Pathophysiology

• While the underlying cause of most cases of canine CKD Kidney: chronic kidney disease (CKD) remains obscure, a number of different etiologies have been documented, eg dysplasia Kidney: dysplasia , glomerulopathy, chronic tubulointerstitial disorders, pyelonephritis Kidney: pyelonephritis , polycystic renal disease Kidney: polycystic disease (congenital or acquired), amyloidosis Amyloidosis (familial or acquired), cystadenocarcinoma (German shepherd dogs) nephrotoxins (eg ethylene glycol Ethylene glycol poisoning , aminoglycoside antibiotics, grapes raisins Raisin poisoning , hypercalcemia Hypercalcemia: overview , hydronephrosis Hydronephrosis / hydroureter (eg from a blocked ureter), renal ischemia Kidney: ischemia , renal lymphoma or carcinoma Kidney: neoplasia , and as an eventual result of untreated pre-renal or post-renal failure.
• As the renal function Renal function assessment decreases to less than about 1/3 of normal, the ability of the nephrons to concentrate urine decreases and the urine becomes less concentrated, resulting in polyuria and a secondary polydipsia.
• Potassium and B vitamins are lost in increasing amounts as the amount of urine produced increases, and may result in deficiencies.
• When the glomerular filtration rate (GFR) drops below 25% of normal, metabolites and uremic toxins may accumulate. These include the metabolic products of protein metabolism which are reflected in the serum as increased urea and creatinine.
• As the GFR decreases to less than about 15%, the excretion of phosphorus decreases and serum phosphorus increases.
• Along with the retention of phosphorus, parathyroid hormone concentrations may increase (renal secondary hyperparathyroidism Renal secondary hyperparathyroidism , contributing to signs of uremia Uremia. Production of erythropoitin from the kidneys may decrease resulting in a non-regenerative anemia Anemia: non-regenerative.
• Decreased production of calcitriol (vitamin D) may contribute to renal secondary hyperparathyroidism.
• Dehydration and loss of bicarbonate leads to a tendency for metabolic acidosis Acid base imbalance.
• Signs of chronic kidney disease include polyuria, polydipsia, weight loss, poor appetite, hypertension Hypertension , weakness, and anemia.
• Therapeutic interventions may be based upon the International Renal Interest Society (IRIS), although the strength of evidence varies among treatments.

Dietary requirements

Special considerations

Diet for dogs with chronic kidney disease

Further Reading

Publications

Refereed papers

• Recent references from PubMed and VetMedResource.

Other sources of information

• Elliott D A (2012) Nutritional management of kidney disease. In: Applied Veterinary Clinical Nutrition. Editors Fascetti A J and Delaney S J. Wiley Blackwell, West Sussex, UK. pp 251-268.
• Polzin D J, Osborne C A, Ross S (2009) Evidence-based management of chronic kidney disease. In: Kirk's Current Veterinary Therapy XIV. Editors Bonagura JD, Twedt DC. Saunders Elsevier, St Louis, Mo. pp872-879.
• Squires R A (1996) Uraemia. In: BSAVA Manual of Canine and Feline Nephrology and Urology. Editors: Bainbridge J and Elliott J. BSAVA, Gloucestershire, UK. pp52-67.