Colonoscopy is performed after a complete diagnostic work-up and therapeutic plan have failed to resolve problems linked to the lower intestine. To perform colonoscopy, the patient is anesthetized and a flexible fiberoptic endoscope is passed into the colon. Air, passed through the scope, increases the view within the colon. Biopsies can be obtained by passing an instrument through an opening in the scope. Colonoscopy provides a valuable, non-surgical means to diagnose large bowel disorders. To perform colonoscopy, it is important that the colon be clean of fecal matter so that the surface of the colon can be visualized. This often requires withholding food for 24 to 48 hours and giving your pet a solution to drink which 'cleanses' the colon. Warm-water enemas may also be used to clear the colon. Most patientsare discharged the same day of the procedure.
The major symptoms and reasons to perform a colonoscopy are:
1. Chronic diarrhea
2. Blood in the stool (persistent hematochezia)
3. Study of a growth in the colon or rectum
4. Straining during defecation (persistent tenesmus)
5. Excessive mucus in the stool
6. Stools of significantly decreased or narrowed size
More recently, colonoscopy has been playing an important role in upper intestinal problems such as weight loss, chronic diarrhea, and vomiting. In this case, the goal of the colonoscopy is to attain biopsies from the ileum. This is especially important in cats because it is thought that up to 40% of cats with intestinal lymphoma will only have evidence of lymphoma in the ileum.
Lastly, colonoscopy could be used to diagnose and dilate rectal strictures as well as to remove colonic polyps that are not surgically excisable.