From the Guidelines
Diagnosis of bowel perforation requires prompt recognition through clinical assessment, laboratory tests, and imaging studies, with a CT scan with intravenous contrast being the gold standard for detecting free air and identifying the perforation site 1. The initial evaluation should include vital signs assessment, looking for tachycardia, hypotension, and fever which suggest systemic inflammatory response.
- Laboratory tests should include complete blood count (showing leukocytosis), comprehensive metabolic panel, and lactate levels to assess for sepsis.
- Imaging is crucial, with upright chest X-ray being the first-line test to detect free air under the diaphragm (pneumoperitoneum).
- If inconclusive, CT scan with intravenous contrast is the most accurate imaging tool to diagnose bowel perforation, offering high sensitivity for detecting even small amounts of free air and identifying the perforation site 1. Additional findings may include free fluid, bowel wall thickening, and adjacent fat stranding.
- In unstable patients where CT is not feasible, bedside ultrasound can detect free fluid and sometimes free air. Once diagnosed, management includes:
- Fluid resuscitation
- Broad-spectrum antibiotics (typically a combination of piperacillin-tazobactam 4.5g IV every 6 hours or meropenem 1g IV every 8 hours plus metronidazole 500mg IV every 8 hours)
- Nasogastric decompression
- Urgent surgical consultation as most cases require operative intervention, with the decision between surgical and non-operative treatments depending on the type of injury, the quality of the bowel preparation, the underlying colonic pathology, and the clinical stability of the patient 1. Early diagnosis is critical as delayed treatment significantly increases morbidity and mortality due to progressive peritonitis and sepsis 1. The treatment strategy must be chosen based on the clinical setting and the patient’s characteristics, but it should also be adapted to the medical team’s experience and local resources 1. Endoscopic repair should be attempted whenever the perforation is detected during the procedure, though outcomes depend on the size and cause of the iatrogenic injury, as well as on the operator’s level of experience 1. Non-operative (conservative) management may be appropriate in selected patients who remain hemodynamically stable in the absence of signs of sepsis, with conservative management consisting of complete bowel rest, short-course broad-spectrum antibiotics, and close monitoring 1.
From the Research
Diagnosis of Bowel Perforation
- The diagnosis of bowel perforation can be made using computed tomography (CT) scans, which can identify direct findings such as extraluminal gas or contrast and discontinuity along the bowel wall 2.
- Indirect CT findings, including bowel wall thickening, pericolic fat stranding, abnormal bowel wall enhancement, abscess, and a feculent collection adjacent to the bowel, can also support the diagnosis 2.
- The accuracy of CT scans in diagnosing small-bowel perforation has been reported to be high, with a sensitivity of 92%, a specificity of 94%, and negative and positive predictive accuracies of 100% and 30%, respectively 3.
- Diagnostic peritoneal lavage can also be used to diagnose small-bowel perforation, with high sensitivity and specificity rates if a specially designed positive criterion is applied 4.
Imaging Findings
- CT findings in intestinal perforation can be subtle and nonspecific, and any unexplained abnormality on CT after blunt abdominal trauma may signal the presence of intestinal perforation 3.
- The site of perforation can be identified on CT scans, with the sigmoid colon being the most common site of perforation 5.
- Extraluminal air, contrast extravasation, and free fluid without solid organ injury are all CT findings that can suggest bowel perforation 2, 3.
Clinical Presentation
- Bowel perforation can present with abdominal tenderness, which is a common but nonspecific finding 4.
- The severity of peritonitis can be assessed using Hinchey's classification and the Mannheim peritonitis index (MPI), which can help predict mortality and guide treatment decisions 6.
- The management of bowel perforation depends on the etiology, size, severity, location, available expertise, and general health status of the patient 5.