Intestinal malrotation with volvulus is primarily a condition of infancy but can be seen in older children and adults. During week 4 of embryonic development, the primary intestinal loop bulges into the yolk sac and rotates 270 degrees counterclockwise. Between weeks 8 and 10, it returns to the enlarged abdominal cavity and is fixed via mesentery that extends from the ligament of Treitz to the ileocecal valve in the right lower quadrant. In malrotation, the duodenum, jejunum, and cecum are partially rotated with the bowel anchored by an abnormally thin band of mesentery. The bowel can twist on this thin mesentery, which contains the superior mesenteric artery, leading to acute intestinal obstruction and midgut vascular compromise known as volvulus. Also, the abnormally positioned cecum now rests in the upper abdomen fixed to the right lateral abdominal wall by bands of peritoneum (Ladd bands) that cross and can obstruct the duodenum.
Presentation is with vomiting in 50% of cases and in 90% of newborns. The vomiting may not be bilious, but it is classically described as such. Patients are often irritable with significant abdominal tenderness. Third space fluid losses increase as gut ischemia progresses. Differential diagnosis includes pyloric stenosis, intestinal atresias, appendicitis, necrotizing enterocolitis, and intussusception.
Intestinal Malrotation with Volvulus. Anteroposterior x-ray of the abdomen in a newborn with bilious emesis. Dilated, air-filled stomach with a relative paucity of gas in the distal bowel. (Photo contributor: Alexander Towbin, MD.)
Management and Disposition
Emergent surgical consultation is indicated. Plain x-rays are rarely diagnostic but may show signs of small bowel obstruction. A normal ultrasound does not rule out malrotation. An upper gastrointestinal (GI) series is the most helpful study. One-quarter of cases may have an equivocal result. Preoperative management consists of resuscitation with IV fluids, placing a gastric tube for decompression, and administration of broad-spectrum antibiotics.
Fifty percent of patients with malrotation present with volvulus in the 1st month of life.
Over 30% of cases of malrotation with volvulus present beyond early childhood, usually with an insidious onset with abdominal pain as the most common symptom.
The imaging test of choice is the upper GI series, but computed tomography (CT) should be considered in ill-appearing patients in whom administration of enteral contrast may be difficult.
Intestinal Malrotation with Volvulus. Anteroposterior radiograph from an upper GI series shows malrotation with midgut volvulus. The duodenum (arrowheads) does not cross midline and does not extend superiorly to the level of the pylorus. The spiraling downward appearance is consistent with volvulus. (Photo contributor: Alexander Towbin, MD.)
Intestinal Malrotation with Volvulus. Soft-tissue mass (arrow) surrounded by air within ...