Jonathan Elliott, Department of Veterinary Basic Sciences,
Royal Veterinary College, London, UK - 2001
 

With the increasing use of routine plasma biochemistry testing in small animal veterinary practice, the recognition of azotaemia (raised plasma creatinine and urea concentrations) is commonplace in dogs and cats. The challenge for the practitioner is firstly to identify those cases where the azotaemia is completely reversible (pre-renal or post-renal problems which can be corrected) and the animal’s renal health is good. If intrinsic renal disease is identified as the cause of the azotaemia, the clinician then needs to:
 

• (i) define the extent of the renal dysfunction, distinguishing animals with a very poor prognosis from those which are able to cope with their renal dysfunction and lead a reasonable quality of life
• (ii) design a rational treatment regimen tailored to the severity of renal dysfunction which improves the animal’s quality of life and perhaps protects the remaining functioning nephrons, slowing progression of the renal disease. Recent developments have occurred in the field of nephrology which may help the busy first opinion practitioner to achieve some of these goals. In particular, the number of treatment options which are novel to veterinary practice has increased and is likely to increase further in the near future as approaches which have been demonstrated to be effective in experimental animals and humans are applied to our patients. Renal disease is a complex field and it would be helpful to establish guidelines and a classification system that has been tried and tested in the clinic to assist practitioners in deciding on the best course of action for the animals under their care.

In addition, it is well recognised that by the time clinical and biochemical evidence of renal disease can be detected clinically in dogs and cats, considerable amounts of functioning renal tissue have been lost. Hence, another goal for veterinary nephrology is to devise methods, applicable to general practice, which can be used to detect a decline in renal function and chronic renal insufficiency at an earlier stage than is currently possible using routine laboratory tests. If this were possible, one might predict that treatments designed to slow progression would have the greatest chance of achieving this if administered to cases in the earlier stages of their disease.
 

The International Renal Interest Society (IRIS) was established in 1998 with the specific aim of helping veterinary practitioners better diagnose, understand and treat renal disease in dogs and cats. The IRIS board has brought together veterinary nephrologists from nine countries. The first step the group took was to identify the common features used by members in the diagnosis and treatment of chronic renal disease in dogs and cats and to rank these in order of importance. This information was then used to design an algorithm which would help practitioners diagnose and categorise cases of renal disease into different stages, much in the same way as is done for congestive heart failure cases. This algorithm has been tested and refined by IRIS members. The group then reached a consensus on the treatment recommendations they would make for each stage of renal disease in the dog and cat. Both the diagnostic algorithm and treatment recommendations are now available for use by veterinarians in practice.
 

By making the algorithm and treatment recommendations available to general practitioners we hope this will prove beneficial in a number of ways:
 

• It should provide you with a logical approach to investigating the dog or cat you see which you suspect of having renal disease. 
• It should help you in selecting, what the IRIS board currently consider to be appropriate management regimens for cases in different categories. 
• It may assist you in communicating with (a) owners about renal disease and the prognosis and treatment options for their pet and (b) other veterinarians, unifying the terminology used throughout the world in the classification of cases of renal disease.
• If you are prepared to share the case information that you feed into the algorithm with the IRIS board this will be beneficial to veterinary nephrology world wide as discussed below. Initially, the case data submitted by practitioners will allow us to determine the types of renal disease that are seen in clinical practice, discern geographical differences and other information based on a very large number of cases presented to first opinion practices. If the IRIS classification system proves to be robust and stands up to clinical testing, it should, in a further refined form, also assist in prospective clinical studies which assess the effect of drug therapies or dietary management strategies on the progression of naturally occurring cases of chronic renal failure.

Many questions remain to be answered by prospective clinical studies and a major goal of the IRIS group is to identify those areas where there is an urgent need for answers to be found. The information provided by practitioners using the algorithm will enable the IRIS board to truly quantify the international importance of these questions. International collaborative studies would be highly desirable and one of the advantages of having the IRIS group is that such multi-centre studies based in many countries will be facilitated. IRIS exists through the generous financial support of Novartis Animal Health. However, the IRIS board is independent of Novartis Animal Health and any case data practitioners choose to share with us will be analysed by IRIS and will be shared with the whole veterinary community by its publication in veterinary journals.
 

Many exciting advances have occurred in nephrology over the last 10 years, both in experimental studies and in human and veterinary clinical studies. IRIS hopes to help practitioners make the best use of these advances to manage clinical cases of renal disease and, in turn, hopes that practitioners will help by submitting case data that will facilitate further advances within veterinary nephrology in the future. If you use the algorithm, please consider contributing your case data.