Ileosigmoid knot: A case report of the lethal twist

Abstract

Ileosigmoid knot (ISK) is a rare and rapidly fatal surgical emergency characterized by the twisting of the ileum around the sigmoid colon, leading to acute bowel obstruction, ischemia, and gangrene. Due to its nonspecific clinical presentation, ISK is often misdiagnosed causing a delay of definitive treatment. The condition is most frequently reported in regions with high-fiber diets and anatomical predispositions, but remains a globally uncommon entity. Radiological imaging, particularly CT scans, plays a crucial role in preoperative diagnosis, with the whirl sign including sigmoid and ileum being a key diagnostic clue. However, most cases are only confirmed intraoperatively, and outcomes depend on the extent of bowel necrosis and the timeliness of surgical intervention. Mortality rates remain high, particularly in cases complicated by sepsis and multiorgan failure. We present the case of a 49-year-old male who developed acute abdominal pain, with CT imaging and laparotomy confirming an ileosigmoid knot, ultimately resulting in a fatal outcome.

Keywords: Computed tomography; Emergency radiology; Ileo-sigmoid knot; Intestinal volvulus; Laparotomy.

Fig. 1

CT axial images of dilated bowel, peritoneal effusion indicating peritonitis and unenhanced ileum (star in A) and sigmoid (star in B) indicating bowel necrosis.

Fig. 2

Sagittal CT image showing the sigmoid (star) narrowing in an ileal twist (arrow).

Fig. 3

Axial CT images of Whirl Sign formed with the sigmoid (A) and the ileum (B).

Fig. 4

Coronal CT images showing medial deviation of the descending colon (arrows).

Fig. 5

Surgical findings of ISK: the ileum (triangle) revolving around the sigmoid (star) forming a knot (arrow).