Chronic Enteropathy in Dogs: A Review & Interesting Research

Chronic enteropathy (CE) in dogs is characterized by chronic vomiting and diarrhea, along with other signs such as loss of appetite, weight loss and other clinical symptoms. While these signs might sound simple, they can potentially be caused by innumerable other diseases, are multifactorial, and so are the treatments.

We know that CE results from the intersection of an individual’s genes with a dysregulated immune system, as well as environmental causes such as food, other diseases, and the balance of beneficial vs harmful microbiota in the gut from weaning until the onset of symptoms. The recognition of any early reactions at weaning is important as it demonstrates that factors from early life still can impact adulthood. For instance, we know that the microbiota that colonize after birth help the development of mucosal immunity. In turn, that makes an impression on the immune system for life, also known as “immune memory”. Of course, opening the jigsaw puzzle box does not put the puzzle pieces together. Is the CE due to another disease, early diet, current diet, genetic predisposition and genes, or something else? A couple of those? All of the above?

Indeed, dogs that survive canine parvovirus as a puppy have an increased chance of developing chronic gastrointestinal diseases. Is this because of the havoc caused by the parvovirus, use of antibiotics which are a part of the standard treatment protocol, or both? In humans, it is known that early-life administration of antibiotics and the resulting changes in microbiota increase the risk of allergies, asthma, obesity, and inflammatory bowel disease later in life. For companion dogs, this is considered to be similar, although the details are still being unraveled.

A Finnish questionnaire study found that serving puppies and adolescent dogs a non-processed meat-based diet, berries and human meal leftovers decreased the chances of CE development later in life. On the flip side, they found that a carbohydrate-rich kibble diet during the same ages increased the risk of CE later on.

As you can see, CE remains complicated and is a disease syndrome often categorized by the bodily response to treatment and not the cause: e.g., food-responsive enteropathy, steroid-responsive enteropathy, and antibiotic-responsive enteropathy. One example of an exception is protein-losing enteropathy – the loss of proteins from the bloodstream into the gastrointestinal tract – which describes what is happening, not the cause.

Let’s delve into each of these enteropathies a bit more.

Protein-Losing Enteropathy (PLE)

As mentioned, PLE is the excess loss of body and dietary proteins into the gastrointestinal tract. Certain breeds such as Soft-Coated Wheaten Terriers are often afflicted with PLE. However, PLE can be secondary to other microbial gastrointestinal infections, food intolerances, cancer, heart disease, inflammatory bowel disease (IBD), and diseases of the lymphatic system.

Food-Responsive Enteropathy (FRE)

Diarrhea and/or vomiting resolves after a companion dog’s diet is switched, completes a food elimination or limited ingredient dietary trial, or is placed on a hydrolyzed or other specialized diet.

Hydrolyzed diets may prove beneficial at first. Increasingly, however, researchers and clinicians are seeing that they are unsuitable.

Another protocol is a food elimination trial. An elimination trial places a companion dog on a novel diet that typically consists of one protein and one carbohydrate to which the dog has had no or limited exposure. A typical trial lasts eight to twelve weeks. It is often recommended to start dogs on lamb and potatoes. Let’s say some of the symptoms may resolve, but intermittent diarrhea is still occurring. The question then becomes: is it the lamb or the potatoes?  Was the lamb grass-fed or grain-fed, as this can be an issue?

Personally, Dr. Dodds recommends the patented, unique NutriScan Food Sensitivity & Intolerance Test to get to the bottom of a possible FRE. Then, a companion pet parent will know for certain which of the more common ingredients should be avoided.

Another problematic area is that many companion pet parents are advised to jump from one kibble to another kibble diet. Most kibble diets contain many other ingredients that may be contributing to CE. Additionally, kibble is highly processed and baked. The possibility exists that a dog with CE may do better on a raw, freeze dried, dehydrated diet, canned, or balanced homemade diet.

Antibiotic-Responsive Enteropathy (ARE)

Diarrhea and/or vomiting resolved after a companion dog is treated with antibiotics (e.g., metronidazole or tylosin).

The issue with antibiotics is that they not only destroy the ‘bad’ bacteria, but also the ‘good’ bacteria in the gut. What is the flipside to antibiotics? Probiotics, prebiotics, or synbiotics.

