Understanding Colonoscopy: Procedure, Preparation, and Benefits

12 MINUTES

What is colonoscopy?

Colonoscopy is a diagnostic and therapeutic procedure that allows doctors to visualize the inside of the colon and rectum using a colonoscope. The colonoscope is a flexible, tube-like instrument that is about the thickness of a finger. The colonoscope is inserted into the rectum and advanced through the colon while the doctor observes the images on a monitor.

Why is colonoscopy done?

Colonoscopy is done for various reasons such as:

  1. Screening for colon cancer: Colonoscopy is the most accurate test for detecting colon cancer. It is recommended for everyone over the age of 50 to undergo colonoscopy to screen for colon cancer. Individuals with a family history of colon cancer or polyps may need to undergo colonoscopy earlier and more frequently.
  2. Diagnosis of gastrointestinal symptoms: Colonoscopy is used to diagnose the cause of various gastrointestinal symptoms such as abdominal pain, rectal bleeding, diarrhea, and constipation.
  3. Detection and removal of polyps: Polyps are small growths in the colon that can develop into cancer over time. Colonoscopy allows doctors to detect and remove polyps before they become cancerous.
  4. Inflammatory bowel disease (IBD) diagnosis: Colonoscopy is used to diagnose IBD such as Crohn’s disease and ulcerative colitis.
  5. Follow-up after colorectal cancer treatment: Colonoscopy is used to monitor the recurrence of colorectal cancer after treatment.

How to prepare for colonoscopy?

Proper preparation is essential for a successful colonoscopy. The colon must be completely empty and clean for the procedure to be accurate. The following steps are usually taken to prepare for colonoscopy:

  1. Bowel preparation: The day before the procedure, the patient is instructed to follow a clear liquid diet and drink a bowel preparation solution that causes diarrhea. The bowel preparation solution helps to clear the colon of stool and debris.
  2. Medication adjustments: Patients may be instructed to stop taking certain medications such as blood thinners or iron supplements before the procedure.
  3. Fasting: The patient is instructed to fast for several hours before the procedure.
  4. Transportation: Patients should arrange for transportation to and from the procedure as they will be sedated during the procedure and will not be able to drive afterward.

How is bowel preparation done for a colonoscopy?

Bowel preparation is a crucial step in ensuring that the colon is adequately cleaned before a colonoscopy, which can help the gastroenterologist to detect any abnormalities or potential health issues accurately. The preparation process typically involves several steps and may vary depending on the patient’s specific needs and gastroenterologist’s preferences. Here are some general guidelines on how bowel preparation is done for a colonoscopy:

  1. Medications: Patients may be instructed to stop taking certain medications that can affect the colon, such as iron supplements, blood thinners, and non-steroidal anti-inflammatory drugs (NSAIDs), a few days before the procedure.
  2. Clear liquid diet: The day before the colonoscopy, patients are typically instructed to follow a clear liquid diet. This may include water, broth, clear fruit juices (without pulp), and popsicles. Avoid any red, purple or blue foods or beverages, as they can discolor the colon and potentially mask any abnormalities.
  3. Laxatives: Patients will be prescribed a laxative medication or a combination of laxatives to help clear the colon. This may include oral solutions or pills, which can be taken at different intervals before the procedure. Follow the gastroenterologist’s instructions carefully and drink plenty of clear fluids to avoid dehydration.
  4. Enemas: In some cases, patients may be instructed to use enemas to help further clean out the colon before the procedure. This may involve using a solution that is inserted into the rectum and colon to help flush out any remaining stool.
  5. Follow-up instructions: Patients will be given specific instructions about when to stop eating or drinking before the procedure, when to take their medication, and what to expect during and after the colonoscopy.

Follow the bowel preparation instructions carefully to ensure that the colon is adequately cleansed before the procedure. A poorly prepared colon may interfere with the ability to detect abnormalities, potentially leading to inaccurate or inconclusive results.

