Vail Daily Pet Talk column: The straight poop on chronic diarrhea |

Vail Daily Pet Talk column: The straight poop on chronic diarrhea

Last month, we talked about acute diarrhea, which is bad enough. Now, we will progress to the more serious condition of chronic diarrhea, defined as diarrhea lasting longer than three weeks. Talk about wanting to pull your hair out!

Chronic diarrhea really opens up a can of worms as far as disease possibilities. It is ranked as the No. 7 reason people seek veterinary care for their cats and dogs by Veterinary Pet Insurance. It is a very large topic; this article is a summary and far from inclusive.

A lot of the discussion with your veterinarian will now center on what we call signalment: How old is your dog or cat? What breed? When did the diarrhea start? How has it progressed? Are there any other clinical signs? Vomiting? Weight loss? Increase in water or urination? Increase or decrease in appetite?

As with acute diarrhea, we will try to determine if the diarrhea is originating in the small or large bowels; often the sections of the bowel and diseases can overlap. Here is a quick review from last month: Large bowel diarrhea is usually small, frequent amounts of diarrhea with red blood and/or mucus; usually there is no abdominal pain or weight loss. Small bowel diarrhea is accompanied with large amounts, less frequency, little to no blood or mucus; usually there is abdominal pain and/or weight loss. Let’s examine them more closely (yuck).

Small Intestinal Diarrhea

We will divide small intestinal diarrhea into four major groups: primary small intestinal diseases, malabsorption/maldigestion, dietary and metabolic disorders. Primary small intestinal diseases are caused by things such as parasites, inflammatory bowel diseases, bacterial, viral and fungal organisms, cancer, obstructions, ulcers and bacterial overgrowth are all possibilities. Maldigestion is typical among German Shepherd and some Nordic breeds but can be seen in any breed. Food issues can also cause small intestinal diarrhea and include food allergies, gluten sensitivity, rapid food changes and dietary intolerances. Metabolic disorders are a nice way of saying the diarrhea is secondary to liver, kidney, endocrine diseases or toxins.

Large Intestinal Diarrhea

Moving down the GI tract, let’s look at causes of large intestinal diarrhea. Here the list actually gets shorter. Inflammatory bowel disease is, in my opinion, the biggest cause. It can be caused by stress, allergic reactions, dietary changes and also infiltrative diseases. It is similar to inflammatory bowel disease in humans, so most people nod their heads in empathy when we talk about it. Large intestinal diarrhea can also be caused by many of the same parasites, viruses, bacteria and fungi that cause small intestinal diarrhea. Cancer, rectal polyps and dietary issues can also contribute to large intestinal diarrhea.

What Can You Do?

So what is a well-intentioned pet owner with a chronic loose stooled dog or cat to do? As you have just read, the list can be exhaustive. Let’s take a deep breath and start with a good physical examination of your pet and cross examination of yourself! These two steps will guide what we do next because, in all honesty, we can’t run every single test in the book.

That said, the minimum data base (meaning diagnostic tests) to start will be a direct fecal exam, fecal float, giardia screening and complete blood count and serum biochemistry. This can eliminate probably 50 to 60 percent of the diseases on that long list, which by the way is called a differential diagnosis list. X-rays (radiographs) or ultrasound can rule out some cancers, obstructions, thickened bowels, urinary or enlarged abdominal organs such as liver, spleen or pancreas.

There are special tests to see if the gut is overgrown with bacteria or if your pet has malabsorption/maldigestion syndrome. Fecal cultures or enzyme tests may be necessary to diagnose clostridium, salmonella or campylobacter type bugs. Chronic pancreatic issues can also be eliminated by running certain tests. FYI the pancreas can cause issues by either being inflamed (pancreatitis) or by not secreting enough digestive enzymes (exocrine pancreatic insufficiency).

If these tests fail to reveal the cause and your pet is not responding to treatment, then an endoscopy and intestinal biopsy may be the next step. If these tests are not available in your area, then an exploratory surgery and biopsy can be done. Both techniques have advantages and disadvantages your veterinarian can discuss with you.

Treatment is aimed at the specific disease, if one can be found. If not, then we can start what we call empirical treatment, which is aimed at the symptoms and less targeted at a specific known disease. Empirical therapy is much less effective.

It may take months to resolve chronic diarrhea as the gut needs to re-grow cells and re-establish a normal bacterial flora. A low fat, novel (i.e. new) protein, easy-to-digest diet and probiotics may be necessary for a long time. Or your pet may need a high-fiber diet if it is a dietary intolerance or allergy or a fiber responsive condition. See, no one said this was going to be easy.

Stephen Sheldon, DVM, practices at Gypsum Animal Hospital. He can be reached at 970-524-3647, or by visiting the hospital website,

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