Sigmoidoscopy

Sigmoidoscopy is a diagnostic and therapeutic endoscopic procedure used to examine the inner lining of the rectum and lower part of the large intestine, particularly the sigmoid colon. During the procedure, a gastroenterologist carefully passes a thin, flexible instrument called a sigmoidoscope through the anus. The instrument contains a light and a small camera that provides detailed images of the lower bowel lining.

This procedure helps identify inflammation, ulcers, bleeding sites, polyps, abnormal tissue, narrowing, diverticula, and suspicious growths affecting the rectum and lower colon. A biopsy or polyp removal may also be performed during the procedure when clinically required.

Benefits of the Test

• Provides direct examination of the rectum and lower colon.
• Helps identify the cause of rectal bleeding or blood in stools.
• Detects inflammation, ulcers, polyps, and abnormal growths.
• Supports the diagnosis of ulcerative colitis and other bowel conditions.
• Helps investigate persistent changes in bowel habits.
• Allows tissue samples to be collected for biopsy when required.
• Enables removal of certain polyps during the same procedure.
• Generally requires less bowel preparation than a complete colonoscopy.
• Supports accurate diagnosis and appropriate treatment planning.
• Provides immediate visual information about the lower bowel.

Why Doctors Recommend This Test

Doctors may recommend sigmoidoscopy for individuals experiencing rectal bleeding, blood or mucus in stools, persistent diarrhoea, chronic constipation, lower abdominal discomfort, changes in bowel habits, unexplained iron-deficiency anaemia, or symptoms suggestive of inflammation in the lower bowel. It may also be performed to follow up previously detected polyps, abnormal imaging results, or known inflammatory bowel disease.

Preparation Before Test

• Follow the bowel-preparation instructions provided by your doctor.
• An enema or prescribed laxative may be required to clean the lower bowel.
• Dietary restrictions or a clear-liquid diet may be advised before the procedure.
• Fasting requirements depend on the planned procedure and whether sedation will be used.
• Inform your doctor about diabetes, heart disease, pregnancy, allergies, and other medical conditions.
• Inform the doctor if you take blood thinners, iron supplements, insulin, or regular medicines.
• Do not stop any prescribed medicine without medical advice.
• Share details of previous bowel procedures, surgeries, or relevant reports.
• Arrange for someone to accompany you if sedation is planned.

Normal Reporting Time

Initial sigmoidoscopy findings are generally explained by the gastroenterologist soon after the procedure, and the procedure report is usually provided on the same day. If a biopsy or polyp sample is collected, the histopathology report requires additional laboratory processing time and will be issued separately according to laboratory protocols.

Who Should Take This Test?

Sigmoidoscopy may be recommended for:

• Individuals experiencing rectal bleeding.
• People with blood or mucus in their stools.
• Patients with persistent changes in bowel habits.
• Individuals with chronic diarrhoea or constipation.
• People experiencing unexplained lower abdominal discomfort.
• Patients with suspected ulcerative colitis or lower bowel inflammation.
• Individuals with unexplained iron-deficiency anaemia.
• People with abnormal stool-test or imaging results.
• Patients requiring follow-up of previously detected polyps.
• Individuals requiring biopsy of abnormal lower-bowel tissue.

Detailed Information

The sigmoid colon is the lower curved portion of the large intestine that connects the descending colon to the rectum. Conditions affecting this region may produce symptoms such as rectal bleeding, mucus in stools, bowel-habit changes, abdominal discomfort, diarrhoea, constipation, and an urgent need to pass stools.

During sigmoidoscopy, the patient usually lies on the left side. The sigmoidoscope is gently inserted through the anus and advanced through the rectum into the sigmoid colon. The camera transmits images to a monitor, allowing the gastroenterologist to carefully inspect the bowel lining.

A small amount of air or carbon dioxide may be introduced into the bowel to expand it and improve visibility. This can cause temporary pressure, mild cramping, or bloating during or after the procedure. Sedation or pain-relieving medication may be offered depending on the patient’s condition and the clinical protocol.

Sigmoidoscopy can identify irritated or swollen tissue, ulcers, polyps, diverticula, bleeding sites, narrowing of the bowel, and suspicious growths. If abnormal tissue is identified, the doctor may collect a small biopsy sample for histopathological examination.

Certain polyps may also be removed during the procedure when considered safe and clinically appropriate. Although many colon polyps are non-cancerous, some can gradually develop into cancer. Laboratory examination helps determine the nature of the removed tissue.

Unlike colonoscopy, sigmoidoscopy examines only the rectum and lower portion of the colon. It does not provide a complete examination of the entire large intestine. If significant abnormalities are identified or symptoms require further investigation, the gastroenterologist may recommend a complete colonoscopy.

After the procedure, mild bloating, cramping, or a small amount of rectal bleeding may occur, especially if a biopsy or polyp removal was performed. Patients should seek immediate medical care if they develop severe abdominal pain, fever, persistent vomiting, dizziness, heavy bleeding, or breathing difficulty.

Results should be interpreted by the gastroenterologist along with the patient’s symptoms, medical history, bowel-preparation quality, procedure findings, and biopsy results where applicable.

At Focus Diagnostics, sigmoidoscopy procedures are performed by trained healthcare professionals using appropriate endoscopic equipment, established clinical protocols, infection-control measures, and patient-safety standards to support accurate examination and reliable diagnosis.