Retention of the Patency Capsule: A Complication That Deserves Attention

Abstract

Video capsule (VC) endoscopy is useful in examining the entire length of small bowel for conditions like suspected Crohn's disease, complicated celiac disease, obscure GI bleeding and surveillance of polyposis syndromes. While VC endoscopy is a non-invasive, and easy-to-perform procedure, a significant complication is capsule retention. The estimated capsule retention rate is approximately 2%. The risk is 0% in healthy adults but increases to 13% in suspected Crohn's disease patients. To minimize this complication, pre-screening is performed by small bowel imaging or via a patency capsule (PC). The PC is a self-dissolving capsule: it is the same size as the video capsule and consists of a biodegradable cellophane film, containing lactose and barium sulfate. Because small-bowel imaging may not accurately predict the passage of the VC, the PC is used to determine if the VC will pass through the affected small bowel. Per the manufacturer, the PC is expected to dissolve in 30 hours post-ingestion - even if it gets lodged in the small bowel. However, one study of 30 adult patients reported the average PC transit time to be 40 hours. In one case report, it was retained for 76 hours. We report an adolescent female whose PC was was retained for 8 days. She had clinical and radiographic features suggestive of Crohns disease affecting the terminal ileum. Tissue diagnosis could not be obtained as narrowing of the ileocecal valve prevented intubation of terminal ileum. VC endoscopy was indicated to visualize the inflamed area. To predict VC passage, a PC was swallowed to assess patency of the diseased segment. The PC was retained in the right lower quadrant for 8 days (192 hours), with some decrease in size on serial X-rays even though she received a 5-day course of steroids. Contrary to the PC manufacturer specification, even after 8 days, the PC did not dissolve completely causing microperforation and peritonitis of the terminal ileum requiring resection. At surgery, the PC was visualized as an empty parchment paper-like shell in the diseased ileum. Pathology was consistent with active transmural fibrostenotic Crohns disease. Clinicians should be aware that the PC may be retained in the small bowel for longer than the manufacturer's specified time for dissolution and its persistence may lead to complications requiring surgery. This should be discussed with patients, prior to the examination, particularly those with suspected Crohn disease.