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56 CHRONIC VOMITING IN CATS PEER REVIEWED laparotomy with biopsies of all possibly affected organs is generally recommended to avoid missing the primary disease process or a chance to achieve surgical cure. Collecting Samples for Biopsy Endoscopically collected biopsy samples can be both highly sensitive and specific for GI disease, depending on the histologic quality of the samples. 48 To be considered histologically adequate, samples must contain 3 or more villi and lamina propria extending to the mucosa–muscularis mucosa border. A 99% likelihood of detecting cellular infiltrates and villus blunting in the stomach and duodenum can be achieved with as few as 6 adequate samples; 54 if samples are histologically inadequate, 18 to 26 specimens are required for this level of confidence. Histologic quality cannot be determined on the basis of gross appearance; therefore the endoscopist should collect a reasonable number of biopsy samples and follow best practices for sample alignment to avoid overlooking a subtle lesion. 48 Sensitivity of endoscopic biopsy for detection of lymphoma does not vary according to sample quality, 54 although distinguishing between lymphoma and lymphoplasmacytic enteritis can be difficult regardless of sample quality. 55 The use of immunohistochemistry and PCR for antigen receptor rearrangements can help differentiate between the two differentials. 56–59 Simultaneous collection of ileal biopsy specimens increases the chance of detecting regional disease, particularly with regard to ileal lymphoma. 60 Because this necessitates colonoscopy, clinical judgment should be used in deciding whether the increase in patient preparation, anesthesia time, costs, and potential complications is warranted. CONCLUSION Chronic vomiting in cats is a frustrating condition, and accurate diagnosis hinges on use of a systematic approach. Endoscopy is warranted after systemic diseases have been ruled out, particularly in cases without solitary jejunal disease. In the absence of other findings, the presence of muscularis thickening does not indicate a need for laparotomy. As technology advances and endoscopy becomes more sophisticated, it may become more useful or reliable in obtaining samples and performing interventional techniques. REFERENCES 1. Norsworthy GD, Estep JS, Hollinger C, et al. Prevalence and underlying causes of histologic abnormalities in cats suspected to have chronic small bowel disease: 300 cases (2008-2013). J AVMA 2015;247(6):629-635. 2. Norsworthy GD, Scot Estep J, Kiupel M, et al. Diagnosis of chronic small bowel disease in cats: 100 cases (2008-2012). J AVMA 2013;243(10):1455-1461. 3. Guilford WG, Jones BR, Markwell PJ, et al. Food sensitivity in cats with chronic idiopathic gastrointestinal problems. J Vet Intern Med 2001;15(1):7-13. 4. Washabau RJ, Day MJ, Willard MD, et al. Endoscopic, biopsy, and histopathologic guidelines for the evaluation of gastrointestinal inflammation in companion animals. J Vet Intern Med 2010;24(1):10-26. 5. Felts JF, Fox PR, Burk RL. Thread and sewing needles as gastrointestinal foreign bodies in the cat: a review of 64 cases. JAVMA 1984;184(1):56-59. 6. Nussbaum LK, Scavelli TD, Scavelli DM, et al. Abdominal ultrasound examination findings in 534 hyperthyroid cats referred for radioiodine treatment between 2007-2010. J Vet Intern Med 2015;29(4):1069-1073. FIGURE 2. Diffuse muscularis thickening (arrows) and lymphadenopathy (caliper markings) in a cat with chronic vomiting due to lymphoma. Kyle Restle Kyle Restle is a small animal surgery resident at the University of Tennessee's small animal teaching hospital. He is a 2016 graduate of Auburn University's College of Veterinary Medicine. His primary interests are veterinary surgery, 3-dimensional printing, and medical technology/instrumentation. Jacqueline Whittemore Jacqueline Whittemore is an associate professor at the University of Tennessee College of Veterinary Medicine, where she also serves as the minimally invasive procedures service chief and the Acree Research Chair in Small Animal Medicine. She received her DVM from the University of California, Davis, and completed her residency and PhD at Colorado State University. Her major research foci are identification and amelioration of adverse effects of exogenous therapies (particularly antiplatelet, immunosuppressive, and antibiotic) on the gastrointestinal tract, development of simulators for veterinary training, and validation of minimally invasive diagnostic techniques to decrease patient morbidity and improve patient outcome.