Ileosigmoid knotting in early pregnancy: a case report

Abstract

Introduction:

Ileosigmoid knotting (ISK) is a rare cause of intestinal obstruction, occurring when the ileum wraps around the colon and its mesentery. Its occurrence during pregnancy, especially before the third trimester, is extremely uncommon.

Case Report:

A 31-year-old woman at 12 weeks’ gestation presented with 1 day of acute, severe abdominal pain, obstipation, vomiting, and abdominal distention. Physical examination revealed abdominal distention and severe rebound tenderness. Abdominal ultrasound showed a viable 12-week singleton pregnancy, colonic wall thickening, and free intraperitoneal fluid. Intraoperatively, an ileosigmoid knot was identified, with gangrenous changes affecting 150 cm of ileum and the sigmoid colon. The necrotic bowel was resected, with primary ileo-ileal anastomosis and a descending end colostomy. Postoperatively, the patient remained stable, and the fetus was viable.

Clinical Discussion:

ISK is a rare but life-threatening cause of intestinal obstruction. Imaging studies, including plain abdominal X-ray and non-contrast CT scan, can aid diagnosis, but definitive diagnosis is typically made intraoperatively. Prompt surgical intervention is essential because the condition can rapidly progress to gangrene, peritonitis, septic shock, and death.

Conclusion:

This case highlights the importance of maintaining a high index of suspicion for intestinal obstruction in pregnant patients and demonstrates the critical impact of timely surgical management on favorable maternal and fetal outcomes.

Introduction

Ileosigmoid knotting (ISK) occurs when a freely mobile ileal segment tightly encircles the base of the sigmoid colon, or less commonly vice versa^[1–3^]. It forms a mechanical, double-loop intestinal obstruction that rapidly progresses to gangrene of both the ileum and sigmoid colon, leading to septic shock, electrolyte imbalance, and death^[3–5^]. The mortality rate of ISK can reach up to 48%. Factors such as sepsis, electrolyte imbalance, pregnancy, and comorbidities are often associated with poor outcomes^[6,7^].

The condition is four times more common in men, typically in the third to fifth decades of life. Its occurrence during pregnancy is exceedingly rare, with most cases reported after the third trimester, as the gravid uterus displaces bowel loops^[7^]. ISK in early pregnancy is extremely rare, with only a few cases reported worldwide^[8,9^].

HIGHLIGHTS.

• Ileosigmoid knotting (ISK) is a rare cause of intestinal obstruction that quickly results in bowel gangrene.

• Occurrence of ISK in early pregnancy is extremely rare, with only a few reported cases.

• ISK presents with the clinical picture of small bowel obstruction that rapidly progresses into bowel strangulation and ischemia.

• Diagnosis of ISK in early pregnancy requires a wide index of suspicion.

• Management of ISK in pregnancy requires a multidisciplinary approach.

• Early surgical intervention promotes better maternal and fetal outcomes.

The diagnosis for ISK is often made intraoperatively due to the rarity of the condition and absence of specific clinical and laboratory signs^[3,6-8^]. In pregnancy, diagnosis is particularly challenging because some ominous signs may be mistaken for mild pregnancy-related symptoms. Additionally, some patients may be reluctant to undergo diagnostic X-rays or CT scans due to concerns about radiation exposure^[9,10^].

Because symptoms progress rapidly, a high index of suspicion should be made for pregnant women presenting with intestinal obstruction, irrespective of the cause, to promote timely diagnosis and management, which is crucial for improving both maternal and fetal outcomes^[11^].

This case report aims to contribute to current knowledge by detailing the presentation and successful management of ISK in early pregnancy. This case report is written according to the SCARE criteria^[12^].

Case presentation

We present a case of a 31-year-old gravida 3, para 2 woman at 12 weeks’ gestation who presented with a 1-day history of acute periumbilical abdominal pain, obstipation, and vomiting that initially involved ingested matter and later progressed to bilious content, accompanied by abdominal distention. She reported no vaginal bleeding. On examination, she appeared acutely in pain, with an oxygen saturation of 92% on room air, blood pressure of 102/75 mmHg, pulse rate of 98 beats per minute, temperature 37.8°C, and respiratory rate of 24 per minute. Abdominal examination revealed marked direct and rebound tenderness and significant distention. Digital rectal and vaginal examinations were unremarkable.

