There’s not much worse than coming home to diarrhea piles all over the house. The smell, the mess, the cleaning, not to mention your dog or cat not feeling well. How do you get it to stop?
There are two broad diarrhea categories, small bowel and large bowel, and there can be overlap between the two. The large bowel, or colon, is responsible for absorbing water from feces and moving it back into the bloodstream. When there’s colon inflammation (also known as colitis), there’s reduced water absorption and decreased ability to store feces. Thus, there’s an urgency to poop more frequently, and the stool is typically cow pie in consistency. Inflammation in the colon leads to mucus formation, and the diarrhea often looks slimy or gelatinous. Bleeding can occur as well, and since it’s in the colon, blood seen in the stool will be bright red. Animals with colitis frequently strain to poop, which some owners mistake for constipation since there may be no more stool coming out.
The small intestines move water from the bloodstream into the intestinal tract to help break down food. They also absorb nutrients and start to resorb some of the water as feces get closer to the colon. Diarrhea due to small intestinal inflammation produces a more watery stool with no mucus. If there’s blood, it will be dark red or tarry in appearance. Most animals with small bowel diarrhea don’t need to poop more frequently and don’t usually strain to poop.
The most common type of diarrhea we see in dogs is large bowel diarrhea. There are a number of different causes, but most are easily treated or self-limiting. For example, stress. Boarding facilities, separation anxiety, and thunderstorm phobia can all contribute to stress, which can lead to colitis. But the most common reason for colitis is the dog eating something that didn’t agree with them. This could be a new food or treat, something dropped from the table, or something found outside. Generally, for dietary indiscretion, I recommend withholding food for 12 to 24 hours followed by feeding small meals of something easily digested. The best food is a prescription diet made for diarrhea, as these foods contain water-absorbing fiber to help stop the diarrhea quickly while providing nutrients that are lost in the stool.
In a pinch, you can make something at home. The basic recipe is three parts boiled white rice or boiled white pasta to one part boiled, skinless chicken breast (or boiled then rinsed hamburger). This special diet is fed in several small meals per day for a couple of days until the stool becomes formed, then the normal diet is gradually introduced over another two days. Your vet can provide gastrointestinal food as well as medication that may help stop diarrhea more quickly.
If your pet is still having soft stools, the next step is to take a sample to your vet (they love it when you collect it in a sealed plastic bag then put that into a gift bag, but you only need to bring in a couple of tablespoons!) so they can check it for intestinal parasites and Giardia. If you have a puppy with diarrhea that also has low energy, possibly vomiting, and hasn’t been fully vaccinated, please take your pup to your vet or an emergency vet quickly. The cause may be parvovirus, and puppies can quickly dehydrate and die. There are other causes of large bowel diarrhea, so if your dog isn’t improving and the fecal sample is negative for parasites, your veterinarian will have other tests and therapeutic trials to reach a diagnosis.
Small bowel diarrhea can have many different causes, making it challenging to diagnose and treat. Intestinal parasites can be a cause, so it’s always best to start by bringing a fecal sample to your vet for analysis. Inflammatory bowel disease (IBD), similar to IBS in humans, is a common cause. It could be due to a food ingredient sensitivity (generally a protein), which can show up at any time. If your vet suspects IBD, they will recommend a therapeutic diet trial, where you feed one specific diet (usually a prescription hydrolyzed protein diet or limited ingredient diet) for 8 to 12 weeks to see if the diarrhea improves. If you’re doing one of these diets, it’s very important that the pet get no other food, treats, or bones, as the offending ingredient could be found in anything.
Small bowel diarrhea that comes and goes could be a sign of Addison’s disease. This might be the cause if your dog tends to have diarrhea after a stressful event: going to the groomer, being left at home, going to the vet, etc. A blood test for resting cortisol (a steroid made in the body) can help rule this out or determine if further testing is required.
Exocrine pancreatic insufficiency (EPI), where the pancreas isn’t producing normal enzymes that break down food, will also cause small bowel diarrhea. Dogs with EPI are always thin, as their intestines aren’t absorbing the nutrients from the food they eat, and the diarrhea can be greasy looking and smell really bad (even worse than “normal” diarrhea). EPI is diagnosed with a blood test, and treatment consists of mixing pancreatic enzymes with the dog’s food at each meal.
If your pet has diarrhea, it’s worth trying to figure out what category it falls into. Purina has a Fecal Scoring Chart you can find online that helps you grade the poop from 1 (small and hard) to 7 (watery with no texture) and lists the characteristics of large and small bowel diarrhea. If you think the diarrhea is mostly large bowel, then a few days of home care may be all that is needed. But if the diarrhea doesn’t improve or you think it could be small bowel diarrhea, then make an appointment with your vet. And don’t forget the gift bag!
