Glomerular Disease & Hypertension Flashcards
how does the glomerulus control filtration
contains small pores that prevent filtration of large proteins
negatively charged to prevent passage of significant amounts of protein
what happens to small proteins that pass through the glomerulus
taken up by renal tubular epithelial cells and degraded by lysosomes
receptor mediated - can get saturated if too many proteins pass through
proteinuria
the presence of abnormal amounts of protein in the urine
indicative of kidney damage IF the proteinuria is renal in origin
UPC for proteinuria
dogs: UPC > 0.5
cats: UPC > 0.4
UPC for DEFINITIVE non proteinuria
UPC < 0.2
in both dogs and cats
urine protein creatinine ratio
measures the amount of protein in the urine relative to the amount of creatinine
normal UPC
< 0.5
UPC for significant proteinuria
> 2.0
UPC for glomerular disease
UPC > 5.0
UPC for amyloidosis
UPC > 8-12
prerenal proteinuria
excessive amount of small proteins that fit through a normal glomerulus
- hemoglobin
- myoglobin
renal proteinuria
can be functional/transient vs pathologic
functional: caused by an underlying condition; will resolve when condition is treated
- fever, seizures, cortisol, hypertension
pathologic:
- glomerular damage
- tubular damage
postrenal proteinuria
entry of proteins into the urine after it enters the renal pelvis
enters at the ureter, bladder, prostate or urethra
ddx: cystitis, prostatic disease, hematuria, tumors
what is microscopic hematuria
urine appears yellow but >100 RBCs on UA
should NOT impact UPC
consequences of proteinuria
- progression of renal tubular disease
- hypoalbuminemia
- altered coagulation
- hyperlipidemia
- nephrotic syndrome
how does proteinuria cause renal tubular disease to worsen
albumin in the urine is nephrotoxic –> azotemia
can lead to or worsen hypertension
effects of hypoalbuminemia due to urinary losses
leads to interstitial fluid overload –> edema and ascites w/ poor perfusion parameters
altered drug metabolism
how does proteinuria cause altered coagulation
loss of antithrombin in the urine
increases risk of thromboembolic disease
how does proteinuria cause hyperlipidemia
urinary loss of albumin –> liver goes into overdrive to try and produce more –> overactive liver also increases cholesterol and triglyceride production
nephrotic syndrome
indicates a more severe PLN
(low albumin + high cholesterol –> PLN)
includes all 4:
1. proteinuria
2. hypoalbuminemia
3. hypercholesterolemia
4. edema/ascites
how to diagnose proteinuria
- urinalysis + dipstick
- UPC ratio
interpretation of UA/dipstick results
only detects proteinuria at > or = 30 mg/dL
always interpret alongside USG - expect more protein in concentrated urine
if negative for protein on UA –> no further testing
if positive for protein on UA –> perform a culture before proteinuria workup
is UPC ratio more or less accurate than dipstick
more accurate- not affected by USG
always perform TWO UPC ratios at different times to determine if transient or persistent
if borderline proteinuria –> recheck in 2-4 weeks
if persistent proteinuria –> consider workup
treatment for PLN
- treat underlying cause (if present)
- low to moderate protein diet
- treat proteinuria
- ACE inhibitors
- ARBs
- Amlodipine (if severe hypertension) - omega 3 FAs
- clopidogrel
ACE inhibitors
prevents constriction of efferent arterioles –> decreases pressure across the glomerulus + decreases protein loss into tubule
do NOT use with severe azotemia because will decrease GFR
first choice for non-azotemic patients
angiotensin receptor blockers (ARBs)
telmisartan
synergistic effects with ACE inhibitors
role of clopidogrel in PLN treatment
prevents thromboembolic disease and fibrin deposition in the kidneys
can a patient have significant glomerular proteinuria without azotemia
yes - if early primary glomerular disease with NORMAL GFR and tubular cells
glomerular proteinuria
damage to the glomerulus causing protein loss into urine
- immune mediated vs non-immune mediated
determine if glomerular proteinuria by ruling out pre and post renal causes in prior workup
how to work up glomerular proteinuria
rule out underlying disease that causes immune mediated disease
- UA, culture, UPC x2 (should have already performed at this point)
- minimum database
- abdominal US
- thoracic radiographs
- blood pressure
- fundic exam
- infectious disease testing
- antithrombin testing
- renal biopsy
renal biopsy
evaluates for underlying immune mediated disease
- can diagnose immune complex glomerulonephritis vs amyloidosis
entire biopsy needs to be through the cortex (“parallel” to kidney) and avoid the medulla
ALWAYS do coag testing prior to biopsy and avoid clopidogrel
immune mediated PLN treatment
- immunosuppressive therapy
- mycophenolate - general PLN treatment
- low/mod protein diet
- ACE Inhibitors, ARBs
- omega 3 FAs
- clopidogrel
monitoring while on ACE inhibitors
ACE inhibitors can decrease proteinuria by reducing glomerular hypertension
always monitor for progression of azotemia secondary to ACE inhibitors
