Renal function and Labs Flashcards
relationship between serum creatinine and concentration and GFR
non linear every GFR halves, the serum creatinine doubles 50 GFR, Cr is 2.0
Example: GFR 25 Cr? GFR 12.5
Cr 4 and Cr 8
What affects BUN?
High protein diet, upper GI bleed, anti anabolic effects of corticosteroids (can increase GFR without increasing Cr)
Neither BUN/Cr ratio nor small changes in BUN are helpful indcators of GFR.
what can causes elevated Cr?
trimethoprim and cimetidine can increase serum and creatinine without decreasing GFR.
can also seen Cr increase without GFR decrease can be seen with ketone and cefoxitine and flucytosine.
what is seen on urine sodium lab for pre renal AKI?
see volume depletion with prerenal AKI and so will see spot urinary sodium level <20 mEq/dl.
should we be alarmed when resolved obstructive uropathy has high UOP?
no post obstructive uropathy has a post obstructive diuresis ( as kidney) tries to excrete retained fluid
rate can be at 500-1000cc/hr
type of proteinuria types and mechanism and suggested evaluation
what is isolated proteinuria?
proteinuria without hematuria or elevated serum creatinine
orthostatic proteinuria is a
condition seen in kids, adolescents, and young adults <30 yrs. Seen with significant proteinuria in upright position but minimal proteinuria in a supine position.
Long term follow up individuals with condition shown resolution or proteinuria with advancing age wihtout development of renal failure.
how to diagnose orthostatic proteinuria?
get a spot urine sample for protein/cr to quantify the protein amount.
Collect in the AM with first morning void - should have little protein
Then collect later in the day after being in the upright position - should have protein
If there’s no protein in the supine position compared to significant proteinuria in upright position supports diagnosis of orthostatic proteinuria (benign condition)
orthostatic proteinuria is seen in
children and young adults 2-5%
see about 1g/day of protein but can have up to 3g/day in some pts.
the 3 formulas that estimate GFR actually underestimate it and
least accurate for people who have normal GFR. >60 ml/dl is the best they can do
also must be in a steady state clinical setting. not validated in obese pts.
They are most accurate for people who have CKD or GFR<60
Common Side effects of tacrolimus and cyclosporine
both drugs are metabolized by cytochrome P450 and excreted into bile. Thus it can interact with hepatic cytochrome P450 can alter the drug’s level and effect.
things like grapefruit juice can increase the levels.
