Colonoscopy

A colonoscopy involves the use of a long, flexible tube called a colonoscope. The instrument is inserted through the rectum and advanced through the colon. The camera at its tip allows the doctor to view the entire length of the colon on a screen.

In addition to diagnosis, a colonoscopy can also be therapeutic, allowing the removal of polyps, control of bleeding, and biopsy of suspicious tissue.

Why is a Colonoscopy Performed?

Doctors recommend colonoscopy for both screening and diagnostic purposes. Common reasons include:

• Screening for colorectal cancer – usually recommended from age 45 onward.
• Detection and removal of polyps – preventing cancer development.
• Investigation of gastrointestinal symptoms such as:
• Chronic diarrhea
• Rectal bleeding
• Unexplained abdominal pain
• Changes in bowel habits
• Unexplained weight loss or anemia
• Diagnosis of inflammatory bowel diseases such as Crohn’s disease and ulcerative colitis.
• Monitoring patients with a history of polyps or colorectal cancer.

Preparation for Colonoscopy

Proper preparation is critical for a successful colonoscopy. A clean colon ensures the doctor has a clear view. The preparation usually involves:

• Bowel cleansing – Patients are asked to drink a prescribed laxative solution a day before the procedure.
• Clear liquid diet – Allowed fluids include water, broth, tea, apple juice, and clear sports drinks.
• Fasting – No solid food 6–8 hours before the test.
• Medication review – Patients should inform their doctor about blood thinners, diabetes medicines, or other drugs.

How is a Colonoscopy Performed?

The procedure usually takes 30–60 minutes and follows these steps:

• Sedation – Patients are given sedatives or anesthesia for comfort.
• Insertion of colonoscope – The doctor inserts the scope through the rectum and advances it slowly through the colon.
• Examination – The lining of the colon is carefully inspected for inflammation, ulcers, bleeding, polyps, or tumors.
• Biopsy or polyp removal – If abnormal tissue or polyps are found, they can be removed or biopsied immediately.
• Completion – The scope is withdrawn while the colon is re-examined.

Conditions Detected by Colonoscopy

Colonoscopy is considered the gold standard for diagnosing colon-related conditions. Some common findings include:

• Colorectal polyps
• Colon and rectal cancers
• Diverticulosis and diverticulitis
• Inflammatory bowel disease (Crohn’s, ulcerative colitis)
• Unexplained gastrointestinal bleeding
• Infections or ischemic colitis

Benefits of Colonoscopy

• Cancer prevention – Early removal of polyps reduces colorectal cancer risk.
• Accurate diagnosis – Direct visualization allows detection of even small lesions.
• Therapeutic use – Polyps can be removed, and bleeding controlled during the same procedure.
• Guided treatment – Biopsies help determine the exact cause of symptoms.
• Improved survival rates – Early detection of colon cancer significantly improves outcomes.

Risks and Complications

Although colonoscopy is generally safe, minor risks may include:

• Bloating or cramping after the procedure
• Bleeding at biopsy or polyp removal sites
• Perforation of the colon (very rare, <1 in 1000 cases)
• Reactions to sedatives

The overall risk is very low, especially when performed by experienced specialists.

Recovery and Aftercare

After the procedure:

• Patients are monitored until sedation wears off.
• A mild bloating or gas sensation may occur due to air introduced during the procedure.
• Normal diet can usually be resumed the same day.
• Driving is not allowed for 24 hours due to sedation.
• Any severe abdominal pain, fever, or heavy rectal bleeding should be reported immediately.

Colonoscopy vs. Other Screening Methods

• Fecal occult blood test (FOBT)
• Stool DNA tests
• CT colonography (virtual colonoscopy)
• Sigmoidoscopy

However, colonoscopy remains the most reliable since it allows both detection and treatment in one session.

When Should You Get a Colonoscopy?

• Average-risk individuals – Start at age 45, repeat every 10 years if normal.
• High-risk individuals – Those with a family history of colorectal cancer, polyps, or genetic syndromes may need earlier and more frequent screening.
• Symptomatic patients – Any unexplained rectal bleeding, persistent changes in bowel habits, or unexplained anemia warrants an immediate evaluation.