The Mayo Clinic of South Africa


Gastro-Intestinal Unit

The digestive system - diseases35% of the population experience problems related to the digestive system. These include difficulty in swallowing food or fluids, reflux, heartburn and chest pain.

Constipation, diarrhoea and abdominal pain that persist may require more indepth investigations into the causes.

One of the Mayo Day Clinic's newest additions is the introduction of a specialised gastro-intestinal enterology unit.

Gastroscopy - Upper endoscopy
Colonoscopy - Examining the lining of your colon
ERCP - Examining the ducts of the gallbladder, pancreas and liver
Oesophageal manometry - Oesophageal motility disorders


Mayo Clinic Operating TheatreA gastroscopy lets your doctor examine the lining of the upper part of your gastrointestinal tract, which includes the oesophagus, stomach and duodenum (first portion of the small intestine). Your doctor will use a thin, flexible tube called a gastroscope, which has its own lens and light source, and will view the images on a video monitor. You might hear your doctor or other medical staff refer to a gastroscopy as an upper GI endoscopy.

Why are gastroscopies done?
Upper endoscopy helps your doctor evaluate symptoms of persistent upper abdominal pain, nausea, vomiting or difficulty in swallowing. It's an excellent test for finding the cause of bleeding from the upper gastrointestinal tract. It's also more accurate than X-ray films for detecting inflammation, ulcers and tumors of the oesophagus, stomach and duodenum.

Your doctor might use upper endoscopy to obtain a biopsy. A biopsy helps your doctor distinguish between benign and malignant tissues. Your doctor might use a biopsy to test for Helicobacter pylori, the bacterium that causes ulcers. He may introduce a small brush to collect cells to perform a cytology test.

Upper endoscopy is also used to treat conditions of the upper gastrointestinal tract. Your doctor can pass instruments through the endoscope to directly treat many abnormalities with little or no discomfort. For example, your doctor might stretch a narrowed area, remove polyps or treat bleeding.

How should I prepare for the procedure?
You will need to inform your medical aid that you are going to the Mayo Clinic for the gastroscopy (procedure code 1587) if possible, at least three days before your appointment.

An empty stomach allows for the best and safest examination, so you should have nothing to eat or drink, including water, for approximately ten hours before the examination.

Tell your doctor in advance about any medications you take; you might need to adjust your usual dose for the examination. Discuss any allergies to medications as well as medical conditions, such as heart or lung disease.

What can I expect during a gastroscopy?
Your doctor might start by spraying your throat with a local anaesthetic or by giving you a sedative such as Dormicum to make you drowsy. You'll lie on your side, and your doctor will pass the endoscope through your mouth and into the oesophagus, stomach and duodenum. The endoscope doesn't interfere with your breathing but you may experience the gagging reflex if you only have the anaesthetic spray, so many patients prefer the conscious sedation technique whereby you are given Diprivan, a general anaesthetic drug to make you sleep. Although you do not have a general anaesthetic, an anaesthetist will be in attendance. The procedure takes 5 to 20 minutes to perform, after which you will be taken to the recovery room and then back to the ward to sleep off the sedative. Your doctor generally can tell you your test results on the day of the procedure, however certain laboratory results may take a few days.

If you received sedatives, you won't be allowed to drive after the procedure even though you might not feel sleepy. You should arrange for someone to accompany you home because the sedatives affect your judgment and reflexes for the rest of the day. You should also apply for a day's leave of absence from work.

What are the possible complications of gastroscopy procedures?
Although complications can occur, they are rare when doctors who are specially trained and experienced in this procedure perform the test. Bleeding can occur at a biopsy site or where a polyp was removed, but it's usually minimal and rarely requires follow-up. Other potential risks include a reaction to the sedative used, complications from heart or lung diseases, and perforation (a tear in the gastrointestinal tract lining).  If you have a fever after the test, trouble swallowing or increasing throat, chest or abdominal pain, tell your doctor immediately.



A colonoscopy enables your doctor to examine the lining of your colon for abnormalities by inserting a flexible tube (as thick as your finger) into your anus and slowly advancing it into the rectum and colon. This allows the doctor to see the lining of your large bowel. Sometimes a sample of the lining of the bowel (a biopsy) may be taken and sent to pathology for analysis. This is painless. If polyps (an overgrowth of bowel tissue) are found, they can be removed during the procedure. 

What preparation is required?
For this examination to be successful and allow a clear view of your colon, your bowell must be as empty as possible. Your doctor will tell you what dietary restrictions to follow and what cleansing routine to use. As part of your preparation you may be given a laxative and be told what clear liquids you may consume. The colon must be completely clean for the procedure to be accurate and complete, so be sure to follow your doctor's instructions carefully. If you have any questions about the laxative then please contact your doctor. You may be given an enema at the hospital prior to the procedure.

Here is an example of a typical preparation procedure prior to going for a colonoscopy:
Two days before your colonososcopy, take 5 laxative tablets
The day before your colonoscopy drink only clear fluids such as black tea or coffee, water, dissolved stock cube in hot water (not soup), clear apple or white grape juice, Sprite (no other soft drink), Jelly.
Do not eat any solid foods.
Do not drink milk.
You will also be given suppositories and other laxatives to ensure that the colon is completely clear to be taken during the two preparation days, and on the day of the colonoscopy.

