An uncommon case of gallstone ileus in a patient with ileostomy

Clinical History

An 81-year-old female previously treated with radiotherapy for endometrial carcinoma, subsequent small bowel obstruction secondary to adhesions resulting in right hemicolectomy and ileostomy came to the emergency department with swelling around her ileostomy and progressive decrease in stoma output.

Imaging Findings

A CT of the abdomen and pelvis revealed distension of the small bowel to the point of the stoma. A small volume of free fluid was present around the stoma in the abdominal wall but there was no significant parastomal hernia. Within the stoma bag, a 2.5 cm rounded structure with lamellated calcification was seen. The gallbladder was in a close plane of contact with the duodenum and bubbles of gas were also noted within the intrahepatic biliary tree (Fig. 1). Review of a previous CT acquired a year earlier revealed a stone with identical morphological features within the gall bladder, with no biliary tree gas (Fig. 2).

Discussion

Small bowel obstruction represents 15% of surgical admissions [1]. 80% of mechanical obstruction of the bowel involves the small bowel, the main causes being postoperative adhesions and herniae [7].

The sensitivity and specificity of CT in assessing the cause of small bowel obstruction is shown to be greater than 95% [1]. Although infrequent, gallstone ileus is an important cause of mechanical bowel obstruction in patients with cholelithiasis [5, 6]. The incidence of this pathology in the general population is less than 0.5% but accounts for 25 percent of nonstrangulated small bowel obstruction in patients over 65 years [1]. The mean age of patients with gallstone ileus is 75 years and the incidence is 3 to 16 times higher in women [2, 3]. CT can differentiate and precisely locate ectopic biliary stones in 88.5% of cases, which are seen in only 50% of abdominal radiographs [5, 8].

The main point of entry of a gallstone into the bowel is via a biliary-enteric fistula, 60% representing cholecysto-duodenal fistulas, the remainder representing cholecysto-gastric or cholecysto-colonic fistulas.

This is the second case in the literature that illustrates gallstone ileus as a cause of mechanical obstruction in patients with ileostomy [4]. In this previous reported case, the patient underwent examination under anaesthesia which revealed a 2.5 cm gallstone wedged near the entry point of the stoma, determining mechanical bowel obstruction as suggested by the abdominal radiograph.

In our particular case, the patient’s symptoms gradually improved over the next 12 hours under conservative treatment. We hypothesise that the obstructing stone had passed into the stoma bag just prior to the CT acquisition. She was discharged free of symptoms with a good stoma output the next day. No further follow-up was recommended on discharge.

In conclusion, gallstone ileus represents a rare cause of small bowel obstruction, occurring more frequently in elderly female patients. In patients with ileostomy, gallstone ileus can be a potential cause for small bowel obstruction and decrease in stoma output, although parastomal hernias or intra-abdominal adhesions are much more frequent causes.

Differential Diagnosis List

Final Diagnosis

Gallstone ileus

URL:	https://www.eurorad.org/case/13938
DOI:	10.1594/EURORAD/CASE.13938
ISSN:	1563-4086