Is Capsule Endoscopy Safe?

A capsule endoscope houses a camera and lights in a clear housing. A patient swallows the capsule and the camera takes magnified photos and video for diagnosis of gastrointestinal disorders.

Video or wireless capsule endoscopy is a noninvasive diagnostic procedure for examining the gastrointestinal tract, particularly the small intestine. 

Capsule endoscopy is performed with a capsule endoscope, which is a large capsule containing a micro-camera, a light bulb, a battery, and a radio transmitter.

The patient swallows the capsule endoscope which transmits images of high resolution and magnification as it passes through the digestive tract. These images are recorded and can be viewed on a computer to check for abnormalities.

Traditional endoscopy and colonoscopy enable a doctor to visualize the upper gastrointestinal tract (esophagus, stomach and duodenum) and the colon, respectively, but are not helpful in studying the entire small intestine.

Barium swallow tests with X-rays have been available for evaluating the small intestines, but the radiological images are not accurate in identifying small tumors and subtle abnormalities.

Technical advances in imaging, optical design and light-emitting diodes enabled the development of capsule endoscopy in the late 1990s. Currently research is underway on the development of magnetically guided capsule endoscopy.

Capsule endoscopy is primarily performed to evaluate the small intestine’s health, though it is useful in diagnosing disease in any part of the digestive tract. 

Currently, it is recommended after upper endoscopy and colonoscopy have not been successful in finding the cause for

• blood in stool
• abdominal pain
• diarrhea or constipation
• change in bowel habits
• unexplained weight loss

Capsule endoscopy is especially useful in diagnosing conditions affecting the small intestines including:

• Obscure gastrointestinal bleeding from lesions (angiodysplasia)
• Inflammatory bowel disease (IBD) such as
  • Crohn’s disease
  • Ulcerative colitis
• Tumors and cancer
• Polyps
• Celiac disease (gluten intolerance)
• Henoch-Schonlein purpura (a disease that causes inflammation and bleeding of the small intestines) 
• Intestinal graft-versus-host disease (when immune cells in donor tissue attack the patient’s healthy cells) after small bowel transplant
• Capsule endoscopy may also be indicated in patients with
• HIV displaying gastrointestinal symptoms
• Malabsorptive syndromes other than celiac disease

Capsule endoscopy is usually performed by a gastroenterologist as an outpatient procedure. It is noninvasive and requires no sedation.

Preparation

• The patient must not eat or drink anything for 12 hours prior to the procedure.
• The patient may have to take laxatives to ensure that the digestive tract is clear of gastric contents.
• The patient may go through imaging tests to ensure there are no strictures or obstructions in the bowel.

Procedure

• The doctor attaches eight antennas to the abdominal skin, connected to a recorder worn around the patient’s waist.
• The patient swallows the capsule endoscope with a little water.
• The capsule sends two images per second as it passes through the gastrointestinal tract.
• The patient may drink liquids two hours after swallowing the capsule and eat after four hours.
• The batteries in the capsule endoscope last for eight hours and the antennas and recorder will be removed after that period.
• The patient will be able to go through normal daily activities during the period.
• The capsule will be excreted along with stools normally.
• The recorded images will be analyzed by the doctor for abnormalities.

The time taken by the capsule endoscope to pass through the digestive system varies from individual to individual. It may take 8-72 hours, or in some cases, even a week or two.

Capsule endoscopy has a few limitations such as

• Slow transit, resulting in incomplete examination before battery failure
• Rapid transit resulting in blurred images
• Getting stuck in strictures or obstructions
• Unsuitability for therapeutic purposes such as
  • removing polyps
  • extracting tissue for biopsy
  • treating bleeding sites

Capsule endoscopy is a safe and well-tolerated procedure for most people. It is the safest non-invasive diagnostic tool currently available for examining the small intestine.

Capsule endoscopy has few risks. It is safe for even children and the elderly. The procedure’s main risk is the capsule’s retention in the bowel, which may

• cause bleeding
• necessitate surgery for removal

Retention of the capsule is primarily due to existing stricture or obstruction of the bowel. 

These conditions can be detected by having the patient first swallow a similar-sized capsule (patency capsule) that dissolves in 40 hours. The decision to perform capsule endoscopy can be made based on whether the patency capsule passes out or dissolves in 40 hours.