Intestinal perforation caused by foreign body

Clinical History

A 2-year-old boy, with history of increasing recurrent transient abdominal pain over two days, was referred from another hospital to be evaluated by a paediatric surgeon.
He had good vital signs, no pain complaints or signs of dehydration. The abdomen was soft and compressible, without masses, organomegaly or signs of peritoneal irritation.

Imaging Findings

The plain abdominal film showed no free air (Fig.1). An ultrasound revealed a thickening in the ileocaecal region bowel wall with a linear echogenic image (32 mm long and 4 mm wide), in a transverse position, suggesting transparietal fixation, compatible with a foreign body (FB) (Fig.2).
A colonoscopy was performed, showing spasticity of the distal ileum and findings of nodular lymphoid hyperplasia (Fig.3).
The patient remained fasting for reassessment. The next day, ultrasound showed the same findings (Fig.4).
CT examination was performed and no obvious FB was found, only parietal oedematous thickening of caecum and some mesenteric lymph nodes were detected (Fig.5). No pneumoperitoneum or intraperitoneal fluid collections were visualised.
Although CT and colonoscopy did not identify a FB, given the ultrasound findings and persisting symptoms, laparoscopy was performed. An inflammatory process in the right iliac fossa was found, secondary to ileum perforation caused by a wood 'toothpick' fixed with one tip protruding freely outside the bowel wall.

Discussion

FB ingestion is more common in children and adults with altered mental status[1]. Approximately 80% of cases involve 1 to 3-year-old children[2].

More than 80% of ingested FB pass through the gastrointestinal tract without major complications, only causing varying degrees of discomfort[2, 3]. However, ingestion of FB increases the risk of impaction at a point of intestinal narrowing or bending and also gastrointestinal perforation, especially if the object has sharp edges[1, 4].

Perforation of gastrointestinal tract by ingested FB is rare (<1%)[1, 4]. Objects more frequently associated with perforation are wooden sticks, poultry and fish bones[2, 3, 5]. Wooden sticks, such as toothpicks, most often cause injury at the level of the duodenum, followed by sigmoid colon[1]. Foreign bodies can also be lodged in the esophagus, which is the most common site for perforation[6].
In this risk group, few are aware of an episode of FB ingestion and it becomes difficult to reach a diagnosis when imaging tests are negative[2, 3].

Most FB are radiopaque and can be detected by X-ray or CT. Radiolucent objects, such as small fish bones, pieces of wood or plastic, are more easily diagnosed by endoscopy or ultrasound[2]. Contrast studies should be avoided because of aspiration risk, and because contrast coating of FBy and mucosa can compromise subsequent endoscopy[7].
Ultrasound may detect a FB depending on its material constitution, size, shape and position within the organ and tissue[2, 3]. It has the advantage of being an accessible technique without radiation, which is very important in the paediatric group.
In the case of wooden objects, the X-ray is limited by the nature of the wood. Sometimes, these materials can be hyperdense on CT, showing better resolution on CT compared to plain abdominal film.
Other times, as in the case reported, wooden objects are not sufficiently dense to be diagnosed by CT, although secondary findings as perforation or intra-abdominal inflammatory process may be revealed[2, 4].
In cases where endoscopic extraction is not possible, the object is removed by laparotomy or laparoscopy, in order to avoid perforation and its complications. Surgery is also performed if perforation or intra-abdominal abscess occur[2, 5].
Bowel perforation by FB ingestion should be part of the differential diagnosis of abdominal disease of unknown origin, particularly if the patient is within the risk groups of FB ingestion, and that the ultrasound can be very valuable in cases of radiolucent objects, hardly identifiable on plain abdominal film and CT.

Differential Diagnosis List

Final Diagnosis

Ileal perfuration from an ingested wood foreign body

URL:	https://www.eurorad.org/case/10138
DOI:	10.1594/EURORAD/CASE.10138
ISSN:	1563-4086