Capsule Endoscopy
Salmaan A. Jawaid, MD
David R. Cave, MD
Video endoscopic capsules (PillCam, Medtronic, MN, USA; EC-10, Olympus America, PA; Mirocam, South Korea; and CapsoCam, Capsovision, CA) can be swallowed and images obtained from the entire small bowel without the need for sedation.1 Individual digital images are transmitted out of the body by radio frequency to a recording device worn about the patient’s waist (PillCam and EC-10 use human body conduction and CapsoCam capsule is recovered from the fecal stream). The images are processed and viewed as a video on a computer workstation after completion of the study.
INDICATIONS
Capsule endoscopy is indicated as a procedure for evaluation of suspected disease of the small intestine including the following:
1. Small intestinal bleeding (aka obscure gastrointestinal bleeding)2: These are patients with GI bleeding in whom no diagnosis has been made after upper endoscopy and colonoscopy. Capsule endoscopy has been shown to be superior to both push enteroscopy and radiographic imaging of the small bowel in the evaluation of these patients.3 If a source of bleeding is detected by capsule endoscopy, a targeted deep enteroscopy (either through an anterograde or retrograde approach) has been shown to increase the diagnostic and therapeutic benefit in these patients.4,5
2. Known or suspected Crohn disease: In one study capsule endoscopy detected all the lesions seen on small bowel series and computed tomography scanning and detected additional lesions in 47% of cases.6 In addition, capsule endoscopy findings can alter treatment strategies in a number of patients.7
3. Other suspected small bowel diseases. A growing body of literature supports the superiority of capsule endoscopy over other imaging modalities of the small bowel to detect and further characterize polyposis syndromes, celiac disease, and other malabsorption disorders.8
CONTRAINDICATIONS
1. Swallowing disorders (though the capsule can be placed endoscopically)
2. Implanted pacemakers and defibrillators. This is an FDA recommendation that has been questioned by multiple studies
3. Small bowel obstruction
4. Small intestinal strictures (degree of stricturing can be assessed with the patency capsule)
PREPARATION
The typical timing of a capsule exam is to begin the study at 8 AM. with completion of the study at 4 PM. This allows 8 hours of image acquisition during one working day. However, most manufactures now have capsules with a battery life of more than 12 hours, so the capsule recorder may be returned the following day.
1. Instruct the patient to present on the morning of the exam after a 12-hour fast. Some facilities use a 2 L polyethylene glycol preparation the night before.
2. Discontinue oral iron supplementation 3 days prior to the exam.
3. Advise them not to take medications, antacids, or sucralfate, since they can coat the intestinal lining, limiting visualization. Narcotics and antispasmodics can delay both gastric and intestinal emptying, making it difficult to visualize the entire small bowel during the 8-hour acquisition time.
4. Instruct patients to bring their medications with them to take during the day, if necessary. If a patient is diabetic, insulin doses may need to be adjusted.
5. Anticoagulants do not need to be stopped prior to the exam.
6. Instruct the patient to wear loose clothing on the day of the exam. Dresses should be avoided. A buttoned shirt and loose-fitting pants work best.
7. Charge the recorder’s battery the evening prior to the study.
8. Bowel preparation may improve the quality of small bowel visualization but has minimal to no effect on transit times or visualization of the cecum, thus is not recommended.9
EQUIPMENT
1. Small bowel capsules are approximately 11 × 26 mm. They contain light-emitting diodes as a strobe type light source, a lens, a color camera chip, two silver oxide batteries, a radio frequency transmitter, and an antenna. The PillCam is a complementary metal oxide semiconductor chip while the EC-10 uses a CCD chip. The capsules obtain 2 to 3 images per second and transmit data via radio frequency or human body conduction to the recording device worn about the patient’s waist. The capsules are disposable and do not need to be retrieved by the patient. They are passed naturally with a bowel movement. However, the CapsoCam, which has four cameras, needs to be recovered from the fecal stream with a simple collection kit. The video may be retrieved from the capsule and processed locally or mailed to a central reading facility.
2. Recording devices: These are mini-computers worn on a belt with up to 5 GB of memory, allowing for storage of the raw data obtained during a typical 8- to 12-hour examination. Once the study is completed, the recorded data are downloaded to a computer workstation with software that processes the images into a video for reading.
3. The real-time viewer: Recording devices with this capability can allow real-time viewing of the intestinal tract without having to wait for images to be downloaded. This allows for the quick detection of active bleeding or determining whether the capsule has left the stomach, without having to wait at least 8 hours before determining location of bleeding. CapsoCam does not have this facility.Related posts:
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