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Feline Chronic Bowel Disease
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A D V A N C E S
FELINE CHRONIC BOWEL DISEASE Background In cats, chronic small bowel disease (CSBD) is associated with mild-to-severe chronic vomiting, weight loss, chronic small bowel diarrhea, or a combination of these. In some cats, chronic disease, especially chronic or intermittent vomiting, may be interpreted by the owner as normal. Abdominal ultrasonography is a means of noninvasive diagnostic evaluation of CSBD, because it allows anatomic assessment of wall thickness, layers, and motility. It is not possible to sequentially trace entire small intestine, so during visual examination, it is not known whether that segment is the duodenum, jejunum, or ileum. However, anatomic landmarks are helpful in identifying specific features of the duodenum and ileum. Inflammatory bowel disease (IBD) and enteropathy-associated T-cell lymphoma (EATL) are the most common small bowel disease of middle-aged and older cats. Inflammatory bowel disease, a chronic inflammatory disease most frequently characterized by lymphoplasmacytic inflammation, is diagnosed if
A D V A N C E S
lymphoma and other known causes of chronic enteritis have been excluded. Enteropathy-associated T-cell lymphoma type 2, which is characterized by small lymphocytes, is the most common infiltrative intestinal lymphoma in cats and can appear morphologically similar to IBD. Differentiation between IBD and EATL type I (large cell) typically is based on established histologic criteria. The differentiation between IBD and EATL type 2 can be difficult, because inflammatory infiltrates and neoplastic infiltrates are morphologically similar. Ambiguous cases can be differentiated on the basis of results of immunohistochemical testing and clone testing by use of PCR for antigen receptor rearrangements (PARR).
Objectives To determine whether a diagnosis of chronic small bowel disease could be established in a subset of cats that had clinical signs of chronic vomiting, chronic small bowel diarrhea, weight loss, or a combination of these, combined with ultrasonographically determined thickening of the small bowel.
Procedure Medical records of 100 cats with clinical signs of chronic vomiting, chronic small bowel diarrhea, weight loss, or a combination of these, combined with ultrasonographically determined small bowel thickening, and who underwent laparotomy and multiple small bowel biopsies were examined. Biopsy specimens were submitted for histologic evaluation, immunohistochemical evaluation, and, when findings were ambiguous, PARR.
Results Chronic small bowel disease was diagnosed in 99 of the 100 cats. The most common diagnoses were chronic enteritis and intestinal lymphoma.
Author Conclusion Cats with clinical signs of chronic small bowel disease should undergo detailed diagnostic testing, because they are likely to have diagnosable and treatable disease.
Inclusions Three figures, 2 tables, 21 references.
Editor Annotation This long-term study demonstrates some
important points for veterinarians who treat cats. The number one point is that vomiting in a cat is not a normal process. Some owners think that is normal and may not report this clinical sign during wellness exams. It is important for the veterinarians to be direct in asking about vomiting during history taking. Owners may be reluctant to report this observation. The authors have described a testing process which, at this time, appears to be the method of choice in evaluation of cats with clinical signs of CSBD. Not all owners are willing to explore the possibility that their cat has a treatable inflammatory bowel disease. They should be offered this procedure as the best possible diagnostic process to determine the treatment potential and prognosis. With the extensive protocol utilized by these clinicians, almost 50% of the cats had a form of intestinal lymphoma. Another important observation is to recognize that the pathologic lesions develop segmentally. A single biopsy may miss the histologic changes. At least 3 full thickness biopsies of the intestine are encouraged. Another important point is that routine histopathology alone may not be diagnostic. Additional testing of the samples may be required. There are specific criteria for IBD and intestinal lymphoma listed in this paper. The veterinary pathologist will be familiar with these criteria. This study is a good start, but additional studies and case numbers will be beneficial in confirming this information. These researchers have described the best current means to diagnose the cause of CSBD in cats. Cat owners that depend upon their veterinarians for the best care possible should have access to this evaluation. (LDM) Norsworthy GD, Estep JC, Kiupel M, et al. Diagnosis of chronic small bowel disease in cats; 100 cases (2008-2012). J Am Vet Med Assoc 2013;243:1455-1461.
