Journal of Feline Medicine and Surgery (2016) 18 , 219 –239 SPECIAL ARticle ISFM Consensus Guidelines on the Diagnosis and Management of Feline Chronic Kidney Disease Practical relevance: Chronic kidney disease (CKD) is one of the most commonly diagnosed diseases in older cats. In most cats, CKD is also a progressive disease and can be accompanied Andrew H Sparkes by a wide range of clinical and clinicopathological changes. These ISFM Consensus Guidelines BVetMed PhD DipECVIM have been developed by an independent panel of clinicians and academics to provide practical MANZCVS MRCVS Veterinary Director, ISFM 1 advice on the diagnosis and management of this complex disease. Panel Chair* Clinical challenges: Although CKD is a common clinical problem in cats, the manifestations of disease Sarah Caney vary between individuals. Thus there is a need for careful and repeat evaluation of cats with CKD and BVSc PhD DSAM (Feline) adjustment of therapy according to individual needs. In addition to addressing problems arising from CKD MRCVS 2 and improving quality of life (Qol) for the patient, therapy may also target slowing the underlying progression Serge Chalhoub 3 of disease and hence prolonging life. While maintaining QoL is of paramount importance in our patients, this BSc DVM DipACVIM can be challenging when multiple therapies are indicated. In some cases it is necessary to prioritise therapy, Jonathan Elliott given an understanding of what is likely to most benefit the individual patient. MA VetMB PhD CertSAC DipECVPT MRCVS 4 Evidence base: In preparing these Guidelines, the Panel has carefully reviewed the existing published Natalie Finch literature, and has also graded the quality of evidence for different interventions to help to provide practical BVSc PhD MRCVS 5 recommendations on the therapeutic options for feline CKD. This is a field of veterinary medicine that has Isuru Gajanayake benefited from some excellent published clinical research and further research findings will undoubtedly BVSc CertSAM DipACVIM modify the recommendations contained in these Guidelines in the future. DipECVIM MRCVS 6 Catherine Langston DVM DipACVIM 7 INTRODUCTION CONTENTS page Hervé Lefebvre DVM PhD DipECVPT 8 < Introduction 219 < Diagnosis and assessment of CKD Joanna White Chronic kidney disease (CKd) is a common BVSc DipACVIM PhD 9 feline disease. its prevalence will vary between in cats 220 – Routine diagnosis of CKD in cats 220 Jessica Quimby populations, but a large UK study estimated DVM PhD DACVIM 10 that the prevalence of feline renal disease in – Routine investigation and staging first opinion practices was ~4% (CKd was the of CKD in cats 222 1International Cat – Advanced and emerging tests Care/ISFM, UK seventh most common specific diagnosis 2Vet Professionals, UK made). 1 CKd is more common in older cats, 2–4 for feline CKD 222 3Faculty of Veterinary ⩾ – Recommended monitoring of cats Medicine, University of and may affect 30 –40% of cats over 10 years Calgary, Canada 4 of age. Renal disease was the most common with CKD 223 4Department of Comparative cause of mortality in cats ⩾5 years of age in a – Prognosis 223 Biomedical Sciences, Royal Approach to management 224 Veterinary College, UK UK study, being the cause of death of >13% of < 5School of Veterinary cats at a median age of 15 years. 5 < Management of CKD patients 224 Sciences, University of – Managing hydration in CKD 224 Bristol, UK The underlying aetiology of CKd often 6 – Managing diet and mineral/ Willows Referral Service, remains obscure. Most cats investigated have Solihull, UK chronic tubulointerstitial nephritis and renal bone disease in CKD 225 7Department of Veterinary 6,7 – Managing hypertension in CKD 228 Clinical Sciences, Ohio fibrosis on histology (Figure 1) – lesions State University, USA thought to be the end phase of a variety of – Managing anaemia in CKD 229 8Clinical Research Unit, potential underlying aetiologies that may – Managing proteinuria in CKD 230 National Veterinary School – Managing inappetence, nausea of Toulouse (ENVT), France include toxic insults, hypoxia, chronic 9Small Animal Specialist glomerulonephritis, chronic pyelonephritis, and vomiting in CKD 231 Hospital, Sydney, Australia – Managing UTIs in CKD 232 10 Department of Clinical – Other treatments 233 Veterinary Sciences, Colorado State University, < Specific therapeutic issues in cats USA with CKD 233 *Correspondence: [email protected] doi: 10.1177/1098612X16631234 © The Author(s) 2016 JFMS CLINICAL PRACTICE 219 SPECIAL ARticle / ISFM guidelines on chronic kidney disease Figure 1 Typical DIAGNOSIS AND ASSESSMENT histopathology of a kidney OF CKD IN CATS from a cat with chronic kidney disease (CKD), characterised by Routine diagnosis of CKD in cats inflammatory infiltrate, tubular loss, increase in extracellular matrix and CKd in humans is defined as a sustained ( ⩾3 fibrosis x 20. Courtesy of Jessica Quimby months) reduction in glomerular filtration rate (GFR, <60 ml/min/1.73 m 2) or evidence of sus - tained ( ⩾3 months) kidney damage (eg, struc - tural damage, proteinuria). 