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Recognition And Management Of Chronic Bowel Disease PDF Print E-mail
Cavalier Health Articles - Chronic Bowel Disease
Written by Myra Ehrman, RN, BA, BS, MScN   
Article Compiled by Myra Ehrman, RN, BA, BS, MScN, on behalf of the Health Education Committee, CKCSCC. Originally Published in The Cavalier King Charles Spaniel Club of Canada Newsletter,"Quotes", in January, 1996.

Diarrhea is defined as the rapid movement of fecal matter through the intestine, resulting in poor absorption of water, nutritive elements and electrolytes, and producing frequent, watery, stool. When the diarrhea originates with problems in the stomach or small bowel, there is always an increase in quantity, and vomiting and weight loss may occur as well. When it originates in the large bowel, the quantity of stool may be normal but is often increased. Weight loss, vomiting, lack of energy, and loss of appetite are NOT common when the disease originates in the large intestine. The colon is the part of the intestinal system that extends from the end of the small bowel (or ileum) to the rectum. Recurrent diarrhea of the large bowel may also be referred to as colitis (inflammation of the colon).
The clinical findings of acute colitis include the sudden onset of severe, watery, sometimes bloody, mucoid diarrhea, accompanied by occasional vomiting. The animal may show signs of depression, be dehydrated, and may be running a fever with abdominal pain. Once this becomes an ongoing problem, and chronic colitis has been established, the dog may have frequent bowel movements, but pass small amounts of stool each time. The dog may be seen to have a sense of urgency, accompanied by ineffectual and painful straining at stool. When the situation is chronic, the feces may be semi-formed to liquid, and fresh blood and mucous may be present.

The types of laboratory examinations ordered by your veterinarian to help confirm a diagnosis would typically include: a complete blood count (CBC), serum biochemistry panel, urinalysis, fecal cultures, and fecal examinations (we probably know this better as testing for ova and parasites). The definitive diagnosis is made after a biopsy is taken for histologic evaluation (microscopic study of the form and structure of the various tissues). Sometimes endoscopies are performed (visual examination of interior structures of the body with specially designed instruments).

The usual list of causes to be considered by your vet would include the following:

  1. Parasites, such as whipworms, may be hard to diagnose. Giardia, a protozoal disease, is easy for vets to miss, and it is recommended at least 3 zinc sulfate flotation analyses using centrifugation be done by a laboratory before it can be certain they are not responsible for the infection.

  2. Bacteria (including Salmonella, Campylobacter, Yersinia), Fungal diseases (including Histoplasma and Prototheca), and Hookworms have all been shown to cause colitis, but this is rare.

  3. Foreign body colitis, such as a dog eating chicken bones, sticks, etc.

  4. Chronic inflammatory bowel disease (CIBD). This is a group of chronic intestinal disorders characterized by an overabundance of cells invading the mucosa and submucosa of the stomach, small intestine, and/or large intestine. These cells include: lymphocytes (a colorless blood corpuscle whose chief function, is to protect the body against microorganisms causing disease); plasma cells; eosinophils (which are a type of medium-sized white blood cells which make up 1-2 % of the white blood cells and also helps protect the body against disease); or neutrophils (mature leukocytes which also have a protective function). The disorder is not yet well understood in dogs, but may be immune-mediated, which means the system is reacting against something. In most cases, the antigen (substance which when present in the body stimulates production of an antibody to react with it) is not known. The antigen may be dietary, bacterial, or parasitic in origin. This invasion or infiltration of the intestinal mucosa leads to malabsorption (disorder of normal nutritional absorption). A food allergy involves an immunologic intolerance of a specific dietary component leading to immediate or delayed hypersensitivity reactions. Signs include excessive itching, diarrhea and itching, or (rarely) diarrhea alone. It is usually difficult in the clinical situation to establish if a certain dietary antigen is the causal factor, and dietary manipulation may or may not be helpful. Usually animals diagnosed with inflammatory bowel disease (IBD) are middle aged, and may be either sex, with an average age reported of about 6 years, and a range of 6 months to 20 years.

  5. Chronic idiopathic colitis is probably the most common form of nonparasitic colitis diagnosed in small animals. Idiopathic means self-originated; occurring without known cause. Infectious agents have been suspected, however, an agent has never been identified. Genetic and psychological factors may play a role. It may also be referred to as irritable bowel syndrome.

Appropriate management of this problem will be determined by your veterinarian's diagnosis. Typical treatment plans might include:

  1. Antibiotics when an infectious agent such as a bacteria, protozoa, or worm infestation have been confirmed by laboratory analysis. Commonly mentioned in the literature are products such as metronidazole (Flagyl(r)), tylosin, amoxicillin, and sulfa drugs such as sulfasalazine. Sulfapyridine (another sulfa drug) is not thought to have therapeutic effects on IBD, whereas sulfasalazine does. Metronidazole has been mentioned in the literature as being used by itself to manage IBD in dogs and cats. Most authors recommend metronidazole be given in conjunction with sulfa drugs or prednisone. Metronidazole is also known for its antiprotozoal effects, as well as being a broad spectrum antibiotic with activity against anaerobic bacteria (those that live in the absence of oxygen), and it may have other immunosuppressive effects. Tylosin can be used for those animals that do not respond to dietary management, sulfasalazine, prednisone, or metronidazole, or when adverse effects to these drug therapies occur. There is some controversy amongst veterinarians regarding the long-term effectiveness of this drug.

