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By Linda Bren
Lights! Camera! Swallow!
Through the marvels of miniaturization, people with symptoms that indicate a possible problem in the gastrointestinal tract can now swallow a tiny camera that takes snapshots inside the body for a physician to evaluate.
The miniature camera, along with a light, transmitter, and batteries, is housed in a capsule the size of a large vitamin pill. The capsule, called the PillCam, is used in a procedure known as capsule endoscopy, a noninvasive and painless way of looking into the esophagus and small intestine. The procedure requires no sedation and no recovery time, as in a conventional endoscopy where the physician pushes a lighted instrument (endoscope) down the patient's throat to view interior regions. The disposable PillCam passes naturally and painlessly out of the body in eight to 72 hours.
In November 2004, the Food and Drug Administration cleared the PillCam ESO for use in adults to help detect abnormalities in the esophagus. In 2001, the agency cleared the PillCam SB for detecting problems in the small bowel, or small intestine, in adults and children at least 10 years old. Both types of PillCam are made by Given Imaging Ltd., an Israel-based company with North American headquarters in Norcross, Ga.
Physicians use the PillCam ESO to look for conditions such as gastroesophageal reflux disease (GERD). GERD occurs when a muscle valve in the esophagus malfunctions, allowing stomach acid to flow up into the esophagus and cause heartburn. Left untreated, GERD may lead to a pre-cancerous condition called Barrett's esophagus.
Blair Lewis, M.D., a gastroenterologist at Mount Sinai School of Medicine in New York City, notes that the PillCam ESO views only the esophagus--not the stomach or the beginning of the small intestine where peptic ulcers may form. "It does not replace conventional endoscopy," Lewis says, because endoscopy allows the physician to view these areas and to take a tissue sample (biopsy). If a capsule endoscopy suggests a serious problem, the patient will still need conventional endoscopy to confirm a diagnosis, he says.
Lewis uses the PillCam ESO for patients "who are reticent to have an upper endoscopy but are still concerned that they may develop problems such as Barrett's esophagus." Capsule endoscopy, as with traditional endoscopy, can help guide treatment, he says.
The PillCam SB, which views the small intestine, can help determine the cause of persistent abdominal pain, unexplained rectal bleeding, or diarrhea. Physicians use it to detect polyps, cancer, and other causes of bleeding and anemia, such as Crohn's disease, a chronic inflammation of the digestive tract that can cause abdominal cramps, diarrhea, and anemia.
"[The PillCam] can see lesions that indicate sources of gastrointestinal bleeding," says Jamie Barkin, M.D., professor of medicine at the University of Miami and chief of gastroenterology at Mount Sinai Medical Center in Miami Beach, Fla. "Crohn's disease is not apparent on X-rays," he says, "so it can find Crohn's at an earlier stage and tell us the extent of Crohn's.
"The advantage of capsule endoscopy is that it sees areas that were never seen before--areas that were overlooked by conventional endoscopy and small bowel X-ray," adds Barkin. Only about 20 percent of the small intestine can be seen with conventional endoscopy, he says.
The PillCam SB allows doctors to see the entire 20-foot-long small intestine; however, it does not photograph the large intestine--the site of colon cancer. "It doesn't replace the colonoscopy," says Jeffrey Cooper, D.V.M., an FDA medical officer who evaluated the PillCam. "The battery has an eight-hour life expectancy, which generally is long enough to photograph the small intestine but not the entire gastrointestinal tract," he says.
A person must fast for 10 hours prior to undergoing capsule endoscopy for the small intestine, but can eat four hours after swallowing the capsule. Lewis says he schedules patients early in the morning, so they can eat lunch and dinner. Wire leads with sensors on the end are affixed to the patient's abdomen and connected to a data-recording device worn on a belt around the waist.
The PillCam SB takes about eight hours to move through the small intestine, taking two pictures per second with its single camera. During this time, the person can leave the doctor's office and go about a regular routine while wearing the sensors and recorder. Later, the person returns to hand over the sensors and data recorder. The physician downloads about 57,000 color images into a computer, which compresses them to form a video. The physician then views the video on a monitor to determine the next step in treatment.
A two-hour fast is required before taking the PillCam ESO, which views the esophagus. Wire leads with sensors are placed on the patient's chest and connected to a recording device. The person swallows the capsule with water while lying flat on the back. Every two minutes over a six-minute period, the person is raised by 30-degree angles until sitting upright, then remains upright for an additional 15 minutes to make sure the capsule has traveled through the entire esophagus.
The gradual rise to a sitting position slows down the movement of the PillCam ESO, giving it additional time to take pictures. In contrast to the PillCam SB, which moves slowly through the snake-like turns of the small intestine over several hours, the PillCam ESO "moves through the esophagus in minutes," says Cooper. Given Imaging added a second miniature camera to the ESO capsule, putting one camera at either end, to take about 2,600 total color images of the esophagus.
The FDA clearance of the PillCam devices was based on their safety, ability to detect abnormalities in the small intestine and esophagus, and lack of side effects.
No cramping or discomfort has been reported with the PillCam, says Lewis, who has conducted clinical studies involving the device. People have "no clue it's there," he says, adding that he's gotten calls from some patients who insisted that it did not pass in their stool and requested an X-ray to confirm it was no longer there.
The size of the capsule--a little more than an inch long and a little less than one-half inch wide--may be daunting for some individuals. "Children and people who have trouble swallowing pills may have a hard time swallowing the capsule," says Cooper.
"Once inside, if a patient has a small blockage, the device could get hung up, sometimes requiring surgery to remove it," he says. The device is not for use in a person with a known intestinal blockage or a significantly narrowed small intestine.
Lewis notes that, in studies worldwide involving a total of 150 patients, the esophageal capsule never became lodged in the body. In larger studies, the capsule for the small intestine became lodged in the gastrointestinal tract in less than 1 percent of those studied.
Most insurance carriers will reimburse patients for the capsule endoscopy for the small intestine, says Lewis. However, the newer esophageal capsule endoscopy is not yet widely accepted by carriers, who consider it on a case-by-case basis.
Find a physician who uses capsule endoscopy (not an FDA Web page).