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What To Do When a Dog's Diarrhea Isn't Going Away

There are a lot of common issues that pet owners tend to do what they can to treat on their own. Consequently, when we vets see them, they're usually ongoing, severe, or not easily addressed with the simple, DIY solutions many pet owners try first.

Often, our canine patients will be perfectly fine and happy, with otherwise normal behavior and some of the most awful liquid stool you've ever experienced. Sometimes, it's obvious something more is going on, and the patient has lethargy, weakness, weight loss, or other symptoms. Treating a patient with long-term diarrhea is essential to prevent long-term health effects and address underlying problems.

For Pet Owners

While our blog is usually focused on advice for vets and fellow caregivers, this is the kind of topic that will attract plenty of attention from pet owners as well. So, first, let's start with a little advice for our clients.

It can be useful to know the common causes of diarrhea in dogs, so see if any of these apply:

  • They ate, or you suspect they ate, something they shouldn't have. Household chemicals, inorganic materials, foods they shouldn't get into, and even mildly toxic plants around the neighborhood can all be causes. Whenever you bring them outside, keep an eye on what they're getting into and avoid letting them eat things they shouldn't.

  • Abrupt dietary changes can result in temporary diarrhea while they get used to the new diet. This includes changing foods, even between brands, as different brands of the same kind of food can have different ingredient lists and cause digestive upset. When a dietary change is called for, try to adjust gradually over the course of a couple of weeks unless otherwise instructed by your veterinarian.

  • Parasites, most commonly worms, can cause diarrhea. Fleas can carry tapeworms, and heartworm infections can cause all manner of symptoms. Make sure your dog is up to date on their antiparasitics.

Start by withholding food for 12 hours. Oftentimes, diarrhea can be traced to something akin to food poisoning, or your dog ate something they shouldn't have, and it's irritating their digestive system. In many cases, it can go away if the digestive system is allowed to calm down and sort itself out. Unfortunately, that means skipping meal time – and any other edible items, including bones, treats, and scraps.

Pick back up with a bland diet. A bland diet is something that eliminates pretty much every possible food-borne cause of diarrhea. Basically, buy and cook chicken with no spices or additives, and cook plain rice, mixing them together into a food for your dog. Generally, you want to feed them this mixture every 3-4 hours in smaller portions rather than in larger lumps to avoid upsetting their digestive system any further.

If these two combined manage to alleviate the diarrhea, then you're good to start adding their normal foods back into their diet. Your goal here is to track what you give them, and if they start to have diarrhea again, you'll know which food, treat, or other item is causing it and can remove it from their diet.

If this elimination and reset process doesn't solve the issue, or if your dog is experiencing other symptoms, such as lethargy, pain, fever, weakness, fluid buildup, weight loss, dull fur, vomiting, bloody stool, or a loss of appetite, make sure to bring them into your vet to be treated.

Fortunately, the majority of the time, the prognosis for diarrhea – even long-term diarrhea – is good. It's relatively rare that the cause is something very dangerous. Most often, it will involve short-term medication and possible dietary control, but the dog in question will generally be able to return to normal in short order.

For Veterinarians

Alright, vets, let's talk about how to handle these chronic or severe diarrhea cases.

The first step carries on from what we just listed above: identify any symptoms other than diarrhea that might indicate what's going wrong. In addition to the above, check for signs of parasites.

Some relevant questions to ask your client:

  • How long has the patient been experiencing this diarrhea?

  • Is the condition getting worse or staying about the same? It could be getting better, too, but clients are less likely to bring their dogs to you if it seems like it's resolving.

  • Has the dog had access to something they shouldn't, like roadkill, garbage, spoiled food, or hazardous items?

  • Has the dog experienced any behavioral changes, like lethargy or a loss of appetite? 

  • Has there been blood or mucous in the stool, and if so, what color has it been? If your client brought a stool sample, you can inspect it yourself.

You'll also want to classify the diarrhea. Is it a small bowel or a large bowel?

  • Small bowel or small intestine diarrhea is usually less frequent and larger. It's usually caused by some irritation or damage to the stomach or small intestine. The dog may vomit and may have weight loss because they can't effectively digest food. They may also have gas. They won't have difficulty passing stool. There's also the possibility that the stool may be black in color, indicating internal bleeding.

  • Large bowel or large intestine diarrhea is smaller and more frequent. Clients whose dogs have this may report accidents in the home or a change in toilet habits. This can indicate damage or irritation of the large intestine. The dog in question generally won't have weight loss or vomiting; conversely, they may strain to pass the stool, and if there's blood, it will be red because it's fresher.

Emergency procedures may come into effect depending on the state of the dog. Primarily, if they're weak, losing weight, and feverish, you'll want to take action to get them fluids and liquid nutrition.

