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A gastroscopy, also called an upper gastrointestinal endoscopy, is the insertion of a small flexible camera system, called an endoscope, into the intestine to examine the oesophagus and the stomach. We take a look at the procedure and the conditions that it is used to diagnose.

An upper gastrointestinal endoscopy, otherwise known as a gastroscopy, is the insertion of a thin flexible camera system, called an endoscope, into the upper part of the intestine to examine the oesophagus and the stomach and the first parts of the duodenum.

It is used to investigate upper gastrointestinal symptoms, including heartburn, indigestion, dyspepsia or difficulty swallowing, upper abdominal pain, a reduced number of red blood cells (anaemia), and vomiting. These would be the classic symptoms covered for this test, but there is a wider range of digestive conditions it can diagnose, including:

  • gastric ulcers, which develop in the lining of the stomach;
  • gastro-oesophageal reflux disease (GORD), which involves excessive stomach acid entering the oesophagus;
  • coeliac disease, which is an inability to eat gluten;
  • Barrett's oesophagus, which is abnormal growth of cells in the oesophagus;
  • portal hypertension, increase in the blood pressure within the system of veins that supports the digestive process;
  • and cancers of the stomach and oesophagus.

Sometimes biopsies may be done, which involves taking small tissue samples and sent away for analysis. The biopsies taken are very small and the procedure is painless.

A gastroscopy can also be used to treat some digestive-related problems, such as stopping internal bleeding found in the stomach and oesophagus, widening a narrowed oesophagus which causes pain and discomfort, removing foreign objects, cancerous tumours and non-cancerous growths, and providing nutrients through a feeding tube for patients who have difficulty eating.

Patients are admitted to hospital, and they are then given the choice of having the back of their throat numbed with a local anaesthetic solution or an intravenous sedation. The majority of patients have the local anaesthetic because this allows for a quicker procedure to take place.

They will lie on their side and the doctor, or the endoscopist with the help of some nursing staff, will insert the tube through the mouth and oesophagus and into the stomach. The patient may be asked to swallow to help the tube pass through quicker. The stomach will be inflated with air in order to make it easier for the doctor to conduct the examine the lining of the stomach, oesophagus and duodenum. The procedure will take only a few minutes to complete.

It's important the patient follows the starving instructions that the doctor will issue. Not only is this crucial for the doctors to see the whole area of the stomach as clearly as possible, but it is quite dangerous to undergo an endoscopy with a full stomach. This can lead to a patient vomiting during the procedure which can go into the lungs and doctors are very keen to avoid this. Patients are usually advised to stop eating at least six to eight hours and stop drinking two to three hours prior to the operation.

Patients who take certain medication, such as antacids, drugs for treating diabetes, and blood-thinning drugs, including low-dose aspirin or clopidogrel, may be advised to stop for up to two weeks before the operation or given special arrangements. This is because these medications can interfere with the main aim of the gastroscopy to identify problems.

The benefits are to investigate the symptoms to either make a clearer diagnosis, find serious pathology, or provide reassurance about symptoms and administer treatment more reliably.

This is a very safe procedure. Although there are risks, they are very rarely seen, particularly in a non-emergency setting. The risk of complications following an endoscopy for diagnosing symptoms and conditions are experienced by one in every 1,000 patients. The risks are higher for those receiving treatment from an endoscopy, with around one in 100 patients experiencing complications.

A key risk is damage to the teeth, but precautions are taken to avoid this. The patient can also vomit and breath in the stomach contents, but again if the patient follows the instructions issued by the doctor and it is not an emergency, this is very rare.

As the patient will be sedated, there are a number of possible risks associated with this, including infection, nausea, a burning sensation near the site of the injection, an irregular heartbeat, and breathing difficulties. There is also the risk the endoscope will perforate the upper gut, but this again is very rare in a non-emergency setting.

Usually patients are home very quickly. If the patient has had a local anaesthetic, there is a period of restrictions of eating and drinking because the back of the throat is numb and there is a risk of over-spill into the lungs but that usually is only for an hour or two.

If the patient was given a sedative, they will be transferred to the recovery unit to rest. Once the sedation has worn off, which is usually within an hour, the patient can go home. But the effects of sedation may still remain so the patient will not be able to drive, drink alcohol, operate machinery, cook or sign legal documents for around 24 hours afterwards. The patient should be able to return to work the next day.

Due to the effects of sedation, patients should arrange for someone to pick them up from hospital and remain with them for the rest of the day or night if possible or advised by the doctor. If the patient is not able to arrange for someone to be with them at home, they should be near a telephone in case of an emergency.

Patients should expect to hear their results straight after the operation, which will be discussed with the doctor or nurse. If the patient has been given a sedative, it is advised they have a friend or family member with them when discussing the results, as their concentration and attention abilities may be compromised by the sedative. If the patient has had a biopsy, the results will be made available within two to three weeks. The patient may also have a follow-up appointment, especially if any complications arise as a result of the operation.

There are no significant lifestyle changes required for the operation. However, patients will be advised to stop smoking to improve their long-term health and avoid further digestive complications. They should also maintain a healthy weight, avoid being obese and lose weight if needed. This will be aided through regular exercise and a healthy diet, high in protein and fibre, low in fat, and plenty of fruit and vegetables.

Depending on a patient's symptoms, it may be possible to diagnose their condition using an X-ray procedure in which the patient drinks some barium liquid. Barium is a substance which X-rays cannot penetrate, so the outline of the stomach will appear on the X-ray picture.

However, this test involves radiation and the image will be less accurate than what an endoscope camera can provide, and patients are likely to still require a gastroscopy if any abnormalities are found. Furthermore, a barium test cannot enable doctors to take biopsy samples. Other tests may include a CT scan, MRI scan or ultrasound scan. However, whilst these tests will be carried out on patients, none can provide an accurate diagnosis as an endoscopy.

Specialists Offering Gastroscopy

Dr Devinder Bansi

Consultant Gastroenterologist


BMI The Clementine Churchill Hospital 2 more BMI Syon Clinic BMI The London Independent Hospital

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Mr Andrew Wyman

Consultant General and Upper Gastrointestinal Surgeon


BMI Thornbury Hospital

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Dr Sukh Chatu

Consultant Gastroenterologist & Physician

MBBS (Hons), MRCP (UK), MD (Research), MRCP (Gastroenterology)

BMI Chelsfield Park Hospital 1 more BMI The Sloane Hospital

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Professor Humphrey Scott

Consultant General & Colorectal Surgeon


BMI The Runnymede Hospital

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Mr Shaw Somers

Consultant General & Gastrointestinal Surgeon

BSc (Hons), MBChB, FRCS, MD

BMI The Clementine Churchill Hospital

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Dr Roger Prudham

Consultant Gastroenterologist

MB BS (Lond), FRCP(UK), Accredited Bowel Cancer Screening Programme Colonoscopist

BMI The Highfield Hospital

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