What is gastroscopy?
Gastroscopy (Esophagogastroduodenoscopy, or EGD) is a procedure where a doctor examines the upper part of your gastrointestinal tract (gut). The upper gut consists of the oesophagus (gullet), stomach and duodenum. The doctor uses an endoscope for this procedure.

The procedure is painless and is usually done under a light sedative as a day-case patient in a specialised endoscopy unit.

The Scope
An endoscope is a thin, flexible, telescope. It is about as thick as a little finger. The endoscope is passed through the mouth into the oesophagus and down towards the stomach and duodenum. The tip of the endoscope contains a light and a tiny video camera so the doctor can see inside your gut.

The endoscope also has a "side channel" down which various instruments can pass. These can be manipulated by the doctor. For example, the doctor may take a small sample (biopsy) from the inside lining of the stomach by using an thin "grabbing" instrument which is passed down the side channel

Who has a gastroscopy?
A gastroscopy may be advised if you have symptoms such as recurring indigestion, recurring heartburn, pains in the upper abdomen, repeated vomiting, difficulty swallowing, or other symptoms thought to be coming from the upper gut. The sort of conditions which can be confirmed (or ruled out) include:

• Oesophagitis (inflammation of the oesophagus). The operator will see areas of redness on the lining of the oesophagus.
• Duodenal and stomach ulcers. An ulcer looks like a small, red crater on the inside lining of the duodenum or stomach.
• Duodenitis and gastritis (inflammation of the duodenum and stomach).
• Cancer of the stomach and oesophagus.
• Various other rare conditions.

The Procedure
During gastroscopy, the doctor may numb the back of your throat by spraying on some local anaesthetic, or give you an anaesthetic lozenge to suck. You may be given a sedative to help you to relax. This is usually given by an injection into a vein in the back of your hand. The sedative can make you drowsy, but it does not "put you to sleep". It is not a general anaesthetic.

You lie on your side on a couch. You are asked to put a plastic mouth guard between your teeth. This protects your teeth and stops you biting the endoscope. The doctor will then ask you to swallow the first section of the endoscope. Modern endoscopes are quite thin and easy to swallow. The doctor then gently pushes it further down your oesophagus and into your stomach and duodenum.

The video camera at the tip of the endoscope sends pictures to a screen. The doctor watches the screen for abnormalities of the oesophagus, stomach and duodenum. Air is passed down a channel in the endoscope into the stomach to make the stomach lining easier to see. This may cause you to feel "full" and want to belch.

The doctor may take one or more biopsies of parts of the inside lining of the gut — depending on why the test is done and what they see. This is painless. The biopsy samples are sent to the lab for testing, and to look at under the microscope. The endoscope is then gently pulled out.

Why is gastroscopy useful?

• The doctor can study the mucous membrane of the stomach from the top to the bottom, and see irritation, wounds, or tumours. Gastroscopy is effective, and has now replaced the use of X-rays in many cases. It helps the doctor see any abnormalities in the gullet, the stomach and the duodenum. It is precise and safe.
• Through the gastroscope, the doctor can take samples or photographs of the mucous membrane. The most modern gastroscopes can also show the areas in the stomach on a TV screen, so that the mucous membrane can be studied thoroughly. This can be recorded on a videotape, and used for later comparison.

Patients are often given a gastroscopic examination because of their indigestion symptoms, which can usually be treated with tablets.

Occasionally, the cause of indigestion is an ulcer and it is now known that many ulcers are due to bacterial infection in the stomach.

A biopsy (a small piece of the lining of the stomach) may be removed during an endoscopy and examined under the microscope in the laboratory to pinpoint an infection.

A very small number of patients with indigestion will turn out to have cancer and, again, the diagnosis can be made accurately by biopsy. Further investigation can then be planned to ensure the most effective treatment.

How Long Does It Take?
A gastroscopy usually takes about 10 minutes. However, you should allow at least 2 hours for the whole appointment to prepare, give time for the sedative to work (if you have one), for the gastroscopy itself, and to recover. A gastroscopy does not usually hurt, but it can be a little uncomfortable, particularly when you first swallow the endoscope.

What preparation do I need to do?
You should get instructions from the hospital department before your test. The sort of instructions given commonly include:

• You should not eat for 4-6 hours before the test. The stomach needs to be empty. (Small sips of water may be allowed up to two hours before the test.)
• If you have a sedative you will need somebody to accompany you home. 
• Advice about medication which may need to be stopped before the test.

What can I expect after a gastroscopy?
Most people are ready to go home after resting for half an hour or so.

If you have had a sedative - you may take a bit longer to be ready to go home. The sedative will normally make you feel quite pleasant and relaxed. However, you should not drive, operate machinery or drink alcohol for 24 hours after having the sedative. You will need somebody to accompany you home and to stay with you for 24 hours until the effects have fully worn off. Most people are able to resume normal activities after 24 hours.

The operator writes a report and sends it to the doctor who requested the gastroscopy. The result from any biopsy may take a few days which can delay the report being sent. The operator may also tell you what they saw before you leave. However, if you have had a sedative you may not remember afterwards what they said.

Is gastroscopy reliable?
Gastroscopy is a good test for seeing abnormalities in the upper gut. However, it is not foolproof. For example, gastroscopy may not detect a small number of cases of early ulcers or early cancer. Sometimes a repeat gastroscopy may be advised if symptoms persist or get worse, even if a previous gastroscopy was reported as normal.

Are there any side-effects or complications from having a gastroscopy?
Most gastroscopies are done without any problem. Some people have a mild sore throat for a day or so afterwards. You may feel tired or sleepy for several hours if you have a sedative. There is a slightly increased risk of developing a chest infection or pneumonia following a gastroscopy.

Occasionally, the endoscope causes some damage to the gut. This may cause bleeding, infection, and rarely, perforation. If any of the following occur within 48 hours after a gastroscopy, consult a doctor immediately:

• Abdominal pain. (In particular, if it becomes gradually worse, and is different or more intense to any 'usual' indigestion pains or heartburn that you may have.)
• Fever (raised temperature).
• Difficulty breathing.
• Vomiting blood.

A small number of people have a heart attack or stroke during, or soon after, a gastroscopy. These tend to be older people who are already in poor health. These serious complications are rare in most people who are otherwise reasonably healthy.

Rarely, some people have an allergic reaction to the sedative.