Mineral Bone Disorder in Cats with CKD

Presentation Description / Summary:

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a systemic disorder that encompasses a complex interplay between mineral and hormonal metabolism, bone remodelling and extra-skeletal calcification, that occurs as a result of CKD. It is well-established that dietary phosphate restriction improves survival in feline chronic kidney disease (CKD). However, feeding a phosphate-restricted diet may disrupt calcium homeostasis, sometimes leading to the development of hypercalcemia in certain CKD cats. Although transferring these cats onto a less phosphate-restricted diet appeared to restore normal calcium status, long-term implications on renal health and mortality associated with a lesser degree of dietary phosphate restriction in azotemic CKD cats remains uncertain.

Nephrocalcinosis is prevalent in both humans and cats with CKD, especially in patients with hypercalcemia. Currently, little is known about the implications of nephrocalcinosis for cats with CKD, but this pathological feature has been suggested to be associated with accelerated deterioration of renal function.

This presentation will firstly, discuss the regulation of calcium in cats, and the adaptive and maladaptive responses as CKD progresses; secondly, evaluate the effects of dietary phosphate restriction on calcium homeostasis in feline CKD; thirdly, examine the potential implications associated with hypercalcemia in CKD cats; fourthly, compare the evidence of macroscopic and microscopic nephrocalcinosis detected using ultrasonography, micro-computed tomography and histopathology in cats with CKD; and lastly, discuss the findings from a randomized controlled clinical trial, which demonstrated an anti-calcaemic effect of dietary magnesium supplementation in cats with CKD.