Intestinal malrotation (intestinal nonrotation or incomplete rotation) is a common congenital intestinal defect resulting from cessation of normal intestinal rotation during embryonic development. Malrotation predisposes patients to volvulus of their small bowel, presenting with emesis, abdominal pain and, at times, bowel ischemia or perforation. Intestinal malrotation most often occurs within the first year of life but can present as late as adulthood in rare cases. Boys are most likely to present with symptoms within the first month of life; however, there appears to be no sexual predilection in presentation in patients older than 1 year.

Some patients with malrotation will be asymptomatic and can be diagnosed incidentally on imaging studies. Malrotation is diagnosed on approximately 1 in 500 upper gastrointestinal series, and it is thought that its prevalence in the general population is likely underestimated, as asymptomatic patients may never be diagnosed.

Delay to diagnosis can occur in infants, as the condition may be mistaken for infantile colic until more severe symptoms develop (vomiting, lethargy, etc), prompting an evaluation. Children, adolescents, and young adults can also present with symptoms of intestinal malrotation. Outside of infancy, patients present with either acute symptoms, resembling the presentation often seen in infants, or with chronic concerns: intermittent abdominal pain, nausea with emesis, diarrhea, and/or weight loss.

Infants most commonly present with midgut volvulus, a life-threatening complication of intestinal malrotation characterized by proximal bowel obstruction and ischemia. Acute midgut volvulus is the typical presentation and involves a neonate or infant with acute onset of bilious vomiting and diffuse abdominal pain that is out of proportion to examination findings.

Chronic midgut volvulus occurs due to incomplete twisting from lymphatic and venous obstruction. The typical presentation involves a patient with recurring abdominal pain and malabsorption syndrome. Other clinical symptoms include recurring diarrhea and constipation, obstructive jaundice, solid food intolerance, and gastroesophageal reflux.

Midgut volvulus is a surgical emergency and requires urgent attention, as intestinal torsion may result in necrosis of the small bowel. Immediate surgical repair (Ladd procedure) is needed to prevent ischemia or resect infarcted bowel loops.

Older children or adults usually present with episodes of duodenal obstruction that may spontaneously resolve. These patients may also present with internal hernias. Common symptoms include abdominal distension, abdominal pain, bloody stools, shock, tachypnea, and vomiting (with or without bile). Malrotation is also associated with congenital heart defects, congenital diaphragmatic hernias, and omphaloceles. All patients with heterotaxy should be screened for malrotation.