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Diarrhea in dogs can be fatal if untreated

This story was originally printed in the Las Cruces Sun-News on July 25, 2014.

According to surveys made by the American Veterinary Medical Association, the third most common problem that veterinarians treat among dogs is canine diarrhea. If your dog has ever had this problem, you know how much it can affect your daily routine.

Diarrhea is not a disease. It is a symptom of many different diseases. Many mild cases of diarrhea can be resolved quickly with simple treatments. Others are the result of fatal illnesses, such as cancer. Even diarrhea caused by mild illnesses may become fatal if treatment is not begun early enough to prevent severe fluid and nutrient losses.


Diarrhea is categorized either as chronic or acute. In chronic cases, symptoms persist for weeks or even months while in acute cases, symptoms arise suddenly and are short-lived. In the majority of cases, canines suffer from the acute form of diarrhea. Healthy adult dogs that are fed once a day tend to defecate once a day. Similarly, adult dogs that are fed twice a day typically defecate twice a day. When experiencing diarrhea, however, dogs need to defecate more frequently and urgently than normal.

In addition to the categorizations of chronic and acute diarrhea, this problem can also be divided on the basis of whether it is related to the large intestine or the small intestine. This distinction can be important, as different medical conditions and illnesses can cause diarrhea in different sections of the intestines. When diarrhea comes from the large intestine, a dog may have trouble passing its feces. Furthermore, mucous may accompany the stool. On the other hand, when diarrhea originates from the small intestine, stools tend to be abnormally large and have a particularly bad odor.

The reason that a dog's system may trigger diarrhea is an attempt to quickly expel toxins from the body, before they have a chance to be absorbed. Sometimes one or two episodes of diarrhea are enough to get rid of these toxins, but when the underlying cause is more serious, the body may continue to react in this manner, providing a warning sign of the triggering illness or medical condition and leading to other problems, such as dehydration.


Since so many different factors can give rise to diarrhea, it's not always easy to determine the particular cause in an individual case. However, there are a number of different tests that can be used when attempting to make a diagnosis for a dog that is suffering from diarrhea. Some of these tests include blood tests, fecal tests, x-rays, endoscopies, and ultrasounds.


The potential causes of diarrhea are numerous, ranging from minor incidents or conditions to more serious and severe illnesses. Many times, diarrhea is caused by something that a dog has eaten. This can include swallowing foreign objects, ingesting garbage, eating food that is of low quality or that has gone bad, or eating food that a dog is allergic to. Toxins such as insecticides can also cause diarrhea, as can contaminated water, intestinal parasites, and viruses. Canines living in kennels are particularly prone to exposure to infectious parasites and to bacteria such as salmonella, which often cause diarrhea.

Furthermore, life-threatening illnesses have also been known to give rise to diarrhea in some canine patients. Numerous other factors can also trigger diarrhea, and the ones listed above are just a few of the broader and more common causes. If your dog's diarrhea is causing you concern, contact your veterinarian and he or she will be able to determine whether or not the underlying cause of the problem is serious or not.

Besides the reasons mentioned again, there are several other causes, including internal parasites (worms), parvovirus, distemper and giardia.

Dr. Beth Vesco-Mock is executive director of the Animal Service Center of the Mesilla Valley.

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