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128 Cards in this Set
- Front
- Back
Aspects of microscopic examination that should be standardized
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1. Volume of urine analyzed
2. Length and force of centrifugation 3. Re-suspending volume and concentration of sediment 4. Volume and amount of sediment examined 5. Terminology and reporting format |
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What materials are necessary for the collection, centrifugation and microscopic examination of urine?
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conical centrifuge tubes (or regular test tubes) up to 15 mL, centrifuge, pasteur pipette/disposable pipette, slides/cover slips, microscope
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Procedure for microscopic examination of urine
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1. Mix the specimen
2. Transfer about 10-12 mL of urine into labeled centrifuge tube 3. Centrifuge at medium speed for 3-5 minutes 4. Discard the supernatant by quick inversion of the tube 5. Resuspend the sediment by tapping 6. Take sediment by Pasteur pipette and transfer a drop onto slide 7. Apply cover slide 8. Place on microscope and look at sample under 10x 9. Change to 40x and examine 10. Report what is found under low and high powers |
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Sources of errors in microscopic examination of urine
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Drying of specimen on slide
Poor technique in decanting supernatant Improper centrifugation (too high, too low) |
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What does phase contrast microscopy help identify in a urine sediment?
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low refractive casts, mucous threads, Trichomonas
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What does polarizing microscopy help identify in a urine sediment?
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crystals and lipids
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Dark-field microscopy is usually used to identify what in urine?
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Treponema pallidum
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Name the non-formed materials found in urine
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calcium carbonate, calcium oxalate, triple phosphate, alkaline urine crystals, amorphous phosphate, calcium phosphate
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Name the formed elements found in urine
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RBC, WBC, epithelial cells, renal tubular cells, spermatazoa, yeast, bacteria, casts
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How do normal RBCs usually appear in a fresh urine sample?
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intact, small and faint yellowish discs that are darker at the edges
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Red blood cells usually measure ______ micrometers
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7-8
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In ______ urine, red blood cells may appear crenated and become small
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hypersthenuric
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In ______ urine, red blood cells may appear swollen and lyse
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hyposythenuric
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In alkaline urine, red blood cells may appear ________.
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small or entirely destroyed forming massive amounts of brown granules
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"Ghost cells" appear in ____ urine, as the red cells rupture and release hemoglobin, leaving a faint and colorless cell membrane
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dilute, alkaline
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Acetic acid does what to a urine sample?
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Lyses red blood cells
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Causes of red blood cells in the urine
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acute and chronic glomerulonephritis, tumor, renal stone, cystitis, prostates, trauma of the kidney, traumatic catheterization
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Substances that may be confused with red blood cells
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yeast cells, leukocytes, bubbles
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How do you differentiate red blood cells and non-budding yeasts?
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acetic acid
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How do you differentiate red blood cells and bubbles (oil droplets)?
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Bubbles are extremely refractive and shiny. They also vary considerably in size
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Compared to red blood cells, leukocytes have a __________ appearance
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large and granular
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Leukocytes measure ________ micrometers
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10-15
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In alkaline urine, leukocytes may _______.
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increase in size and become irregular
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Increased numbers of leukocytes in a urine sample may be seen in:
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urinary tract infections, renal disease, bladder tumors, cystitis, prostatitis, fever, strenuous exercise
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What is a clue cell?
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A squamous epithelial cell covered with Gardnerella (associated with vaginal infection)
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Transitional epithelial cells in urine samples originate from the __________.
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bladder, ureters and renal pelvis
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Squamous epithelial cells in urine samples originate from _________.
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the urethra and the superficial lining of the vagina
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Renal tubular cells appear:
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very granular and refractive. They have clearly visible nuclei and are 10-18 micrometers in size.
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The presence of renal tubular cells in urine indicates
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necrosis in the renal tubules
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Oval fat bodies may be stained by
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Sudan III or Oil Red O
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Lipiduria is frequently associated with what syndrome?
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Nephrotic syndrome
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What pathological conditions favor the formation of casts?
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increased acidification, increased osmolar concentration, the presence of protein constituents in the tubular urine
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Most urinary casts are formed where? Why?
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in the distal convoluted tubules or in the collecting ducts, this is where urine is most concentrated and maximally acidified
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What does a very broad cast indicate?
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Severely decreased function of the nephron
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What are the major types of casts?
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hyaline casts, epithelial casts, white blood cell casts, red blood cell casts, granular casts, waxy casts, fatty casts
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Hyaline casts consist of what protein matrix?
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Tamm-Horsfall protein
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How do hyaline casts appear under the bright field microscope?
