deck 4 Flashcards
what casts are assciated w/ nephrotic syndrome?
fatty casts
what does high specific gravity indicate?
dehydration and shock
what do transitional epithelial cells (urothelial cells) indicate?
possible neoplasm
what are the types of crystals?
uric acid, calcium phosphate, cystine, struvite
what do eosinophils indicate?
allergy
what does dipstick test for blood?
erythrocytes, free hemoglobin, and myoglobin
best ua sample
clean catch, midstream, 1st morning void
what do casts often suggest?
renal parenchymal disease
what do crenated RBCs indicate (shrunken/scalloped)?
concentrated urine
what casts are indicative of tubules that have become dilated and atrophic due to chronic parenchymal disease and end stage renal disease?
broad casts
what do squamous epithelial cells indicate?
contamination >10/HPF repeat collecting
what does protein in urine indicate?
often first indication of renal disease, most sensitive to albumin
what doest conjugated bilirubin suggest?
hepatocellular disease
specific gravity show what?
hydration status and concentration ability of kidney, correlates well with urine osmolality
what are struvite crystals?
infection stones, need urease producing organisma such as proteus or klebsiella
what appears as a pear shaped, flagellated organism?
trichomonas
what do you need to do to get microscopic urinanalysis?
request micro, and examined at 10 high powered views
what is nitrite?
gram negative bacteria convert nitrate to nitrite, positive indicated bacterial infection, but negative does not rule out
what do dysmorphic RBCs (irregular) indicate?
nephritic syndrome
what are ketones used for?
screen for ketosis, diabetic ketoacidosis, can be elevated in starvation/fasting/carb free diet, post exercise, pregnancy
where does urine acidify?
DCT and collecting duct
what number of erythrocytes is concerning on microscopy?
> 3 RBCs per HPF, rule out menstruation
false pos and negative for blood?
false pos: menses
false neg: high ascorbic acid intake
what do neutrophils indicate?
bacterial infection
when is BUN decreased?
liver disease, less ammmonia converted to urea
what casts are characteristic of acute pyelonephritis?
WBCs
when is BUN usually elevated?
chronic or acute renal failure, urinary obstuction, dehydration
what does pyuria indicate overall?
urinary tract injury, may or may not be related to infection
what does an increase in urobilinogen indicate?
hemolysis and hepatocellular disease (hepatitis and cirrhosis)
what do renal tubular epithelial cells indicate?
diagnostic for ischemic or nephrotoxic acute tubular necrosis
what casts suggest severe renal stasis and are seen in chronic renal failure?
waxy casts
what is serum creatinine?
means of estimating GFR
when is a BUN: creatinine ratio decreased?
intrinsic renal disease
what is the most important parameter of renal function?
GFR
in actue renal failure, if the FEna is >1%? what does that suggest?
INTRINSIC RENAL DISEASE: the kidney is losing sodium inappropriately
when is BUN usually elevated?
chronic or acute renal failure, urinary obstruction, dehydration (reduced renal perfusion)
what is leukocyte esterase?
produced by neutrophils, when positive indicated WBC in urine
what are the two main mechanisms that control GFR?
blood flow in and out of glomerulus, and control of glomerular surface area
what casts are characterisiticallly sen in acute tubular necrosis?
renal tubular epithelial cell casts, and granular “muddy brown” casts
what is GFR?
amount of filtrate formed by both kidneys per minute
what are you supposed to do if you see bacteria in a uncontaminated specimen?
get it cultured
nitrite false positive?
gross hematuria, contamination
what do you do if dpstick is positive for blood?
confirm w/ microscopic evaluation
what does lower values of specific gravity indicate?
overhydration or impaired ability to concentrate urine
what is considered a positive culture?
100,000 colony forming units
what are cystine crystals?
hereditary cystinuria
when is BUN: creatinine ratio elevated?
pre-renal and post renal azotemia (build up of waste)
what are the hallmarks of glomerulonephritis?
red cell casts, bleeding from glomeruli or renal tubules)
hyaline casts suggest what?
nothing, they are not specific for any renal disease
in acute renal failure, if the kidney FEna <1% what does that suggest?
DECREASED PERFUSION: hypovolemia or dehydration and the kidney is retaing Na to increase intravascular volume
how many leukocytes are concerning on microscopy?
> 5 leukocytes/HPF considered pyuria
fals pos and negative for leukocyte esterase?
false pos: specimen contamination
false neg: not waiting long enough prior to testing
tools to calculate GFR?
cockroft gault, modification of diet in renal disease
how long to use urine sample?
w/in 1 hour or refrigerate
when is serum creatinine elevated?
acute or chronic renal failure, urinary tract obstruction
when is fractional excretion of sodium FE na used?
acute renal failure, most accurate when the patient is oliguric
what do round/ normal RBCs indicate?
disease along epithelial lining
where are casts formed?
DCTs and collecting ducts
what is the MC way of measuring GFR?
creatinine clearance
what do cell ghosts RBCs (swollen) indicate?
dilute urine
what drugs make the urine color orange?
phenazopyridine, nitrofurantoin, rifampin, metronidazole
if you see transitional epthelial cells (urothelial cells) what do you need to do?
confirm w/ urinary cytology
what makes the urine cloudy?
pyuria (pus in urine) or suspended crystals
what is the gold standard for measring GFR?
clearance of injected carb. (inulin)
benign glycosuria can be secondary to what?
heavy metal
