Capsule retention: prevention, diagnosis and management.

Capsule retention (CR) has been defined as capsule remaining in the digestive tract for a minimum of two weeks. CR occurs approximately in 2% of all patients undergoing small bowel capsule endoscopy (CE). Prompt diagnosis of CR is important, as it has relevant clinical implications. CR should be suspected in (I) all asymptomatic patients who do not report capsule excretion within 15 days from capsule ingestion; and (II) patients with obstructive or perforation-related symptoms in which the capsule has not been excreted, regardless of the time between the onset of symptoms and capsule ingestion. Abdominal plain X-ray is the preferred test to confirm CR. An abdominal CT scan should be performed, on individual basis, if knowledge of the precise location of the retained capsule is necessary or whenever clinically indicated. Since CR is usually asymptomatic, an initial watchful monitoring is suggested. In inflammatory bowel disease (IBD) patients, a short course of medical therapy may allow capsule excretion. Nevertheless, in long-term CR, some cases of capsule fragmentation, acute obstruction and perforation have been described. Therefore, retrieval of the retained capsule is recommended if asymptomatic CR lasts for long time. A safe capsule retrieval is usually performed by endoscopy, whereas surgery remains a viable alternative if the first is unsuccessful or when clinically indicated. Either Patency Capsule® (PC) or dedicated small bowel cross-sectional imaging techniques have been proposed to prevent CR. Both have pros and cons, but head-to-head comparative studies are lacking.