Practitioner reality – How I deal with chronic renal insufficiency (Proceedings)

• 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.