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A D V A N C E S
FELINE CHRONIC BOWEL DISEASE Background In cats, chronic small bowel disease (CSBD) is associated with mild-to-severe chronic vomiting, weight loss, chronic small bowel diarrhea, or a combination of these. In some cats, chronic disease, especially chronic or intermittent vomiting, may be interpreted by the owner as normal. Abdominal ultrasonography is a means of noninvasive diagnostic evaluation of CSBD, because it allows anatomic assessment of wall thickness, layers, and motility. It is not possible to sequentially trace entire small intestine, so during visual examination, it is not known whether that segment is the duodenum, jejunum, or ileum. However, anatomic landmarks are helpful in identifying specific features of the duodenum and ileum. Inflammatory bowel disease (IBD) and enteropathy-associated T-cell lymphoma (EATL) are the most common small bowel disease of middle-aged and older cats. Inflammatory bowel disease, a chronic inflammatory disease most frequently characterized by lymphoplasmacytic inflammation, is diagnosed if
A D V A N C E S
lymphoma and other known causes of chronic enteritis have been excluded. Enteropathy-associated T-cell lymphoma type 2, which is characterized by small lymphocytes, is the most common infiltrative intestinal lymphoma in cats and can appear morphologically similar to IBD. Differentiation between IBD and EATL type I (large cell) typically is based on established histologic criteria. The differentiation between IBD and EATL type 2 can be difficult, because inflammatory infiltrates and neoplastic infiltrates are morphologically similar. Ambiguous cases can be differentiated on the basis of results of immunohistochemical testing and clone testing by use of PCR for antigen receptor rearrangements (PARR).
Objectives To determine whether a diagnosis of chronic small bowel disease could be established in a subset of cats that had clinical signs of chronic vomiting, chronic small bowel diarrhea, weight loss, or a combination of these, combined with ultrasonographically determined thickening of the small bowel.
Procedure Medical records of 100 cats with clinical signs of chronic vomiting, chronic small bowel diarrhea, weight loss, or a combination of these, combined with ultrasonographically determined small bowel thickening, and who underwent laparotomy and multiple small bowel biopsies were examined. Biopsy specimens were submitted for histologic evaluation, immunohistochemical evaluation, and, when findings were ambiguous, PARR.
Results Chronic small bowel disease was diagnosed in 99 of the 100 cats. The most common diagnoses were chronic enteritis and intestinal lymphoma.
Author Conclusion Cats with clinical signs of chronic small bowel disease should undergo detailed diagnostic testing, because they are likely to have diagnosable and treatable disease.
Inclusions Three figures, 2 tables, 21 references.
Editor Annotation This long-term study demonstrates some
important points for veterinarians who treat cats. The number one point is that vomiting in a cat is not a normal process. Some owners think that is normal and may not report this clinical sign during wellness exams. It is important for the veterinarians to be direct in asking about vomiting during history taking. Owners may be reluctant to report this observation. The authors have described a testing process which, at this time, appears to be the method of choice in evaluation of cats with clinical signs of CSBD. Not all owners are willing to explore the possibility that their cat has a treatable inflammatory bowel disease. They should be offered this procedure as the best possible diagnostic process to determine the treatment potential and prognosis. With the extensive protocol utilized by these clinicians, almost 50% of the cats had a form of intestinal lymphoma. Another important observation is to recognize that the pathologic lesions develop segmentally. A single biopsy may miss the histologic changes. At least 3 full thickness biopsies of the intestine are encouraged. Another important point is that routine histopathology alone may not be diagnostic. Additional testing of the samples may be required. There are specific criteria for IBD and intestinal lymphoma listed in this paper. The veterinary pathologist will be familiar with these criteria. This study is a good start, but additional studies and case numbers will be beneficial in confirming this information. These researchers have described the best current means to diagnose the cause of CSBD in cats. Cat owners that depend upon their veterinarians for the best care possible should have access to this evaluation. (LDM) Norsworthy GD, Estep JC, Kiupel M, et al. Diagnosis of chronic small bowel disease in cats; 100 cases (2008-2012). J Am Vet Med Assoc 2013;243:1455-1461.
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