Facts about Kidney Disease Flashcards
(43 cards)
1
Q
Why are kidneys susceptible to injury?
A
- Filter 25% of blood from each cardiac cycle
- Medulla poorly perfused
- Concentrates some drugs/toxins
2
Q
What are the main functions of the kidney?
A
- Maintain body water balance
- Concentrate urine
- Excrete waste products
- Make hormones
- erythropoietin, active vitamin D, renin/angiotensin
3
Q
What goes wrong in renal failure?
A
- Kidneys can’t regulate water = dehydration
- Can’t excrete waste = uremia
- Can’t make hormones = anemia, renal secondar hyperparathyroidism
4
Q
How do you diagnose renal failure?
A
Appropriate history and clinical signs
Concurrent azotemia and isosthenuria
5
Q
What’s different when diagnosing RF in cats?
A
Can become azotemic before entirely losing urine concentrating ability
6
Q
How does outcome and prognosis differ between acute (ARF) and chronic (CRF) renal failure?
A
- Acute: poor short term prognosis (px) (~50% die)
- Chronic: can remain compensated and respond to supprotive therapy, but no cure long-term
7
Q
Anuria
A
No urine output (<0.1 ml/kg/hr)
8
Q
Oliguria
A
<0.25 - 0.5ml/kg/hr
9
Q
Polyuria
A
> 2 ml/kg/hr
10
Q
Polydypsia
A
50-100 ml water consumption/kg/day
11
Q
Distinguishing features of ARF
A
- Recent (< 7 days) onset illness
- History: toxin, ischemic event, really uremic
- Renal size: normal to large +/- painful
- Anuria/oliguria possible (can be polyuric)
- Normal body condition score
- Really “sick” (uremic) for degree of axotemia
12
Q
Distinguishing features chronic renal failure
A
- 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
13
Q
What stages are described in the Chronic Kidney Disesae Staging System
A
- Stages 1-4
- Stage 1: mild clinical signs, not yet azotemic
- Stage 4: severe renal disease (creatinine > 5 mg/dl)
14
Q
What causes acute renal failure?
A
- Toxin (ethylene glycol, lily, raisins/grapes)
- Drugs (aminoglycosides, cisplatin, amphotericin 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
15
Q
What causes chronic renal failure?
A
- 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
16
Q
Following initial diagnosis with renal failure, how long do dogs and cats live? (in other words, what is the long-term prognosis?)
A
- Can be widely variable for both
- Dogs range from 100-300 days (some much less)
- Cats: depending on stage at diagnosis, can live for relatively long time
- Stage 4 - 30 days
- Stage 1 - 1200+ days
17
Q
What 2 factors independently reduce survival (shorten lifespan, reduce prognosis) in both dogs and cats with chronic renal failure?
A
Hypertension + Proteinuria
18
Q
Why does oliguria or anuria cause hyperkalemia?
A
The kidneys are the primary excretory mechanism for potassium.
19
Q
What are clinical manifestations of hyperkalemia?
A
- Cardiac abnormalities, weakness, death
- Cardiac signs:
- Bradycardia
- Loss of P waves
- Wide, bizarre QRS complex
20
Q
How is hyperkalemia treated?
A
- 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-bicarb - shifts K+ into cells
- Calcium gluconate - protects myocardium until other treatments can work
- Regular insulin IV - shifts K+ into cells
21
Q
What signs are consistent with ethylene glycol toxicity?
A
- History of exposure or possible exposure
- Erratic behavior (can seem “drunk” early in exposure)
- Intense polydipsia early on
- Metabolic acidosis, hypocalcemia
- Calcium oxalate crystalluria
- ART (grave prognosis at this stag)
22
Q
Treatment of ethylene glycol toxicity
A
Fomepazole (dogs)
Ethanol (dogs or cats)
Induce vomiting if recent exposure
23
Q
What criteria do you use to decide between recommending in-hospital vs at-home management of renal failure?
A
- 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
24
Q
How do you monitor an animal receiving intravenous fluid therapy?
A
- Monitor catheter and delivery system (appropriate rate, catheter functioning normally)
- Physical parameters: body weight, heart rate, respiratory rate, skin turgor, mucous membrane moisture, body temp, urine output
- Lab parameters: PCV, total protein, sodium, potassium, chloride
25
What is the fluid dose for hypovolemia?
* Treat both dogs and cats to "end poitns"
* Dogs:
* Up to 80-90 ml/kg crystalloid or 20 ml/kg colloid rapdily IV
* Administer 1/4 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 1/4 to 1/3 calculated dose and re-evaluate
26
What is the fluid dose for dehydration?
