Biliary ileus: an infrequent cause of intestinal obstruction

Clinical History

A 44 year-old female patient presented at the emergency department with abdominal pain. Abdominal ultrasound and computed tomography were performed. It showed uncomplicated cholelithiasis. She was discharged with antibiotic treatment. Six months later, she returned referring abdominal pain in right upper quadrant and vomiting. In the blood test, she had leukocytosis.

Imaging Findings

The first time which the patient presented at the emergency department, an abdominal ultrasound and computed tomography (CT) were performed. An uncomplicated cholelithiasis was found (Figs 1 and 2).
When the patient went to the emergency department for the second time, an abdominal radiograph was performed. It showed hydro-aereo levels. Therefore, an abdominal CT was requested to rule out an intestinal obstruction. CT showed an irregular gallbladder with gas (Fig 3, blue arrow) and perivesicular fluid (Fig 3, orange arrow). These findings were due to complicated acute cholecystitis. It associated dilation of small bowel loops prior to an ileal segment that contained a lithiasis (Fig 4, red arrow). This lithiasis was coinciding with the gallstone seen on the previous CT. These features are compatible with gallstone ileus. The treatment consisted of urgent enterolithotomy.

Discussion

Gallstone ileus is a rare cause of intestinal obstruction that can occur due to impaction of one or more gallstones in any segment of the digestive tract. It represents 1-3% of the causes of intestinal obstruction and 60% of patients associate previous history of cholelithiasis [1].
The aetiopathogenesis lies in a "chronic" lithiasic cholecystitis that evolves to inflammation/ fibrosis in adjacent tissues with the consequent formation of adhesions, cholecystocholedochal fistulas and/or migration of the lithiasis to the intestine [2].
The clinical course is insidious. It can manifest with abdominal pain, due to the migration of the gallstone through the intestinal tract, until intestinal obstruction occurs, associating nausea, vomiting and/or diarrhoea. Its mortality oscillates around 12-27% [2] due to the difficulty in the diagnosis.
In 50% of cases the diagnosis is made by exploratory laparotomy [3, 4]. However, imaging tests have a fundamental role, with CT being the technique of choice in these cases. This imaging test reveals the presence of pneumobilia, the existence of a cholecystoduodenal fistula, the level of stone impaction and intestinal obstruction [4]. The differential diagnosis includes other entities such as paralytic ileus, intestinal ischaemia or lithiasis in the abdominal cavity post-cholecystectomy. The treatment of choice is surgical, with enterolithotomy being the most frequently performed technique [5] as indicated in the case presented. In our case the patient showed a favourable evolution. Imaging tests were the key to make an early diagnosis of a rare entity with significant comorbidity.

Differential Diagnosis List

Final Diagnosis

Gallstone ileus

URL:	https://www.eurorad.org/case/15806
DOI:	10.1594/EURORAD/CASE.15806
ISSN:	1563-4086