18 Although CKd has not been clearly defined in cats, similar A good principles should apply; notably there should be evidence of sustained functional or structur - relationship al kidney damage (eg, ≥3 months’ duration). and good As CKd is more common in older cats, these patients should be targeted for more communication upper urinary tract obstructions, and potential - detailed and frequent health assessments. ly viral infections involving retroviruses as Recommendations from international Cat between the well as a recently recognised morbillivirus. 8–12 Care/international Society of Feline clinic and the other specific causes of CKd sometimes recog - Medicine, the American Association of Feline nised include amyloidosis, polycystic kidney Practi tioners and the American Animal cat’s owner is disease, renal lymphoma, hypercalcaemic Hospital Association suggest health checks nephropathy and congenital disorders – some every 6 months for cats >7 years of age vital for of these have breed associations. 4,8,13 (including evaluation of body weight, body successful other than age, clear risk factors for devel - condition score and blood pressure), together opment of CKd have not been identified in with selected diagnostic testing (including management cats, 14 –17 but weight loss or poor body condi - haematology, serum biochemistry screening tion, polyuria/polydipsia (PU/Pd), higher and routine urinalysis) at least annually. 19,20 of CKD. creatinine concentrations, dehydration and Historical and clinical findings suggestive potentially lower urine specific gravity (USG) of CKd, such as weight loss, altered kidney may indicate the presence, or predict develop - size, unexplained dehydration, PU/Pd, ment, of CKd. 14 –17 systemic hypertension or an unexplained The purpose of these Guidelines is to give low USG (<1.035 –1.040), also justify further practitioners an up-to-date, critically assessed investigation. overview of the current diagnostic and A simple, accurate biomarker to assess renal treatment options to guide in the practical function does not currently exist. Thus in management of CKd. clinical practice the combination of azotaemia (increased serum creatinine and/or urea) and Quality of evidence as an intervention an inappropriately low USG are routinely The Panel has provided guidance on the current quality of evidence for used to diagnose CKd. However, their inter - different therapeutic interventions based on peer-reviewed published data – pretation is not always straightforward: 21,22 summarising (as ‘ GOOD ’, ‘ POOR ’ or ‘ NONE ’) any evidence that a therapy < Although often measured together, improves longevity, and also that a therapy improves quality of life (QoL). creatinine is preferred over urea as a marker However, it should be noted that many interventions have not yet been of GFR as its concentration is inversely adequately evaluated. related to GFR, and is affected by fewer non-renal factors. < Creatinine is an imprecise marker of GFR though; it lacks specificity if reference intervals are set low enough to detect early stage disease, but lacks sensitivity if reference intervals are set higher. < Creatinine concentration is affected by lean tissue mass and hydration. < Creatinine concentrations (and reference intervals) vary between different assays, analysers and laboratories. < The exponential relationship between GFR and creatinine means that substantial early declines in GFR may be accompanied by only Figure 2 Blood pressure measurement Figure 3 Ocular examination (in this case small changes in creatinine,while in the latter should be part of the routine evaluation of all distant indirect ophthalmoscopy) is valuable, stages of disease large changes in creatinine cats with proven or suspected CKD. Courtesy given the strong association between CKD of Sarah Caney and hypertension. Courtesy of Sarah Caney may reflect only small changes in GFR. 220 JFMS CLINICAL PRACTICE SPECIAL ARticle / ISFM guidelines on chronic kidney disease Bearing in mind these limitations, in clinical produce a USG <1.035, this can be affected by practice feline CKd is often diagnosed on the diet, 23 and occasionally some cats with basis of: azotaemic CKd will produce a USG ⩾1.035. 24,25 < An increased serum creatinine < Some cats have reduced urine concentration >140 µmol/l (>1.6 mg/dl); concentrating ability before they develop together with overt azotaemia. < An inappropriately low USG (<1.035); and < A persistent