Chronic Renal Failure Flashcards
What is chronic kidney disease?
Loss of functional renal tissue due to a prolonged process (generally>2months)
Renal insufficiency leading to renal failure and uremia
T/F: chronic kidney disease is progressive but can be reversed
False
Usually irreversible
What is the prevalence of chronic kidney disease ?
1-3% in cats
0.5-1.5 % in dogs
What are degenerative causes of CKD?
Chronic interstitial nephritis
Renal infarcts
What are developmental causes of CKD?
Familial renal dysplasia
PKD (Persians)
What metabolic disorder can cause CKD?
Hypercalcemia
-> due to primary or secondary hyperPTH (diet neoplasia)
Infectious causes of CKD?
Pyelonephritis
Lyme
Leptospirosis
What are iatrogenic causes of CKD?
Vit D supplementation
Nephrotoxic drugs
What percent of nephron loss is there in an animal that has lost the ability to concentrate its urine?
66%
What percent of nephron loss is there in an animal that has developed azotemia?
75%
Failure of excretion of nitrogenous wastes leads to ?
Uremia
In CKD, the kidney fails to produce what substances that lead to hypocalcemia, anemia,and uremic gastritis ?
Calcitriol (Vit D3) -> hypocalcemia and renal secondary hyperPTH
Erythropoietin -> anemia
Failure to catabolism peptide hormone (gastrin) -> uremic gastritis
How does CKD sometimes result in defective hemostasis?
Antithrombin loss —> hypercoagulable
Once CKD develops, what secondary processes are activated that contribute to the renal damage?
Systemic and glomerular hypertension
Mineral imbalance
Proteinuria
Renal fibrosis
What are classical presenting signs for CKD?
PU/PD GI signs - vomiting, anorexia, weight loss, diarrhea, hypersalivation, and constitution Dehydration Poor body condition Pale mucus membranes Small kidney Hypertensive retinopathies
Depression and lethargy
Sudden onset of blinds
Pathological fractures
Isosthenuria range for cats and dogs?
Cat SG 1.008 - 1.030
Dog SG 1.008 - 1.022
What are possible sources of an azotemia ?
Reduced GFR
Increased catabolism
Gastrointestinal hemorrhage
What diagnostic tests do you do to confirm CKD?
Biochem CBC UA -with sediment, UPC, culture and sensitivity Abdominal imaging BP Ophthalmoscope Blood gas analysis
What do you expect to see on a biochem of a patient with CKD?
Hyperphosphatemia
Hypo/hyperkalemia
Hypo/hypercalcemia
Metabolic acidosis
What causes a hyperphosphatemia in CKD?
Kidney are the primary route of phosphate excretion
Reduced renal function -> phosphate retention
At what stage of CKD is phosphate increased?
Stage III and IV
During stage I and II compensatory mechanisms lead to increased phosphate loos from remaining nephrons.
What are DDX for hyperphosphatemia?
CKD Reduced GFR (pre, renal, post) Ruptured bladder Tumor lysis syndrome Young HypoPTH VitD toxicity
DDX of hypokalemia ?
Reduced intake
Increased renal potassium loos
What are the consequences to hypokalemia?
Neuromuscular weakness
Anorexia
Impaired protein synthesis -> weight loss
Decreased renal fxn
Promotes lymphoplasmacytic interstitial lesions
Promote PU/PD
Why do you get a metabolic acidosis in CKD?
Reduced excretion of H+ by kidney
What are the causes of the anemia seen with CKD?
EPO deficiency Decreased RBC life span PTH effect on bone marrow and RBC Anemia of chronic dz GI hemorrhage
Why do sediment and culture with CKD?
Concurrent UTI? -> increased risk
Concurrent infection can lead to disease progression
T/F: proteinuria is a potential cause of renal injury
True
-> increases risk of developing end-strange CKD
What are therapies that can reduce the magnitude of proteinuria ?
ACEi (benazepril) or ARB (telmisartan)
What would you see in radiographs that would indicate CKD?
