In dogs and cats this disease syndrome is likely due to a variety of disease processes that result in an accumulation of inflammatory cells within the lining of the stomach, small intestine, large intestine or a combination of these areas.
What Is it?
Chronic enteropathy is usually classified according to the types of inflammatory cells present and location affected. The causes of chronic enteropathy are not well known but are suspected to be a result of an abnormal response by the body to certain intestinal bacterial or dietary antigens (proteins). Many dogs and cats with chronic enteropathy respond to dietary changes, and these patients are referred to as having dietary-responsive enteropathy.
The signs seen with chronic enteropathy vary with the severity of the disease and the location of the gastrointestinal tract affected. Animals with chronic enteropathy primarily involving the small intestine usually present with chronic vomiting, weight loss, diarrhea, loss of appetite or some combination these clinical signs. Those with predominately large intestinal disease (chronic colitis) present with diarrhea with or without blood and mucous present, straining to defecate, increased urgency to defecate and occasionally vomiting.
Chronic enteropathy cannot be diagnosed on physical examination, history, fecal checks, radiographs or laboratory work. These tests, however, are necessary to help rule out other diseases that may present with similar clinical signs, i.e., parasitic infections, intestinal foreign bodies, liver disease, kidney disease, metabolic diseases and cancer. Blood studies are also helpful to assess the metabolic status and screen for concurrent problems. Some dogs with severe chronic enteropathy may have low protein levels in their blood due to loss of proteins through their intestines (protein-losing enteropathy). This finding often severely worsens the long-term prognosis for the patient.
Dietary modification may initially be recommended after preliminary studies ruling out other causes for the clinical signs. Approximately 60-70% of patients will respond to dietary modification. The reasons for this are not entirely clear. If dietary modifications do not resolve clinical signs, intestinal and stomach biopsies are ultimately necessary to differentiate chronic enteropathy from other causes of chronic intestinal disease (infiltrative cancers, fungal infection, and others). These can be obtained either endoscopically or surgically. The ultimate recommendation of endoscopic or surgical biopsies is made based on history, clinical signs, laboratory findings and diagnostic imaging studies. The pathologist’s evaluation of biopsy samples will specify the type of cellular infiltrate involved, stage the severity of the disease, and help the clinician to establish a treatment plan and prognosis for your pet.
Types of IBD
This is the most common form of chronic enteropathy and is the result of an excessive accumulation of two types of white blood cells, lymphocytes and plasma cells, in the lining of the gastrointestinal tract. Excessive protein loss from the blood stream into the intestines is seen in very severe cases and is termed a protein-losing enteropathy. If inflammation is persistent and untreated, fibrosis (scar tissue) can result causing irreversible tissue damage. Lymphangiectasia (see below) may develop secondary to severe chronic enteropathy. When lymphangiectasia is present, the prognosis is very poor as compared to those without this change.
Prognosis depends on the severity of the inflammation, presence of fibrosis, your pet’s body condition and response to therapy. In cats, severe lymphocytic-plasmacytic enteritis may be a premalignant lesion, meaning that cancer (specifically lymphoma) may develop at a later date.
This appears to be an allergic reaction to a dietary protein, although other factors may be involved. A strict elimination diet in conjunction with medical therapy is often needed to resolve the signs. Prognosis is variable since some animals are unusually sensitive to many foods and are difficult to control.
Antibiotic Responsive Diarrhea
This occurs when there is an overgrowth of one or more bacterial species in the small intestine. The bacteria may be present because of anatomic defects, underlying intestinal disease, overuse of medications (frequently antibiotics) or for other unidentified reasons. Prognosis is often good.
Primary lymphangiectasia is not an inflammatory disease, although the clinical signs may be very much the same. This is an obstructive disorder involving the lymphatic system of the intestinal tract. The underlying cause is rarely found. Secondary lymphangiectasia may develop in patients with severe chronic enteropathy. In either case, the long-term prognosis is generally very poor. Small to medium breeds of dogs may initially respond fairly well to dietary and medical therapy; however, large breeds of dogs often do poorly despite dietary and medical therapy.
Any disease that produces inflammation, infiltration, congestion or bleeding in the gastrointestinal tract can produce signs similar to chronic enteropathy. Examples would include fungal disease, infiltrative cancers, advanced heart failure, and chronic nonsteroidal or steroidal drug therapy. Low grade intestinal lymphoma is commonly encountered in cats and rarely in dogs. This is a slow, progressing disease with clinical signs that mimic those of chronic enteropathy. Unfortunately, surgical intestinal biopsies, rather than endoscopic biopsies, are typically required to confirm diagnosis of intestinal lymphoma.
The goal of dietary management is to reduce the antigenic stimulation of the gastrointestinal tract’s immune system and to meet your pet’s nutritional requirements in an easily digestible form. This may be done with homemade diets (using recipes we provide you) or one of several commercially available diets. Diet therapy is often critical in achieving control of these diseases. In some patients, a limited ingredient diet with unique protein sources may be required.
The goal of drug therapy is to “settle down” the immune response by suppressing the inflammation caused by the infiltration of cells into the gastrointestinal tract. Several types of anti-inflammatory drugs are used as the initial medications depending on the type of inflammation present. In patients with more severe disease, a combination of immunosuppressive medications may be prescribed.
Budesonide is a newer corticosteroid medication having largely local effects on the lining of the intestine with minimal absorption into the body. Budesonide may not be effective in dogs or cats with severe inflammatory bowel disease. Side effects are much less than those seen with other corticosteroid medications. Some patients, however, have side effects similar to those of prednisone or prednisolone. Budesonide is expensive, and the dosing of small pets requires compounding of the medication.
Some pets may require either long-term dietary management or low dose medical therapy throughout their lives. The ideal goal of treatment is to control the clinical signs without the need for medications. If recurrence of signs is seen, medical therapy may need to be re-instituted. Please contact your veterinarian before restarting any medication with your pet.