Page 186 - WSAVA2018
P. 186

 25-28 September, 2018 | Singapore
F. Gaschen1
1Louisiana State University School of Veterinary Medicine, Baton Rouge, LA USA
Clinical presentation:
Middle-aged to older cats with vomiting, anorexia, diarrhea and weight loss, and general malaise are the most commonly observed clinical signs. However, some cats may have a normal to increased appetite. Unlike
in dogs, diarrhea is only occasionally a presenting complaint. Many cats will be presented for hyporexia/ anorexia, lethargy and weight loss. These non-specific signs are often waxing and waning, and the owners
may seek veterinary attention only late in the course of disease. Abnormal findings on physical exam include loss of body condition, dehydration, possible palpation of thickened bowel loops and/or abdominal pain.
Diagnostic approach:
Because the clinical signs may be very non-specific,
the first step is to rule out diseases originating outside GI tract that may present with a similar clinical picture. These include conditions such as hyperthyroidism, chronic kidney disease, liver disease and pancreatitis.
A minimal database is recommended that consists of CBC, chemistry profile, serum thyroxin concentration and abdominal imaging (radiographs, ultrasound). Once the GI tract has been confirmed as the origin of the disease, several steps should be considered in view of the most common causes of chronic intestinal diseases in cats. Parasitic diseases should be ruled out with fecal analysis or appropriate empirical treatment with broad-spectrum anthelminthics. Diagnosis of giardiasis using direct fecal smears (trophozoites) or zinc sulfate flotation (cysts) may be difficult. Analysis of several fecal samples may be required due to the erratic shedding of cysts. Several commercially available immunoassays detect Giardia cyst antigen in feces and are helpful diagnostic tools.
Diagnostic imaging:
In chronic enteropathies, the most common abnormality of the small intestine is thickening of the tunica muscularis. It is seen equally frequently in inflammatory bowel disease (IBD) and alimentary lymphoma, and cannot be used to differentiate these 2 diseases. Norsworthy et al. (JAVMA, 2015) reported that jejunal wall thickness >2.8mm at 2 sites or >3.0mm at one
site correlates with clinically relevant histopathological disease.
Empirical treatment trial:
Cats with mild to moderately severe clinical signs and maintained appetite may respond to a diet change using highly digestible, novel protein or hydrolyzed peptide diets within 2 weeks. In cats that do not respond to a dietary approach, antimicrobials have been successful in some instances, presumably to correct intestinal dysbiosis (e.g. metronidazole 10-15 mg/kg PO q12 h or tylosin 10-15 mg/kg PO q12h). Improvement is usually noticeable within a few days. In cats that respond to treatment, there are
no reports about the optimal duration of antimicrobial treatment, and the author usually attempts to discontinue treatment after 3-4 weeks.
Collection and evaluation of intestinal biopsies:
In cats that do not respond or only partially respond to dietary or antimicrobial treatment, it is often necessary to obtain intestinal biopsies for histopathological evaluation to differentiate between enteropathy-associated
T-cell lymphoma (EATL type II) and IBD. Endoscopic mucosal biopsies and surgical full thickness biopsies are both appropriate, and each sampling method has
its strengths and weaknesses. In difficult cases when the pathologist cannot easily differentiate between inflammation and neoplasia, immunohistochemistry for T and B-cell markers and PCR assay for antigen receptor rearrangement (PARR) have been used successfully to rule in or out the possibility of enteropathy-associated T-cell lymphoma (EATL) type II. Unfortunately, the sensitivity of PARR is 78% for T cell lymphoma and 50% and for B cell lymphoma, and false negative results are therefore possible.
Inflammation of multiple digestive organs:
IBD, neutrophilic or lymphocytic cholangitis and chronic pancreatitis or any combination of these diseases have been reported to occur concurrently in middle-age to older cats. Simultaneous occurrence of all 3 diseases has been described as “triaditis”. This multi-organ inflammation may be a consequence of the unique pancreatico-biliary anatomy of the cat with fusion of pancreatic and common bile ducts prior to the duodenal papilla. It is suspected that bacteria may penetrate
and ascend the pancreatic and bile ducts and permit extension of inflammation to these organs. Diagnosis is suspected based on finding changes suggestive of IBD (see above), increased serum liver enzymes and possibly bilirubin, and ultrasound abnormalities in the pancreas and/or increase serum fPL or DGGL lipase. Confirmation of diagnosis relies on histopathologic analysis of intestinal, liver and pancreatic biopsies. Treatment
is based on prednisolone at immune-suppressive (IBD) or anti-inflammatory (chronic pancreatitis) doses, and possible broad spectrum antibiotics in case of neutrophilic cholangitis (e.g. amoxicillin and clavulanic acid 20 mg/kg q12h).

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