Inflammatory Bowel Disease in Dogs - Symptoms and Treatment

Canine inflammatory bowel disease (IBD) is a type of chronic enteropathy, i.e. a pathology affecting the intestine. It is characterized by gastroenteritis (inflammation of the intestinal tract) due to infiltration of cells such as lymphocytes, plasma cells, eosinophils, macrophages or combinations thereof. They affect the lining of the dog's intestine known as the mucosa.

Causes of Inflammatory Bowel Disease in Dogs

The origin is uncertain, but the existence of an exacerbated response to a series of antigens is likely. This could be in response to:

• Bacteria of the intestinal microflora
• Dietary food allergens
• Components of the digestive system itself in contact with the mucosa of the intestine

This exaggerated response of the immune system of the dog's intestine can be caused by an alteration of the intestinal permeability. This leads to an increase in the exposure of existing antigens. The inflammatory infiltration that forms causes a lesion in the mucosa that results in greater absorption of antigens and proinflammatory substances that make the process chronic.

The intestinal microbiota can suffer alterations due to changes in absorption and intestinal peristalsis caused by the disease.

Different inflammatory cells in the lamina propria are infiltrated. This is the thin layer of connective tissue on the intestinal mucus membranes. The type of IBD in dogs will depend on the cells which are infiltrated:

• Lymphoplasmacytic enteritis: lymphocytes and plasma cells of the intestinal lamina propria are infiltrated. This type of IBD is the most commonly diagnosed in dogs. Basenji, German Shepherd and Shar Pei dogs are more predisposed than other breeds.
  
  
• Eosinophilic enteritis: infiltrate of eosinophils in the intestinal mucosa. It is most prevalent in the Rottweiler breed.
  
  
• Granulomatous enteritis: infiltrate of granulomatous formations of epithelial cells. The predominant cell type is macrophages.

Sometimes the colon can be affected, resulting in four distinguishable types of colitis :

• Lymphoplasmacytic colitis: infiltrate of lymphocytes and plasma cells in the mucosa of the colon.
• Eosinophilic colitis: infiltrate of eosinophils in the mucosa of the colon.
• Granulomatous colitis: infiltrate of granulomatous formations of epithelial cells in the colon.
• Ulcerative-histiocytic colitis: especially frequent in Boxer dogs. It is characterized by a decrease in quality of the lumen of the large intestine. Produces a thickened, irregular, eroded, congestive mucosa and areas of active bleeding.

Intestinal lymphagiectasia can be part of inflammatory bowel disease in dogs as a concurrent disease. It is characterized by edema and dilation of the lymphatic vessels.

Dogs with inflammatory bowel disease have chronic diarrhea symptoms. This is opposed to cats with IBD which are more likely to show vomiting and weight loss. In addition to chronic diarrhea, dogs with enteritis or inflammatory colitis may show:

• Weight loss
• Changes in appetite
• Nutrient malabsorption
• Malnutrition
• Bilious vomiting
• Bulky stools in enteritis
• Bloody or mucous stools in colitis
• Intestinal rumbling
• Flatulence
• Abdominal pain
• Anemia

Ascites or peripheral edema can develop if protein-losing enteropathy presents. These are types of fluid build up and can result in the dog having pain in the abdomen when you touch the area.

The first action when diagnosing IBD in dogs is to rule out other differential diagnoses that may cause similar symptoms before performing an intestinal biopsy for pathological study. This provides the definitive diagnosis of this disease.

To do this, in addition to analyzing the dog's medical history and a physical examination, the following tests should be performed:

• Blood analysis and biochemistry
• Bone scan
• Ultrasound
• Coprological analysis
• Stool culture

If these diseases are ruled out, the diagnosis should be confirmed by taking biopsies. These biopsies consist of obtaining a fragment of the dog's intestine for further study. Biopsies must be obtained by endoscopy or laparotomy (exploratory surgery). Depending on the predominant cell type or types in the histopathology, the type of inflammatory bowel disease that the dog suffers from will be diagnosed.

Learn more about diagnosing disease in dogs with our guide to understanding a dog's blood test.

The treatment of IBD is never curative. Instead, it involves symptom management due to the persistence of intestinal inflammation.