Small renal size
Tissue mineralization
How does BP relate to CKD?
Hypertension can be a result of CKD or can be the cause
-> leads to ocular, cerebral or cardiovascular damage
When you suspect a diagnosis of CKD what lab data is important for staging/prognosis the disease?
Creatinine
Proteinuria
Blood pressure
How do the goals of management change with stage of CKD??
Stage 1 - find underlying disease and eliminate if possible
Stage 2/3 - renoprotective therapy and slow progression
Stage 3/4- symptomatic
What is the treatment for pyelonephritis ?
Antibiotics for 4-6weeks
- based on culture and sensitivity
- renally excreted (nitrofurans)
Avoid aminoglycosides and tetracycline in renal failure
In an animal with CKD what are possible causes of vomiting/nausea?
Uremic gastritis
Hypergastinemia
Stimulation of the CTZ by uremic toxin
How can vomiting/nausea be treated?
Antiemetic
- maropitant (NK1 antagonsit)
- metoclopramide (dopamine and serotonin receptor antagonist)
- ondasetron (serotonin antagonist)
Proton pump inhibitors (omeprazole/pantoprazole)
H2 blockers (famotidine/ranitidine/cimedtdine)
Gastric mucosal protectants (sucralfate)
Treatment for anorexia associated with CKD?
Warm food, hand fed, quiet environment
Appetite stimulants
- cyproheptadine (cats) - serotonin antagonist antihistamine
- mirtazapine -serotonin antagonist/ tricyclics antidepressant
Feeding tube
Treatment for hyperphosphatemia??
IV fluids
Restrict phosphate intake
-dietary restriction
-intestinal phosphate binder (aluminum, calcium, lanthanum - carbonate)
—> mix with food and give with every meal
—> titration dose to effect
What are the features of renal diets?
Phosphate restricted High energy High quality reduced protein Sodium restricted Potassium supplemented Increased vit B
Neutral effect on acid-base
Omega 3 supplemented
Increased soluble fiber
Anti-oxidant supplemented
Why are renal diets so important in CRF?
Reduce risk of uremic crisis
Increase long term survival
for long term benefit
When should renal diets be started ?
Cat - IRIS stage II and higher
Dog - IRIS stage III and higher
Hyperphosphatemic animals
Metabolic acidosis
Hypertensive animals
How do you treat hypokalemia?
Iv supplementation
Renal diets are potassium supplemented
Oral potassium supplements
Patients with non-regenerative anemia due to CRF can receive EPO therapy. At what PCV should you initiate this therapy?
<20%
Exclude and treat other causes of anemia
When survival is suspected to be <6months
risk of production of neutralizing antibodies to EPO
How can you treat hypertension in CRF?
Moderate salt restriction
Emergency therapy
Long term
- ACE inhibitors
- Amlodipine (first choice in cats)
Monitor
What are the benefits of ACE inhibitors for treatment of hypertension due to CRF?
Reduce glomerular capillary pressure and glomerular size
Reduce proteinuria
Mild anti-hypertensive effect
Reduce sodium and water reteion
Limit pro-fibrotic effect of angiotensin II on kidney
Improve appetite in proteinuric cats
Telmisartan MOA?
Angiotensin receptor blocker
What are the side effects of telmisartan?
Mild and transient GI signs
Elevated liver enzymes
Reduced BP
Decrease in RBC counts
How can you treat proteinuria?
ACEi
Angiotensin receptor blockers
Correct BP
Methods of long-term monitoring for CRF?
Kidney palpation PCV Electrolytes BUN/CREA/PO4 UA and possible culture and sensitivity Urine protein: creatinine (UPC) ratio Systolic BP Ophthalmic examination
Increased creatinine and phosphate indicates what about the prognosis for CRF?
Poor
What is the prognosis for CKD in dogs?
Stage 1/2- 18months
Stage 3- 6 months
Stage 4- 30days
What is the prognosis for CKD in cats?
Stage II - 3 -8 years
Stage IV - 35days
