What is Inflammatory Bowel Disease or IBD?
IBD is a common cause of chronic gastrointestinal (GI) signs in dogs and cats. It is defined by the presence of characteristic inflammatory cells within the GI tract, once other causes of inflammation (e.g. infection) have been excluded.
Stricter definitions subdivide the disease into patients who respond to dietary management (‘food responsive’) or correction of dysbiosis (previously termed ‘antibiotic responsive’), whilst those that respond to neither of these and require anti-inflammatory treatment are classified as having true (aka “idiopathic”) IBD. However, for simplicity we’ll use IBD as an umbrella term for all three forms. It is different to irritable bowel syndrome (IBS) – a non-inflammatory disease affecting gut motility and much more common in people than pets.
What are the signs or symptoms of IBD in cats and dogs?
Common signs include chronic (typically >4 weeks duration) vomiting, diarrhoea, reduced appetite, weight loss, flatulence or a rumbly tummy/abdominal discomfort. These vary in severity and can be persistent or intermittent, with some patients experiencing episodic symptoms. Concurrent signs of allergic skin disease (e.g. red, itchy ears) are sometimes present (supportive of sensitivity to food playing an important role). In cats, we often see concurrent diseases alongside IBD (namely liver disease and pancreatitis) which may cause additional signs (e.g. jaundice).
What are the causes of IBD?
IBD is caused by an abnormal ‘local’ immune response (hypersensitivity) causing inflammation within the GI tract. This can be driven by an overreaction to (non-infectious) bacteria within the bowel or to food antigens. It is not caused by feeding the ‘wrong’ food – the guts simply become sensitised to food antigens they have been exposed to for any length of time (e.g. common ingredients such as chicken). Proteins seem to be more to blame than carbohydrates, although gluten is typically avoided with any diet trial.
Genetics also play a role, since certain breeds are more susceptible. However, any breed can be affected. IBD is not indicative of ‘poor breeding’ per se and it is not possible to predict/ avoid the disease with selective breeding. The resulting inflammation can cause discomfort, nausea and reduced food absorption (weight loss +/- diarrhoea). In severe cases, protein loss occurs into the GI tract (known as ‘Protein Losing Enteropathy’ or PLE).
How is a diagnosis of IBD reached?
A definitive diagnosis is reached once inflammation is demonstrated on gut biopsies and other potential causes for this have been excluded.
A typical workup may include:
- Blood tests e.g. to check protein levels, other organ function and vitamin levels.
- Faecal analysis may be occasionally performed to rule out infectious causes of diarrhoea.
- An ultrasound scan is often performed to rule out blockages, lumps/bumps and look for changes (e.g. thickening, altered layering) within the GI tract.
- Gut biopsies are sometimes performed at this stage, although in many cases, a treatment trial first is more appropriate, with biopsies only becoming necessary if this fails or signs are severe. Biopsies can be obtained via endoscopy (also enabling visual assessment of the inside of the GI tract) or surgery (sometimes preferred if a specific lesion needs to be assessed, or additional tissues sampled).
What treatment is available for IBD in cats and dogs?
Treatment varies depending on the severity of the disease, which strategies have been tried already and a client’s personal preference (e.g. whether they prefer all alternative options to be tried before steroids).
In milder cases, an exclusion diet is often the first step (for further information click here to see our fact sheet on exclusion diets) and, even if this has already been tried, we may recommend switching to an alternative diet (since there is no ‘one diet fits all’ and some patients do better on one particular diet than another). We would expect to start to see improvement after approximately two weeks if the disease is ‘diet responsive’.
An attempt to manipulate the resident GI bacterial population may be made e.g. with a course of probiotics (click here to see our fact sheet on probiotics). Worming may also be recommended.
If all of these fail to significantly improve symptoms, we will consider suppressing the inflammation with drugs such as steroids (ideally only after we’ve performed biopsies). Alternative drugs may be used instead or in conjunction if the disease does not respond well to steroids, or if steroids are contraindicated or poorly tolerated. Faecal matter transplants are sometimes performed, although we don’t yet have a good feel for which patients may benefit the most from this procedure.
What is the outlook for cats and dogs diagnosed with IBD?
The prognosis for IBD is variable. In a minority of cases (typically young dogs with diet-responsive disease), complete recovery is possible, however, for most patients this is a life-long condition but it is manageable. Despite this, some patients with IBD can respond well to treatment and enjoy good quality of life (and normal life expectancy). Long-term disease control in ‘responders’ may be achieved by continuing an exclusion diet alone in some cases, whereas chronic drug therapy may be required in others (in these cases we try to reduce to the lowest effective dose to minimise side effects). Flare-ups are a problem, especially after scavenging and some clients resort to muzzling their dog on walks (or keeping their cat indoors, if tolerable!). Unfortunately, some patients (especially those with severe signs or PLE), do not respond to treatment and continue to deteriorate or suffer frequent relapses, in which case their quality of life may have to be questioned.