Albert E. Jergens (Iowa State University) and Romy Heilmann (University of Leipzig) penned an excellent review of current and emerging treatment options for CE. We gleaned that they want probiotics to become more widely prescribed and used, but believe better and more uniform studies need to be completed before that can effectively be implemented. They discuss the shortcomings of many studies: probiotic effects are strain-specific, and the documented effects will depend on the specific strain used, which was not always specified; different probiotics were used in different studies to treat different forms of CE; composition of the vehicle used for a specific probiotic could influence probiotic effects; and, most studies were substantially underpowered.

We can understand their frustration. More money and research need to be focused towards probiotics. Additionally, over 500 probiotic strains have been identified, so it’s a lot to sift through.

Our opinion? Probiotics are more than likely necessary for companion dogs with any form of CE, but finding the right one may take time.

Antibiotics also impact the larger environmental issue of antibiotic resistance. Researchers out of the University of Torino investigated oxidative stress in companion dogs with acute enteropathies and found an imbalance is happening. Their study suggests that antioxidant therapy through diet may support the management of acute enteropathy. We hope they continue down this path of investigation and apply it to CE.

Steroid-Responsive Enteropathy (SRE) / Immunosuppressant-Responsive Enteropathy (IRE)

Diarrhea and/or vomiting resolves after a companion dog is treated with glucocorticoids (i.e. steroids) or another immunosuppressive medication (IRE).

Steroids are often quickly prescribed after food trials and antibiotics fail to produce the desired side effects. The SRE is ultimately assigned because of idiopathic (unknown) inflammatory bowel disease (IBD). Of course, the potential for long-term harmful side effects of their use is well documented.

We have voiced our consternation over FRE and ARE. However, jumping to use of glucocorticoids is unwarranted until other protocols to diagnose and manage FRE are shown to be unsuccessful. Usually, only two dietary trials of food elimination or hydrolyzed dietary intervention have been tried. Would we prefer they use NutriScan first or next? Sure. However, if the chosen protocol of food elimination is used, please complete it before resorting to glucocorticoids or immunosuppressants.

Conclusion

While we are pleased that enlightenment of the potential causes of CE are being realized, outdated diagnostics and inadequately standardized treatment protocols still are used despite the fact that more successful alternative options like Nutriscan exist.

Alternative treatment options such as probiotics, prebiotics, synbiotics, fecal microbiota transplantation, stem cell therapy, and the right foods, need to explored first before choosing antibiotics and steroids. Additionally, research and development of therapeutic monoclonal antibodies that target pro-inflammatory cytokines and integrins for companion dogs with CE needs to occur.

One of the easiest and least expensive helpers in CE treatment may have been overlooked, namely, cobalamin (aka vitamin B12). Many dogs with cobalamin deficiency suffer from CE because CE causes diminished absorption of the vitamin. Serum measurements need to be taken to determine hypocobalaminemia. Standard treatment protocol is typically with injectables, although a recent study from Texas A&M University found that oral supplementation is just as effective.

Another common cause of hypocobalaminemia in dogs is chronic small intestinal disease where damaged ileal mucosa results in reduced cobalamin receptor expression with subsequently diminished cobalamin absorption. Hypocobalaminemia in dogs can manifest as lethargy, inappetence, vomiting, diarrhea, weight loss, anemia, and failure to thrive in puppies.

Additional References

Scarsella, Elisa et al. “Characterization of the Blood Microbiome and Comparison with the Fecal Microbiome in Healthy Dogs and Dogs with Gastrointestinal Disease.” Veterinary sciences vol. 10,4 277. 5 Apr. 2023, doi:10.3390/vetsci10040277, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10144428/.

Toresson, Linda et al. “Clinical Effects of Faecal Microbiota Transplantation as Adjunctive Therapy in Dogs with Chronic Enteropathies-A Retrospective Case Series of 41 Dogs.” Veterinary sciences vol. 10,4 271. 3 Apr. 2023, doi:10.3390/vetsci10040271, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10145442/.

Toresson, Linda et al. “The Intestinal Microbiome in Dogs with Chronic Enteropathies and Cobalamin Deficiency or Normocobalaminemia-A Comparative Study.” Animals vol. 13,8 1378. 17 Apr. 2023, doi:10.3390/ani13081378, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10135184/.

Yu, Jane et al. “Serum proteome of dogs with chronic enteropathy.” Journal of veterinary internal medicine vol. 37,3 (2023): 925-935. doi:10.1111/jvim.16682, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10229361/.

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