Gastroscopy and Colonoscopy: What are the Differences?

Gastroscopy and Colonoscopy: What are the Differences? | UPMC Italy

Gastroscopy (or digestive endoscopy) and colonoscopy are two minimally invasive, safe and effective endoscopic procedures.

They allow examination of the oesophagus, stomach, duodenum, intestines, colon and rectum for conditions of the upper and lower gastrointestinal tract.

With endoscopic procedures, the specialist can diagnose and, where possible, treat:

  • Haemorrhages.
  • Cancer.
  • Celiac disease.
  • GERD (gastroesophageal reflux disease).
  • Inflammatory bowel disease.
  • Precancerous colon polyps.
  • Stenosis (abnormal narrowing of the oesophagus or intestine).
  • Ulcer in the stomach.
  • Unexplained pain in the stomach or abdomen.

During an gastroscopy, the gastroenterologist inserts the endoscope, an illuminated flexible tube equipped with a camera, orally to examine 

  • Throat.
  • Oesophagus (the tube connecting the mouth to the stomach).
  • Stomach.
  • Upper part of the small intestine.

The endoscope is also equipped with specific instruments and can, for example, remove a polyp or piece of tissue for a biopsy, or cauterise a blood vessel to stop bleeding.

In colonoscopy, the doctor inserts a tube called a colonoscope into the patient's anus and rectum to examine:

  • Rectum.
  • Colon.

Depending on the indication, it is possible to investigate the large intestine only partially (e.g. rectoscopy, rectosigmoidoscopy, etc.) or up to the caecal fundus (total colonoscopy or pancolonoscopy). This not only allows the diagnosis of intestinal diseases, but also the removal of any polyps (neoformations of the intestinal mucosa) and the removal of small tissue fragments (biopsy). Both the biopsy and the removal of polyps are painless and are performed using small forceps introduced through the colonoscope.

What Happens During Endoscopy?

Gastroscopy typically takes less than 30 minutes. During the procedure, you lie on your back or side. The healthcare professional can:

  • Attach sensors to monitor breathing, heart rate and blood pressure.
  • Administer medication through an IV into the arm to help the patient relax. It is possible for the patient to fall asleep during the procedure.
  • Spray an anaesthetic spray down the throat so that the tube cannot be felt.
  • Insert the endoscope into the mouth and throat. There may be a request to swallow to help move the endoscope, but this should not cause pain. During the endoscopy, you can breathe normally, but you cannot speak.
  • Use the endoscope to examine, take tissue samples or treat areas of the oesophagus, stomach or small intestine.

The doctor will remove the endoscope as soon as the examination or treatment is finished. You will then wait in the recovery room until the anaesthesia wears off. You may feel a slight sore throat due to the tube or some nausea, but these symptoms will improve with time.

Do not drive for the next 24 hours.

The report is delivered by the doctor immediately after the examination. If, however, tissue samples were taken for analysis (histological examination), the results will be sent later.

What to Expect During a Colonoscopy

A colonoscopy lasts between 30 and 60 minutes.

How is it performed?

  • Sensors are attached to monitor the heart, blood pressure and breathing.
  • The patient is placed on their side with their knees raised towards the chest.
  • A sedative or other medication is administered through an IV to put the patient to sleep.
  • The camera and colonoscopy tube are inserted into the rectum. The specialist will slowly advance the camera through the entire colon to examine the lining for polyps or other abnormalities. As it moves, the colonoscope inflates the large intestine with air to allow the doctor to get a better view.
  • Any polyps or tissue samples for analysis are removed using special instruments located at the end of the colonoscope. When finished, the endoscopist removes the colonoscope and the patient is taken to the recovery room. For about an hour, one may feel bloated or gassy due to the air used to inflate the colon.

Do not drive after the examination.

The report is delivered by the doctor immediately after the examination. If, however, polyps have been removed or tissue samples taken for biopsy, the results will be sent later.

Preparation for Endoscopy and Colonoscopy

It is necessary to prepare for each of these examinations differently, precisely following the doctor's specific instructions, which vary somewhat from one specialist to another. If you do not prepare properly, your doctor may have to reschedule the procedure.

In general, however, we can summarise the preparation instructions as follows.

Preparation for endoscopy

It is essential to have an empty stomach first. In general, preparation requires

  • Stop eating solid food from midnight the day before the examination.
  • Stop drinking all liquids, including water, six hours before the procedure.

In order to be able to perform deep sedation, it is necessary to bring along examinations (maximum 3 months validity from the date of performance) such as: blood count, blood sugar, creatinine, prothrombin time (PT) (PTT), azotemia, sodium, potassium, ECG.

Preparation for colonoscopy

For a colonoscopy, everything in the colon must be removed. If there are faeces, the doctor cannot pass the colonoscopy camera through the colon. The specialist will give the patient precise written instructions, but usually before a colonoscopy:

  • In the three days before the examination it is necessary to follow a low-fibre diet a few days before, avoiding most fresh fruit, vegetables, beans, nuts, seeds and whole grains, and to drink at least 1 ½ litres of water
  • On the day before the examination you can have a regular breakfast (e.g. coffee, tea, milk, white yoghurt, biscuits, non-wholemeal rusks), a light lunch (e.g. broth, noodles, white yoghurt) and a water diet with clear liquids (tea, camomile tea, broth, herbal tea) at dinner.
  • On the day of the examination, complete fasting. Generally, water intake is permitted up to four hours before the examination.
  • The evening before and the morning of the examination, an intestinal preparation will be performed to eliminate any residue in the colon. This is done by taking specific laxatives orally and following the suggested dietary advice. The preparation causes diarrhoea, but no painful cramping. It is unpleasant, but completing this step is essential to allow the doctor to clearly see the lining of the colon.
  • To perform the examination under deep sedation, it is necessary to bring along tests such as blood count, blood glucose, creatinine, prothrombin time, azotemia, sodium, potassium, ECG.
You can address any doubts or questions to our endoscopy service, particularly if you are following particular therapies or taking medication.