Here are the general steps involved in bowel preparation for a colonoscopy:

  1. Your gastroenterologist will provide you with instructions on how to prepare for the procedure. This may include dietary restrictions, such as avoiding solid foods for a period of time before the procedure.
  2. You will be given a prescription for a bowel preparation solution, which you will need to take as directed. This solution will help clean out your colon.
  3. You will need to drink plenty of clear fluids, such as water, clear broths, or clear juices, to prevent dehydration during the bowel preparation process.
  4. You may experience diarrhea or loose stools during the bowel preparation process. This is normal and is a sign that the bowel preparation is working.
  5. Follow all of the instructions provided by your gastroenterologist for the bowel preparation process to ensure that your colon is properly cleaned out before the procedure.
  6. On the day of the colonoscopy, you will need to avoid eating or drinking anything for a period of time before the procedure, as directed by your gastroenterologist.

Also read:

Colonoscopy preparation with Eziclen

What diet should I follow before a colonoscopy?

The diet before a colonoscopy is an essential aspect of bowel preparation and plays a critical role in ensuring that the colon is adequately cleansed before the procedure. Here are some general dietary guidelines to follow before a colonoscopy:

  1. Clear liquid diet: The day before the colonoscopy, patients are typically advised to follow a clear liquid diet. This may include water, broth, clear fruit juices (without pulp), and popsicles. Avoid any red, purple, or blue foods or beverages, as they can discolor the colon and potentially mask any abnormalities.
  2. Low-fiber diet: A low-fiber diet is recommended a few days before the colonoscopy to help reduce the amount of residue in the colon. This may include avoiding high-fiber foods such as fruits and vegetables, whole grains, nuts, and seeds.
  3. Avoid solid foods: Patients should avoid solid foods the day before the colonoscopy to prevent any remaining stool in the colon from interfering with the procedure.
  4. Avoid fatty foods: Foods that are high in fat can slow down the digestive process and make it harder to clear the colon. It is recommended to avoid high-fat foods such as fried foods, fatty meats, and dairy products a few days before the colonoscopy.
  5. Avoid alcohol: It is recommended to avoid alcohol a few days before the colonoscopy, as it can irritate the digestive system and interfere with the bowel preparation process.

Patients should talk to their gastroenterologist if they have any questions or concerns about the diet before a colonoscopy or if they experience any side effects or complications.

What to expect during colonoscopy?

During a colonoscopy, patients can expect the following:

  1. Sedation: Before the procedure, patients are given a sedative to help them relax and reduce discomfort during the procedure. The sedative can cause drowsiness and memory loss, so patients may not remember much of the procedure.
  2. Positioning: Patients are typically positioned on their left side with their knees drawn up towards their chest.
  3. Insertion of colonoscope: The doctor inserts the colonoscope into the rectum and advances it through the colon while observing the images on a monitor. Patients may feel pressure or cramping as the colonoscope moves through the colon.
  4. Insufflation of air: To provide a better view of the colon, the gastroenterologist may insufflate air into the colon. This can cause discomfort and a feeling of bloating or gas.
  5. Biopsy and removal of polyps: If the gastroenterologist detects any abnormalities such as polyps, they may remove them or take a biopsy for further examination. This is typically painless.
  6. Monitoring: During the procedure, the patient’s vital signs are monitored, including heart rate, blood pressure, and oxygen levels.
  7. Completion of the procedure: After the procedure, the gastroenterologist removes the colonoscope, and the patient is moved to a recovery area. The patient may feel groggy and disoriented for a short period after the procedure.
  8. Recovery: Patients are typically monitored for a short time after the procedure to ensure that there are no complications. Patients may experience cramping, bloating, or gas after the procedure, but this typically resolves within a few hours.
  9. Results: The gastroenterologist will discuss the findings of the procedure with the patient and provide recommendations for follow-up care if necessary. If biopsies were taken, it may take a few days to receive the results.

What are the complications of colonoscopy?

