What is a colonoscopy?

Have you ever felt that your stomach or intestines are sending signals that are impossible to ignore? In this article, I will explain what a colonoscopy is, why it is important, how to prepare for it, and what to expect. The goal is to provide clear, understandable, and practical information to help you make an informed decision about your health.

What is a colonoscopy and why is it performed?

A colonoscopy is an endoscopic diagnostic procedure that allows the examination of the large intestine from the inside. Using a flexible optical instrument – a colonoscope – a gastroenterologist can examine the intestinal mucosa and detect polyps, inflammation, sources of bleeding, or tumors. This procedure is essential for colorectal cancer screening, especially for people over the age of 50. International associations of gastroenterologists emphasize that early diagnosis significantly improves survival rates.

Symptoms for which a colonoscopy is prescribed

A colonoscopy is prescribed if a patient experiences long-term bloating, rectal bleeding, changed bowel habits (diarrhea or constipation), unexplained weight loss, or anemia. ASGE guidelines indicate that the most common indicators are rectal bleeding (28%), altered bowel habits (20%), anemia (18%), and abdominal pain (15%).

When is a colonoscopy recommended?

A doctor may recommend a colonoscopy if the following symptoms are present:

• Rectal bleeding – common causes include hemorrhoids, anal fissures, polyps, diverticulosis, inflammatory bowel diseases, or tumors.
• Black or bloody stools – may indicate bleeding in the stomach, duodenum, or rectum.
• Persistent abdominal pain – suspicion of diverticulosis, diverticulitis, or inflammatory bowel diseases.
• Constipation or diarrhea – caused by age, irritable bowel syndrome, medications, Crohn’s disease, or ulcerative colitis.
• Unexplained weight loss – may indicate colorectal cancer, polyps and adenomas, inflammatory bowel diseases, or malabsorption disorders.
• Anemia – iron deficiency anemia often occurs due to chronic, low-grade, but long-term bleeding in the digestive tract.
• Positive fecal occult blood test – bowel cancer screening.
• Bowel cancer screening after the age of 40–50.

How to prepare for FKS?

Preparation for a colonoscopy is essential for an accurate examination. ESGE guidelines emphasize that bowel cleanliness is the main quality indicator. The patient must follow a diet for 3–5 days before the procedure, avoid fiber, and use special bowel cleansing agents. Inadequate preparation can lead to inaccurate diagnosis or the need to repeat the examination.

What to expect during the procedure?

The procedure is usually performed under light sedation to make the patient feel comfortable. The colonoscope is inserted through the anus, and the examination lasts about 20–40 minutes. From my experience, I can say – most patients after the procedure say: “It was much easier than I expected.” Gastroscopy without sedation, which is an examination of the stomach, often causes more discomfort than a colonoscopy.

Is a colonoscopy painful?

This is one of the most common questions. Honestly – for the majority of patients, the procedure is not painful. With sedation and in the hands of an experienced gastroenterologist, discomfort is minimal. There have been cases where patients who were previously afraid said after the procedure: “If I had known it was this easy, I would have come earlier.” In comparison – gastroscopy sometimes causes a gag reflex, but a colonoscopy is calmer.

The most comfortable way for both the patient and the gastroenterologist is to perform the colonoscopy under intravenous anesthesia, where an anesthesiologist also participates to monitor the patient’s well-being.

How is a colonoscopy performed?

• The patient lies on their left side.
• Sedative medications or general anesthesia are administered.
• The colonoscope is inserted through the rectum.
• The doctor observes the mucosa, looking for inflammation, polyps, ulcers, or tumors.
• If necessary, the following are performed:
  • Biopsy (taking tissue samples) – a medical procedure during which a doctor uses special instruments to take a small tissue sample from the intestinal mucosa to microscopically examine the cell structure in a laboratory.
  • Polypectomy (removal of polyps) – a medical procedure where polyps are removed from the mucosa of the large intestine or rectum to prevent bleeding and reduce the risk of future malignancy.
  • Hemostasis (stopping bleeding) – the process by which a doctor stops bleeding by ensuring vessel closure.

How long does the procedure last?

A colonoscopy usually lasts 20–45 minutes, depending on the necessary manipulations. If biopsies or polyp removals are required, it may take more time.

Interpretation of results and next steps

After the colonoscopy, the doctor explains the findings. If polyps are found, they are often removed immediately. If a tumor is suspected, tissue samples are taken. ASGE guidelines recommend regular screening for people at increased risk. Gastroscopy and colonoscopy are often performed in combination to fully evaluate the gastrointestinal tract.

What can be detected during a colonoscopy?

Detected problems	Description
Polyps	Benign growths that can become malignant
Ulcers	Mucosal lesions that can bleed
Inflammation	Colitis, Crohn’s disease
Tumors	Colorectal cancer
Diverticula	Protrusions of the intestinal wall
Hemorrhoids	Can be observed during the procedure

How to prepare for a colonoscopy?

Preparation is critical because the doctor’s ability to see even the smallest formations depends on the cleanliness of the intestines.

Diet before colonoscopy (3–5 days before)

• Forbidden – whole grain bread, groats, vegetables, fruits (especially with skins and seeds – tomatoes, cucumbers, berries, kiwi), nuts, and seeds.
• Allowed – white bread, rice, pasta, eggs, lean meat (chicken, fish), cheese, yogurt without additives.

Day before the procedure: “Liquids only”

• Breakfast – light, low-fiber breakfast allowed (e.g., white bread with cheese). After that – only liquids.
• Clear liquids – transparent broth, apple or grape juice (no pulp), tea, coffee (no milk), still water.
• Important – avoid red or purple drinks.

Bowel cleansing preparations

• Fortrans (Macrogol): The “gold standard.” Requires drinking about 4 liters. Very safe, does not cause electrolyte imbalance.
• Eziclen (Sulfates): Smaller volume of the medication itself (1 liter), but requires drinking an additional 2 liters of water.
• Picoprep / CitraFleet: Best taste (lemon/orange). Only two small glasses (150 ml), but critical to drink 2-3 liters of water extra to avoid dehydration.
• Moviprep / Plenvu: New generation, total volume reduced to 1–2 liters. Effective as Fortrans but less to drink.

Useful tips before preparation

• Chill the liquid: It will taste better cold.
• Use a straw: To bypass some taste buds.
• Lemon slice: Suck on a lemon after drinking to remove the aftertaste.

Procedure day

• Fasting – if performed under sedation, DO NOT EAT for 6 hours before. Water is allowed up to 2 hours before.
• Smoking – not recommended.
• Medications – take blood pressure meds early. For blood thinners (Warfarin, Xarelto, Pradaxa, Aspirin, Ticagrelor), consult your doctor 3-5 days in advance.

After the procedure

• Possible bloating or mild discomfort (Espumisan can help).
• Do not drive for 24 hours after anesthesia.
• Biopsy results are available within 10–14 days.
• After polypectomy: no heavy physical work, hot baths, or saunas for 72 hours.

Don’t wait. Book your visit to the gastroenterologist at “Republikas laukuma klīnika” in Riga today.