Renal Failure Flashcards
Kidney Function
FLuid balance
Electrolyte and acid-base balance
Waste removal
Drug excretion
BP control
Hormone production
Functions - Gone Wrong
Fluid balance
- Reduced conc ability
Electrolyte & Acid-Base Balance
* Hypokalemia (CKD), hyperkalemia (AKI), hyperphosphatemia (both)
* Metabolic acidosis
Waste removal and excretion
* Nephron destruction → reduced GFR → reduced urinary excretion of waste → azotemia →
uremia
Blood pressure control
* Activation of RAAS → Hypertension
Hormone Production
* Erythropoietin (EPO) – non regenerative anemia
* Calcitriol (Vitamin D) – renal secondary hyperparathyroidism
Clinical Signs
Dehydrated
Weight loss
Blood in anterior chamber - high BP
Vomiting
Muscle weakness - low K+
Pale MM = Anaemia
Hx - Specific Qs
PU/PD
- Cats >45ml/kg/d
- Dogs >100ml/kg/d
Dysuria, pollakiuria, haematuria, nocturia
Exposed to nephrotoxins
Meds
Exam
Hydration
Oral cavity
Fundic exam
Abdo palp - assess kidneys, bladder
Prostate gland and genital areas
Assess Glomerular Filtration
Indirect
- Creatinine
- Urea
- SDMA - early KDx
Direct
- Urinary clearance
- Plasma clearance
- Renal scintigraphy
Assess Glomerular Barrier
Proteinuria
Assess Tubular Function
Urinalysis
Stone analysis
Blood gas analysis
Protein:creatinine ratio
Assess Fluid Balance
Urine specific gravity
Assess Endocrine
PCV, haematology
Ca,
Phosphate - Hyperphosphataemia
- CKD
- -> 2° hyperparathyroidism
Assess Control of BP
Measure BP
Fundic exam
Potassium
Hyperkalaemia -> AKI
- Life threatening
- -> bradycardia
Hypokalaemia -> CKD
- Cats
- PU, muscle weakness
- Lethargy, constipation, inappetent
Haematology
Non-regen anaemia - CKD
Causes
* Insufficient erythropoietin production
* GIT bleeding
* Poor nutrition
* Reduced red cell lifespan
Proteinuria
Glomerular Dysfunction
- Large proteins filtered, not absorbed
- Severe proteinuria
Tubular Dysfunction
- Small proteins filtered normally
- No absorption
- Proteinuria
Pre-renal (haemoglobin, myoglobin, myeloma)
Renal (glomerular, tubular, interstitial)
Post-renal (urine sediment: bacterias, urolithiasis, neoplasia)
Blood Pressure - Hypertension Signs
Eyes
➢Retinal h+, retinal detachment, hyphema, vascular tortuosity
Nervous system
➢Behaviour changes
Renal system
➢Worsening proteinuria, decreased urine conc
Cardiovascular system
➢New murmur, arrhythmia, gallop rhythm
Misc Tests
Endocrine disease testing
o Hyperthyroidism
o Hypothyroidism
o Hypoadrenocorticism
Infectious disease testing
o Leishmania & Ehrlichiosis → CKD
o Leptospirosis & Babesiosis → AKI
Glomerular filtration rate
o renal function in non azotemic dogs
o In dogs <1.5ml/min/kg abnormal
o Requires eval of Iohexol clearance utilising serial blood samples
Limitations - Urea
- Late marker
- Low specificity and sensitivity
- Affected by liver disease, GI
bleeding, high protein diet
Limitations - Creatinine
- Late marker
- Low specificity and
sensitivity. > pre-renal, renal, post renal diseases - Affected by muscle mass
- 75% kidney function loss
Limitations - USG
- Late marker
- Not 100%
specific or sensitive to identify renal disease - 60-70% loss of function
Limitations - SDMA
- Early marker
- Not 100% specific
or sensitive to identify renal disease. Can > due to pre-renal and post renal diseases
Acute Kidney Injury
- Rapid reduction in renal function
- Increase in creatinine
- Decrease in urine output
AKI - Stages
Stage 1: Initiation phase
➢Period of exposure to the cause.
➢Non azotemic.
Stage 2: Extension phase
➢Localised inflammation and
ischaemia.
Stage 3: Maintenance phase
➢Moderate to severe azotaemia.
➢Rapid rise in creatinine and urea.
Stage 4: Recovery phase
➢ -> scar formation and only partial return of tubular function.
Chronic Kidney Dx
Irreversible
Progressive
Long periods before signs
Increase w age
CKD - Causes
- No 1° cause ID.
- Neoplasia
- Polycystic kidney disease
- Renal amyloidosis
- Hypercalcaemic nephropathy
- Pyelonephritis
- Periodontal disease