Can I take my current medications?
Most medications can be continued as usual, but some medications can interfere with the preparation or the examination. It is important to inform your doctor about medications you're taking, particularly insulin, aspirin products, arthritis medications, anticoagulants (blood thinners such as Warfarin or Clopidogrel), or iron products. Iron tablets or stool bulking agents (such as Fybrogel or Ispagel, which contain Ispaghula) should be stopped one week before your examination. Also, be sure to mention allergies you have to medications. You should only stop taking any medication with the knowledge and agreement of your doctor. Bring a list of any medications that you are taking and remember to bring any asthma inhalers or angina sprays with you.

What happens during the colonoscopy examination?

  • A small needle will be inserted into a vein so that a sedative and painkiller can be given before the examination. This will be cause you to fall into a deep sleep and you will not be aware of any discomfort during the procedure. Often an anaesthetist is present during the procedure to monitor your condition
  • A small device for recoding your pulse and breathing rate will be attached to your finger and you will be given oxygen
  • Then while you are lying comfortably on your left side your doctor will gently advances a colonoscope through your back passage and into your large intestine.
  • Air will be passed into the bowel to expand it  so the linig can be seen more clearly. This may later give you some cramp-like discomfort but it will last for only a short time. The ait that has been passed into the bowel will obviously have to come out again as wind. Please do not worry about this, it is quite normal.
  • A biopsy may be taken during the examination. This is painless. Similarly, any polyps may be removed.
  • Your doctor will again examine the lining as he slowly withdraws the colonoscope.
  • The procedure itself usually takes 15 to 60 minutes, and you will sleep in the ward for approximately half an hour afterwards.
  • Once you have recovered you may eat and drink as normal.
  • The doctor may give you the results oif the examination before you go home, but any biopsy results willo take longer.
  • After the sedation you may feel a little groggy for the remainder of the day.

What if the colonoscopy shows something abnormal?
If your doctor thinks an area needs further evaluation, he or she might pass an instrument through the colonoscope to obtain a biopsy to be analysed. Biopsies are used to identify many conditions, and your doctor might order one even if he or she doesn't suspect cancer. If a colonoscopy is being performed to identify sites of bleeding, your doctor might control the bleeding through the colonoscope by injecting medications or by coagulation. Your doctor might also find polyps during colonoscopy, and he will remove them during the examination. These procedures don't usually cause any pain.

What are polyps and why are they removed?
Polyps are abnormal growths in the colon lining that are usually benign. They vary in size from a tiny dot to several centimetres. Your doctor can't always tell a benign polyp from a malignant one by its outer appearance, so he might send removed polyps for analysis. Because cancer begins in polyps, removing them is an important means of preventing colo-rectal cancer.

How are polyps removed?
Your doctor might destroy tiny polyps by fulguration (burning) or by removing them with wire loops called snares or with biopsy instruments. Your doctor may use a technique called "snare polypectomy" to remove larger polyps. This technique involves passing a wire loop through the colonoscope and removing the polyp from the intestinal wall using an electrical current. You should feel no pain during the polypectomy.

What happens after a colonoscopy?
Your physician will explain the results of the examination to you, although you'll probably have to wait for the results of any biopsies performed.

You must arrange for someone to drive you home and stay with you. You must not drink alcohol, operate machinery or sign important documents for at least 24 hours following the sedative. Even if you feel alert after the procedure, your judgment and reflexes could be impaired for the rest of the day. You may have some cramping or bloating because of the air introduced into the colon during the examination. You should also apply for a day's leave of absence from work. 

You should be able to eat after the examination, but your doctor might restrict your diet and activities, especially after a polypectomy. You may find that your bowels do not immediatly return to normal

What are the possible complications of colonoscopy?
Colonoscopy and polypectomies are generally safe when performed by doctors who have been specially trained and are experienced in these procedures.

One possible complication is a perforation, or tear, through the bowel wall that could require surgery. Bleeding might occur at the site of biopsy or polypectomy, but it's usually minor. Bleeding can stop on its own or be controlled through the colonoscope; it rarely requires follow-up treatment. Some patients might have a reaction to the sedatives or complications from heart or lung disease.

Although complications after a colonoscopy procedure are uncommon, it's important to recognise early signs of possible complications. 

If any of the follwoing occur within 48 hours after a colonoscopy consult a doctor immediately:

  • Severe abdominal pain, especially if it becomes gradually worse and is different to anu 'usual' pains you may have.
  • Fever and chills.
  • Rectal bleeding of more than one-half cup. Note that bleeding can occur several days after the procedure.
  • Blood in the stool


Endoscopic retrograde cholangiopancreatography, or ERCP, is a specialised technique used to study the ducts of the gallbladder, pancreas and liver. Ducts are drainage routes and the drainage channels from the liver are called bile or biliary ducts.