Routine laboratory investigations revealed a WBC count of 13.4 × 10³/µl (normal range 4.1–10.9 × 10³/µl) with 88.8% neutrophils, platelets 234 000/µl, hemoglobin 15 mg/dl, and normal serum creatinine, blood urea nitrogen, and electrolytes. Bedside abdominal ultrasound showed a viable 12-week intrauterine singleton pregnancy, diffuse colonic wall thickening, and free intraperitoneal fluid. Although these sonographic features were nonspecific, further imaging was not performed due to a lack of informed consent, despite counseling that the minimal radiation risk was outweighed by the diagnostic benefit.

The patient was admitted to the emergency room, resuscitated intravenously, kept NPO for bowel rest, and underwent nasogastric tube decompression. After 2 hours, her abdominal pain worsened, and vital signs became unstable, prompting preparation for an emergency exploratory laparotomy due to signs of imminent bowel strangulation.

During surgery, approximately 1200 ml of hemorrhagic fluid was evacuated. A complex knot was identified, with the ileum tightly wrapped clockwise around the base of the sigmoid colon (Fig. 1). A diffusely necrotic, distended loop of the sigmoid colon (Fig. 2) and a 150 cm segment of the ileum, ending 10 cm from the ileocecal valve, were also identified (Fig. 3).

Figure 1.

Intraoperative image showing the gangrenous ileosigmoid knot. The dark, discolored ileum (white arrows) is seen wrapped around the base of the sigmoid colon.

Figure 2.

Intraoperative image demonstrating distended and gangrenous sigmoid colon.

Figure 3.

Intraoperative view demonstrating the extensive gangrene of the ileal segment.

The gangrenous ileal and sigmoid segments were resected en bloc to prevent spillage into the peritoneum. Small bowel continuity was restored with a two-layer, end-to-end ileo-ileal anastomosis. Due to the extensive necrosis, a primary colonic anastomosis was deemed unsafe. The distal sigmoid stump was closed, and the proximal descending colon was exteriorized as an end colostomy (Hartmann’s procedure). The peritoneal cavity was thoroughly irrigated with warm saline before closure.

Postoperatively, the patient was transferred to the Post-Anesthesia Care Unit for close monitoring. Her vital signs stabilized, and urine output remained adequate. An urgent postoperative gynecological assessment confirmed fetal viability with a normal fetal heart rate. She was subsequently transferred to the surgical ward for continued care, and her postoperative course remained uneventful. The timeline for major clinical events is summarized in Table 1.

Table 1.

Timeline of major clinical events

Time point	Event
Day 1, 0 hours	Onset of periumbilical abdominal pain
Day 1, 6 hours	Presentation to the emergency room with vomiting and abdominal distension
Day 1, 8 hours	All routine lab investigations and abdominal ultrasound performed
Day 1, 10 hours	Patient condition worsened with increased severity of persistent abdominal pain, tachycardia, and abdominal distention. Decision for Laparotomy was made
Day 1, 11 hours	Surgery commenced; ileosigmoid knot with gangrene identified and resected
Day 1, 15 hours	Patient was stable in Post-Anesthesia Care Unit, fetal viability was confirmed and decided to transfer her to surgical ward
Day 7	Patient discharged with an appointment scheduled after 2 weeks

Discussion

Intestinal obstruction in pregnancy is rare, with an incidence ranging from 1 in 1500 to 1 in 66 431 deliveries. Common causes mirror those in nonpregnant patients, with adhesions being the most frequent^[8,9^]. Because constipation, vomiting, and abdominal distention can occur in otherwise healthy pregnant women, the clinical presentation of intestinal obstruction may be masked, especially in early gestation^[10,13^].

ISK is a rare cause of intestinal obstruction worldwide, though it occurs relatively more often in Africa, Asia, the Middle East, South America, and Eastern and Northern Europe^[1,4^].

The exact cause remains unclear, but anatomical factors such as a long, mobile small bowel mesentery and a long sigmoid colon with a narrow base have been implicated. Dietary factors, particularly consuming bulky carbohydrate-rich meals after prolonged fasting, are also associated with knot formation^[5,9,14,15^].