As with any medical procedure, there are potential complications associated with colonoscopy. However, the risks of complications are generally low, and the benefits of colonoscopy outweigh the risks for most patients. Some possible complications of colonoscopy include:

  1. Bleeding: Colonoscopy can cause bleeding if a biopsy is taken or a polyp is removed. Most cases of bleeding are minor and stop on their own, but in rare cases, the bleeding can be severe and require hospitalization or surgery.
  2. Perforation: Colonoscopy can cause a tear or hole in the colon or rectum. This is a rare complication, but it can be serious and may require surgery to repair.
  3. Reaction to sedation: Some patients may experience an allergic reaction or adverse side effects from the sedative used during the procedure.
  4. Infection: Although rare, colonoscopy can lead to infection, particularly if the colonoscope is not properly sterilized.
  5. Discomfort: Patients may experience discomfort, cramping, or bloating during or after the procedure.
  6. Missed or incomplete diagnosis: In rare cases, colonoscopy may miss a small polyp or lesion that is difficult to detect, leading to an incomplete diagnosis.
  7. Cardiovascular events: There is a small risk of cardiovascular events such as heart attack or stroke associated with sedation during colonoscopy.

The risk of complications is higher for patients who have certain medical conditions such as inflammatory bowel disease, previous abdominal surgery, or advanced age. Patients should discuss their individual risks with their gastroenterologist before undergoing colonoscopy.

Is colonoscopy painful?

Colonoscopy may cause some discomfort, but the procedure is typically not painful. Before the procedure, patients are given a sedative to help them relax and reduce discomfort during the procedure. The sedative can cause drowsiness and memory loss, so patients may not remember much of the procedure.

Dr. Zavos performs endoscopies with the use of deep sedation and thus both gastroscopy and colonoscopy are completely pain-free.

After the procedure, patients may experience cramping, bloating, or gas, but this typically resolves within a few hours. Patients are typically monitored for a short time after the procedure to ensure that there are no complications.

What should I do after the colonoscopy?

After a colonoscopy, patients will be monitored for a short period to ensure that there are no complications. Once they are discharged, they should follow these steps:

  1. Rest: Patients should rest for the remainder of the day and avoid any strenuous activity.
  2. Diet: Patients should start with clear liquids and gradually resume their normal diet as tolerated. It’s important to avoid heavy or greasy foods for the first few days after the procedure.
  3. Medications: Patients should resume their normal medications unless instructed otherwise by their doctor. If any polyps were removed during the procedure, the doctor may recommend avoiding certain medications such as blood thinners for a few days to reduce the risk of bleeding.
  4. Hydration: Patients should drink plenty of fluids to prevent dehydration and help flush any remaining air from the colon.
  5. Follow-up: The doctor will discuss the findings of the procedure with the patient and provide recommendations for follow-up care if necessary. Patients should follow their doctor’s recommendations for any additional testing or treatment.
  6. Symptoms: Patients should be aware of any signs of complications such as severe abdominal pain, fever, or bleeding and contact their doctor immediately if these symptoms occur.
  7. Driving: Patients should not drive or operate heavy machinery for at least 24 hours after the procedure due to the sedative used during the procedure.
  8. Work: Patients can usually return to work the day after the procedure unless their job involves heavy lifting or strenuous activity.

Diarrhea or no stool after colonoscopy

You may experience diarrhea or no stool for up to 3 days after colonoscopy. Please contact your gastroenterologist if you experience diarrhea or no stool after colonoscopy.

Fever after colonoscopy

Fever up to 3 days after colonoscopy or polypectomy may be associated with bacteremia or with a reaction to sedation, usually to propofol. Please contact your gastroenterologist if you experience fever after colonoscopy.

Is it possible to have an esophagogastroduodenoscopy and a colonoscopy performed during the same session?

It is possible to have an esophagogastroduodenoscopy (EGD) and a colonoscopy performed during the same session, which is commonly referred to as an “upper and lower endoscopy.” This approach can be convenient for patients as it minimizes the need for multiple procedures and sedations.