Treatment will depend on the severity of the inflammatory bowel disease and the presence of hypocobalaminemia (low vitamin B12). For this reason, we can show four different approaches to treatment of inflammatory bowel disease in dogs depending on the clinical index (extent of the symptoms):

Treatment of canine IBD with a low clinical activity index

In this case, the histopathology shows no abnormalities, so IBD is questionable. In addition, the albumin concentration is normal. In these cases, treatment should include:

• Fenbendazole (50 mg/kg for 5 days): for the possible control of Giardia and other internal parasites.
• Hypoallergenic diet with hydrolyzed or novel protein: if the signs subside, it indicates that it is a diet-responsive enteropathy or food hypersensitivity, not an IBD.
• Antibiotics: such as tylosin or metronidazole. If there is a good response, it is an enteropathy that responds to antibiotics.

Treatment of canine IBD with a mild-to-moderate clinical activity index

There are changes indicative of IBD in the histopathology, but the albumin concentration is greater than 2 g/L. The treatment in this case will be:

• Fenbendazole (50 mg/kg for 5 days): for the possible control of Giardia and other internal parasites.
• Hypoallergenic diet with hydrolyzed or novel protein: for a minimum of two weeks.
• Antibiotics: such as tylosin or metronidazole for two weeks. If there is a good response, the course will be continued for a month.
• Glucocorticoids at immunosuppressive doses: prednisone (2 mg/kg/24 h) is administered for 2-4 weeks until the symptoms improve, subsequently gradually reducing the dose to the minimum effective dose.

Learn more about immunosuppressive medications with our article on prednisone for dogs.

If the response is not adequate, other immunosuppressants should be administered. They may include:

• Azathioprine (2 mg/kg/24 h for 5 days and then 2 mg/kg every 2 days)
• Cyclosporine (5 mg/kg/24 h)

Treatment of canine IBD with moderate-severe clinical activity index

In this case, the histological changes are quite advanced and the albumin concentration is less than 2 g/l. Treatment of severe IBD is as follows:

• Fenbendazole (50 mg/kg for 5 days): for the possible control of Giardia and other internal parasites.
• Hypoallergenic diet with hydrolyzed protein.
• Antibiotics: such as tylosin or metronidazole for two weeks. If there is a good response, administration will continue for a month.
• Glucocorticoids at immunosuppressive doses: if not effective, other immunosuppressants (azathioprine (2 mg/kg/24 h for 5 days and then 2 mg/kg every 2 days) or cyclosporine (5 mg/kg/24 h) will be used. If these not effective or low intestinal absorption is suspected, injectable corticosteroids can be attempted.
• Antithrombotics: if they have developed protein-losing enteropathy, adding antithrombotics such as aspirin or clopidrogel should be considered. This is because these dogs have a higher risk of developing thromboembolic disease due to the loss of antithrombin from the intestine.
• Cobalamin: administer cobalamin (vitamin B12) once a week for one month, and then once a month for 3 months. Repeat the diagnostic tests to see if it is necessary to continue supplementation or not.

In dogs with ulcerative-histiocytic colitis, the use of enrofloxacin for dogs over long periods is the indicated treatment. This disease is associated with strains of Escherichia coli that invade deep layers of the large intestine.

Many people speak of irritable bowel syndrome (IBS) in dogs when they usually mean inflammatory bowel disease (IBD). With IBS, the problem is not due to inflammation, but issues with gastrointestinal motility. They both share symptoms in that diarrhea can be a symptom of bowl inflammatory bowel disease and irritable bowel syndrome. However, it is not exclusive in IBS.

Irritable bowel syndrome is more common in humans and not something often diagnosed in dogs. It is a catch-all term for various gastrointestinal motility problems and is often associated with mental health issues such as stress and anxiety. While these issues can affect your dog, they don't usually occur to the same degree. IBS also does not affect intestinal absorption.

For this reason, inflammatory bowel disease is more likely affecting your dog than irritable bowel syndrome. Some veterinary medical professionals prefer the use of chronic enteropathy over inflammatory bowel disease. This is because it is less specific and helps to distinguish between IBD in humans which does not always respond the same way as dogs.

Regardless of the terminology, if you see symptoms such as vomiting and diarrhea in dogs, it is imperative you take them to a veterinarian for diagnosis.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Inflammatory Bowel Disease in Dogs - Symptoms and Treatment, we recommend you visit our Intestinal problems category.