Wireless Capsule Endoscopy
- Small bowel capsule endoscopy uses a wireless miniature encapsulated video camera designed to image the entire small bowel.
- It was developed in the mid-1990s, received FDA approval for use in 2001, and was FDA approved as a first line small bowel imaging device in 2003.
- It is noninvasive, painless, and disposable.
- It can be used in an ambulatory or hospital setting.
- The camera takes 50,000-60,000 digital images per study.
- The system consists of an ingestible pill camera (26 x 11 mm), a data recorder, and computer software for interpretation.
- The procedure takes about eight hours, but the patient can go to work or perform routine activities during the study.
- The most frequent indications are evaluation of obscure gastrointestinal bleeding and the diagnosis of suspected Crohn’s Disease. Other indications may include diagnoses or suspicion of small bowel tumors, celiac disease, polyposis syndromes, abdominal pain, and malabsorption.
- Capsule endoscopy should not be performed when small bowel obstruction is present. Care must be used in patients with swallowing disorders. Patients with implantable cardiac devices must consult with their physician.
- Risks include capsule retention, which is usually transient, but may require endoscopic retrieval or rarely surgical resection.
- It is a diagnostic tool and cannot be used to biopsy or treat findings.
Wireless capsule endoscopy is a technique designed to allow doctors to visualize the most inaccessible parts of the gastrointestinal (GI) tract. The small bowel capsule is an ingestible camera in a pill, approximately the size of a large vitamin, which passes through the patient’s GI tract, taking about 50,000-60,000 digital images for the doctor’s review. The vast majority of capsule endoscopy studies are for visualization of the small bowel (intestine). There are also capsule devices for use in the esophagus and the colon.
The first capsule was developed in the mid-1990’s and was given FDA approval for use in the U.S. in 2001. It was approved as a first line small bowel imaging modality in 2003. Since that time, there have been over 500,000 ingestions of the capsule and nearly 1,000 scientific articles about its clinical use.
The system consists of a sensor array, or electrodes, which are attached to the patient’s abdomen, much like EKG leads or a Sensor Belt, worn around the abdominal area. These are connected to a data recorder which is worn by the patient during the study. The capsule, which is swallowed by the patient, is 26mm x 11mm in size, and consists of an optical dome, a lens, several light emitting diodes, a semiconductor, transmitter, and an antenna. The disposable capsule is propelled physiologically through the entire GI tract, taking its most accurate images in the small bowel. Images recorded by the capsule camera are transmitted and stored on a data recorder worn by the patient. After the study, the images are downloaded onto a computer where the images are then viewed and interpreted by a specially trained gastroenterologist.
A bowel prep to clean the intestine, similar to that used for colonoscopy, may be recommended by your doctor to take the night before undergoing a capsule endoscopy. The exam is usually done in an office setting. Sensors are placed on the patient’s abdomen and the data recorder is attached to a large belt worn by the patient. The capsule is then activated and swallowed with a sip of water. The patient may leave the doctor’s office and continue with routine daily activities, including eating a light meal after several hours. Later, the patient returns for removal of the equipment, and then returns home. There is no sedation needed for the procedure and it is completely painless. The capsule is disposable and usually passes out of the GI tract unnoticed. The results are discussed in a follow up appointment with the patient’s doctor. Capsule endoscopy can also be performed in hospitalized patients and in children as young as 2 years old in special circumstances.
The most frequent indication for performing a capsule endoscopy is the evaluation of obscure GI bleeding. Patients who have unexplained iron deficiency anemia or are losing blood from an unknown source in the GI tract are first evaluated with a colonoscopy and upper endoscopy (EGD). However, if these exams show no identifiable source of blood loss, then a wireless capsule endoscopy study is the next step in trying to find the cause of the bleeding. About five percent of all obscure GI bleeding emanates from the small bowel, most often from small vascular lesions called angioectasias. These are small blood vessels with thin walls that may be found throughout the GI tract, and may bleed profusely or very subtlely over an extended time. Other causes of bleeding from the small bowel include ulcerations, erosions, inflammation, tumors, masses, or rare hereditary conditions.
Another common indication for capsule endoscopy is evaluation for Crohn’s Disease. Crohn’s is an inflammatory bowel disease which can affect the small intestine causing pain, inflammation, ulceration, and bleeding.
Small bowel capsule endoscopy is also a useful tool in evaluation of the small bowel for tumors such as lymphoma, carcinomas, or carcinoids. This technology can be beneficial as an adjunctive diagnostic study in patients with celiac sprue and for surveillance in patients with hereditary polyposis syndromes. Other potential indications for capsule endoscopy are under consideration and may include the evaluation of certain types of abdominal pain, refractory diarrheas, or malabsorption.
Known small bowel obstruction is a contraindication for capsule endoscopy. Patients who are at risk for obstruction, have swallowing disorders, or have pacemakers or other implanted cardiac devices should have careful evaluation by a specialist before undergoing a capsule endoscopy.
The capsule endoscopy system is purely diagnostic and is not used to biopsy or treat any conditions.
The primary risk with capsule endoscopy is possible retention of the device in the small bowel. In patients who undergo the test to evaluate for bleeding, the risk is very low, approximately one to two percent. For patients with Crohn’s Disease, the risk may increase to four to five percent. Most cases of retention resolve spontaneously after a short delay in the passage of the capsule, and most patients have no symptoms whatsoever. Occasionally, medications are given to help facilitate passage. In rare instances, there is an abnormality in the small bowel which blocks the passage. In such a case, the capsule can be retrieved during an endoscopic procedure called a double balloon enteroscopy, or in unusual instances, by surgical resection.
If the doctor is concerned about a possible blockage in the small bowel, a patency (or ‘dummy’) capsule can be ingested as a test beforehand to insure that no blockages exist.
The esophageal capsule is the same size as the small bowel capsule, but has lenses on both ends of the ‘pill.’ It is designed for imaging the esophagus to evaluate for Barrett’s mucosa and esophageal varices. Its role is currently under investigation. Insurance coverage for this procedure varies regionally.
A wireless capsule for visualizing the colon for screening purposes has been developed, but is not currently FDA approved for use in the U.S.
Reviewed November 2010