However, whether or not both procedures can be performed during the same session will depend on several factors, including the patient’s medical history and current health status, the indication for the procedures, and the preferences and expertise of the gastroenterologist performing the procedure.

What is the cost of a colonoscopy?

The cost of a colonoscopy can vary widely depending on several factors such as geographic location, facility, and insurance coverage. Patients should check with their insurance provider to determine their coverage and any potential out-of-pocket expenses. Some insurance plans may require prior authorization or referral from a primary care physician before the procedure is covered. Patients should discuss any financial concerns with their gastroenterologist or the facility where the procedure will be performed.

What are the benefits of a colonoscopy compared to a CT (or virtual) colonoscopy?

Both colonoscopy and CT colonoscopy (also called virtual colonoscopy) are methods of screening for colon cancer and other colorectal diseases, but there are some differences between the two procedures. Here are some of the benefits of colonoscopy compared to CT colonoscopy:

  1. Detection of polyps: Colonoscopy is considered the gold standard for detecting and removing polyps in the colon. During a colonoscopy, the gastroenterologist can view the entire colon and remove any polyps or abnormal tissue for further examination. CT colonoscopy can also detect polyps, but it cannot remove them during the procedure.
  2. Accuracy: Colonoscopy is more accurate than CT colonoscopy in detecting small polyps and lesions. CT colonoscopy can miss small polyps or lesions that may be detected by a colonoscopy.
  3. Biopsy: If a polyp or abnormal tissue is detected during a colonoscopy, the doctor can take a biopsy for further examination. This is not possible during a CT colonoscopy.
  4. Preparation: Colonoscopy requires a bowel preparation to cleanse the colon before the procedure. This can be challenging for some patients but ensures that the colon is adequately cleansed for the procedure. CT colonoscopy also requires bowel preparation but may be less intensive than the preparation for a colonoscopy.
  5. Radiation exposure: CT colonoscopy exposes the patient to radiation, which may be a concern for some patients, particularly those who require frequent screening.
  6. Sedation: Colonoscopy is typically performed with sedation to help the patient relax and reduce discomfort during the procedure. CT colonoscopy does not require sedation and is typically less uncomfortable than a colonoscopy.

In summary, while both colonoscopy and CT colonoscopy are effective methods of screening for colorectal diseases, colonoscopy is more accurate, allows for biopsy and removal of polyps during the procedure, and does not expose patients to radiation. However, CT colonoscopy may be a good alternative for patients who are unable or unwilling to undergo a colonoscopy or who require more frequent screening due to a high risk of colorectal cancer.

Ultimately, the decision about which screening method to use should be made in consultation with a gastroenterologist based on the individual patient’s medical history and preferences.

How can I contact gastroenterologist Dr. Zavos to arrange for me an appointment for a colonoscopy?

Dr. Chris Zavos is a board-certified gastroenterologist and hepatologist, located in Thessaloniki Greece, and specifically in Kalamaria suburb, about 7 kilometres (4 miles) southeast of downtown Thessaloniki. His private office is at: Fanariou 8 street (near Aigaiou and Adrianoupoleos avenues), Kalamaria (Thessaloniki), Greece. Dr. Zavos is a respected member of the medical community and is dedicated to providing the highest quality care to his patients.

Thessaloniki International Airport is only 10 km away from his private office in Kalamaria and can be reached by taxi within 13 minutes from the airport.

Dr. Chris Zavos performs endoscopies at Bioclinic private hospital in downtown Thessaloniki (Mitropoleos 86 street).

You can contact Dr. Zavos at phone numbers: (+30)-6976596988 and (+30)-2311283833, or you can email him at czavos@ymail.com. Dr. Zavos responds to Greek and English languages.

Last update: 6 October 2023, 10:24

DR. CHRIS ZAVOS, MD, PHD, FEBGH

Gastroenterologist - Hepatologist, Thessaloniki

PhD at Medical School, Aristotle University of Thessaloniki, Greece

PGDip at Universitair Medisch Centrum Utrecht, The Netherlands

Ex President, Hellenic H. pylori & Microbiota Study Group