation of the Bowel
Introduction
Malrotation of the bowel is failure of the bowel to assume its normal place in the abdomen during intrauterine development. Diagnosis is by abdominal x-ray. Treatment is surgical repair. (See also Overview of Congenital Gastrointestinal Anomalies .) Malrotation is the most common congenital anomaly of the small intestine. It is estimated that asymptomatic rotational anomaly occurs in 1 in 200 to 500 live births; however, symptomatic malrotation occurs less frequently (1 in 6000 live births) ( General references ). During embryonic development, the primitive bowel protrudes from the abdominal cavity. As it returns to the abdomen, the large bowel normally rotates counterclockwise, with the cecum coming to rest in the right lower quadrant. Incomplete rotation, in which the cecum ends up elsewhere (usually in the right upper quadrant or midepigastrium), may cause bowel obstruction due to retroperitoneal bands (Ladd bands) that stretch across the duodenum or due to a volvulus of the small bowel, which, lacking its normal peritoneal attachment, twists on its narrow, stalk-like mesentery ( General references ). occur in 30 to 60% of patients, most commonly other gastrointestinal (GI) malformations (eg, Gastroschisis , Patients with malrotation can present in infancy or in adulthood; however, 30% present in the first month of life and 75% in the first 5 years of life. Patients can present with acute abdominal pain and bilious emesis, with an acute volvulus, with typical reflux symptoms, or with chronic abdominal pain ( General references ). In some patients, malrotation is found incidentally as part of an evaluation for another problem. Bilious emesis in an infant is an emergency and should be evaluated immediately to make sure the infant does not have malrotation and a midgut volvulus; untreated, the risk of bowel infarction and subsequent Short Bowel Syndrome or death is high. 