During an ERCP, your doctor will pass an endoscope through your mouth, oesophagus and stomach into the duodenum. An endoscope is a thin, flexible tube that lets your doctor see inside your bowels. After your doctor sees the common opening to ducts from the liver and pancreas, he will pass a narrow plastic tube called a catheter through the endoscope and into the ducts. Your doctor will inject a dye into the pancreatic or biliary ducts and will take X-rays.

What preparation is required?
You should fast for at least eight hours (and preferably overnight) before the procedure to make sure you have an empty stomach, which is necessary for the best examination. Your doctor will give you precise instructions about how to prepare.

You should talk to your doctor about medications you take regularly and any allergies you have to medications, or intravenous contrast material. Although an allergy doesn't prevent you from having ERCP, it's important to discuss it with your doctor prior to the procedure.

Also, be sure to tell your doctor if you have heart or lung conditions, or other major diseases.

What can I expect during ERCP?
Normally an anaesthetist  will give you a general anaesthetic for this procedure, but sedation may be used if this is contra-indicated. You will lie on your left side on an X-ray table. Your doctor will pass the endoscope through your mouth, oesophagus, stomach and into the duodenum. The instrument does not interfere with breathing, but you might feel a bloating sensation afterwards because of the air introduced through the instrument.

Your doctor may need to remove stones which have collected in the biliary or pancreatic ducts. He will do this at the same time as the ERCP using either a stone extraction basket, or by dilating the duct to enable the stones to pass through naturally.

Inflated balloon extraction of biliary stones

Extracted calculus

Stone extraction can be done by using different devices. A balloon inflated and extracted from the bile duct will clear it and dislodge the stones to the duodenum. The left photograph shows an inflated balloon, the right one an extracted calculus.

A second device is the retrieval basket made of 4 parallel, extendable wires. Stones can be trapped in the wires and the basket is then cautiously extracted with its content. Stones bigger than 1,5 to 2,0 cm are crushed before the pieces are extracted.

What are possible complications of ERCP?
An ERCP is a well-tolerated procedure when performed by doctors who are specially trained and experienced in the technique. Although complications requiring hospitalisation can occur, they are uncommon. Complications can include pancreatitis (an inflammation or infection of the pancreas), infections, bowel perforation and bleeding. Some patients can have an adverse reaction to the sedative used. Sometimes the procedure cannot be completed for technical reasons.

Risks vary, depending on why the test is performed, what is found during the procedure, what therapeutic intervention is undertaken, and whether a patient has major medical problems. Patients undergoing a therapeutic ERCP, such as for stone removal, face a higher risk of complications than patients undergoing a diagnostic ERCP. Your doctor will discuss your likelihood of complications before you undergo the test.

What can I expect after an ERCP?
You might experience bloating or pass gas because of the air introduced during the examination. You can resume your usual diet unless you are instructed otherwise.

Someone must accompany you home from the procedure because of the sedatives used during the examination. Even if you feel alert after the procedure, the sedatives can affect your judgment and reflexes for the rest of the day.

Please contact your doctor promptly if you have any follow-up questions or if you are experiencing any complications due to the procedure.

Oesophageal manometry

This was introduced at the Mayo Day Clinic as an important extension to our endoscopy theatre as an aid to the effective diagnosis and treatment of oesophageal motility disorders.

After patients have had a gastroscopic evaluation performed by a physician in the Mayo Day Clinic's endoscopy theatre, abnormalities may indicate that further tests are required. This is when an oesophageal manometry investigation and pH study is recommended in our gastro-intestinal unit.

Oesophageal manometry is the recording of muscle pressures within the oesophagus, including the evaluation of muscle waves in the main section of the oesophagus, as well as the valve at the end of it. The 24 hour pH monitoring is very important in the diagnosis of acid exposure caused by reflux.

The procedure is very simple. After a local anaesthetic is sprayed into your throat, a thin, soft tube is gently passed through the nose into the throat. With swallowing, the tip of the tube enters the oesophagus and the technician then quickly passes it down to the desired position. Swallow tests are recorded and the tube is then removed. A second, smaller tube is then inserted and passed into the stomach. The catheter is attached to a pH recorder, a small instrument which hangs from a strap around your shoulder, and the you are then sent home.  The following day you return and the catheter is removed. The technician downloads the information from the recorder onto a computer for analysis and interpretation. Notes that you have made during the 24 hour period detailing when you had heartburn or chest pain, when you ate and when you slept are correlated with the computer data.

These test will indicate to the physician what the best treatment will be for your condition, be it conservative or surgical.

Reflux analysis

The above graph is an ambulatory pH study on a patient where the electrode was placed 5cm above the lower oesophageal sphincter. Acid reflux was defined as a drop in pH below 4.0 (indicated by the red line).

The total length of the study was 21 hours 33 minutes. During this period the patient experienced 243 acid refluxes with seven of them lasting more than five minutes.  The study revealed a deMeester score of 55.5, where normal is less than 14.72, indicating signs of pathological acid reflux. The lower oesophageal sphincter is defined as incompetent with the function of the oesophagus revealing occasional dropped swallows as well as low amplitude peristaltic contractions.


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