Acute duodenal injuries are notably rare and present significant challenges in clinical detection. The advent of bariatric surgery has introduced further complexity, altering the anatomy of the upper gastrointestinal tract and potentially masking typical presentations of duodenal injuries. We present the case of a 58-year-old woman with a history of omega loop bypass, who suffered a traumatic duodenal perforation following a fall from a height of 2 meters. Despite clinical suspicion, the perforation was initially missed due to the absence of free air in the retroperitoneum, likely influenced by the altered anatomy post-bypass surgery. This case highlights the difficulty in timely diagnosis of duodenal injuries and the importance of heightened vigilance in post-bariatric surgery patients who’ve sustained abdominal trauma.