1 year old boy with abdominal distention and BNO for 3 days
Supine AXR show multiple dilated bowel loops throughout the abdomen. A gas-filled bowel loop is projected abnormally over the left groin, below the expected position of the left inguinal canal, suspicious for inguinal hernia.
Note is also made of an area of abnormal lucency projected over the left hypochondrium, of uncertain origin or clinical significance on this supine projection. If clinically warranted, a left decubitus abdominal radiograph may be obtained to clarify if this represents intra-luminal bowel gas or pneumoperitoneum.
Bowel obstruction secondary to an incarcerated left inguinal hernia.
Often in paediatric AXRs, it is difficult to definitively ascertain whether the gas-filled bowel loops are small or large bowel in origin. It also makes little sense to apply the same upper limit of bowel diameter for adults (eg. small bowel diameter up to 3 cm in adults) to the developing paediatric patient. Nevertheless, the vertebral inter-pedicular distance is a useful gauge to upper limit of normal for bowel diameter in paediatric patients.
In this case, the multiple dilated bowel loops hint towards a mechanical bowel obstruction in the given clinical context. The take-home message for this case would be to always to alert to “abnormal” gas pockets:
(a) gas-filled bowel loops in abnormal locations such as below the inguinal canal in this case
(b) suspicious gas pockets which cannot be confidently be ascribed to be intra-luminal (ie. pneumoperitoneum); a decubitus projection may be useful to clarify.