Small Bowel Diarrheas: IBD Is Not the Most Common Cause

Inflammatory bowel disease (IBD), depending upon how you define it, is not the most common cause of chronic small or large bowel diarrhea in dogs and may not be as common in cats as was once believed. In this discussion, we will define IBD as “idiopathic inflammation of the intestines”. This means that you cannot diagnose IBD just by histopathology. You diagnose IBD by finding intestinal inflammation and showing that it is idiopathic by eliminating diet, parasites, bacteria and fungal agents as the cause. You cannot eliminate dietary causes and bacterial causes by histopathology or blood tests; therapeutic trials are necessary. This is very important because diagnosing IBD generally results in anti-inflammatory or immunosuppressive drugs being used. However, if the patient has dietary-responsive or antibiotic-responsive disease, then these drugs are generally unnecessary. I stress this point because many patients have been erroneously diagnosed, improperly treated, and significantly harmed because IBD is a “fashionable” or “trendy” diagnosis. IBD is a real syndrome and is important for the veterinary practitioner to understand. However, it often degenerates into an excuse of convenience rather than a real diagnosis. More and more evidence is accumulating that shows that bacteria are probably a major source of the inflammation in dogs and cats with this disease. See below, under Antibiotic-responsive enteropathy. […]