Classically, ISK is classified based on the active segment forming the knot and its direction. In Type I, the ileum is the active component, wrapping around the sigmoid colon in either a clockwise or counterclockwise direction. In Type II, the sigmoid colon is the active component, encircling loops of ileum in a clockwise or counterclockwise direction. In Type III, the ileocecal segment is the active component, wrapping around the sigmoid colon. In Type IV, it is difficult to determine the active segment^[14,16,17^]. In our case, the classification was Type I, which is the most common type, accounting for up to 57% of cases^[16^]. More recent classifications consider patient age, systemic illness, and bowel gangrene to guide management and predict prognosis^[2^].

ISK in pregnancy is extremely rare, usually occurring in the third trimester, when the enlarged uterus displaces bowel loops. Multiparity is also a risk factor due to laxity of the abdominal wall^[8,9,13^].

In our case, the patient was in early pregnancy but multiparous. Anatomic risk factors, as well as a notable change in her eating habits during the fasting season of the Ethiopian Orthodox Church, in which devout believers abstain from food for up to 12 hours and then consume carbohydrate-rich meals while avoiding animal products, likely contributed to the development of the knot.

The clinical picture of ISK often resembles small bowel obstruction marked by the abrupt onset of periumbilical colicky abdominal pain, vomiting and abdominal distention^[1,4,13,18^]. Some studies also found diarrhea to be associated with knot formation^[15^].

Diagnosis can be assisted by plain abdominal X-ray, CT, or MRI. X-ray features of ISK include a dilated sigmoid colon on the right side of the abdomen and multiple small intestinal air-fluid levels on the left. CT or MRI may reveal a whirl pattern of the ileum and sigmoid colon mesenteries, along with dilated sigmoid loops and intestinal air-fluid levels; when present, these findings are suggestive of ISK in over 90% of cases. Imaging findings often depict a large bowel obstruction^[3,4,16,19^].

Although ultrasound is the safest option for pregnant patients, it is highly nonspecific and expert dependent. Studies recommend the usage of abdominal X-ray or CT scan in patients with an acute abdomen, even in the presence of early pregnancy. A single abdominal or pelvic diagnostic CT scan is nowhere near the toxic radiation dose of 100–200 mGY^[7^].

However, in many instances, including our case, patients are initially diagnosed with nonspecific intestinal obstruction due to a lack of imaging to guide an accurate preoperative diagnosis, and their condition may deteriorate rapidly^[13^].

Definitive management often requires laparotomy, as endoscopic detorsion is strictly contraindicated due to the risk of perforation. In patients with bowel gangrene, such as ours, resection of the necrotic segments is necessary, with restoration of small bowel continuity via end-to-end ileo-ileal anastomosis. End colostomies are frequently required when the sigmoid colon is extensively necrotic^[3,6,19^].

Pregnant patients will require a multidisciplinary team consisting of general surgeons and obstetricians to ensure the well-being of both the mother and the fetus^[8,9^].

Conclusion

This case highlights the importance of considering ISK in the differential diagnosis of acute abdomen during pregnancy. Early detection and prompt surgical management can improve both maternal and fetal outcomes.

Ethical approval

Our institution does not require formal ethical approval for the publication of individual case reports. However, we have maintained a high level of respect for patient anonymity and confidentiality throughout the preparation and presentation of this case.

Consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images.

Sources of funding

None.

Author contributions

A.M.A.: Conceptualization, Methodology, Investigation, Writing – Original draft. R.T.K.: Conceptualization, Methodology, Visualization, Validation, Supervision, Writing – Original draft, Writing – Review & editing. M.A.G.: Investigation, Data curation, Visualization, Writing – Original draft, Writing – Review & editing. K.M.Y.: Investigation, Writing – Review & editing. B.D.B.: Investigation, Writing – Review & editing.

Conflicts of interest disclosure

The authors declare that they have no known competing financial interests or personal relationships that could have influenced this work.

Guarantor

Dr Robel Tibebu Kasaye.

Research registration unique identifying number (UIN)

Not applicable.

Provenance and peer review

Not commissioned; externally peer reviewed.

Data availability statements

All data relevant to the case are included in the article.