From the Guidelines
The first sign of delayed small bowel injury is typically abdominal pain that gradually worsens over time, often becoming diffuse and more severe 24-72 hours after the initial trauma. This pain may be accompanied by abdominal distension, nausea, vomiting, and absence of bowel sounds. Patients might also develop fever, tachycardia, and hypotension as peritonitis develops. Laboratory findings may show leukocytosis (elevated white blood cell count) and metabolic acidosis. The delay in presentation occurs because small bowel perforations may initially be small or partial thickness, with full perforation developing later as tissue necrosis progresses. The injury often results from blunt abdominal trauma where shearing forces tear the bowel at fixed points, or from penetrating trauma.
Key Points to Consider
- Diagnostic evaluation should include serial physical examinations, laboratory tests, and imaging studies such as CT scan with intravenous and oral contrast 1.
- Early recognition is critical as delayed diagnosis significantly increases morbidity and mortality due to peritonitis, sepsis, and multiorgan failure 1.
- The role and diagnostic accuracy of CT remains low in diagnosing bowel injuries, with radiological signs that are sensitive rarely holding much weight in management when alone, and those signs that are specific for bowel injury rarely occurring 1.
- Free peritoneal fluid, bowel wall thickening, and mesenteric stranding are sensitive signs, while bowel wall hematoma, oral contrast extravasation, and the presence of free intraperitoneal air without pneumothorax are highly specific signs for bowel injury 1.
- Serial physical examinations and laboratory tests, such as leukocytosis and metabolic acidosis, can aid in the diagnosis of delayed small bowel injury 1.
- A high index of suspicion and prompt decision making are crucial in all trauma situations to avoid missing hollow viscus injuries and to reduce morbidity and mortality 1.
From the Research
Delayed Small Bowel Injury
The first sign of delayed small bowel injury can be subtle and may not be immediately apparent.
- Abdominal pain, vomiting, and watery stool are common symptoms that may present days after the initial trauma 2.
- A case study reported a patient who presented with small bowel stricture and obstruction 3 months after a car accident, highlighting the potential for delayed presentation 3.
- Diagnostic delays are associated with increased morbidity and mortality, emphasizing the importance of prompt and accurate diagnosis 4.
Diagnostic Approaches
- Computed tomographic (CT) scans are commonly used for diagnosis, with 77% of respondents in a survey reporting use of CT scans most or all of the time 4.
- Point-of-care ultrasound (POCUS) can also be useful in evaluating delayed traumatic small bowel obstruction, as demonstrated in a case study where POCUS showed dilated loop of small bowel with a "to-and-fro" sign 2.
- Repeat CT scans can provide clinically useful information to exclude bowel injury, particularly in patients with significant closed head injury or occult bowel injury 5.
Management Variations
- There is significant variation in the diagnostic approach to suspected small bowel injury, with respondents in a survey varying in their management of patients with unreliable abdominal exams and CT scan findings of isolated free fluid 4.
- A more aggressive approach with diagnostic and operative intervention is often advocated by surgeons with more experience or a perception of greater morbidity and mortality from delayed diagnosis 4.