Endoscopy is often used to obtain GI biopsy samples because the lesions can be viewed directly, multiple samples can be harvested,
the procedure can be faster than performing routine abdominal exploratory surgery, and recovery time is reduced. The odds
of obtaining an accurate diagnosis from endoscopically collected biopsy samples depend on the quantity and quality of samples.
Harvest at least eight good tissue samples from each location in the GI tract (Figure 5). Submitting an adequate number of samples increases the chances of obtaining a diagnosis because lesions are not always
evenly distributed throughout the GI tract and some samples may be inadequate. Consider obtaining both large and small intestinal
biopsy samples, even if the signs appear to localize to the upper or lower GI tract. For example, some cats will vomit with
ileal or colonic lesions, and these lesions would be missed if only upper GI samples were obtained.
Figure 5. Gastrointestinal biopsy samples obtained endoscopically.
Endoscopically obtained GI biopsy samples are likely to be diagnostic in cats, provided the samples are obtained from the
proximal small intestine (or duodenum) and not just the stomach. Most cases of alimentary lymphoma in cats involve only the
small intestine, and pockets of lymphocytes occur in the villi from which biopsy samples can be easily obtained endoscopically.
In one report when alimentary lymphoma was present in cats that ranged in age from 6 to 18 years, endoscopic biopsy was used
to obtain the diagnosis in more than 90% of the patients.4
Laparoscopy has several advantages over other diagnostic procedures. It allows you to obtain large biopsy samples and is particularly
useful for liver biopsies. Small lesions on peritoneal surfaces can be difficult to visualize on ultrasonographic examination,
but lesions < 1 mm in diameter can be seen with laparoscopy. The ability to see small lesions can be used to diagnose and
stage abdominal neoplasia. The pancreas, which can be particularly difficult to image, can be visualized and biopsied safely
Weight loss is commonly noted in geriatric cats. A thorough history and physical examination will usually reveal valuable
clues as to the most likely causes. But even if weight loss is the only abnormality identified, a complete diagnostic workup
is often indicated. Early diagnosis can prevent further weight loss and the development of other clinical signs as well as
improve a patient's response to therapy.
*Samples for TLI, PLI, cobalamin, folate, and fecal alpha1-protease inhibitor measurement can be submitted directly to the laboratory that performs the assays or to your usual laboratory
that then forwards the samples. The laboratory that performs these assays is the Gastrointestinal Laboratory, 4474 TAMU, College
of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4474; phone (979) 862-2861; fax (979) 862-2864;
Anne Mattson, DVM, MS, DACVIM
Veterinary Specialty Practice
10262 N. Greenview Drive
Mequon, WI 53092
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2. Merchant SR. The skin as a sensor of internal medical disorders. In: Ettinger SJ, Feldman EC, eds. Textbook of veterinary internal medicine. 6th ed. St. Louis, Mo: Elsevier Saunders, 2005;31-33.
3. Pion PD, Keene BW, Miller M, et al. Nutrition and management of cardiovascular disease. In: Fox PR, Sisson D, Moise NS, eds.
Textbook of canine and feline cardiology. 2nd ed. Philadelphia, Pa: WB Saunders Co, 1999;739-755.
4. Richter K. Feline gastrointestinal lymphoma, in Proceedings. 19th Annu Meet Am Coll Vet Intern Med 2001;547-549.
5. Center SA, Warner K, Corbett J, et al. Proteins invoked by vitamin K absence and clotting times in clinically ill cats. J Vet Intern Med 2000;14:292-297.