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Colonoscopy

Colonoscopy — endoscopic examination of the large intestine and the terminal ileum.

An endoscope is inserted through the anus to visualize the entire colon and the last portion of the small intestine; the gold standard for polyp and cancer screening.

Indication

  • Colorectal cancer screening in individuals aged 50 and over
  • Earlier-age screening in those with a family history of colon cancer or polyps
  • Investigation of occult/visible blood in stool and iron deficiency anemia
  • Persistent change in bowel habits, chronic diarrhea or constipation
  • Unexplained abdominal pain and weight loss
  • Diagnosis and follow-up of inflammatory bowel disease (ulcerative colitis, Crohn's)
  • Surveillance after previously detected polyps or cancer

Preparation

  • Starting 2 days before the procedure, a low-fiber, low-residue diet (avoiding red meat, raw vegetables, fruit, grains, sesame and nuts)
  • Clear liquid diet on the day before the procedure (water, weak tea, broth, sweetened drinks)
  • Drinking the bowel-cleansing solution (PEG or similar) in split doses as advised by the physician
  • Adjustment of iron, blood thinners and certain diabetes medications with physician approval
  • Fasting for at least 6 hours on the day of the procedure and arriving with an accompanying person

How it's performed

  1. An intravenous line is placed and vital signs are continuously monitored
  2. Sedation (a sleep-inducing medication) is given through the IV line
  3. The patient is positioned on the left side and the colonoscope is advanced through the anus
  4. Air or CO2 is delivered to distend the bowel; the entire colon and the terminal ileum are inspected
  5. Polyps that are found are removed in the same session (polypectomy); biopsies are taken from suspicious areas
  6. The procedure usually takes 20-45 minutes; all findings are photographed

Post-procedure

  • Rest under observation for 30-60 minutes after sedation
  • Mild bloating and gas may occur for a few hours after the procedure and are relieved by walking
  • No driving and no important decisions on the same day
  • If polyps were removed, heavy lifting and aspirin/blood thinners may be restricted for 1-3 days
  • Follow-up interval is planned according to the pathology result (between 3 and 10 years)

Risks

  • Sedation-related respiratory depression and blood pressure fluctuations (rare)
  • Bowel wall perforation — about 1 in 1,000, slightly higher after polypectomy
  • Bleeding at the polypectomy site (usually stops on its own or is controlled endoscopically)
  • Cardiopulmonary events (especially in older patients with comorbidities)
  • Temporary abdominal pain and bloating after the procedure

FAQ

Is the procedure painful?

The procedure is performed under sedation; most patients are asleep, do not feel pain and do not remember the procedure. Mild gas bloating may occur afterwards.

What happens if my bowel preparation is not adequate?

Inadequate preparation can cause polyps and lesions to be missed. The procedure may be incomplete or need to be repeated soon. Strict adherence to the instructions is very important.

How often should it be performed?

It depends on the risk group. In average-risk individuals aged 50 and over with a normal result, every 10 years; in those with polyps or a family history, the physician may recommend every 3-5 years.

When can I return to a normal diet after the procedure?

Usually water and light foods are started about 2-3 hours later; most patients can return to a normal diet by the same evening. If polypectomy was performed, follow your physician's specific advice.