ORLANDO, FLA. — Indications for capsule endoscopy may expand in the future as researchers investigate new ways to use the technique in the small bowel to detect disease, evaluate its extent, or locate its cause, David R. Cave, M.D., said at the annual meeting of the American College of Gastroenterology.
Capsule endoscopy with the Pillcam SB (formerly called the M2A video capsule) is indicated for obscure GI bleeding, suspected small bowel tumors, and suspected Crohn's disease, although many insurers do not cover the last two indications, said Dr. Cave, professor of medicine at Tufts University, Boston.
He discussed some of the current areas of research on capsule endoscopy:
▸ GI bleeding without hematemesis. This condition can be difficult to evaluate if the hospital does not have a 24-hour bleeding team in the emergency department that can provide support in the detection of GI bleeding. Dr. Cave and his colleagues thought they might be able to save time with capsule endoscopy and still diagnose GI bleeding without hematemesis accurately. At St. Elizabeth's Medical Center in Brighton, Mass., they used capsule endoscopy to investigate the source of bleeding in 24 patients.
In the randomized feasibility study, 16 patients underwent capsule endoscopy within 4 hours of arriving at the emergency department, with further endoscopic procedures if needed. After capsule endoscopy finished, the investigators immediately interpreted the data and provided the information to the attending physician on the GI team without making any recommendations. Another eight patients first received a conventional work-up with esophagogastroduodenoscopy (EGD) and colonoscopy before they underwent capsule endoscopy more than 4 hours after presenting to the emergency department.
The patients who received capsule endoscopy early had a specific diagnosis in a median of 19 hours, compared with 35 hours in the patients who had capsule endoscopy later. Capsule endoscopy located active bleeding in 13 of 24 patients, while EGD detected active bleeding in 2 of 17 patients and colonoscopy found it in 0 of 13 patients.
▸ Suspected Crohn's disease. Capsule endoscopy can be used to verify the presence of Crohn's disease and other inflammatory bowel diseases in the small bowel, and it may turn out to be even more valuable: A Crohn's disease activity index based on capsule endoscopy is being developed.
The technique also may be used to assess the extent of disease, especially in preparing for surgery or assessing the degree of healing before and after treatment with some of the new biologic medications, Dr. Cave said.
▸ Celiac disease. Clinicians can take duodenal biopsies and perform serologic tests to diagnose celiac disease, but they haven't really been able to measure the extent of disease. Capsule endoscopy should help to visualize neoplasias, such as lymphomas or adenomas, and ulceration that can occur in patients with celiac disease. The technique also should be able to detect coexistent inflammatory bowel disease.
▸ Abdominal pain. Capsule endoscopy may be useful in patients who present to the emergency department with abdominal pain for which it is difficult to distinguish between an organic disease and a pain syndrome. Only about 15% of people with abdominal pain turn out to have structural abnormalities. The goal is to avoid repeat endoscopies and CT scans in patients without lesions; instead, these patients can be treated for a pain syndrome. But there is currently very little research on this issue, Dr. Cave said, “maybe because insurance carriers are not paying for this indication.”
▸ Chronic diarrhea. Gastroenterologists may sometimes give “short shrift” to patients with substantial diarrhea by diagnosing them with diarrhea-predominant irritable bowel syndrome, Dr. Cave suggested. Full-thickness biopsies taken during laparoscopy in these patients have shown lymphocytic infiltration of the myenteric plexus. Capsule endoscopy could help to determine if there is a counterpart to this infiltration in the small bowel mucosa. No systematic study has examined mucosal changes in these patients, he noted.
Capsule endoscopy also may be able to help researchers understand the nature of the Brainerd diarrhea syndrome, which is “often labeled as [irritable bowel syndrome], but it might not be,” he said. Brainerd diarrhea syndrome is an acute condition that can occur sporadically or in outbreaks and may last for months to years. It “probably has an infectious etiology,” Dr. Cave said.
▸ Small bowel obstruction. Gastroenterologists initially had great concern that a retained capsule in patients with small bowel obstruction would cause trouble, “but some of us have started to look at capsule retention now in a more positive light and are actually using it as a means of detecting patients who have small bowel obstruction with no definable source,” he said. It's important to get consent from patients and explain to them that in this procedure, you are actually expecting the capsule to be retained, Dr. Cave advised. The gastroenterologist must work with a surgeon to arrange laparoscopic surgery and, possibly, intraoperative enteroscopy.