Colonoscopy: Purpose, Procedure, Preparation & Safety
A colonoscopy is a diagnostic and therapeutic procedure used to examine the inner lining of the large intestine (colon and rectum). It helps doctors identify causes of bowel symptoms, detect polyps and cancers early, and treat certain conditions during the same procedure.
During colonoscopy, a thin, flexible tube with a camera (colonoscope) is gently passed through the anus into the colon. The camera transmits images to a monitor, allowing detailed inspection of the bowel lining.
Colonoscopy is considered the gold standard for evaluating lower gastrointestinal problems.
Chronic diarrhea or constipation
Abdominal pain or weight loss
Positive stool occult blood test
Screening for colorectal cancer
Surveillance in inflammatory bowel disease (IBD)
Biopsy of suspicious lesions
Dilatation of strictures (selected cases)
Who Should Get a Screening Colonoscopy?
Average-risk adults: From age 45–50 years, every 10 years (if normal)
Higher risk (family history, IBD): Earlier and more frequent screening as advised
Post-polyp removal: Follow-up intervals depend on polyp type and number
Preparation for Colonoscopy (Most Important Step)
A clean colon is essential for accurate results.
Low-fiber diet 2–3 days before
Clear liquids the day before (water, clear soups)
Avoid red or purple liquids
Laxative solution taken as prescribed (often split-dose)
Continue clear fluids to prevent dehydration
Poor preparation can lead to missed lesions or repeat procedure.
How the Procedure Is Performed
Usually done under sedation
Takes about 20–40 minutes
Air or CO₂ is gently introduced to expand the colon
Polyps, if found, can be removed immediately
Most patients feel minimal discomfort due to sedation.
Colonoscopy is generally very safe.
Bleeding (especially after polyp removal)
Abdominal bloating post-procedure
Serious complications are uncommon, especially when performed by experienced specialists.
Mild bloating or gas may occur
Resume normal diet unless advised otherwise
Avoid driving for 24 hours if sedated
Biopsy results are usually available in a few days
Seek medical attention if there is:
What Can Colonoscopy Detect?
Inflammatory bowel disease
Sources of lower GI bleeding
Early detection can prevent cancer by removing precancerous polyps.
Persistent bowel habit changes
Unexplained anemia or weight loss
Family history of colorectal cancer
Disclaimer:
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