Feline chronic enteropathy Flashcards
What is the definition of feline chronic enteropathy
It is defined as the presence of clinical signs of gastrointestinal disease for more than 3 weeks in the absence of extraintestinal causes or infectious, obstructive or localised neoplastic intestinal diseases
How is feline chronic enteropathy subdivided
Most authors will subclassify cases based on the response to treatment into:
- food-responsive enteropathy
- idiopathic inflammatory bowel disease
- small cell lymphoma
What is the suspected pathomechanism for IBD
Although the etiopathogenesis is unknown, IBD is thought to occur as the results of perturbations in the crosstalk between the environment, the immune system and the microbiome in a genetically susceptible host
What is the metabolism of cobalamin
Cobalamin is a water-soluble vitamin present in dietary proteins
In the small intestinal tract, it is bound to intrinsic factor which, in cats, stems mostly from pancreatic secretion
Cobalamin is absorbed in the distal small intestinal tract, especially the ileum through the binding of intrinsic factor to its respective receptors
What are the causes of hypocobalaminemia
Hypocobalaminemia has been documented with:
- diffuse distal small intestinal disease (e;g., inflammation, neoplasia, …)
- exocrine pancreatic insufficiency with intrinsic factor deficiency
- receptor defects, which have so far only been documented in dogs
What is the metabolism of folate
Folate is a water-soluble vitamin present in a wide variety of food sources and can also be produced by certain bacteria
Folate is mainly absorbed in the proximal small intestinal tract
What are the causes for increased or decreased folate concentrations
Serum folate concentrations can be decreased due to:
- diffuse proximal small intestinal mucosal infiltration and subsequent malabsorption
They can be increased as a result of bacterial production during dysbiosis
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Explain why it is recommended to supplement cats with signs of chronic enteropathy and serum cobalamin concentrations of < 400 ng/L
Studies in cats with gastrointestinal signs have shown rising serum concentrations of methylmalonic acid with cobalamin concentration < 400 ng/L, indicating cellular cobalamin deficiencies
What is the histological difference between IBD and SCL
IBD consists of a mixed infiltrate of lymphocytes and plasma cells
SCL comprises a monomorphic population of small mature lymphocytes infiltrating and effacing the lamina propria and the epithelium (if epitheliotropic), and sometimes deeper tissue layers of the submucosa and muscularis (transmural)
How can you cope with ambiguous cases on histology
Additional tests including immunohistochemistry and clonality assays are now considered state-of-the-art to differentiate IBD from SCL
Immunohistochemistry is the first step for further differentiation between IBD and SCL
- specific stainings will determine whether all lymphocytes seen on regular H&E stain are of a single lineage or whether the infiltrate consists of a mixture of T-cells, B-cells and plasma cells
- the former supports a diagnosis of lymphoma
- the latter supports a diagnosis of inflammation
- SCLs can often be accompanied by inflammation and thus a diagnosis can be difficult even with IHC
Clonality testing
- PCR for receptor antigen rearrangement is the most commonly used method as it can be performed on formalin-fixed, paraffin-embedded tissue samples
- clonality assays permit visualisation of the diversity of the antigen receptor
- presence of diverse receptors suggests the existence of inflammatory lesions (i.e., polyclonal)
- uniform receptors indicate neoplastic lesions (i.e., clonal)
- cell lineage cannot be determined by PARR because of cross-lineage rearrangement. Therefore, clonality assays should not be used to determine the lineage of the clone
What are the alterations found in the microbiome in cats with IBD
The number of mucosa-associated Enterobacteriaceae is higher in cats with signs of gastrointestinal disease than in healthy cats
- the composition and number of mucosa-associated bacteria correlate with the presence and severity of IBD
A study found that cats with IBD had lower FISH counts on fecal samples for total bacteria, Bacteroides species and Bifidobacterium species, but higher counts of Desulfovibrio species, compared with healthy cats
- Desulfovibrio species are able to produce hydrogen sulphide, which may be associated with the pathogenesis of feline IBD
What is the difference between food intolerance and food allergy (hypersensitivity)
Food intolerance
- a nonimmunologic, abnormal physiologic response to aa food, nutrient, or a food additive
- is the most common cause of food sensitivity in cats
Food allergy
- is characterized by adverse reactions to a food or food additive (typically a protein) with a proven immunologic basis
Food allergy is more commonly associated with vomiting and dermatologic signs, whereas intolerances of food can present with vomiting or diarrhea but do not produce dermatologic signs
How can you investigate food hypersensitivity or intolerance
The diagnosis of both food hypersensitivity and intolerance is based on removing the offending substance from the diet
The major difference between the diagnostic processes of these two types of adverse food reactions is the length of time the diet that is required to achieve a response and the need to identify a novel protein source
- cats with food hypersensitivity require 8 to 12 weeks on a novel antigen (e.g., novel protein or hydrolyzed protein) elimination diet before an improvement will be seen
- cats with food intolerance will usually have resolution of signs within days (7-14 days is typical)
If one type of highly digestible food has been fed for at least 2 weeks with minimal response, it is entirely reasonable to try either another comparable product or a different dietarry strategy
What is the general agreement among gastroenterologists regarding food
General agreement exists among gastroenterologists that food with fewer carbohydrates (a source of intolerance and maldigestion) and based on highly digestible protein sources (primarily meat) are beneficial in cats with IBD, reducing the bacterial changes that can occur when undigested foods remain in the GI tract
What are prebiotics
Prebiotics include inulin, non-starch polysaccharides, and disaccharides
They are fermented by colonic bacteria, generating short chain fatty acids that provide nutrients for enteric epithelium, induce anti-inflammatory T regulatory cells, and reduce luminal pH which can stimulate colonic motility
What are probiotics
Probiotics are formulations of live organisms that may offer benefits such as reducing intestinal permeability, increasing mucin and defensin secretion to prevent pathogen colonization, production of short chain fatty acids, stimulation of IgA secretion, reduced luminal pH, and promote tolerance to commensals while maintaining protection against pathogens
What is fecal microbiome transplantation
Fecal microbiome transplantation involves the transfer of feces from a healthy donor (tested negative for fecal pathogens) into the intestinal tract of a recipient with GI disease
