Capsule Endoscopy - The Gastroenterology revolution
Gastroenterology is in essence a specialty for treating diseases of the gut. This includes looking at how food passes through this organ, how it is absorbed and the diseases that occur within it. Many people will associate a gastroenterologist with stomach and swallowing disorders such as acid reflux and stomach ulcers. Many will also recognise that gastroenterologists often see patients with large bowel (or colon) disorders such as diarrhoea, bleeding and colon cancers.
Perhaps less appreciated are that gastroenterologists also tend to look after disorders of the liver and the pancreas. These two organs are heavily involved in the absorption and processing of the food we all eat and are particularly affected by alcohol. We also frequently see patients with abnormal reactions of the gut to food in conditions such as irritable bowel syndrome, which is an abnormal cramping of the gut in response to stress and certain types of food.
The human gut and gastroenterology can be split into four broad areas:
- The upper gastrointestinal tract comprising the oesophagus (gullet), stomach and first part of the small bowel called the duodenum. This area is largely used for breaking your food into smaller parts so the body can process it for absorption.
- The hepatobiliary system including the liver, pancreas, gallbladder and the bile ducts. The latter connect the liver, pancreas and gallbladder to the gut. These organs deliver enzymes into the gut to digest your food and then convert it into the building blocks your body needs.
- The colon or large bowel which is used principally to absorb water from your food and to allow the body to pass a solid motion when necessary.
- The small bowel, this absorbs all the nutrients, and virtually all the vitamins and minerals we eat in our food.
For hepatobiliary problems we use x-ray tests and blood tests to provide a lot of information about the function of the liver, gallbladder and pancreas. We are also able to examine the upper gastrointestinal tract and the colon in detail with flexible cameras at endoscopy.
Until recently however the small bowel has been an incredibly difficult area to get high quality images from resulting in many missed or delayed diagnoses in patients with small bowel problems. The advent of wireless capsule endoscopy, however, has revolutionised our ability to visualise the small bowel in a non-invasive and painless manner.
What is Wireless Capsule Endoscopy?
The capsule itself is a self-contained miniature camera with its own light source measuring 11mm x 26mm that is swallowed.
The shape of the capsule makes it very straight forward for an adult to swallow and most teenagers require no help. Once the capsule is swallowed the patient is able to leave the hospital and have a relatively normal day. It then transmits images to a small recording device worn on the hip over a 12 hour period.
It transmits pictures from the patient’s small bowel to the small recorder via some sticky pads and leads attached to your tummy exactly like when we perform a tracing of the heartbeat (ECG). Patients are unaware that the capsule is inside them and all the leads can be removed before bedtime as the capsule test is usually started early in the morning. The capsule itself does not need to be retrieved.
During the examination over 100,000 images of the small bowel are sent to the recorder and these pictures are then watched like a video by the gastroenterologist in the following few days.
It is exceptionally well tolerated and provides high resolution images of previously inaccessible areas. Capsule endoscopy in now approved by NICE, the governments cost-effectiveness watchdog, and by other UK bodies such as the British Society of Gastroenterology.
When might a Gastroenterologist advise a capsule examination?
The three main uses for capsule endoscopy:
- Obscure bleeding into the gut such as for iron deficiency anaemia or more overt blood loss in patients with normal results from other camera tests,
- To assess for possible small bowel Crohn’s disease which is an inflammatory condition typically causing abdominal pain and possibly diarrhoea and weight loss,
- For the assessment of coeliac disease, an allergic condition to gluten which is part of wheat.
What about other tests?
Previously doctors would have used either x-ray tests to examine the small bowel (such as barium follow though) or very long cameras (enteroscopes). It has been shown that capsule endoscopy is more sensitive in head to head comparison with these other tests and these tests are typically less well tolerated.
Patients have also typically undergone many different and often repeatedly negative examinations (an average 6.8) prior to a capsule examination.1 This has led to a delay in the diagnosis of Crohn’s Disease by up to 36 months in patients presenting with abdominal pain.3 In studies where patients who previously had multiple negative investigations who were then offered a capsule examination this test subsequently yielded a diagnosis in 50-80%.1,2
What conditions can be found?
Superficial blood vessels lying abnormally close to the surface called “angiodysplasia” are the most common cause of gastrointestinal blood loss found on capsule examination. The patient usually becomes aware of this blood loss by developing anaemia which causes symptoms of tiredness or breathlessness. Angiodysplasia account for approximately 60% of all diagnoses related to anaemia.4-7 The vast majority of angiodysplasia are easily treated by cauterising the small area and the others are all also treatable conditions.
Other diagnoses include polyps and small bowel cancers (around 5% of all findings)8 and inflammatory bowel disease and coeliac disease in 20%.
The prognosis of small bowel cancers is very closely linked to how early they are detected and inflammatory bowel disease is easier to treat if detected earlier.
Since the service has been introduced into both Surrey and West Sussex local results have been very successful. Patients have had curative operations for small bowel cancers or had therapy applied either at endoscopy or with drugs to stop ongoing small bowel bleeding. Additionally patients have been freed from repeated hospital admissions or regular infusions of iron or blood. The introduction of wireless capsule endoscopy locally has already benefited gastroenterology patients and will continue to do so in the future.
About the author
Gary Mackenzie, Consultant Gastroenterologist, BSc MB BS MRCP PHD. Gary qualified as a doctor from St Bartholomew’s Hospital in London after previously obtaining a first class honours degree in epidemiology and medical statistics from the University of London. Subsequently, he has been awarded a PhD from University College London for studies into gastro-oesophageal reflux disease, Barrett’s oesophagus and the development of cancer. He is interested in novel diagnostic therapeutic endoscopy and minimally invasive endoscopic techniques. He has introduced wireless capsule endoscopy at East Surrey hospital and at the Spire Gatwick Park.
He is a consultant physician and gastroenterologist at Surrey and Sussex Healthcare and is endoscopy training lead . He also works at both North Downs and Gatwick Park hospitals.
References
(1) Lewis BS. Small intestinal bleeding. Gastroenterol Clin North Am 2000;67-95.
(2) Hadithi M, Heine GD, Jacobs MA, van Bodegraven AA, Mulder CJ A prospective study comparing video capsule endoscopy with double-balloon enteroscopy in patients with obscure gastrointestinal bleeding. Am J Gastroenterol. 2006 Jan;101(1):52-7.
(3) Maglinte DD, Chernish SM, Kelvin FM, O'Connor KW, Hage JP. Crohn disease of the small intestine: accuracy and relevance of enteroclysis. Radiology 1992; 184(2):541-545.
(4) Descamps C, Schmit A, Van Gossum A. ‘‘Missed’’ upper gastrointestinal tract lesions may explain ‘‘occult’’ bleeding. Endoscopy 1999;31:452–5.
(5) Foutch PG. Angiodysplasia of the gastrointestinal tract. Am J Gastroenterol 1993;88:807–18.
(6) Askin MP, Lewis BS. Push enteroscopic cauterization: long-term follow-up of 83 patients with bleeding small intestinal angiodysplasia. Gastrointest Endosc 1996;43:580–3.
(7) Morris AJ, Mokhashi M, Straiton M, et al. Push enteroscopy and heater probe therapy for small bowel bleeding. Gastrointest Endosc 1996;44:394–7.
(8) Lewis BS, Kornbluth A, Waye JD. Small bowel tumours: yield of enteroscopy. Gut 1991;32:763–5.
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