Capsule endoscopy in the diagnosis of small bowel disease

Abstract

Capsule endoscopy (CE) is a method for examining the small bowel by means of an ingested encapsulated video camera, propelled by peristalsis, to continuously take images during its passage through the gastrointestinal tract. The method has been in clinical use in Sweden since 2002 and is considered user-friendly and well tolerable by patients. CE is used to diagnose obscure small-bowel bleeding, Crohn´s disease (CD) and suspected small-bowel tumors. It is known for having a high sensitivity but a lower specificity.

In study I CE was performed in 18 patients with chronic intestinal dysmotility (CID), in which a high frequency of mucosal breaks (89%) was observed. There were signs of motility disturbances but the small-bowel transit time did not differ significantly between the two types of CID or to a control group. This was the first study to use CE in CID patients. CE was shown to be feasible for the examination of small bowel mucosa in patients with CID.

When CE is used to find a bleeding source in the small bowel, the most common finding are vascular malformations; angioectasias. These can also be found in non-bleeding patients but what triggers bleeding in some patients is not fully understood. In study II a group of 25 patients with bleeding from gastrointestinal angioectasias were tested for bleeding disorders with special focus on acquired von Willebrand syndrome (AVWS), a condition previously identified as a possible explanation for bleeding. Compared to a control group, no significant differences between groups were found in coagulation parameters, bleeding time or von Willebrand multimer levels. These results did not support the need for routine bleeding tests in cases of bleeding from angioectasias and do not demonstrate an overall increased risk of AVWS among these patients.

Inflammatory lesions in the small bowel showed by CE may be due to CD but also to other conditions. Since biopsies from the small bowel might be difficult to obtain the relevance of the lesions may remain unclear. In study III 30 patients with small bowel lesions were tested for inflammatory markers in blood (CRP) and faeces (calprotectin). Harvey-Bradshaw Index (HBI) was used to grade patient symptoms. The patients were followed up after nine months with a second capsule endoscopy, CRP, calprotectin and HBI. A significant correlation was found between endoscopic inflammation and calprotectin that persisted over time. A correlation between endoscopic inflammation and CRP was found at inclusion but did not persist at follow up. Symptoms did not correlate with endoscopic findings of inflammation at any time.

Study IV aimed to evaluate complications of capsule endoscopy, specifically incomplete examinations and capsule retention and to determine the risk factors for these. In this consecutive study 2300 CE examinations - performed at four different hospitals in Stockholm, Sweden from 2003 to 2009 - were included. The frequency of incomplete examinations was 20%. Older age, male gender and suspected or known CD were risk factors for an incomplete examination. Capsule retention occurred in 1.3%. Risk factors for capsule retention were known CD and a suspected tumor. CE was concluded to be an overall safe procedure, although obstructive symptoms and serious complications due to capsule retention can be found in large patient series.