Sigmoidoscopy is a technique of directly visualising the lower part of the bowel – the rectum and sigmoid colon – to look for abnormalities.

How the Test is Performed

Sigmoidoscopy is usually performed without an anaesthetic. The patient is awake but may be offered a mild sedative to ease anxiety. The rigid sigmoidoscope is a narrow, straight metal or plastic tube with a light source attached, which enables the examining doctor to look inside the bowel at its inside surface (mucosa). A flexible sigmoidoscope allows the same examination, but uses fibre-optic technology in a device that can be manipulated to look in different directions. In either case, air is gently pumped into the rectum. This may cause a sensation of fullness and will always result in some air escaping during and after the procedure as flatus – potentially embarrassing but medical staff are used to it!

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Medical Conditions and Symptoms

A sigmoidoscopy (whether rigid or flexible) may be performed for rectal bleeding, chronic diarrhoea – especially with blood and mucus, weight loss, or a feeling of incomplete evacuation of the bowels, known as tenesmus. These symptoms may indicate an infection or inflammation of the colon (colitis), or even a tumour of the rectum or sigmoid colon. Bleeding may also be from a less serious cause such as a polyp, or from dilated fragile blood vessels (angiodysplasia).

Test Results Explained

Sigmoidoscopy results may be reported and explained to the patient immediately after the procedure, or issued as a typed report.

Related Specialists


Related Procedures

      • Colonoscopy
      • Endoscopy of the Upper Gastrointestinal Tract

Related Tests

Also Known As

      • Rigid Sigmoidoscopy
      • Flexible Sigmoidoscopy



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