Capsule Endoscopy (Pill Camera)

You've had an upper GI endoscopy and a colonoscopy, and both were normal. Yet your haemoglobin keeps falling, your stool keeps testing positive for blood, or the pain and diarrhoea that suggest Crohn's disease still have no explanation. The small intestine, several metres long and lying between the areas those two scopes reach, is the likeliest place the answer is hiding.

In capsule endoscopy, you swallow a capsule about the size of a large vitamin tablet that contains a tiny camera, a light and a battery. As the gut's natural movement carries it along, it takes several pictures a second and sends them to a recorder worn on a belt. After about 8 to 12 hours you hand back the recorder, and the capsule passes out in your stool a day or two later. You don't need to retrieve it.

The test is painless and needs no sedation, and it's good at finding bleeding spots, ulcers, inflammation and small tumours in the small intestine. It can't take biopsies or treat anything, though, so some findings lead to a follow-up procedure with a longer scope.

Our gastroenterology department investigates gastrointestinal bleeding, anaemia and inflammatory bowel disease, usually starting with upper GI endoscopy and colonoscopy using high-definition video endoscopes. If both are clear and the small intestine is still suspected, your gastroenterologist will discuss whether capsule endoscopy is the right next test.

Capsule endoscopy is mostly used after upper GI endoscopy and colonoscopy haven't found the answer.

Because there are so many images to review, the report usually comes after a few days. It describes how far the capsule travelled, whether it reached the large bowel before the battery ran out, and any findings, with pictures and an estimate of where along the small intestine each one lies.

Common findings include angiodysplasias (small, fragile blood vessels that ooze, especially in older people), ulcers caused by painkillers such as ibuprofen or aspirin, inflammation suggesting Crohn's disease, and occasionally a polyp or tumour. A normal study makes a significant small-bowel cause much less likely.

Since the capsule can't take samples or treat anything, findings often lead to a next step: medicines, iron replacement, a longer scope called enteroscopy to treat a bleeding spot or take a biopsy, or surgery for a tumour. If the capsule didn't reach the large bowel in time, the study may need repeating.