What can cause diarrhoea?
Essentially, diarrhoea in dogs and cats occurs when the large or small intestine is not working properly. This can be because digestion or absorption of food is failing, because the intestine is producing more fluid than normal, or failing to absorb fluid, or because there is abnormal movement of the bowels.
In most disease states, more than one mechanism contributes to the diarrhoea. Many diseases cause diarrhoea; infections such as Salmonella, foreign bodies, other internal diseases (e.g. kidney failure), failure of digestive enzyme production (e.g. pancreatic insufficiency), dietary intolerances and ‘inflammatory bowel diseases’. Veterinary internal medicine and antibiotics are available to help.
What is ‘acute’ diarrhoea?
Often signs of diarrhoea in dogs and cats that are recent in onset (acute) and not associated with other clinical signs are treated symptomatically and attributed to causes such as ‘dietary indiscretion’. Treatment often involves supportive care such as fluid therapy, often a short period of food withdrawal and a subsequent period of feeding a ‘light’ diet. When more severe signs are apparent or simple treatment fails to resolve the problem, further investigations may be indicated.
What is ‘chronic’ diarrhoea?
When diarrhoea in dogs and cats persists for a period (typically more than three or four weeks) it is termed ‘chronic’ and this is a common point at which further investigations are considered.
How do you investigate patients with diarrhoea?
A wide variety of investigations are used to diagnose the cause of diarrhoea in dogs and cats and to determine the best therapy. Initial blood tests are used to rule out underlying diseases. Specific blood tests can help screen for intestinal disease and rule in, or rule out, pancreatic insufficiency. Faecal examinations are used to test for infections and can be helpful in diagnosing maldigestion. Diagnostic imaging (e.g. radiography, ultrasonography) can be used to examine for abnormal bowel position, blockages and thickening of the bowel wall.
Further investigation often requires some form of tissue sampling procedure. Preferably this is achieved by the use of an endoscope to view inside the bowel. Once the intestine has been accessed, biopsy forceps can be passed down the endoscope to allow pinch biopsies to be taken. Sometimes surgical exploration is necessary, either to allow sampling of otherwise inaccessible sites or to perform procedures such as foreign body removal.
What treatments are available?
Dietary management often forms a major part of the diagnosis and treatment of cases referred to Davies Veterinary Specialists (see related Fact Sheet: Feeding an exclusion diet). Other than surgical treatments for problems such as obstructions, a number of medical treatments may also be used. These include antibiotics for specific infections and ‘antibiotic responsive enteropathy’, anti-parasitic treatments, anti-inflammatory drugs (most commonly corticosteroids) and immunosuppressive treatments.
Will my pet get better?
The likely outcome depends upon a number of factors. Most important is the underlying disease; certain diseases are considered very difficult to treat and carry a poor prognosis. More optimistically, many of the cases of diarrhoea in dogs and cats we see achieve significant improvements; sometimes a cure is achieved, other times signs are controlled effectively as long as treatment (diet and/or drugs) are maintained.
If you have any further questions about diarrhoea in dogs and cats you should speak to your veterinary surgeon who will be able to discuss this with you more fully.
If you are concerned about the health of your pet you should contact your veterinary surgeon.
Related factsheets:
Feeding an Exclusion Diet