What is diarrhoea?
Okay so let’s get started by explaining what diarrhoea is. In a normal healthy animal, the stools or faeces have a well-formed relatively solid consistency with no liquid, blood or mucus. Normal stools are formed from food that the animal has eaten once it has been processed by the stomach and especially the intestines. Processing of food basically involves absorbing certain nutrients as well as water and also adding waste substances into the intestines. Diarrhoea refers to stools or faeces that are not solid and not properly formed but instead loose or liquid in consistency. Some animals will have a single one-off episode of soft stools before their faeces appear normal again and we would not usually class this as diarrhoea. Diarrhoea tends to imply multiple episodes of abnormal stools.
Types of diarrhoea
There are basically two types of diarrhoea although it is important to realise that some animals can shows signs of both types if the cause of the problem is widespread throughout the intestines. The first type is what we call ‘small intestinal diarrhoea’ because the cause of the problem is mainly in the small intestine. The small intestine is the part of the gut that is connected to the stomach and this is where most of the digestion of food and absorption of nutrients occurs. Small intestinal diarrhoea tends to be large in volume and have a liquid watery consistency. Animals don’t tend to strain or try to pass stools more frequently, but weight loss is common. In some animals the diarrhoea looks black or tarry and this suggests that there has been some bleeding into the intestine; we call this melaena and it is a sign that should prompt consultation with your vet.
The second type of diarrhoea is ‘large intestinal diarrhoea’. The large intestine is the part of the gut that connects the small intestine to the outside world via the anus and it includes the colon and the rectum. The colon is the main part and people often refer to animals with large intestinal diarrhoea as having ‘colitis’. The main function of the large intestine is to absorb water from the faeces as it passes through to the outside. Animals with large intestinal diarrhoea often try and pass faeces many times a day with straining and only a small volume of diarrhoea produced on each occasion. The faeces may be loose or soft rather than liquid in consistency, and there is often some fresh blood and slimy jelly-like mucus. Weight loss is uncommon with these patients.
Why is diarrhoea bad?
Okay so now that we have described the different types of diarrhoea, let’s consider why having diarrhoea is a problem. As a general rule, large intestinal diarrhoea is usually less of a risk to the animal than small intestinal diarrhoea. Animals with small intestinal diarrhoea may become malnourished and start to look thin and in poor condition because they are not absorbing their food properly. In more severe cases, the animal may become dehydrated and in the worst of cases, he or she may become very weak and depressed eventually going into shock. Some animals can also lose enough blood in their diarrhoea for this to become a problem to them as well. Other considerations that we have to bear in mind are that some causes of diarrhoea cause discomfort to your pet; some pets feel distressed or embarrassed about soiling themselves or being unclean; and of course there may be some practical problems for you in terms of clearing up the diarrhoea especially if your pet has an accident in the home. Many of the causes of diarrhoea also cause vomiting which as we discussed in the last blog can also cause worrying problems.
What about the causes of diarrhoea?
There are a large number of causes of diarrhoea. Like with vomiting, these range from mild and nothing to worry about to very severe and potentially life-threatening. Although as we said earlier, any animal that has diarrhoea that is severe enough, regardless of the cause, can become very ill. The causes of diarrhoea typically are problems which directly affect the intestines causing a failure in the normal actions of the intestine to absorb food and water and also dump waste substances into the faeces. A number of animals recover from diarrhoea without a specific cause being diagnosed. Also it is worth noting that many animals with diarrhoea will also have some vomiting which often occurs before the diarrhoea starts.
- One of the most common causes of diarrhoea is what we call ‘dietary indiscretion’: this is when your pet either eats something that doesn’t quite agree with him or her, for example because it is too rich or rotten, or they overeat. Foreign body ingestion is also a type of dietary indiscretion that can cause diarrhoea.
- Another relatively common cause of diarrhoea is as a side-effect of certain medications including for example some common antibiotics and also non-steroidal anti-inflammatories.
- Food intolerance or food allergy is another common cause of diarrhoea: this is when your pet is allergic to either their main diet or any other treats that are fed. However it is important to realise that some animals will develop diarrhoea if their diet is changed suddenly. This does not mean that they are necessarily allergic to the new diet. It is often possible to stop the new diet and then when the diarrhoea has cleared, try introducing it again but much more slowly over several days.
- ‘Inflammatory bowel disease’ or ‘IBD’ is another cause of diarrhoea affecting the intestines. This is a bit like irritable bowel syndrome in humans and can be very severe.
- A variety of infections of the intestines can cause diarrhoea, although you should realise that this is actually quite an uncommon cause. In some cases your pet will remain relatively bright and healthy despite the diarrhoea but in others they can become very ill indeed potentially to the point of being life-threatening. One of the most infamous causes of diarrhoea in dogs is a virus called parvovirus which is more common in animals that have not been vaccinated and especially in younger unvaccinated dogs. Parvovirus can very quickly pose a threat to your dog’s life and it is worth noting that the infection is possible even in dogs that have been fully vaccinated. However vaccination has reduced the number of cases of parvovirus in dogs dramatically and you should make sure that your dogs are vaccinated and that this is kept up-to-date as discussed with your vet. Other infections that can cause diarrhoea in dogs and cats include salmonella, campylobacter, giardia, coronavirus and of course worms in the intestine.
- And one more cause of diarrhoea that we always have to keep in mind unfortunately is cancer affecting the intestines.
What information will your vet need to know?
If you ring your vet practice because your dog or cat has diarrhoea, some of the information they will find useful to try and assess the severity of the problem includes:
- When did the diarrhoea start?
- Approximately how many episodes have occurred and is the volume produced each time large or small?
- Does your dog or cat strain and look uncomfortable at the time of passing the diarrhoea?
