Case of the Month
Colonoscopy is a helpful tool in the diagnosis of large bowel diarrhea in dogs and cats. Thanks to colonoscopies we can diagnose infiltrative diseases, neoplasias and some infectious agents affecting the large intestine.
Patient preparation is extremely important prior to colonoscopy; if the colon is not completely empty, fecal material can obscure lesions and interfere with diagnosis. The patient should be fasted for at least 24 hours. Two treatments with GoLyte® should be given and one warm water enema before the procedure is done.
The colon mucosa should be pink, smooth and sub mucosal vessels are easily seen. Some of the pathologic changes are: increase in mucosa granularity and friability; loss of sub mucosa vascularity due to inflammation; edema or neoplasia, masses and polyps; and ulcers and erosions. Although macroscopic changes are often related to pathology, their absence does not rule it out, therefore multiple biopsy samples from all areas of the colon should be taken.
Before a colonoscopy is performed we should localize the problem to the large intestine. Large bowel diarrhea is characterized by an increase in the frequency and a decrease in the amount per defecation. It can be accompanied by fresh blood (hematochezia) mucus and tenesmus. Often times patients do not have weight loss.
A complete history, including complete detail of the current and previous diets should be obtained. This should be followed by a thorough physical exam, including rectal palpation. Multiple fecals are necessary; whipworms are a common cause of large bowel diarrhea and are easily missed. Rectal cytology can help with the diagnosis of Clostridium perfinges. If the patient is clinically stable I like to start with a diet trial for 3 to 4 weeks, with a highly digestive or novel protein diet, fiber, deworming against whipworms and Amoxillin for the treatment of Clostridium.
If the medical trial is not successful, or the patient is ill I do complete CBC, chemistry and urinalysis to rule in or out systemic disease and assess anesthetic risk prior to colonoscopy.
The most common problems of the large intestine are parasites (whipworms), Clostridium, Irritable Bowel Syndrome, dietary intolerance (allergic or non allergic) and fiber responsive colonic dysfunction.
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