Teaching Case

A 53-year-old woman with known Crohn's disease arrived at the emergency department with a two-day history of right lower quadrant abdominal pain and distention, loss of appetite, prostration and vomiting with food and bile content. Blood test revealed leukocytosis and elevated C- reactive protein.

Abdominal radiography revealed intraperitoneal air (Fig. 1), signs of small bowel distention and small radiopaque images with rectangular shapes in the right iliac fossa (Fig. 2).
Computed Tomography (CT) scan of the abdomen with intravenous contrast demonstrated similar radiological findings: pneumoperitoneum, distention of the small intestine loops (Fig. 3) and elongated hyperdense images within the cecum. Mesenteric lymph nodes and free pelvic fluid were noted (Fig. 4a and 4b).
The resection of the terminal ileum and cecum was performed by laparotomy, and small phalanx-like images were observed within these loops, and then the diagnosis of intestinal obstruction and perforation by chicken phalanges was made (Fig. 5).

Accidental foreign body (FB) ingestion is common, but intestinal perforation is rare. Diagnosis is challenging because many patients may not remember their FB intake. In addition, nonspecific clinical manifestations, such as abdominal pain, nausea, vomiting, fever, intestinal obstruction and bleeding, can make the investigation difficult and delay diagnosis [1- 6].
Perforation is usually caused by sharp and elongated FBs, such as fish bones, chicken bones and toothpicks [1,4]. Areas of luminal narrowing and high angulation are the most commonly affected, such as terminal ileum and rectosigmoid junction [1,2,4,5]. Risk groups include use of dental prostheses, seamstresses, carpenters, alcoholics, prisoners, children and psychiatric patients, sometimes intentionally occurring in the last two [1,2,4,7].
Studies reveal that most FBs (80% -90%) pass through the gastrointestinal tract without significant damage, allowing conservative treatment. Approximately 10% to 20% will require endoscopic treatment if the FB is located in the esophagus or stomach. Only 1% of cases require surgical treatment, indicated in cases complicated with bleeding, peritonitis, abscess or fistula, including resection of the affected intestinal segment [1,2,5,8,9]. In case of abscess secondary to gastrointestinal perforation (e.g., in the liver), management should involve drainage of the abdominal cavity, removal of the foreign body and antibiotic therapy [2,10].
FB identification, intestinal wall thickening, mesenteric fat densification, and pneumoperitoneum should be included in the CT findings [1,2,4]. Traumatic mucosal injuries are related to intestinal ischemia and may be demonstrated by pneumatosis [8].
The average time from ingestion to perforation is usually around 10 days. However, there are some reports of FB embedded in the intestinal mucosa for about 9 to 10 months until endoscopic or surgical removal. This proves that the absence of clinical symptoms and negative radiographic findings are not sufficient to institute conservative treatment [7].
Computed tomography (CT) or endoscopic examinations are mandatory, as radiographs have low sensitivity to identify FBs due to their small dimensions, low radiopacity, interposition of intestinal loops and the fact that they do not always demonstrate pneumoperitoneum.
Therefore, CT plays a fundamental role in the diagnosis of acute abdomen, with an accuracy of 86% in identifying the point of intestinal perforation, allowing the correct therapeutic planning [1,2,4,7,11].