- What does the diarrhoea look like? Is it liquid, water-like or more solid? Is there any fresh blood or slimy jelly-like mucus? Do the stools have a black tarry appearance?
- Other questions include…Is your pet still eating? Is he or she still drinking?
- How does your pet seem in himself or herself at the moment? Is he or she still bright and energetic or lethargic and quiet? Are there any other problems such as vomiting – if so, is it bloody? Is your pet’s breathing ok?
- Are you aware of anything that your pet may have scavenged or did you feed him or her anything out of the ordinary before the diarrhoea started?
- Has your pet had any medical problems in the past, especially similar episodes of diarrhoea, and is he or she on any medications at the moment?
How is diarrhoea treated?
Right so now that we have considered some of the causes of diarrhoea, let’s talk about the treatment that may be needed. The main thing to realise is that there are really two aspects to this treatment and our job, working with you, is to figure out to what extent each of these aspects is required for your particular pet. The first aspect is what we call ‘symptomatic and supportive care’. This is basically care that your pet may require depending on how severe the diarrhoea is and for how long the diarrhoea has been going on. You will remember that we mentioned earlier how diarrhoea can cause problems such as dehydration and weakness. In terms of the symptomatic and supportive care that may be needed, this can range from no treatment being required to your pet being sent home with treatment for you to give to your pet being admitted to the practice for a fluid drip into a vein and other treatments and tests. The extent of this type of ‘symptomatic and supportive care’ required is dependent on the individual pet rather than the specific cause of their diarrhoea.
It is worth mentioning at this point that there are very few drugs that have been used in dogs and cats to try and directly stop the diarrhoea and those that have been used are not licensed. These drugs are called anti-diarrhoeals. They can have adverse effects and they are usually only used in exceptional cases. It is important that any animal receiving an anti-diarrhoeal also gets whatever other supportive care they need and that they do not remain on an anti-diarrhoeal without also trying to find the cause. Their use is especially not recommended if the diarrhoea is due to an infection.
Anti-diarrhoeals need to be differentiated from probiotics which are not drugs but actually natural supplements that are quite commonly given to dogs and cats with diarrhoea. Probiotics may help by restoring, maintaining and supporting the growth of those bacteria within the bowel that are beneficial. They may also have a number of other positive effects.
The second aspect to the treatment a pet with diarrhoea requires is more specifically aimed at the cause of their diarrhoea and ultimately this is the best way to stop the problem for good. In animals with mild diarrhoea that are otherwise well, it may be enough just to withhold food for 12-24 hours and then offer a bland diet for a few days and see whether this helps. You can buy a special food designed for animals with bowel problems or alternatively feed low-fat easily digestible foods such as boiled chicken or fish with boiled rice or pasta; feeding plain cottage cheese can also be helpful. Once the diarrhoea has cleared, gradually reintroduce your pet’s normal diet over a few days and continue to monitor.
In a number of cases this sort of treatment at home will either not work, that is the diarrhoea will continue, or your pet will already be too unwell and your vet will recommend a consultation at the practice. Once they have obtained more information from you and had a chance to examine your pet, they can make a recommendation about the next best step both in terms of how much of the ‘symptomatic and supportive care’ we discussed previously is required, and also whether they feel that it is necessary to do some tests to try and diagnose the cause of your pet’s diarrhoea. In some cases it will be necessary to do urgent tests because your vet is very worried about your pet, in other cases these tests can be done more slowly over a period of days or even weeks. It will all depend on your individual pet. Your vet may want to test your pet’s stools for infection, do some blood tests to look for causes and also for example for evidence of dehydration, and in some cases it is appropriate to take x-rays or do an ultrasound. Some animals require endoscopy – this basically involves feeding a video camera through your pet’s mouth or anus into the intestines under a general anaesthetic. It may be necessary to take biopsies, which are little tissue samples, of your pet’s intestines either using an endoscope or even by performing surgery.
Depending on the cause of your pet’s diarrhoea, treatments that may be required include trying different diets under strict management, suitable drugs if an infection is identified, or steroids and other medications if for example inflammatory bowel disease is confirmed. Your vet will be able to talk you through the management needed once the cause is known.
Antibiotics in diarrhoea
Before ending this blog we would just like to say a few words about antibiotics. Antibiotics are used to treat infections caused by bacteria. As we said earlier, diarrhoea is not often due to infection and especially not bacterial infection. We would therefore recommend that antibiotics are only used if a bacterial infection is confirmed by specific tests and you should also bear in mind that antibiotics can in fact cause diarrhoea in dogs and cats. It doesn’t make much sense to give an animal antibiotics without confirming that they definitely need them and then the antibiotics actually make the diarrhoea worse.
Okay so that brings us to the end of this PercyPods Pet Emergency blog on diarrhoea in dogs and cats. As you can see, there are a large number of causes of diarrhoea. It is not uncommon for some animals to have very short bouts of diarrhoea that are basically nothing to get too concerned about, especially if they have a varied diet with treats and scraps or because they scavenge on walks and so on. However at the other end of the spectrum, some patients with diarrhoea have very severe and potentially life-threatening disease. In general it is recommended that you consult your veterinary practice if you are at all worried.
We hope that you have found this episode useful and learned a little about diarrhoea in dogs and cats. The next blog will be in approximately 2 weeks time when we will talk about a condition in dogs known as ‘bloat’ or gastric dilation-volvulus syndrome. Before we sign off just to remind you that you can contact us in various ways. Via email on firstname.lastname@example.org; via the PercyPods Facebook page; or via Twitter on @PercyPods. We would really love to hear your comments on this podcast as well as suggestions for future topics. Also don’t forget to subscribe for future episodes. So thank you for reading this and until next time, may you and your pets be safe.