The instrument has a light source, a magnifying eyepiece, and an open channel through which air may be passed, expanding the colon for easier viewing and biopsy, if indicated. Patients with FAP generally have adenomas in the rectum, therefore, sigmoidoscopy is encouraged from the age of 12 to 14 years for each at-risk child, brother, and sister. Maintaining this screening program should be an ongoing and valued family tradition for preventive health care. This procedure allows detailed exploration of problem areas in the large intestine. Polyps may be biopsied or removed through this instrument.
Patients receive light sedation and are usually examined in the hospital as daypatients.
Clear liquid is required on the day of the test, along with a laxative and an enema, depending on individual circumstances. A person diagnosed to have FAP by screening sigmoidoscopy requires a colonoscopic examination to determine polyp distribution and the choice of preventive surgery. This radiological test may show lesions in the lining of the large intestine. However, very small polyps may be missed on X-ray. Bowel preparation may include dietary restrictions, such as liquids only, and a laxative or an enema.