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faint and almost colorless
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Hyaline cast formation MAY indicate:
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Nephritis, meningitis, chronic renal disease, congestive heart failure, diabetic nephropathy. However, many times hyaline casts are not clinically significant.
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The presence of large numbers of hyaline casts may show possible damage to the:
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glomerular membrane
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What are the two types of granular casts?
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fine and coarse
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Compared to hyaline casts, granular casts are more ____, _____ and ______.
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dense, short, broad
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Granular casts may be _______ casts that have degenerated.
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epithelial
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Granular casts may be seen in:
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acute tubular necrosis, advanced granulonephritis, pyelonephritis, malignant nephrosis, chronic lead poisoning
may also be seen after strenuous exercise in healthy individuals |
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What does an excess of white blood cells in the urine indicate?
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inflammation
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White blood cells casts originate where?
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upper urinary tract (tubules)
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White blood cells casts are characteristically seen in:
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acute pyelonephritis
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Red blood cell casts usually indicate that there is bleeding in the _______.
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nephron
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Waxy casts have a ______ refractive index.
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high
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Waxy casts are usually much more ______ than hyaline casts.
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broad
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Waxy casts usually have _____ edges and have characteristic _____.
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straight, cracks
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Waxy casts are associated with:
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renal failure
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Waxy casts are found in
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chronic renal disease, tubular inflammation/degeneration, localized nephron obstruction, malignant hypertension
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Fatty casts (are/are not) typically seen in healthy individuals
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are not
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How are fatty casts formed?
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fat accumulates in the tubular vessels
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Fat drops are _____ refractile.
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highly
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Clinical implication of fatty casts:
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nephrotic syndrome, chronic renal disease, inflammation and degeneration of renal tubules, lupus, toxic renal poisoning
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Fat bodies can be confirmed using polarizing light. The fat bodies will demonstrate a ________.
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maltese cross
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Epithelial casts are indicative of _____.
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renal parenchymal disease with tubular damage
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Casts are examined under the _____ objective of the microscope.
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10x
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When bacteria in the urine are accompanied by white blood cells, this is significant for _____
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UTI
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Yeast may often be found in the urine specimens of _____ patients
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diabetes mellitus
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Trichomonas is only motile for _____ hours in a urine sample
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2
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What factor can be critical to differentiating important crystal types?
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pH
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Crystals found in neutral or alkaline urine
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oxalate, phosphate, calcium, ammonium and magnesium
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Crystals found in acidic urine
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uric acid, bilirubin, cysteine, tyrosine, leucine, iatrogenic (ie, sulfonamide)
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All clinically significant crystals are found in ___ pH
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acidic
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Amorphous urates are enhanced by what preservation technique?
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refrigeration
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Amorphous urates will dissolve in alkaline pH or with ______.
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heating to 60 degrees celsius
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______ deposits on urate crystals, resulting in "brick dust"
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Uroerythrin
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Large numbers of uric acid crystals may be present in _____ or ______.
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gout, increased purine metabolism (i.e. chemotheraphy)
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The dihydrate form of calcium oxalate crystals are ______ shaped.
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pyramid or envelope
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The monohydrate form of calcium oxalate crystals may be clinical significant and appear ______.
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ovoid or dumbell shapred
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Cysteine crystals appear as _________.
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colorless, hexagonal plates
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Renal disease is classified based on what area it affects. The three possible areas are:
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glomerulus, tubules, interstitial
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What are the two major functions of the kidneys?
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filtration of blood, removal of toxins
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How does an immunologic disorder cause a glomerular disorder?
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Immune complexes circulate and deposit on glomerular membranes. This results in damage to the basement membranes and capillaries.
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What are some non-immunologic origins of glomerular disorder?
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exposure to chemicals (i.e. heavy metals), renal calculi, electrical membrane changes, chronic inflammation, basement membrane damage
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(T/F) Glomerulonephritis is typically a sterile process
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True
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What urinalysis results would be expected in glomerulonephritis?
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red blood cells, protein, casts
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What are the symptoms of acute post-streptococcal glomerulonephritis?
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fever, edema (around eyes), oliguria, hematuria
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Rapidly progressive glomerular nephritis
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acute glomerulonephritis that escalates very quickly
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The urinalysis in acute post-streptococcal glomerulonephritis shows what?
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marked hematuria, proteinuria, RBC casts (characteristic), dysmorphic RBCs, WBCs
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What is the prognosis for acute post-streptococcal glomerulonephritis if it is treated?
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No permanent damage
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Any time dysmorphic RBCs are seen in the urine, you should suspect ________.
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glomerular damage
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Rapidly progressive glomerulonephritis typically is caused by __________.
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immune systemic disorders such as lupus
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Rapidly progressive glomerulonephritis often leads to what?
