A 56-year-old male was brought to emergency with history of fall from height. Slightly distended abdomen was the only finding on examination. Patient was admitted and closely monitored on clinical background. Progressive abdominal distension increased leucocyte count and raised lactate level was detected in next day.
Supine chest radiograph AP (anteroposterior) view on first day of hospital admission was unremarkable (Fig. 1a). Ultrasound examination of abdomen did not show any collection or free fluid. Supine chest radiograph AP view in the second day showed gas under the diaphragm bilaterally (Fig. 1b). To rule out false-positive cause of pneumoperitoneum and other injuries multiphasic contrast-enhanced CT (computed tomography) scan of abdomen was done which showed free air in the peritoneal cavity. On tracing the hollow viscous, abrupt discontinuity of proximal jejunum was seen representing the 'complete cut off sign" with surrounding strandings and fluid (Fig. 2a, 2b and 2c). Circumferential jejunal wall thickening with air in the wall was seen proximally (Fig. 3). Distal bowel loops were collapsed. Mild amount of free fluid was seen in peritoneal cavity. No other abnormality was seen and diagnosis of complete jejunal transsection was made.
Bowel injury in blunt abdominal trauma is uncommon as compared to solid organ injury . Delay in operative intervention is associated with increased morbidity and mortality, from 2% mortality in 8 hours delay to 30. 8% in 24 hours delay . Most cases occur as a result of motor vehicle accident or fall from height and often associated with multiple other injuries . Complete transsection is even rare and handful of case reports are seen in literature with isolated bowel transsection in blunt abdominal trauma [4,5]. Mechanism of injury is mostly by compression between external force and thoracolumbar spine, shear force due to sudden deceleration at or near to the point of fixation like ligament of treiz and ileocecal valve and bursting due to sudden increase in abdominal pressure in fluid-filled bowel 
Diagnosis of bowel injury in blunt abdominal trauma is often delayed due to its rare occurrence and absence of peritoneal signs in some cases . Patients with minor injuries in central abdomen may be associated with hollow viscous injury, so detailed history with mechanism of injury and constant monitoring is important even in trival trauma . Radiological methods, especially CT scan, play a vital role in diagnosis. In our case absence of peritonism and no signs of pneumoperitoneum in early radiograph resulted in delayed diagnosis.
Detection of pneumoperitoneum in the blunt abdominal trauma by abdominal radiography is less sensitive due to large false-negative cases. Various positional changes and radiographic techniques has been developed to detect small amount of air in peritoneal cavity . More accurate diagnosis could be made with thin-section multidetector computed tomography and is superior to diagnostic peritoneal lavage, ultrasonography and clinical examination . Bowel wall discontinuity, extraluminal air and extraluminal contrast extravasation are specific for bowel injury; non-specific findings are bowel wall thickening and abnormal enhancement . Most specific sign of bowel transsection is complete loss of continuity with distal bowel segment named as " complete cut off sign" .
Peritonitis, abdominal sepsis and haemorrhage are major cause of morbidity and mortality in hollow viscous injury . Though slight delay in diagnosis in our case, timely operative intervention resulted in good outcome and also confirmed the radiological diagnosis.
Take-home message/ teaching points:
Absence of clinical symptoms and sign, lack of negative early radiological investigations does not rule out the bowel injury in abdominal trauma. Proper monitoring and surgical intervention in early deterioration can save lives.
Patient consent was obtained.
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