Small Bowel Internal Hernia and Sigmoid Volvulus Through a Congenital Mesenteric Defect

An 11-month-old male infant who presented with excessive crying and constipation of 5 days' duration developed vomiting after admission. Findings of a physical examination revealed an irritable baby with a distended abdomen, and digital rectal examination revealed an empty rectum. A radiograph of abdomen showed bowel filled with feces and the ultrasound scan showed dilated large bowel loops filled with feces and fluid. In view of the inconclusive nature of these reports, an abdominal computed tomography (CT) was done, which revealed dilatation of the proximal large bowel proximal to the sigmoid colon along with dilated proximal small bowel loops. There was clustering of bowel loops and swirling of the mesentery with its vessels (Figure 1). This was suggestive of small and large bowel obstruction. Laparotomy revealed presence of sigmoid volvulus along with small bowel internal hernia through a large contiguous mesenteric defect of the ileocecal mesentery and mesosigmoid with the inferior mesenteric artery forming part of the defect's circumference (Figure 2). The sigmoid colon had looped around the inferior mesenteric artery medially and was traversing through the congenital mesenteric defect (Figure 3). The ileum and cecum had to be divided to free the colon, and an ileostomy and colostomy were done. The child underwent an ileocolic anastomosis after few months to establish bowel continuity and is currently asymptomatic.Figure 3Volvulus of sigmoid colon (arrow) around the inferior mesenteric artery (arrowhead).View Large Image Figure ViewerDownload Hi-res image Download (PPT) The mesentery of the small intestine and colon is regarded as a contiguous structure. The nonattachment of the mesentery to the posterior abdominal wall at specific regions results in the intestine and mesentery being suspended only by the vascular pedicles, making it susceptible to volvulus. Internal herniation of small or large bowel through congenital mesenteric defects can occur spontaneously due to mesenteric atresia and can present with nonspecific symptoms.1Coffey J.C. O'Leary D.P. The mesentery: structure, function, and role in disease.Lancet Gastroenterol Hepatol. 2016; 1: 238-247Abstract Full Text Full Text PDF PubMed Scopus (202) Google Scholar CT imaging of internal hernia may reveal clustering of bowel, and mesenteric swirling can be seen in patients with volvulus.2Hu M.H. Huang G.S. Chen J.C. Wu C.T. Mesenteric defect with internal herniation in the pediatric emergency department: an unusual presentation of acute abdomen.Pediatr Neonatol. 2014; 55: 145-149Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar,3Tannouri S. Hendi A. Gilje E. Grissom L. Katz D. Pediatric colonic volvulus: a single-institution experience and review.J Pediatr Surg. 2017; 52: 1062-1066Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar As the clinical presentation of sigmoid volvulus and internal hernias can mimic common conditions of infancy such as constipation and colic, it is imperative to do urgent CT imaging in patients with a high clinical suspicion. This is required to prevent catastrophic consequences of volvulus or of incarcerated internal hernias, which can include extensive bowel necrosis resulting in short bowel syndrome or even mortality.