If persistent symptoms of acid reflux or symptoms of concern are presented, the doctor should refer you to a gastro-enterologist who will probably request a gastroscopy. This may also be called an endoscopy or an Oesophago-Gastro-Duodenoscopy (OGD).

(Endoscopy refers to probing of any bodily orifices with an endoscope. OGD refers to a scope that looks at the oesophagus, stomach and duodenum.)

What to expect at an endoscopy.

You will usually be able to continue taking any acid suppressant medication. This will ensure your oesophagus has minimal inflammation that may obscure the view.

An endoscopy may be carried out by a gastroenterologist, surgeon or nurse and a few GP surgeries even provide it. It may be carried out at a hospital or treatment centre.Most patients may opt to have sedation - a drug will be administered by injection that will make you feel drowsy. Although some patients do go to sleep, it is not an anaesthetic but sufficient so you are not aware of the procedure. You will need a friend or partner to escort you. You should not drive or operate machinery for 24 hours afterwards.

[Image "Endoscope, USB, 2015-05-30" by Finn Årup Nielsen]

Alternatively, you may opt just to have the throat spray to numb the throat but you will be fully conscious throughout and it may bot be a particularly pleasant experience. Though you will be OK to drive yourself home afterwards.

Endoscopes have come a long way from the original rigid tubes as thick as a broom handle that were used thanks to British academic Harold Hopkins. Prompted by a dinner party conversation with a fellow medical guest who expressed his frustration at being unable to thoroughly scrutinise the lining of the stomach, Hopkins speculated that thousands of glass fibres arranged in parallel should be able both to shine light round corners and transmit the image back upwards to be viewed by the observer. He spent three years on the project that would result in the fibreoptic endoscope which doctors still routinely use. (Five years later Hopkins would trump this achievement with the laparoscope that would dispense with the need for major surgery for many conditions in favour of the now familiar ‘key-hole’ operation.)

The long fexible tube about a centimetre in diameter, houses a fibre optic bundle for viewing, one or two other bundles to deliver light and tow or three other channels to deliver water and air as required together with a channel for instruments such as snares to be inserted. In addition there are cables to enable the operator to manoeuvre the tip which is flexible enough to be turned to look back at itself.

(The latest endoscopes manage to fit all this into a probe just 5 millimetres wide that can be inserted via the nose if necessary.)

The outside of the tube is marked at regular intervals (usually every 2 centimetres) to enable the endoscopist to make measurements of any suspect areas seen.

You will be given a hospital gown which may usually be donned over your normal clothing.

The back of your throat will be sprayed to numb it. In the treatment room, you will lie on a couch on your left side and a bit will be placed between your teeth that has a hole to permit the flexible shaft of the scope to be inserted.

As the scope reaches the back of your throat you may be told to swallow though this is likely to be an automatic response. Air will be pumped into the esophagus and stomach so the probe has more room to operate without damaging the lining.

The endoscopist guides the scope using hand controls whilst he looks at a monitor usually behind you. If anything requires further investigation (eg suspected Barrett's cells), he'll pass a wire snare down the instrument channel to take a biopsy - a small tissue sample. This is a painless procedure; most people are unaware it has been done. (See the page on Biopsies.)

Typically, the throat, oesophagus, stomach and duodenum will be examined this way.