* Various formulas are used for maintenance
* Most involve BW x 45-60 mL, administer over 24 hours
* Formula:
* Maintenance + dehydration + ongoing loss
* Dehydration = (% dehydration)(BW kg)(1000ml/kg)
* Ongoing loss = "guesstimate" - may not need this
27
Clinical signs of hyperkalemia?
* Bradycardia (usually)
* EKG changes in order:
* Tall, tented T waves
* Diminished/absent P waves
* Wide, bizarre, QRS complexes
* Asystole
28
Treatments for hyperkalemia
* Increase K excretion
* IV fluid therapy
* Establish/ensure urine output
* Move K around (shift into cells)
* Regular insulin IV + dextrose (2% hypoglycemia)
* Sodium bicarbonate IV
* Keep the dying heart happy until other drugs work:
* Calcium gluconate (reserve for severe EKG)
29
Treatments for oliguria/anuria
1. Make sure hydration is appropriate!
2. Stop M + dehydr + OL fluid plan
3. New fluid plan: ins and outs
1. 20 ml/kg/day + additional fluid replacement to exactly match urine output
4. Start drugs to increase urine output
30
What drug treatments are used to improve urine output?
Make sure hydration is appropriate before starting any of these!!!
1. Mannitol (osmotic diuretic)
2. Furosemide (loop diuretic)
3. Low-dose dopamine (changes renal blood flow - may not work)
31
What if animal remains oliguric/anuric despite hydration and appropriate drug treatment?
Euthanasia vs dialysis
32
What is dialysis?
Removal of uremic toxins by means other than renal filtraiton (hemo-, peritoneal dialysis)
33
Does dialysis cure ARF?
Does not cure RF, but may provide time for kidneys to heal.
34
Who do I call when deciding dialysis?
Very costly, complicated and not widely available.
Call your referral internist or criticalist if you think you have a case.
35
Uremia Consequences and Treatments
* Oral - ulcers, tongue tip necrosis - good dental care, oral disinfectants
* GI - gastritis, vomiting, ulcers, colitis - acid reduces (H2 blockers, proton pump inhiibitors), antiemetics (maropitant, metoclopramide)
* CNS: reduced mentation - resolve azotemia. monitor carefully
* Respiratory - uremic pneumonitis (ARDS) - resolve azotemia, be careful with overhydration - at risk of ARDS
* Probably pancreatitis
36
What causes anemia of CRF? Treatment?
* Absence of RBC progenitor stimulation - Erythropoietin
* Treatment: look for other causes of anemia (avoid tunnel-vision)
* Minimize blood draw volumes
* Human recombinant erythropoietin (careful - side effects)
37
When is outpatient SQ fluid therapy reasonable?
* Cats, and occasionally small dogs (more painful!)
* Use to maintain hydration if oral water intake not optimal (NOT a tx for dehydration)
* Dose ~1/3 of calculated maintenance dose
* Frequency: usually daily to EOD
* Type: 0.9% NaCl or LRS, NOT plasma-lyte (painful)
38
Dietary Management Principles in CKD
* Renal type diets increase survival and delay uremic episodes in CKD
* "Renal-type" = low protein, phosphorous, high omega-3 fatty acids
* Won't prevent CKD
* Initiate diet change when the animal feels well to prevent "food avoidance"
39
Managing Hyperphsphatemia
1. Maintain hydration
2. Feed renal-type diet
3. Phosphate binders:
1. Aluminum hydroxide (antacids like Amphojel)
2. Calcium carbonate (Tums)
3. Veterinary product Epakitin - CaCarbonate + chitosan
40
CKD sometimes causes renal tubular potassium wasting, especially in cats. How to manage hypokalemia?
* Administer potassium supplementation (oral preferred)
* KCl in IV fluids CRI (NOT bolus - deadly!!)
* K gluconate orally as needed
41
Managing Azotemia
* Maintain hydration
* "Enteric dialysis" - azodyl supposedly traps uremic toxins in the GIT so they are NOT absorbed into the body
* Voodoo? Maybe - but seems to lower BUN and might help - won't hurt
42
Kidney transplant does NOT cure kidney disease. What are the pros/cons of kidney transplantation?
* Provides some functional renal tissue to prolong quality and length of life, but does not "cure" CKD
* Cats can get transplant, but not dogs (rejection)
* Expensive
* Lifelong immunosuppression
* MANY complications
43
End-result of CKD
* All CKD becomes end-stage at some point
* Euthanasia appropriate if anuric, or if clinical signs of uremia cause poor quality of life, or if client wishes to euthanize
