Teaching Case

This 59-year-old women underwent capsule endoscopy as part of extensive work up for iron deficiency anaemia. Twenty-four hours after swallowing the capsule, she presented to the emergency department with vomiting and abdominal pain. Her vital signs were normal apart from mild tachycardia. Blood tests revealed leukocytosis and raised C-reactive protein.

Plain abdominal radiograph (Fig. 1) performed on admission demonstrated the retained capsule endoscope projected over the left lower abdomen. Mild dilatation of the small bowel loops was noted which was suspicious of small bowel obstruction.
Initially the patient was managed conservatively but this failed and the capsule was not passed. Due to clinical deterioration, a CT examination was performed on the 7th day following capsule ingestion. This confirmed mechanical small bowel obstruction due to the retained capsule trapped in the inflamed, narrowed and thick-walled distal ileum (Fig. 3 & 4). Small amount of free fluid and inflammatory changes were present in the adjacent mesentery. A walled off collection containing gas locules was noted in the right iliac fossa (Fig. 4). CT findings suggested Crohn's disease with a localised perforation. Patient underwent an emergency laparotomy. Crohn's disease and perforation were confirmed on the histopathological examination of the resected bowel.

Capsule endoscopy is a non-invasive diagnostic technique, which can evaluate the relatively inaccessible small bowel. It consists of a 26 by 11 mm capsule containing a battery-powered complementary metal oxide silicon imager (CMOS), a transmitter, antenna and four light emitting diodes. The capsule is swallowed and is propelled through the intestine by peristalsis [1]. Its indications include cases of obscure gastrointestinal bleeding, suspected small bowel Crohn’s disease, assessment of coeliac disease and screening and surveillance for polyps in familial polyposis syndromes. The examination is contraindicated in patients with known strictures or swallowing disorders [2].

Capsule endoscopy is generally considered a safe procedure. The most common complication is retention of the capsule with an incidence of approximately 0.75% of capsule examinations [3]. The most common site of detainment is in the ileum [4]. Patients with Crohn’s disease, chronic usage of non-steroidal anti-inflammatory drugs and history of abdominal radiation injury are at higher risk [2]. In our case capsule retention occurred in a patient with previously undiagnosed Crohn’s disease.

In asymptomatic patients, conservative management is appropriate since most retained capsules pass spontaneously [5]. The longest reported case of capsule retention is 2.5 years [6].

To date, there have been twelve documented cases of small bowel perforation caused by capsule retention [7-12]. Perforation happened from 1-75 days after capsule ingestion. Interestingly, six of these occurred in patients with Crohn’s disease. In the present case, we suspect that the presence of stricture in the terminal ileum lead to capsule retention which in turn resulted in acute small bowel obstruction and perforation of an already diseased segment. Our case, in combination with other published cases, suggests that alternative imaging modalities such as barium follow through and CT/ MR enterography should be considered in the evaluation of patients with suspected or known Crohn’s disease, and that the decision to perform capsule endoscopy should not be taken lightly.

In conclusion, clinicians need to be aware of this rare but life-threatening complication of the capsule endoscopy technique. It appears that there is now enough volume of evidence to recognize bowel perforation as a potential complication particularly in cases of patients investigated for Crohn’s disease. Such patients should be informed and counselled adequately. Management of a retained capsule is at the moment considered on an individual basis, but certainly caution is required in patients with Crohn’s disease and evidence of bowel obstruction.