Progressnotes - October/November 2012
- About MUSC Health
By Lindy Keane Carter
For many people, eating means problems, not pleasure. One third of the population has some form of digestive disorder, such as irritable bowel syndrome, gastritis, acid reflux disease, gastroparesis (delayed emptying of the stomach), functional dyspepsia, and chronic constipation.1 In treating these conditions, gastroenterologists seek to identify the site of the problem in the gastrointestinal (GI) tract. But until recently, they could monitor only the stomach and beginning of the small bowel with upper endoscopy and the colon and last part of the small bowel with colonoscopy.
That left twenty-odd feet of small bowel a mystery, explains Donald O. Castell, M.D., MACG, a Professor in the Division of Gastroenterology and Hepatology at MUSC. “We people in gastroenterology like to put tubes in one end or the other, but what lies between is hard to access,” he says.
But now, Dr. Castell and his colleagues at MUSC’s Digestive Disease Center are using a new diagnostic tool that assesses the rest of the small bowel: an ingestible wireless motility capsule (WMC) called the SmartPill (SmartPill Corporation, Buffalo, NY). Its sensors measure the GI tract’s pH, temperature, and pressure as food moves through, data that reveal the food’s transit time. “So we have gastric emptying time, small bowel transit time, and then large bowel emptying time,” Dr. Castell says. “It’s pretty smart”.
Undiagnosed GI problems affect a large number of people. Worse, many diagnoses—of irritable bowel syndrome, for example—are made by specialists on suspicion only. “Everyone gives medications—the primary physician, the gastroenterologist, the psychiatrist—resulting in side effects and cost,” Dr. Castell explains. The SmartPill data enable physicians to locate the problem, make a diagnosis, and recommend the best drug therapy.
Since the U.S. Food and Drug Administration’s approval of the SmartPill in 2006, several studies have evaluated the device against radio-opaque marker studies and scintigraphy. In a study of 86 patients with either lower or upper GI symptoms who were assessed with the WMC vs conventional tests, the WMC provided new diagnostic information in 53% of those with lower GI symptoms and 47% of those with upper GI symptoms.2 Other advantages: the WMC is radiation-free, the patient is ambulatory, and recordings can be done at home.1 Disadvantages include the fact that the patient must swallow the large capsule and wear the data receiver for five days. In addition, there is a risk of capsule retention (0.33%), which may require endoscopic removal or even surgery. “[The WMC’s] getting stuck is rare but surgical removal may be necessary,” Dr. Castell says.
Contraindications include suspected mechanical obstruction, gastrointestinal surgery within three months, and Crohn’s disease.3 Dr. Castell uses the SmartPill primarily with patients with chronic constipation, inexplicable lack of appetite, early satiety, or those with suspected irritable bowel syndrome (after other diagnostic tests). For many, he has been able to hone in on the relevant therapies and discontinue those that are contributing to the problem, resulting in less frustration, lower healthcare costs, and improved quality of life.
¹ Rao SS, et al. Evaluation of gastrointestinal transit in clinical practice: position paper of the American and European Neurogastroenterology and Motility Societies. Neurogastroenterol Motil 2011;23(1):8-23.
² Rao SS, et al. Diagnostic utility of wireless motility capsule in gastrointestinal dysmotility. J Clin Gastroenterol. 2011 Sep;45(8):684-90.
³ Szarka, LA, et al. Methods for the assessment of small-bowel and colonic transit. Semin Nucl Med 42: 113-123.