Diarrhea is a fairly common presenting complaint here in the office. Whether it’s a dog having accidents in the house, a cat having soft stools in the litter box, or a calf or pig or horse with scours, the consistency of an animal’s stool can tell us a lot about the health of the gut. We also know that diarrhea causes dehydration fairly rapidly, especially in a young animal. Also, we don’t want infectious diarrhea to spread from one animal to another. For many reasons, time can be of the essence to treat the animal to get a successful outcome.
Let’s talk about a few of the major causes for diarrhea and what we look for when treating it.
- Intestinal parasites. As in, “worms” in the gut. These can range from roundworms, which look like spaghetti, to giardia, which can’t be seen with the naked eye. Most of these bugs can be found on a good stool sample under a microscope with a trained eye. Some are more elusive and can’t always be found on a stool sample (i.e., they aren’t shed every day by the pet or may be too small to easily see under the microscope). There are more specialized tests that can be run for certain bugs if we are suspicious of them. All parasites drain resources from the animal, usually proteins and/or red blood cells, and can cause weight loss, anemia, weakness, or even death. We recommend checking stool samples on all diarrhea patients.
- Dietary problems. This can include poor-quality food or food sensitivities. We see this in young animals that have a sudden diet change, or older animals that become sensitive to certain food ingredients, such as chicken, beef, corn or soybeans. Some dogs require antibiotics to right the diarrhea, while others need a diet change. Most require a physical exam and fecal exam to rule out parasites before treating for dietary problems.
- Viral or Bacterial infections. One of the most famous and often-seen viruses in puppies is parvovirus. These young dogs are often unvaccinated and suddenly stop eating and have diarrhea. Bacterial infections can range from diarrhea as the only symptom to severe weakness and lethargy. Sometimes we see this type of infection in dogs that dig into the trash and eat raw or rotten meat, or go into the woods and eat a deer carcass. It is not uncommon to see fevers and dehydration with viral or bacterial infections. A good physical exam and fecal exam is necessary to rule out parasites. Other specialized tests can also be helpful, such as a fecal smear or culture, or parvovirus snap test to specifically diagnose and treat infections.
- Structural abnormalities. As in, the gut has a physical issue that causes diarrhea, such as a blockage, a thickening of the lining, or an intussusception (where one part of the bowel inverts and moves inside another part of the bowel). Sometimes these can be seen on an x-ray or ultrasound or endoscopy. Treatment varies, dependent on the cause.
What is the bottom line on diarrhea?
If you see it, get a fresh stool sample, seal it and keep it refrigerated until you can get it into the veterinary clinic. If the animal is lethargic, weak, or goes off feed, make an appointment to get a good physical exam too. Sooner is always better than later, as diarrhea can cause dehydration and weakness and can progress quickly with certain illnesses.