Capsule endoscopy goes where few endoscopes have gone before

Thursday, August 29, 2002

JACKSONVILLE, Fla., Aug. 29, 2002 — A pill-sized camera is making intestinal endoscopy easier to swallow. Patients coming to Mayo Clinic in Jacksonville, Fla., suffering from intestinal bleeding and intestinal disorders such as Crohn's disease, can now swallow a miniature camera to help physicians diagnose the problem.

The Food and Drug Administration approved M2A capsule endoscopy in August 2001 to obtain images of the gastrointestinal tract. M2A has been heralded as a revolution in endoscopic imaging of the small intestine. Traditional endoscopic procedures are invasive. None of them, except for surgical placement of the endoscope (intraoperative enteroscopy), are as good as M2A has proven to be at providing physicians diagnostic information.

The capsule patients swallow is about the size of a large vitamin. It contains a color camera, battery, light source and transmitter. The camera takes two pictures every second for eight hours, transmitting images to a recording device about the size of a portable CD player that patients wear around the waist.

Harriett Lloyd has suffered from intestinal bleeding for three years. She read about capsule endoscopy and came to Mayo Clinic to have it done. "I thought it would benefit me," she says. "I asked for it rather than the poking and prodding I've gone through before. It's simple. It's easy. If you have no problems swallowing a large pill, you should have no problems swallowing the camera."

The camera moves naturally through the digestive tract while patients go about their normal activities. About eight hours after ingesting the camera, patients return the recording device to their doctor so the images can be downloaded to a computer and evaluated. The camera is naturally excreted and not retrieved.

Compare this to the current standard of care. Physicians insert an endoscope into the sedated patient's mouth and push it through the esophagus and stomach into the small intestine. An endoscope is a thin, flexible tube with a camera on its tip. "It's long enough to make it around a couple turns and sometimes a foot or so down into the small intestine," says Dr. Mark Stark, a Mayo Clinic gastroenterologist who is offering patients capsule endoscopy. "But you're still missing much of the length of the small intestine."

Steering the endoscope around hairpin turns of the small intestine is difficult, and it can be uncomfortable for the patient. A physician can only push the scope so far until it gets hung up like a plumber's snake in a drain. "The plumber's snake just curls up if you push hard enough against an iron pipe," Stark says. "But unlike an iron pipe, the intestine will tear and break if you push further on the scope."

So physicians usually combine push endoscopy, as it's often called, with X-rays to get a better look at the entire small intestine. However, Stark says together the two tests are often inconclusive, and some patients still require exploratory surgery to try to explain their problem. "With capsule endoscopy you'll find some bleeding lesions in the small intestine in as many as 60 to 70 percent of the people who had negative results on the standard tests," he says. "Either the lesion is in an area that you couldn't get to with the scope, or it was flat, and you couldn't see it on an X-ray. X-rays see things that are bumps or ulcers that are little depressions. They don't see flat things very well, and the sources of bleeding are often vascular malformations. These are just flat, prominent blood vessels, and they don't really show up on an X-ray."

Once identified, the bleeding lesions may need to be surgically removed, but Stark says that capsule endoscopy helps surgeons localize the culprit lesions in the operating room.

In addition to finding the source of intestinal bleeding, Stark says capsule endoscopy also helps diagnose some cases of unexplained abdominal pain and diarrhea. These problems can have many causes; one is Crohn's disease. Capsule endoscopy can reveal the telltale sores or ulcers of Crohn's disease in the small intestine. Identifying Crohn's disease can lead to effective medical therapies that provide symptom relief.

Aside from its ease on patients, Stark says the main medical benefit of capsule endoscopy is identifying a problem that couldn't be found before. "Some of these people are getting blood transfusions every month," he says. "They're having scary bleeding episodes and don't ever know if they can go anywhere without ending up in an emergency room. If you can find a lesion that's causing this, then you can go to an effective treatment, whether it's surgery to remove that area or a medical treatment if there is one."

Stark calls capsule endoscopy an exciting technology that is rapidly evolving to replace standard tests to look for unexplained bleeding in the small intestine. But he stresses that it is not a replacement for standardized upper endoscopy, used to diagnose diseases of the esophagus and stomach, or for colonoscopy, to screen for colorectal cancer.

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