What is the “trade off hypothesis” and how does it lead to spontaneous progression of CKD?
The renal adaptive processes that maximize kidney function to sustain homeostasis result in ongoing damage to the surviving nephrons. Therefore, CKD can progress even if the initial disease process or insult is cured
What is the prevalence of CKD in canine and feline populations?
Feline: 1-3% of US cats
Canine: 0.5-1.5% of US dogs
For serum creatinine to increase, what percent of kidney function must be lost?
75% of function in both kidneys
Why do kidneys become smaller with CKD?
Functioning nephrons are replaced by scar tissue and chronic inflammation
The majority of cats (70%) and dogs (60%) with CKD display what histopathologic changes in renal biopsy?
Tubulointerstitial nephritis
What is the MST of cats with IRIS Stage II CKD? Stage III? Stage IV?
Stage II: 1,151 days
Stage III: 679 days
Stage IV: 35 days :(
What factors influenced survival time in cats with CKD?
IRIS stage, serum phosphorus, severity of proteinuria
In all dogs with CKD, what was the MST? Dogs with IRIS Stage III and IV had how many times greater risk of mortality?
226 days
Stage III = 2.6 times the mortality
Stage IV = 4.7 times the mortality
What factors are associated with prognosis in dogs with CKD?
Proteinuria, hypertension, BUN, lower body condition score do worse
What are the histopathologic changes that accompany uremic gastritis in dogs?
Mineralization of mucosal and submucosal blood vessels, edema, glandular atrophy
What gastric hormone is increased in CKD due reduced renal clearance?
Gastrin - however, increased gastric pH typically does not occur in CKD patients
What are the clinical signs of uremic stomatitis?
What factors contribute to the decreased urine concentrating ability observed in CKD?
Why might the kidneys develop impaired responsiveness to ADH?
As urine concentrating ability is lost, what determines urine volume?
Daily urine solute load - sodium and urea
- Can modify the diet to alter this
What are the major mechanisms that contribute to hypertension in CKD?
What transcription factor regulates EPO synthesis in the kidneys?
Hypoxia inducible factors, especially HIF-2
What percent of asymptomatic cats with CKD have evidence of renal secondary hyperparathyroidism? What is the overall prevalence in all CKD cats?
47% of asymptomatic cats
84% of all CKD cats
What is urea synthesized from?
Synthesized using nitrogen derived from amino acid catabolism
What is urea metabolized to?
Ammonia and amino acids + CO2
Hyperphosphatemia occurs when GFR declines below what percent of normal?
Below 20% of normal
Why might total calcium increase but ionized calcium decrease in CKD?
Increased calcium binding to organic acids (citrate, PO4, sulfate) that are not being excreted due to CKD
What may the cause of hypokalemia in cats with CKD?
What are the consequences of hypokalemia in CKD cats?