If there are signs of parasites, you can perform additional tests to identify what, if any, are active. Whipworms, tapeworms, heartworms, and other parasites can usually be identified relatively easily, and the treatment is doubtless familiar. Simple tests for illnesses like worms or parvo are easy to perform and can rule out certain causes or positively identify the cause and lead directly to treatment.

If the client suspects their dog ate something they shouldn't have, imaging may be necessary. Often, a simple X-ray can show foreign bodies lodged in the digestive tract. These can include sticks, bone fragments, strings, hair ties, cords, and all manner of other small objects. Often, these end up lodged in an awkward place or a turn in the intestines, partially blocking the digestive system and blocking solids from passing through.

If an X-ray is nondiagnostic, other imaging can be useful. Radiographs with barium contrast can look for unusual issues with the intestines. Ultrasounds or even endoscopies can identify issues that don't show up on something like an X-ray. An endoscopy through the mouth can show issues with the stomach and intestines, while an endoscopy through the colon can show large intestine or colon problems. This is also where you may spot colon cancer or polyps that need to be addressed.

Additional tests can include:

  • A complete blood count. This shows a variety of metrics, including hydration, blood sugar levels, cholesterol, endocrine levels, digestive enzymes, anemia, likelihood of an infection, clotting ability, and immune system response. The combination of abnormalities in any of these can indicate if there's something specific you should be looking at, such as thyroid issues, potential cancers, or a less obvious form of illness.

  • Urinalysis. This is another way to check for systemic issues, as well as infections, dehydration, kidney disease, bladder disease, or diabetes, any of which could lead to diarrhea.

The goal, of course, is to start with the most common options and work to verify or eliminate them. Infections, parasites, and blockages are generally the source of longer-term diarrhea, while food poisoning and similar causes are less likely to be long-term and recurring unless the dog in question has continual access to whatever is causing them problems.

Treating Long-Term Diarrhea

The first order of business, before testing, is to determine if there are emergency procedures you need to enact, like administering fluids to address dehydration. This, of course, involves hospitalization of the dog in question and IV therapy for fluids. Fortunately, this also gives you a stable position to use to perform other diagnostics and administer treatment.

Once you've determined what the issue is, you need to determine what kind of treatment is appropriate. Don't forget to consult patient records to verify there are no relevant medication allergies or other sensitivities that can get in the way of treatment.

Parasitic infections or bacterial/viral/fungal infections are quite common causes of diarrhea and related issues and are, fortunately, usually quite treatable. You may need to keep the dog under observation for a day or two while you give them fluids and start treatment, but often, the client can administer a simple pill at home, so you can send them home with the appropriate prescription as necessary. You may have antidiarrheal medication to add to the list as well.

In the case of an intestinal blockage, there's a decent chance that surgery may be required to remove the foreign body causing the obstruction. If there's systemic damage that needs to be addressed, such as bowel perforation, you can deal with it then.

If there are no obvious signs of infection, blockage, or other issues, you can start to check for things like hormonal imbalances. You can also talk to your client about investigating the places their dog spends their time to look for signs that they're getting into chemicals, eating roadkill, or otherwise consuming something they shouldn't.

Sometimes, you'll discover that the underlying issue is something more serious. It's not common, but it's not unheard of to discover that the underlying cause of an intestinal blockage isn't from within the intestines, but without; a tumor pressing on the system and disrupting its ability to function. Similarly, tumors that disrupt the kidneys or the endocrine system can cause diarrhea as a side effect. A biopsy, fine needle aspiration, or other diagnostic test can identify the specific problem and help you proceed with developing a treatment plan.

In other cases, you might not be able to find any particular evidence of a cause. In these cases, it's most likely something like food sensitivity, and you may be able to tell through immune response markers. Allergens, food sensitivities, and other digestive issues can be addressed depending on what they are. Often, this starts with an elimination diet and slow reintroduction of foods as was outlined above, as strictly regimented as possible to make sure the client can track down specifically what ingredient is causing the issues.

Confirming Suspicions

While most cases of long-term diarrhea end up having an obvious cause, not all of them are clearly cut and dry. In these cases, it's your duty as a vet to make sure you're on the right track. If you're at all unsure of your diagnosis, we're here to help. At Hope Vet, we have a team of highly trained and experienced veterinarians ready to assist you. All you need to do is click "Request a Consult" above and give us a rundown of the symptoms and your suspicions. From there, we can offer advice, second opinions, and our thoughts about what may be happening based on our experience.

Don't forget, too, that we can do more than just internal medicine. For your patients with skin problems, cancer, neurology, or other issues, we're more than happy to help. Remember, while you're the person your clients trust to know what's going on, you can't know everything; rather, it's your job to know how to find out. Whether that means referring the client to a partner nearby, getting an informed second opinion, or taking over cases from others who aren't sure of themselves, it's important to work as a team. We can be part of that team; just drop us a line when you need us.

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