A Practical Approach Chronic Kidney Disease (CKD) in Cats: Improving Diagnosis

Introduction

There are many different causes and degrees of renal dysfunction. These can be broadly categorised as pre-renal, renal and/or post-renal in origin. Even when possibilities for further testing is limited, it is very useful to aim at least to in/exclude the extra-renal abnormalities since these are generally completely reversible. When confronted with renal disease, assessing its duration is also worthwhile since early in the process substantial recovery is possible with adequate support. Clinical improvement should then be visible within a few days but it may take up to three months before full potential for recovery is realised. Unfortunately in most (feline) cases, by the time obvious symptoms are recognisable and the owner seeks veterinary assistance, the disease is already chronic in nature.
Earlier diagnosis can be achieved by improving awareness of predisposing factors such as age, breed, environment and concurrent diseases. There are several laboratory parameters that can be used for screening programs but care should be given to their interpretation.
In less advanced stages of CKD identification of underlying causes can even greatly improve outcome. Many cats with mild CKD have long survival times. In patients with more advanced CKD, it remains important to check for common complications such as dehydration and ascending urinary infections. Ideally, follow up visits consisting of repeat physical examinations as well as laboratory testing, should be part of routine CKD patient care. This will not only help maintain client compliance but can also allow the treatment protocol to be tailored to the individual patient. 

Signalment

Breed predispositions for renal disease have been documented for Persian and Persian related breeds (polycystic kidney disease, PKD), Siamese and Abyssinian (amyloidosis) and Burmese cats (hypokalemia). Hereditary factors leading to nephropathies are suspected in several other breeds (Norwegian Forest Cat, Maine Coon, and Ragdoll) although aetiology and mode of inheritance remain to be elucidated.
In general, older cats are more often diagnosed with CKD but there seems to be no difference in predisposition according to gender.

History

Owners that have had experience themselves or heard of (related) renal patients tend to recognise more subtle symptoms such as mild polydipsia and are probably more likely to seek veterinary assistance when disease is at an earlier stage. Client education could therefore be a valuable tool e.g. via breeder associations.
If time permits, more extensive questioning may reveal circumstances that can be related to renal disease: e.g. subclinical acute tubular necrosis can follow any episode of hypotension and progress to CKD. Re-occurring urinary tract infections are unusual in normal cats but are found regularly in renal patients. [...]