7. Clinical Assessment of Renal Function Flashcards
creatinine: what is it, what does its serum level depend on?
waste product from muscle
depends on muscle mass, age, sex
creatinine: how long does it take for the serum level to rise after renal injury?
after acute renal inj, can take ~5d for serum creatinine to rise
if an elderly patient has a normal serum creatinine, what should I be thinking?
may be normal; may also be high for this patient given that elderly usually have low muscle mass
we can use creatinine clearance to estimate what?
creatinine clearance correlates with GFR: urine creatinine levels can therefore estimate GFR. need a 24 hr urine sample
when GFR decreases, how will BUN and serum creatinine levels change?
both will rise
if the BUN to serum creatinine ratio is >20:1 (very high) what is going on?
prerenal azotemia (hypovolemic injury to kidney). causes BUN to rise more than creatinine
how are serum and urine creatinine levels used to estimate GFR?
i have no effing clue but i need to figure it out
what is the spectrum of GFRs encompassed by Stage 1 thru 5 chronic kidney disease?
Stage 1 GFR: >90
Stage 5 GFR <15 or dialysis
anuria defined as how much urine volume per day?
<50 cc. acute renal failure, possibly life-threatening
oliguria defined as how much urine volume per day?
<500 cc. acute renal failure, possibly life-threatening
normal range of urine production?
500-3000cc/day
definition of polyuria? a few causes?
> 3000cc/day. causes: polydipsia, diabetes insipidus, DM
urine dipstick: what do ketones indicate?
possible DKA, if high glucose as well
urine dipstick: if proteins are low but other tests indicate high urine proteins, what is possible?
Bence-Jones proteins. suggest multiple myeloma
urine dipstick: what does specific gravity indicate?
concentration of urine: dilute = 1.001, concentrated = 1.040. isosthenuria = 1.015
what is isosthenuria/what does it indicate?
urine is isosmotic with plasma. possible renal insufficiency (not concentrating urine)
nephritic syndrome: a few findings? what processes does it indicate?
Hematuria
Oliguria
Azotemia (incr. urea, creatinine, N-rich compounds)
HTN
AHHO
Sx: edema, flank pain, incr creatinine.
indicates that problem is on the capillary lumen side (in contact with bloodstream)
nephrotic syndrome: a few findings? what processes does it indicate?
proteinuria, edema, hypoalbuminemia, hyperlipidemia.
PEHHing proteins
indicates lesion of epithelial cells and/or glo BM. not in contact with bloodstream –> no hematuria
acanthocytes: definition, what do they indicate?
RBCs that crossed the basement membrane and were damaged in transit. indicate glomerularnephritis
lipids in the urine indicates what?
nephrotic syndrome. will appear as oval fat bodies, fatty casts, cholesterol crystals. Fatty casts look like RBC casts but particles vary in size
cysteine crystals: appearance? indicate what?
hexagonal crystals. pathognomic for kidney stones
RBC casts indicate what?
glomerulonephritis, inflammation
Fatty casts indicate what?
nephrotic conditions. liver increases albumin production to make up for loss, also upregs production of lipoproteins –> lipiduria
WBC casts indicate what?
inflammation of tubules and interstitium of kidney
waxy/granular casts indicate what?
various stages of degeneration of casts, therefore nonspecific. can ben seen in a variety of conditions
muddy brown casts: made of what? indicate what?
acute tubular necrosis (ATN). made of tubular epithelial cells
butterfly rash on face indicates what condition?
lupus
hemoptysis and pulmonary infiltrates indicate what condition?
Goodpasture’s (renal/pulm condition)
deafness may indicate what disease?
Alport’s
Ash leaf spots may indicate what disease?
tuberous sclerosis
