Capsule endoscopy: a modern, minimally invasive test for the small bowel

Capsule endoscopy is an advanced diagnostic test that allows specialists to examine the small bowel, an area of the digestive system that is difficult to assess using standard endoscopy. By swallowing a capsule containing a miniature camera, patients can undergo a detailed examination without sedation or invasive instruments.

In this article, gastroenterologist and endoscopist Dr John Martin explains what capsule endoscopy is, why it is used, what the procedure involves, and who may benefit from it.

What is capsule endoscopy?

Capsule endoscopy involves swallowing a small, single use capsule that contains a camera, light source and transmitter. As the capsule travels naturally through the digestive tract, it captures tens of thousands of images of the small intestine. These images are transmitted wirelessly to a recording device worn on a belt around the waist.

The capsule is passed naturally in the stool, usually within 24 to 48 hours, and does not need to be retrieved.

Why is capsule endoscopy used?

The small bowel is approximately six metres long and cannot be fully visualised using traditional gastroscopy or colonoscopy. Capsule endoscopy allows for detailed inspection of this area in a safe and non-invasive manner.

It is commonly used to investigate:

• Iron deficiency anaemia with no obvious cause.
• Suspected Crohn’s disease.
• Obscure gastrointestinal bleeding.
• Suspected small bowel tumours or polyps.

Capsule endoscopy is often recommended when other investigations, such as blood tests or imaging scans, have not provided clear answers.

What happens during a capsule endoscopy test?

The procedure is simple and usually carried out as an outpatient test.

Patients may be asked to follow a specific diet and take bowel preparation beforehand to ensure clear images. On the day of the test, a belt is worn to detect the images and send them to the data recorder. The capsule is then swallowed with water.

Normal daily activities can usually be resumed, and the recording device is returned later the same day. The images are subsequently reviewed by a specialist.

Is capsule endoscopy safe?

Capsule endoscopy is very safe and well tolerated. Most patients are not aware of the capsule as it moves through the bowel. In rare cases, the capsule may become temporarily lodged if there is a narrowing of the intestine. This does not normally cause any problems and generally passes after a short period. In very rare cases, the capsule may not pass by itself and may need to be retrieved either with an endoscope or surgery.

For patients at higher risk, a patency capsule (a dummy capsule that dissolves after a few days, making it safe to take even if it does not pass through the intestine before dissolving) or imaging scan may be performed beforehand to confirm that the test can be carried out safely.

What are the benefits of capsule endoscopy?

• No sedation required.
• Non-invasive and painless.
• Excellent visualisation of the small bowel.
• Performed as a day procedure.
• Minimal disruption to everyday life.

What happens after the test?

Once the images have been analysed, the results are discussed with the patient. If abnormalities are identified, further investigations or treatment may be recommended, such as targeted endoscopy or medical therapy.

Capsule endoscopy is a valuable and patient friendly investigation that has significantly improved the diagnosis of small bowel conditions. For individuals with ongoing digestive symptoms or unexplained anaemia, this test can provide important answers and help guide appropriate treatment.