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Practitioner reality – How I deal with chronic renal insufficiency (Proceedings)
Chronic renal insufficiency involves the permanent damage to any part of the nephron.
- Permanent damage to any part of the nephron
- Multiple possibilities for inciting cause
- Any age or sex cat, more common in older cats
- Progressive disease
Signalment
- History of polyuria/polydipsia
- Usually weight loss
- Anorexia
- +/- vomiting
- Bad breath
- Lethargy
Physical exam findings
- Dehydration
- Unkempt cat
- Kidneys may palpate small and irregular, occasionally large. Usually not painful upon palpation
- Uremic breath, ulcers present in cats usually only end-stage
Diagnosis
- Elevated BUN, Creatinine
- Hypokalemia
- Hyperphosphatemia
- +/- anemia
- Isosthenuria
- +/- hypertension
Differential diagnosis
- Prerenal azotemia – dehydration, high protein diet
- Renal azotemia
o ARF
o CRF
o Diabetes
o Diuretics
- Postrenal azotemia
IRIS staging
- Stage 1: USG <1.030 with proteinuria or <1.025 without proteinuria, no azotemia, creatinine <1.6
- Stage 2: Mild azotemia, creatinine 1.6-2.8, PU/PD and other clinical signs absent or minimal
- Stage 3: Moderate azotemia, creatinine 2.8-5, clinical signs generally present
- Stage 4: Severe azotemia, uremic syndrome, creatinine >5
Treatment
- Fluids
- Control vomiting/nausea
- Dietary therapy
- Phosphorus binders
- Potassium supplements
- Appetite stimulants
- Manage anemia
- Manage hypertension
- Manage proteinuria
- Calcitriol?
Practical management
- Stage 1: Full bloodwork, BP, UA, +/- urine P/C ratio, +/- urine culture. Phosphorus binder if phosphorus over 3 (want to keep under 4), start dietary therapy? Recheck every 6 months with weight, UA, bloodwork
- Stage 2: As above, but definite UP/C. Recheck every 4 months with weight and UA, Electrolytes +/- bloodwork as determined by history and PE, BP every 6 months
- Stage 3: As above, recheck every 3 months. UA every visit +/- urine culture prn, culture every 6-9 months if otherwise stable. Bloodwork and BP every 6 months.
- Stage 4: Hospitalize and stabilize, recheck monthly.
Generalizations
- Start potassium supplementations if serum K <4.2
- Start sq fluids at stage 3-4, or when appetite starts to decrease
- Start H2 blockers when appetite starts to decrease
- Start epogen if pcv <14%
- Keep phosphorus <4 (<5 if stage 3-4)
UP/C in CRI cats – helps classify the proteinuria
- < .2 = normal
- .2 - .4 = borderline
- .4 – 2 = glomerular or tubular
- >2 = glomerular
The higher the number, the faster the progression of the disease. Will start ACE inhibitor if over .3.