Case Report: Delayed complete transection of the sigmoid colon after severe pelvic fracture leading to septic shock

Severe pelvic fractures caused by high-energy trauma may be complicated by bowel injuries. These injuries may be evident at initial presentation or remain occult, resulting in delayed diagnosis. Delayed complete transection of the sigmoid colon associated with pelvic fractures is extremely rare. We describe a 57-year-old woman who was admitted to the Intensive Care Unit (ICU) following a traffic accident that resulted in a Young–Burgess lateral compression type III pelvic ring injury, hemorrhagic shock, impaired consciousness, and multiple associated injuries. Abdominal CT on post-injury days 1, 2, and 3, emergency focused assessment with sonography for trauma (FAST), and repeated bedside ultrasonography showed no definite bowel injury. Bowel sounds were normal on admission, reduced on day 2, and absent from day 3, but abdominal symptoms could not be assessed reliably. Some inflammatory and organ-function indices partially declined after antimicrobial and supportive treatment. On day 6, abrupt biomarker re-elevation, high fever, progressive abdominal distension, and hemodynamic deterioration prompted repeat CT, which demonstrated extraluminal gas adjacent to the sigmoid colon. Emergency laparotomy confirmed complete sigmoid transection with partial stump necrosis and extensive fecal contamination. The patient survived after colectomy, colostomy, prolonged intensive care, and staged pelvic fixation. This case shows that bowel injury may continue to progress despite repeated negative CT and ultrasonographic examinations and transient improvement in inflammatory markers. When a high-risk mechanism and the clinical trajectory remain discordant, renewed surgical assessment and escalation beyond repeated noninvasive observation should be considered.