Cat - Diarrhoea

How is diarrhoea recognised?

Most cats with access to the outdoors defaecate outside, and since they usually bury their faeces, diarrhoea readily passes unnoticed by the owner. It may only be if the cat has an accident in the house or soils the fur around the anus (particularly in a long-haired cat) that the diarrhoea becomes apparent. If the cat uses a litter tray the owner may have much more information about variations in the faeces. Some variation in the appearance (e.g. colour and consistency) of the faeces is quite normal, particularly in some individual cats and may be related to minor factors such as variations in diet. Persistently liquid or semi-liquid faeces, however, should be reported to your veterinary surgeon.

If a litter tray is used in a household with more than one cat it is helpful to establish if it is just the one cat that has diarrhoea or whether more than one cat in the household is affected. If an infectious agent or some dietary factor is involved all the cats in the household are likely to have been exposed to the same problem. It may be necessary to confine one cat to a specific area of the house at a time to determine which cats have diarrhoea.

What causes diarrhoea?

Diarrhoea is not a disease in itself but a sign which may reflect many different problems, some of which involve specific diseases, whilst others may be related more to management factors, such as diet. If chronic diarrhoea has been present for some time, this is most often, but not necessarily, related to some intestinal disorder.

Initial approach to diarrhoea

Many cases of diarrhoea will respond quite readily to simple treatment, frequently without the initial cause ever being established. Generally acute diarrhoea which has been present for only up to a few days will resolve quickly. Chronic diarrhoea which has been present for some time, often over 2-3 weeks, may prove more difficult to treat effectively. It will help your veterinary surgeon to decide on the most appropriate approach to dealing with the case if it can be established whether the diarrhoea is acute or chronic. Therefore any information you can provide on how long the diarrhoea has been present will be very helpful. Information about any other signs your cat has shown will also be helpful in deciding whether symptomatic treatment or further investigations are appropriate.

Particularly important signs to recognise are:-

1. Does your cat seem ill - lethargic, etc.
2. Any marked weight loss
3. Any vomiting
4. Any change of appetite

It is also helpful, particularly in cases of chronic diarrhoea to establish whether the diarrhoea is related to a problem high up in the intestines (small intestine) or lower down in the colon (large intestine).

The pattern and nature of the diarrhoea may provide clues to help differentiate between these two:-

• any weight loss
• the frequency of defaecation
• whether increased quantities of faeces are produced
• the appearance of the faeces - watery, presence of mucus or fresh blood
• any 'digested' blood (black faeces)
• any straining or pain on defaecation

Another important area which can be of help is in reporting any change in management recently, particularly relating to feeding:-

• what is the cat's normal diet
• has the diet changed recently
• does the cat have milk
• does the cat have scraps or titbits
• has the cat stolen any food recently
• does the cat hunt and eat its prey
• does the cat take food from anywhere else - neighbour etc.

If the diarrhoea is mild

If the diarrhoea is so severe that it is causing other problems to develop such as dehydration and weakness, or the veterinary surgeon decides that other worrying signs are present or that a serious underlying problem is involved, he or she may recommend certain investigations. However most cases are relatively mild and in this situation, symptomatic treatment is usually tried initially without any further investigations. Most such cases will resolve even though the underlying cause is never clear.

Symptomatic treatment

Symptomatic treatment (treating the symptoms) is usually tried initially in mild cases of diarrhoea. It may involve a number of measures:

1. Withholding food for up to 24 hours. This may help the function of the intestine to return to normal.
2. Provision of a simple diet. Feeding a readily digestible diet may help. You may be provided with a special 'prescription' diet for this purpose or your veterinary surgeon may suggest a home-made diet of boiled chicken or sometimes fish with rice (as this is not a balanced diet it should not be used longterm). It is very important that the cat does not receive any other foods during this period. This includes milk - the cat should receive only water to drink unless specifically instructed by your veterinary surgeon. It also includes mice or any other prey, tit-bits and next door cat's food! The only effective way of ensuring this may be to confine your cat indoors for a period. This is particularly important if a dietary trial is being undertaken to test whether the cat has sensitivity to a particular food. A single dietary 'indiscretion' may ruin the test! If you do not think it is practical to prevent your cat from having access to foods outside you should mention this to your veterinary surgeon who may suggest hospitalising the cat for a dietary trial.
3. Drugs. There are some drugs which are occasionally used to help improve diarrhoea - by slowing down the passage of food in the intestine, coating the lining of the intestine etc. Antibiotics are sometimes used but are generally reserved for cases in which a specific, severe infection has been diagnosed. Otherwise they may upset the balance of the bacteria in the intestines which may further contribute to the diarrhoea. It is a common misconception that infections are a common cause of diarrhoea. Specific infections are relatively rare causes of diarrhoea in cats.

Do not use human proprietary antidiarrhoeals sold by pharmacists - some of these are very dangerous to cats.

If further investigation is required

If your veterinary surgeon suspects a serious underlying cause to the diarrhoea or complications are developing such as dehydration and weakness, further investigations may be required at an early stage and other treatment may be necessary. In particular it will be important to avoid dehydration. If your cat is only very mildly dehydrated you may be given a special solution to add to your cat's water, but if the dehydration is severe your cat may have to be hospitalised for a 'drip'.

Since there are many possible causes of diarrhoea, there are many potential tests required to establish the underlying cause. Some of the more commonly used tests are:-

• Blood tests: to check for systemic problems such as liver or kidney disease.
• Faecal tests: to hunt for infections, parasites etc. A fresh faecal sample is required for this.
• Radiographs (x-rays): to assess particularly for evidence of blockages, tumours, foreign bodies etc.
• Intestinal biopsy: in some cases a diagnosis will only be achieved by microscopic examination of a small biopsy of the intestine. This may necessitate 'opening up' the abdomen, which is a major operation, but at specialist clinics and now also at many other practices it is possible to obtain biopsies using an endoscope (a flexible viewing tube) passed through the mouth and into the small intestine.

These further investigations can be expensive and do not always provide a diagnosis. Chronic diarrhoea can be a very difficult condition to diagnose. In some selected cases your veterinary surgeon may decide to use a series of trial treatments. It is most important that you follow these very carefully if this approach is to be used effectively. Such a trial usually starts with a dietary trial (as described above). If you anticipate or encounter any problems in sticking to the trial, it is important that you discuss this with your veterinary surgeon.