Proteinuria Flashcards
What are the 3 layers that make up the filtration barrier of the glomerulus?
- Fenestrated capillary endothelium
- Glomerular basement membrane
- Podocyte
What is filtered through the glomerulus?
Anything bigger that 60-70,000 daltons is retained
A. Smaller solutes and water are freely filtered
B. Albumin is 69,000 daltons and is barely retained. A tiny amount may get through but is resorbed under NORMAL conditions.
What is proteinuria an indicator of?
Glomerular permeability, tubular dysfunction, or disease in the body.
Which diseases are associated with proteinuria?
- Kidney disease
- Hyperadrenocorticism
- Neoplasia
- Immune mediated diseases
- Infectious diseases
Why is proteinuria harmful?
- Contributes to renal damage with inflammation and fribrosis over time
- Thromboembolic events are possible with the loss of antithrombin III
- Concurrent or consequential hypertension
- Nephrotic syndrome (end stage proteinuria)
What are the components of nephrotic syndrome?
Proteinuria, hypoalbuminemia, hypercholesterolemia, and edema
Proteinuria leads to a loss in albumin. Cholesterol tries to compensate for a loss of oncotic pressure be raising its levels. Cholesterol is ultimately unsuccessful and edema results.
Which three things make up proteinuria?
Pre-renal, Renal, and Post-renal
What are some examples of Pre-renal proteinuria?
Caused by an abundance of protein that overwhelms the resorptive capacity of the kidneys.
Examples include hemoglobin, myoglobin, etc.
What are the two types of Renal proteinuria? Explain the two types
Pathologic: A defect in the glomerular filtration, tubular resorption, or interstitial damage. Most persistent cause of and contributes the highest levels of proteinuria
Functional: A mild/transient value that may be from heat, stress, seizure, venous congestion, fever, or exercise. It will resolve once the underlying cause is corrected
Explain post-renal proteinuria?
Protein in the urine from a post kidney source. Examples include UTIs, inflammation, and hemorrhage. It is not persistent once the underlying condition is resolved.
How do you determine if proteinuria is persistent?
Repeat the testing. Can do multiple samples 2 weeks apart.
What does a positive urine dipstick (1+, 2+, 3+) tell you?
You need to confirm with a UPC to measure the degree of proteinuria. It is not a substitute. It can be falsely affected by many things like active sediment, prolonged contact time, or alkaline urine.
Explain the UP/C
Should be measured to quantify the protein in the urine only if there is no evidence of urinary tract inflammation or hemorrhage. Do two urine samples collected over a week period.
What about microalbuminuria?
Just know it exists and we don’t know the implications
When should I monitor the UP/C?
When the patient is:
- Non-azotemic with persistent/steady microalbuminuria
- Non-azotemic with UPC less than 0.5
Goal is to identify renal proteinuria having ruled out post and pre renal causes
When should diagnostics be run to identify the cause of proteinuria?
- If borderline proteinuria on a UP/C is detected, reevaluate in 2-4 months
- If proteinuria on a UP/C is repeatably (2 or more UP/Cs) >0.4 in a cat or >0.5 in a dog
What are some of the therapeutic options for controlling proteinuria?
Ace inhibitors, Angiotensin II receptor blockers, and Omega 3 fatty acids
What benefit do Ace inhibitors provide? Give an example of an ace inhibitor?
Decreases arterial resistance by dilating the efferent arteriole. Result is decreased glomerular pressure causing less protein to be pushed out.
Benazepril
What are the effects of an Angiotensin II antagonist? Give an example of the medication
Binds to the angiotensin II receptor and blocks its activity (decreasing aldosterone release and subsequent Na/H20 retention). Add in with the ace inhibitor if needed to help decrease hypertension, but start with just ace inhibitor first.
Telmisartan
What do Omega 3 fatty acids do?
Anti-inflammatory and reduce platelet activity
Why do you need to prevent thromboembolic events associated with proteinuria?
Because of anti-thrombin III loss leads to predisposition of clots occurring
How do you prevent thromboembolic events?
Clopidogrel: It acts on platelets
If hypertension is unresolved after an ace inhibitor, what should you consider adding?
A. Telmisartin
B. Amlodipine: A vascular smooth muscle and cardiac muscle relaxant