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renal failure
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In rapidly progressive glomerulonephritis, crescents form in the Bowman's capsule. What are these crescents?
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Macrophages
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What causes Goodpasture syndrome?
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a cytotoxic autoantibody against glomerular and alveolar basement membranes following a viral respiratory infection
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The urinalysis is Goodpasture syndrome will show what?
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hematuria, proteinuria, RBC casts
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What causes Wegener's granulomatosis?
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An antineutrophilic cytoplasmic antibody that binds to neutrophils
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Wegener's granulomatosis presents with symptoms in what two organs?
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lungs, kidneys
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The urinalysis in Wegener's granulomatosis will show what?
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hematuria, proteinuria, RBC casts, elevated BUN, elevated creatinine
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Henoch-Schonlein purpura primarily occurs in what age group?
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children
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What is another name for IgA nephropathy?
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Berger disease
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In IgA nephropathy, what is increased in the serum?
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levels of IgA
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IgA nephropathy can gradually progress to end-stage renal disease. It may present asymptomatically for up to _______.
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20 years
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Laboratory findings for nephrotic syndrome
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massive proteinuria, high levels of serum lipids, hypoproteinemia, urinary fat droplets, oval fat bodies, renal tubular epithelial cells, fatty and waxy casts, microscopic hematuria
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Key symptom of nephrotic syndrome
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Edema
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Why are serum lipids high in nephrotic syndrome?
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hypoalbuminemia stimulates increased production of lipids
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Nephrotic syndrome may lead to compromise of the ________
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immune system
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How is minimal change disease treated?
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corticosteroids
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What causes minimal change disease?
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dysfunction of podocytes of glomerulus
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Focal segmental glomerulosclerosis is associated with what?
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heroine users, AIDS/immunosuppressed patients
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Alport syndrome typically affects what group?
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males
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Alport syndrome occurs during ______ infections
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respiratory
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Alport syndrome causes what?
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hematuria, abnormality in hearing/vision, thinning of glomeruli, can lead to end-stage renal disease
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Diabetic nephropathy is also known as
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Kimmelstiel-Wilson disease
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In diabetic nephropathy, what pathologic changes occur in the kidney?
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glomerular membrane thickening, proliferation of mesangial cells
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What causes diabetic nephropathy?
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deposition of cells and glycosylated proteins
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Urinalysis results for diabetic nephropathy
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hematuria, proteinuria, glucosuria, cellular and granular casts, waxy casts, broad casts
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Waxy casts indicate what about urine flow?
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urine stasis
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General causes of tubular disorders
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physical damage, metabolic issues, hereditary disorders
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Acute tubular necrosis is caused by what?
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ischemia causing damage to renal tubular epithelial cells - this may be caused by cardiac problems, electric shock, sepsis, crush injury or surgery
toxic damage via ultrafiltrate (antibiotics, cyclosporins, ethylene glycol, large amounts of myoglobin) |
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Urinalysis findings in acute tubular necrosis
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mild proteinuria, microscopic hematuria, presence of renal tubular epithelial cells, casts (hyaline, granular, waxy, broad)
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Fanconi syndrome directly affects what part of the nephron?
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The proximal convoluted tubule
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How is diabetes insipidus acquired?
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sex-linked recessive gene, medication toxicity (lithium, amphotericin B),sickle cell anemia, polycystic kidney disease
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What hormone is disrupted in diabetes insipidus?
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ADH
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Urinalysis results for diabetes insipidus
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low specific gravity, pale yellow color, polyuria
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What can cause a patient to have increased urine glucose concentration but normal blood glucose concentration?
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decreased glucose transporters or affinity of transports for glucose in tubules
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Tubulointerstitial disease is associated with:
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urinary tract infections, inflammation
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Upper UTIs are characterized by what microscopic finding?
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WBC casts
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Acute pyelonephritis occurs when bacteria enters from the ________.
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lower urinary tract
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What is used to treat pyelonephritis?
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management of underlying conditions, broad-spectrum antibiotics
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Symptoms of pyelonephritis:
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rapid onset, lower back pain, urinary frequency
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Urinalysis results for acute pyelonephritis
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increased white blood cells, bacteria, mild proteinuria, hematuria, WBC casts, bacterial casts
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Chronic pyelonephritis is most commonly caused by what?
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congenital defects that result in urinary structural defects
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Urinalysis results for chronic pyelonephritis
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increased WBCs, bacteria, mild proteinuria, hematuria, WBC casts, bacterial casts, granular casts, waxy casts, broad casts
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Chronic renal failure is characterized by what laboratory findings?
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isothenuric urine, proteinuria, glycosuria, abundance of granular, waxy and broad casts, azotemia, marked decreased in GFR
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