A Rare Case of Transmesenteric Herniation of Sigmoid Colon With Ileosigmoid Knotting Causing Intestinal Obstruction

Introduction: Internal herniation of sigmoid colon with ileosigmoid knotting is a rare and complex form of closed-loop obstruction which results in rapid progression of gangrenous changes of bowel that may result in a fatal outcome unless appropriately diagnosed and treated promptly. We report a rare case of intestinal obstruction where abdominal CT scan advocated the preoperative management and aided in successful outcome. Case Description/Methods: A 36-year-old women presented with progressively worsening diffuse abdominal pain of 4 days duration associated with abdominal distension, multiple episodes of bilious vomiting and constipation. No history of abdominal injuries or surgeries. On examination abdomen is distended, diffusely tender with guarding and decreased bowel sounds. Blood investigations revealed WBC 17000, blood urea 34mg/dl, serum creatinine 1.2mg/dl, serum Na+ 131 mEq/L, K+ 3.3 mEq/L and Cl- 98mEq/L. X-ray of abdomen showed dilated small and large bowel loops on the right side with multiple air fluid levels. CT abdomen showed dilated large bowel and multiple small bowel loops. Emergency laparotomy was performed. Intraoperative findings revealed transmesenteric herniation of sigmoid colon through treves’ field and ileosigmoid knotting involving herniated sigmoid colon and distal ileum resulting in gangrene of distal ileum and sigmoid colon. Resection of gangrenous sigmoid colon and end to end anastomosis of descending colon with distal part of sigmoid colon, resection of gangrenous distal ileum with end ileostomy was done. Post-op period was uneventful. Patient recovered well, discharged and is being followed up. Discussion: An unintended protrusion of one or both components of the knot through the defect, which serves as a fulcrum, causes violent hyperperistalsis of the proximal loops, which is the mechanism of ileosigmoid knotting with internal herniation. The propulsive peristalsis, along with the gas-trap effect plus gravity formed by the distention of protruded loops, force more loops to extrude through the aperture, until the herniated loops make a rotatory movement around the redundant sigmoid colon to form a complex ileosigmoid knotting resulting in obstruction. Though internal herniation of sigmoid colon with ileosigmoid knotting is rare and fatal, if diagnosed early and aggressively treated with prompt fluid resuscitation, preoperative antibiotics, and immediate surgical exploration, allows better outcome and patient survival.