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Understanding chronic kidney disease in cats

Quimby JM. Feline chronic kidney disease: understanding pathophysiology is the key to development of new treatments. Vet J. 2015 Mar; 203(3):265-256.

A number of years ago, chronic kidney disease (CKD) was considered the number one concern for cats. Despite a more concentrated research focus on the problem, little has changed in the interim.  With as many as 30-85% of elderly cats potentially afflicted with this gradually worsening condition, CKD remains a leading cause of illness and death in this group.

The primary histologic characterization in cats is termed tubulointerstitial nephritis; fibrosis is the factor best correlated with evidence of disease progression.

Still, in spite of newer testing methodology to achieve earlier diagnosis, management of disease progression over this time period has also remained palliative in nature, focused on correction of metabolic changes that result from reduced kidney function. Treatment primarily involves formulated renal diets, anti-hypertensives for blood pressure, potassium supplementation, phosphate binders, anti-proteinuric agents, subcutaneous fluids and hormone therapy to control anemia. In consideration of evidence-based medicine, the specially formulated renal diets provide the best evidence basis for disease management.

The author’s recent research with others indicates that gastric lesions in cats with uremia differ from other species. Questions then arise if the loss of appetite in cats with CKD stem from GI lesions or from the effects of uremia on the chemoreceptor trigger zone.

While recent efforts have been considerable into obtaining, archiving and standardizing canine kidney tissue for assessment, histopathology samples from cats with kidney disease was very under-represented in archives at several major universities. Much still needs to be learned about the pathophysiology of CKD in cats.  One final pathway to end stage kidney disease is by fibrosis, often brought about by factors such as inflammation, hypoxia, proteinuria, and hyperphosphatemia. Yet, we still need to learn to what degree their significance is to the progression of CKD. Understanding the mechanisms of progression will potentially lead to the means of better therapeutic interventions. (VT)

See also:
Lawson J, Elliott, J, et al. Renal fibrosis in feline chronic kidney disease: known mediators and mechanisms of injury. Vet J. 2015; 203(1):18-26.