Gastroscopy: why would you want to see the stomach from the inside?

Gastroscopy is a test that lets a specialist look directly at the top part of your digestive system using a camera on the end of a thin flexible tube. The test goes by several names, including gastroscopy, OGD, endoscopy and upper GI endoscopy. In the US it is often called an EGD (esophagogastroduodenoscopy).

Usually your doctor will suggest a gastroscopy if you have signs or test results that could point to a problem in the oesophagus, stomach or first part of the small intestine. Some of the common reasons include:

• Heartburn or reflux that will not settle
• Pain in the stomach
• Pain or difficulty swallowing
• Problems with vomiting
• Signs of bleeding, such as vomiting blood or very dark, tarry stools (doctors call these melaena)
• Unexplained weight loss or anaemia
• Looking for Helicobacter pylori (H. pylori) infection
• Keeping an eye on a known condition

Your stomach needs to be empty for the test, both so that no food is in the way and to reduce the risk of being sick during it. You will be given clear instructions, but expect to avoid eating and drinking for several hours beforehand.

On arrival, the nursing team will check you in and make sure all is well, and the specialist doing the test will come to explain it and answer your questions before you agree to go ahead.

For many people the idea of a camera test is quite daunting, and there are options to keep you comfortable. Practice varies between countries and units, but the choices are broadly:

• Throat spray: a numbing spray to the back of the throat only, often chosen by people who want to avoid sedatives or who have heart or lung conditions
• Sedation: a strong painkiller plus something that makes you sleepy and relaxed, but not unconscious. Many people doze off during the test or simply have no memory of it afterwards

For a straightforward look, you lie on your side for the duration. You will usually have some extra oxygen through two small plastic prongs in your nose, and a plastic mouthguard to protect your teeth. The camera goes in through your mouth, over your tongue, down the oesophagus and into the stomach, then on into the first part of the small intestine, called the duodenum. The specialist looks closely at the lining as they go and takes photographs. If useful, they also take tiny samples, or biopsies, to be looked at under a microscope.

Once the test is done you will be looked after in a separate area while any sedation wears off. If you were sedated you will need someone to take you home and stay with you for 24 hours, and for that same 24 hours you should not drive, drink alcohol, operate machinery or sign anything important. A sore throat or some bloating for a day or so is common.