  2. Dietary management, particularly if a food allergy or intolerance is suspected. The dog should be fed a diet that is easily digested and of consistent content (Hill's I/D, or Intestinal Diet, is often used). Generally it is felt the protein component of the food is the one to trigger the antigenic stimulation of the intestinal immune system. Food colorings and preservatives may contribute to adverse gastrointestinal reactions directly, but not through the immune system. The primary feature of a diet formulated to treat IBD is that it have an adequate but not excessive amount of a single protein source which the animal has not been fed or exposed to previously. Realistically, there are no protein sources which are by themselves hypoallergenic (including lamb). Usually dogs and cats will develop immunologic sensitivities to foods which contain antigenic determinants, promote an immune response, and which the animal has eaten many times before. Typical foods which can promote IBD include wheat, beef, milk, eggs, horsemeat, fish, soybeans, oats, corn, and pork. In dogs, the ideal approach may be to start by feeding a homemade diet based on rice, and then gradually adding a single new protein source such as tofu, cottage cheese, or lamb. It is believed that cooked eggs and cottage cheese may be absorbed more readily by the intestine than many meats. Some animals may require a trial of an "elimination diet", which means adding single ingredients to the hypoallergenic diet, one new ingredient every 7-10 days. If signs of the diarrhea are not present, start adding one new dietary component and watch for another 7-10 days, and so forth, to arrive at a balanced diet which the dog can be maintained on. It is very important that the elimination diet be properly planned and implemented in order to be effective. One caution is added, in that once the animal improves on the diet, switching to a commercial diet with that protein source is probably best, unless the homemade diet can be made complete by adding vitamins, minerals, essential fatty acids, appropriate calcium: phosphorus ratio, and so on. Also note that if preparing a homemade diet, vitamin and mineral supplements should be carefully selected, as they too may contain extracts and flavorings. The hypoallergenic diet must be fed for 4-8 weeks, and must be the only source of nutrition the animal receives. Even heartworm preventives should be avoided. Even if the diarrhea does not completely improve when a hypoallergenic diet alone is fed, trying better dietary management in addition to drug therapy may result in better clinical control of the animal's condition. This can also translate into the animal requiring lower doses of medication, and experiencing fewer side effects, than when drug therapy alone is used to treat the disease.

  3. Adding fiber or a bulking agent to the diet has helped in some cases of irritable bowel syndrome. In these dogs, it is not certain whether the fiber is aiding the animals' fight against the disease process or if the fiber is simply "soaking up" excessive water and making the stool appear more normal. How much fiber to add is based on experience, but about one tablespoon of Metamucil or coarse wheat bran per can of food is a place to start, and then increase or decrease the amount based on the effect it has on the dog. Two weeks is usually an adequate trial to see if this is helpful, although 4-8 weeks may be necessary before a patient responds beneficially to a fiber supplemented diet. Please note that fiber is not helpful in all types of chronic large bowel disease, and a few dogs do better on a low residue diet.

  4. Systemically administered steroids such as prednisone and prednisolone may be useful for inflammatory bowel disease, but should only be used if the animal has a colitis which specifically responds to steroids, or if other appropriate therapies have not worked. However, dogs may not respond to this method of treatment as well as cats with similar diseases do. If the cause of the diarrhea is IBD, most dogs and cats will show improvement in gastrointestinal signs within 1-2 weeks after having been started on prednisone. Some dogs may be able to have the steroid gradually tapered off, while others will require continual therapy, perhaps on an every other day basis for the rest of their lives, in order to prevent a recurrence of the diarrhea. Dogs can manifest side effects of prednisone therapy, including an increase in urination, thirst, eating, and weight gain. These side effects are related to dose, so it is important to give the dog the least amount of prednisone that will control the IBD. Also, azathioprine (Imuran(r)) and cyclophosphamide (Cytoxan(r)) are other medications with immunosuppressive properties that can be used with steroids in the management of IBD. Azathioprine takes 1-3 weeks to be fully therapeutic, so steroid doses should not be tapered until the animal has been receiving azathioprine for at least a week. Since bone marrow suppression is known to occur with these medications, complete blood counts need to be monitored frequently (every 2 weeks to monthly) while the drug is administered.

As always, this article should be seen as background information only to assist Cavalier owners to work with your veterinarians in better management of bowel disease. Your dog needs to be properly diagnosed before any treatment begins. This article is not exhaustive regarding all possible causes of bowel disease, and does not address any issues that arise in the diagnosis and treatment of other diseases that can affect the gastrointestinal system such as cancer, adhesions from previous surgery, constipation, ulcers, viruses, gastric dilatation, obstructions, pancreatitis, metabolic disorders, and so on.

Disclaimer: Your veterinarian is the most qualified person to answer all of the questions you have about your pet's health. Nothing in this article should be construed as medical advice regarding any individual animal's condition.

(c) Copyright April 11, 1999.
 
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