Review Question - QID 104532

This patient presents with peritonitis, a positive FAST, and a positive seatbelt sign, concerning for hollow viscus injury. The presence of free air under the diaphragm (Figure C) is the most likely radiographic finding.

Perforated viscus secondary to trauma or any other cause is a surgical emergency, and warrants immediate laparotomy. The seatbelt sign is highly suggestive of possible blunt abdominal trauma, warranting further diagnostic evaluation, typically with computed tomography. Before proceeding to radiographic studies, the patient must be hemodynamically stable. Free air under the diaphragm is highly suggestive of hollow viscus injury, and required immediate surgical consideration.

Lindner et al. discuss the initial diagnosis and management of patients presenting to the shock/trauma bay after blunt abdominal trauma. They conducted a systematic review of the literature and concluded that initial ultrasound investigation in the emergency room should focus on the presence of free intraabdominal fluid and air, along with organ lesions. In the hemodynamically stable patient, further evaluation is warranted with computed tomography, to further characterize surgically necessary interventions.

Kokabi et al. discuss the radiologic findings in traumatic GI tract injuries due to blunt abdominal trauma. They comment that hollow viscus injury is rare, only about 0.6-1.2% of all causes of trauma are complicated by them. Furthermore, due to the poor sensitivity and specificity of physical exam findings, contrast enhanced computed tomography is the mainstay technique for detection.

Figures A, B, D, and E are discussed in the Incorrect Answers section. Figure C shows free air under the right diaphragm, which in this patient would be consistent with a presumed hollow viscus injury. Figure F shows an ecchymosis over the distribution of a lap seatbelt, a finding known as a seatbelt sign. This finding should raise concern for hollow viscus injury (bowel or bladder), hepatic or splenic injury, and lumbar distraction fractures (Chance fracture).

Incorrect Answers:
Answer 1: Radiograph A shows dilated small and large bowels with gas throughout, suggestive of ileus such as secondary to opiates post-operatively.
Answer 2: Radiograph B shows a left sided pneumothorax with mass effect on the mediastinum. This patient's ABCs were intact, making this radiograph unlikely.
Answer 4: Radiography D shows a markedly dilated descending colon without evidence of obstruction through to the rectum. This is a classic finding in colonic-pseudo obstruction of Ogilvie's syndrome.
Answer 5: Radiograph E shows multiple dilated loops of small bowel, with air/fluid levels. Highly suggestive of a small bowel obstruction.