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Diarrhea in Pets

Diarrhea in Pets: A Messy Situation

By Mark Hale DVM

Bolivar, MO


            No one wants to clean up the mess of their pet having diarrhea. I am sure the pet didn't like having diarrhea either. This is one of the most common symptoms listed for a sick pet visiting their veterinarian.

            If we group the more common causes of diarrhea into categories it is sometimes easier to decide on an appropriate treatment. A thorough history and physical exam, along with testing of fecal samples, will usually be necessary to help determine a cause. Following are some examples of the most common types of diarrhea.

1)      Parasitic- These would include intestinal worms, coccidia, and giardia infections. These would especially be common in puppies and kittens, but can also occur in adult pets. A microscopic exam of the feces can usually detect these parasites by seeing their eggs in the sample. More sensitive tests for giardia may be needed if it is still suspect. Many owners think that if they cannot see "worms" in their pets' stool that they cannot be infected. However, most parasites are too small to be seen with the naked eye. Depending on the type of parasite found, a specific treatment and prevention plan can be started. One word of caution; most OTC dewormers do not treat for all types of intestinal worms, so do not think that by giving a dose of discount store dewormer you have eliminated these as a potential cause of diarrhea.

2)      Infectious- This group includes viral diseases Corona and Parvo, along with bacterial causes of enteritis (inflammation of the bowels) such as Salmonella and E coli. Corona is a mild, self-limiting diarrhea in very young puppies. A vaccine is available, but is not very effective and not recommended. Parvo virus is a common, severe, life threatening disease that is very contagious. Classically we see bloody diarrhea, vomiting, and severe depression that begins quickly. However, some cases have different signs so a test to confirm is always a good idea. Aggressive treatment should be started right away. All dogs should be kept current on their Parvo vaccinations since this disease is so prevalent. The bacterial causes are usually brought on by the pet eating something spoiled. Dogs and cats are much more resistant to contaminated food than humans. This is obvious to anyone who has witnessed the nasty things an outside pet might bring up in the yard to chew on. Most of the time antibiotics and symptomatic treatment are sufficient to treat bacterial enteritis. Occasionally, iv fluids and more aggressive treatment is needed.

3)      Diet induced- These would include intolerances to diet changes. The classic example of this is the leftovers from the Thanksgiving turkey. Richer, high fat foods are going to be more likely to induce this type of reaction. These types of treats can also be responsible for inducing pancreatitis at the same time. Mild cases usually respond to symptomatic treatment and time. However, severe cases may require hospitalization and more aggressive treatment. My recommendation is to avoid the urge to give your pet table scraps. While they may do fine with only moderate amounts, they also learn to beg for more and sometimes refuse to eat their food without the addition of people food.

4)      Other systemic diseases- This last group are the ones we never want to be the cause. We must remember that diarrhea is a symptom, not a disease. There are many diseases that may have diarrhea as one of the symptoms. Examples would include Addison's disease (hypoadrenocortisism), dysautonomia, any liver disease, pancreatitis, feline leukemia, or FIP. Others could include foreign bodies in the stomach or intestines, lymphoma, or lymphocytic/plasmacytic enteritis.


            If your pet develops a mild diarrhea, you may start with symptomatic treatment such as pepto bismol or kaopectate. However, if depression or vomiting is also present, or if diarrhea persists beyond 24 hours, please see your veterinarian. Taking a sample of feces can be beneficial. Prompt diagnosis and treatment are essential for a speedy recovery. If you have questions about this, or any other pet health topic, please make an appointment with your pets' veterinarian.