IP9 Renal Flashcards
Why are kidneys susceptible to injury?
Filter 25% of blood from each cardiac cycle
Medulla poorly perfused
Concentrates some drugs/ toxins
What are the main functions of the kidney?
Maintain body water balance (Concentrate urine) Excrete waste products Make hormones erythropoietin, active vitamin D, renin/ angiotensin
What goes wrong in renal failure?
Kidneys can’t regulate water = dehydration
Can’t excrete waste = uremia
Can’t make hormones = anemia, renal secondary hyperparathyroidism
How do you diagnose renal failure?
Appropriate history and clinical signs
Concurrent azotemia and isosthenuria
What’s different when diagnosing RF in cats?
Can become azotemic before entirely losing urine concentrating ability
How does outcome and prognosis differ between acute (ARF) and chronic (CRF) renal failure?
Acute: Poor short term prognosis (Px) (~50% die), but can have better long-term Px if survive short-term
Chronic: Can remain compensated and respond to supportive therapy, but no cure long-term
What is the definition of the following: Anuria Oliguria Polyuria Polydipsia
Anuria: No urine output ( 2 ml/kg/hr
Oliguria: 0.25 to 0.5 ml/kg/hr
Polyuria: 2 + ml/kg/hr
Polydipsia: 50-100 ml water consumption/ kg/day
Distinguishing features of ARF?
Recent (less than 7 d) onset illness
History: toxin, ischemic event, really uremic
Renal size: normal to large +/- painful
Anuria/ oliguria possible
+/- PU
Normal body condition score
Really “sick” (uremic) for degree of azotemia
Distinguishing features of CRF?
Signs for weeks to months
History: PU/PD, occasional vomiting, nausea
Renal size: small, irregular, asymmetrical
Usually polyuric
Usually thin, poor hair coat
May be anemic
Sometimes have remarkable azotemia but still feel OK and be eating
What stages are described in the Chronic Kidney Disease staging system?
Stages 1-4
Stage 1: Mild clinical signs, not yet azotemic
Stage 4: Severe renal disease (Creat > 5 mg/dl)
What causes Acute Renal Failure?
Toxin (Ethylene glycol, Lily, Raisins/ Grapes)
Drugs (Aminoglycosides, cisplatin, ampho B, NSAIDS)
Ischemia (Shock, Heat stroke, Addison’s, Hypotension, Systemic inflammatory response)
Hypercalcemia
Infections (Leptospirosis, Rocky Mountain spotted fever, Lyme disease [Borreliosis])
Immune-mediated disease, Neoplasia
What causes Chronic Renal Failure?
Age-related Congenital (renal dysplasia) Cardiac disease (chronic low perfusion) Inherited tubular disease (Fanconi’s) Glomerular disease (Protein-losing nephropathy) Chronic pyelonephritis Ureteral obstruction Renal calculi Recovered ARF
Following initial diagnosis with renal failure, how long do dogs and cats live? (In other words, what is the long-term prognosis?)
Can be widely variable for both.
Dogs: range of 100-300 days (some much less)
Cats: Depending on stage at diagnosis, can live for a relatively long time
Stage 4 – 30 days
Stage 1 – 1200+ days
Why does oliguria or anuria cause hyperkalemia?
The kidneys are the primary excretory mechanism for potassium.
What 2 factors independently reduce survival (shorten lifespan, reduce prognosis) in both dogs and cats with chronic renal failure?
Hypertension
Proteinuria
What are clinical manifestations of hyperkalemia?
Cardiac abnormalities, weakness, death Cardiac signs: Bradycardia Loss of P waves Wide, bizarre QRS complexes
How is hyperkalemia treated?
IV fluid therapy to rehydrate and improve urine output
Resolve any urinary obstruction or leakage
Drugs (all IV emergency drugs):
Regular insulin IV – shifts K+ into cells
Administer dextrose concurrently
Na Bicarbonate – shifts K+ into cells
Calcium gluconate – Protects myocardium until other treatments can work
what signs are consistent with ethylene glycol toxicity, and how is it treated?
History of exposure or possible exposure
Erratic behavior (can seem “drunk” early in exposure)
Intense PD early on
Metabolic acidosis, hypocalcemia
Calcium oxalate crystalluria
ARF (Grave prognosis at this stage)
Tx: Fomepazole (dogs), Ethanol (dogs or cats), induce vomiting if recent exposure.
What criteria do you use to decide between recommending in-hospital vs. at-home management of RF?
Hospitalize if: ARF (or treating toxin to avoid ARF) Dehydration Hypercalcemia Hyperkalemia Significant uremia (vomiting, nausea) At home therapy if: Eating, well hydrated, stable CRF
How do you monitor an animal receiving intravenous fluid therapy?
Monitor catheter and delivery system (appropriate rate, catheter functioning normally)
Physical parameters: Body weight, heart rate, respiratory rate, skin turgor, mucous membrane moisture, body temperature, urine output
Laboratory parameters: PCV, total protein, sodium, potassium, chloride
What is the fluid dose for hypovolemia?
Treat both dogs and cats to “end points”
Dogs:
Up to 80-90 ml/kg crystalloid or 20 ml/kg colloid rapidly IV – administer ¼ to 1/3 calculated dose and re-evaluate
Cats:
Up to 50-60 ml/kg crystalloid or 10-20 ml/kg colloid rapidly IV – administer ¼ go 1/3 calculated dose and re-evaluate
What is the fluid dose for dehydration?
Various formulas are used for maintenance. Most involve BW x 45-60ml, administer over 24 hours
Formula:
Maintenance + Dehydration + Ongoing loss
Dehydration: (% Dehydr)(BW kg)(1000ml/kg)
Ongoing loss: “Guesstimate” – may not need this
Clinical signs of hyperkalemia?
Bradycardia (usually)
EKG changes in order:
Tall, tented T waves
Diminished/ absent P waves
Wide, bizarre QRS complexes
AsystoleTreatments for hyperkalemia? (Remember how potassium leaves the body?)
Increase K excretion:
IV fluid therapy
Establish/ insure urine output
Move K around (shift into cells):
Regular insulin IV + dextrose (2o hypoglycemia)
Sodium bicarbonate IV
Keep the dying heart happy until other drugs work:
Calcium gluconate (Reserve for severe EKG)
