Occasional digestive upsets are common in dogs and cats, and usually resolve on their own or with supportive veterinary treatments, such as a bland diet or a short medication course. However, when these issues do not resolve with conservative, first-line treatments after two weeks or keep coming back, they are considered chronic, and are likely caused by an underlying disease. 

Chronic gastrointestinal (GI) signs most often include vomiting and/or diarrhea, but can also include stool color changes, weight loss, lethargy, or appetite changes. While many diseases and infections can cause these changes, The Neighborhood Vet wants to share the most common issues that affect dogs and cats.

#1: Inflammatory bowel disease

Inflammatory bowel disease (IBD) is a common diagnosis in young and middle-aged pets. Common presentations include sporadic vomiting in cats, or chronic diarrhea in dogs. IBD is considered an autoimmune disease, meaning inflammation occurs inside the GI tract because the immune system mistakenly attacks these cells, the body becomes overly sensitive to normal bacteria or food antigens, and more inflammation occurs. Diagnosis requires ruling out other diseases with blood tests, fecal tests, and imaging studies, and then confirmation with biopsies taken via endoscopy. Please fast your pet for 12 hours prior to evaluation by our team, so we can get started on diagnostics right away. 

Treatment can be frustrating, because each pet responds a bit differently, but most often includes:

  • Diet change — Hypoallergenic, highly digestible, or fiber-supplemented prescription or home-made diets are most often used. 
  • Antibiotics and probiotics — Most pets with IBD have an unhealthy bacterial balance that contributes to their disease. Antibiotics or probiotics can shift the population into a healthier zone to reduce inflammation and nourish cells. Probiotics that we recommend include: 
  • Immunosuppressants — Steroids or alternative immunosuppressants, such as cyclosporine, can regulate the overactive immune system and reduce inflammation, but many have serious side effects, especially when used long term

#2: Adverse food reaction

Adverse food reaction may be a true allergy or an intolerance to certain food components. True food allergies affect the skin or can resemble IBD, and distinguishing between the two can be difficult. A hypoallergenic food trial using a special diet consisting of a novel protein for six to eight weeks without any outside food, treats, or flavored medications can serve as both diagnosis and treatment. For complete resolution, medications also may be needed. If the food trial is successful, the pet owner may choose to continue the special diet or “challenge” the pet one food at a time, to see if signs return and the offending food can be determined.

#3: Pancreatic or liver disease

The pancreas and liver work closely in conjunction with the intestinal tract, so disease in either organ can result in chronic vomiting, diarrhea, and weight loss. Diagnosis requires specialized blood tests and imaging studies, and sometimes an organ biopsy. Treatment depends on the exact disease variant, but may include a special low-fat diet, supplemental pancreatic digestive enzymes, or medications. The most common diseases leading to GI signs include:

#4: Lymphangiectasia

Lymphangiectasia is a disorder in the GI tract of the lymphatic drainage vessels, which also transport fat into the bloodstream. When these vessels become obstructed, fat malabsorption, chronic diarrhea, weight loss, and protein loss from leakage in the intestines are the result. Low protein levels in the blood can worsen weight loss and cause weakness and fluid buildup around the lungs or in the abdomen. Diagnosis is similar to IBD, with blood, fecal, and imaging studies followed by endoscopic biopsies. Treatment requires an extremely low-fat diet and medications to improve digestion and intestinal bacterial balance and reduce inflammation, which may or may not be effective.

Lymphangiectasia usually occurs in only a few dog breeds, including:

  • Soft-coated Wheaten terrier
  • Yorkshire terrier
  • Basenji
  • Norwegian lundehund

#5: Intestinal lymphoma

This disease is most common in cats 10 to 12 years old. Signs are often indistinguishable from IBD, but older age at onset can be a clue that lymphoma may be to blame. Intestinal lymphoma is the most common lymphoma presentation in cats, and is commonly thought to result from feline leukemia virus infection or exposure. Although generalized lymphoma has a poor prognosis, the GI form progresses slowly and does not usually leave the GI tract. Cats diagnosed with GI lymphoma can live for two to four years after diagnosis using the standard treatment of steroids and oral chemotherapy agents.  

GI lymphoma and IBD treatment are similar, with oral steroids the main therapy. Many pet owners choose to forgo the expense associated with formal diagnosis, and wish to simply treat the disease with steroids and monitor the response. However, steroids can make diagnosing lymphoma more difficult and can blunt response to other treatments, so pet owners who wish to consult with a veterinary oncologist and pursue all possible treatment options are encouraged to obtain a diagnosis before steroid treatment is started.

Chronic GI signs can be frustrating for pet owners, but we have the tools to determine the underlying problem. The Neighborhood Vet can diagnose most GI diseases, or we may refer you to an internal medicine specialist in more complex cases. Contact us if you have concerns about your pet, or to schedule a routine wellness visit.