clinical tools

Question 1

problem with serum creatinine as measure of GFR

Answer 1

small changes in the low range result in dramatic calculated changes in GFR, so better to measure over time

Question 2

increased creatinine reflects ____ GFR

Answer 2

decreased

Question 3

how do you correct SCr for differences in muscle mass due to age, ethnicity, and sex?

Answer 3

use the MDRD equation

Question 4

creatinine clearance is preferred over SCr in patients with?

Answer 4

near normal GFR, pregnancy, amputees, severe liver dz, extremes of age and weight

Question 5

how do you calculate creatinine clearance?

Answer 5

(urine creatinine X total urine volume)/(plasma creatinine*1140min/day)

Question 6

MDRD should be used when GFR is?

Answer 6

less than 60

Question 7

___ is expensive but very accurate at detecting residual GFR

Answer 7

radionucleotide GFR scanning

Question 8

who should receive radionucleotide GFR scanning?

Answer 8

pts with CKD, impaired GFR, renal cell carcinoma, pre-transplant in cases of advanced liver dz, liver donors

Question 9

when should a CKD pt be considered for dialysis?

Answer 9

plot eGFR over time and consider dialysis when consistent/linear decline results in eGFR below 10

Question 10

urine protein/creatinine ratio is used to estimate urinary protein excretion because?

Answer 10

it is unaffected by urine volume or concentration

Question 11

urine protein/creatinine ratio is effective for protein excretion in what range?

Answer 11

0.3-3g (overt proteinuria)

Question 12

if urine protein excretion is less than 0.3g, then you should use the ___ instead

Answer 12

albumin/creatinine ratio (less than 30mg in normal)

Question 13

red urine is a sign of..

Answer 13

secondary tumor of bladder (gross hematuria)

Question 14

tea colored urine is a sign of?

Answer 14

glomerular hematuria

Question 15

if urinalysis shows a dramatic change in protein after sulfa-salicylate is administered, then this is a sign of?

Answer 15

light chains (multiple myeloma)

Question 16

detection of nitrites and leukocyte esterase on urine dipstick indicate?

Answer 16

UTI

Question 17

exogenous solute will ____ urine osmolarity relative to urine specific gravity

Answer 17

decrease

Question 18

these renal injuries do not affect urine sediment

Answer 18

pre-renal, post-renal

Question 19

RBCs, RBC casts, and proteinuria are signs of?

Answer 19

glomerulonephritis, vasculitis, TMA, atheroemboli

Question 20

WBCs, WBC casts are signs of?

Answer 20

pyelonephritis, interstitial nephritis

Question 21

eosinophils in the urine are a sign of?

Answer 21

allergic IN, atheroemboli, glomerulonephritis

Question 22

RTE cells, pigmented casts are a sign of?

Answer 22

tubular endothelial injury (ATN): ischemic or nephrotoxic

Question 23

monomorphic red cells are typically seen with?

Answer 23

UTI, tumors, stones

Question 24

dysmorphic red cells are typically seen with?

Answer 24

glomerulonephritis (parenchymal dz)

Question 25

acanthocytes look like _____ and are a sign of?

Answer 25

"Micky Mouse" cells; glomerulonephritis

Question 26

squamous epithelial cells in urine are a sign of?

Answer 26

poor urine specimen (not midstream)

Question 27

transitional epithelial cells are ____ than renal tubular epithelial cells and indicate?

Answer 27

larger; inflammatory process (UTI, catheter) as opposed to renal tubular injury

Question 28

the combination of white cells in urine + bacteria is consistent with?

Answer 28

urinary tract infection

Question 29

why do "casts" form in the urine?

Answer 29

Tamm-Horsfall protein gels in conditions of high concentration (collecting duct, distal tubule), creating casts that are reflective of tubule contents

Question 30

hyaline casts are made of ___ and seen in states of?

Answer 30

only tamm-horsfall protein; hypovolemia or decreased renal perfusion

Question 31

evolution of a cast over time?

Answer 31

course granular -> broad/fine granular -> waxy

Question 32

coarsely granular casts are indicative of?

Answer 32

renal parenchymal disease (acute or chronic)

Question 33

muddy brown casts are composed of ____ and indicative of ____

Answer 33

necrotic tubular epithelial cells; ATN (ischemic or nephrotoxic)

Question 34

white cell casts are indicative of?

Answer 34

interstitial nephritis or pyelonephritis

Question 35

fine granular casts are indicative of?

Answer 35

renal parenchymal disease (acute or chronic)

Question 36

fatty casts are seen in?

Answer 36

patients with nephrotic range proteinuria

Question 37

how do you make a fatty cast stand out?

Answer 37

polarizing microscopy (lipoproteins look like Maltese Crosses)

Question 38

oval fat bodies are _____ and are most commonly seen in?

Answer 38

epithelial cells with excess lipoprotein; nephrotic syndrome or severe ATN

Question 39

waxy casts are most commonly seen in?

Answer 39

advanced chronic kidney disease (nephrons with especially decreased flow)

Question 40

uric acid crystals are ____ shaped, form in urine when the pH is ___, and are seen in?

Answer 40

tear; <5.5; uric acid stones or tumor lysis syndrome, sometimes type 2 diabetes

Question 41

calcium oxalate crystals are shaped like ____ and most commonly seen in...

Answer 41

pyramids (look like a cross from top view); typical kidney stones or ethylene glycol poisoning

Question 42

an increased anion gap and increased osmolar gap suggests?

Answer 42

ethylene glycol poisoning

Question 43

crystine crystals are ____ shaped and indicate?

Answer 43

hexagon; a defect in the dibasic aminoacid transporter (rare, but more common cause of stones in kids)

Question 44

"coffin-lid" shaped crystals are made of _____ and typically seen in the setting of?

Answer 44

Mg-Ammonium-Phosphate; very high urine pH (>7) such as chronic UTI with urea-splitting organisms

Question 45

triple phosphate crystals are known as ____ stones; how are they excreted?

Answer 45

struvite; often very large and have to be surgically removed

Question 46

rosette or spindle shaped crystals are made of _____ and form when urine pH is _____

Answer 46

calcium-phosphate; >6

Question 47

who gets calcium-phosphate stones?

Answer 47

type 1 distal RTA, tumor lysis syndrome