Sediment Constituents (Casts)

Question 1

What is the term for molds of the renal tubule?

Answer 1

Cylindruria

Question 2

What does cylindruria represent?

Answer 2

Biopsy of individual tubule

Question 3

What is the uniform diameter of the renal tubule mold in relation to RBCs?

Answer 3

7-8 times the diameter of RBCs

Question 4

What is the most difficult and most important urinary sediment constituent?

Answer 4

Casts

Question 5

Where are casts primarily formed in the kidney?

Answer 5

DCT and Collecting Duct

Question 6

What is the major constituent of casts?

Answer 6

Uromodulin (Tamm Horsfall Protein)

Question 7

What has the same significance as casts?

Answer 7

Cylindroids

Question 8

How are casts examined?

Answer 8

Along the coverslip edges with subdued light

Question 9

Under what magnification are casts counted?

Answer 9

LPF (Low Power Field)

Question 10

Under what magnification are casts identified?

Answer 10

HPF (High Power Field)

Question 11

What is the first step in the formation of casts?

Answer 11

Aggregation of uromodulin into individual protein fibrils attached to RTE cells

Question 12

What is the last step in the formation of casts?

Answer 12

Excretion of casts

Question 13

What is the order of cast degeneration?

Answer 13

Hyaline, Cellular, Degenerating cellular, Coarsely Granular, Finely granular, Waxy

Question 14

What is the prototype cast and most frequently encountered?

Answer 14

Hyaline cast

Question 15

What is the appearance of a hyaline cast?

Answer 15

Colorless and translucent, requires subdued light

Question 16

What is the normal value of hyaline cast in urine?

Answer 16

0-2/LPF

Question 17

What pathologies cause hyaline casts?

Answer 17

Glomerulonephritis, pyelonephritis, CHF, CKD

Question 18

What is the most fragile cast that indicates bleeding within the nephron?

Answer 18

RBC Cast

Question 19

What is the color of an RBC cast?

Answer 19

Orange-red

Question 20

In what conditions is RBC cast significant?

Answer 20

Glomerulonephritis, strenuous exercise (physiologic cause in hyaline cast)

Question 21

What is a muddy brown cast composed of?

Answer 21

Hemoglobin from lysed RBCs

Question 22

What is the color and appearance of a blood (hemoglobin) cast?

Answer 22

Orange-red, homogeneous appearance

Question 23

What cast indicates inflammation or infection within the nephron?

Answer 23

WBC/Leukocyte/Pus cast

Question 24

What is required to distinguish WBC casts?

Answer 24

Phase microscope and supravital stain

Question 25

In what conditions are WBC casts significant?

Answer 25

Pyelonephritis, acute interstitial nephritis

Question 26

What is not a true cast but a clump of leukocytes?

Answer 26

Pseudoleukocyte casts

Question 27

Where are pseudoleukocyte casts seen?

Answer 27

Lower UTI (without matrix)

Question 28

What type of cells are visible on the cast matrix in Epithelial (RTE) casts?

Answer 28

Smaller, round and oval cells

Question 29

What is the significance of Epithelial (RTE) casts?

Answer 29

Advanced tubular destruction, tubular damage

Question 30

How is a bacterial cast confirmed?

Answer 30

Gram stain

Question 31

What is the significance of bacterial casts?

Answer 31

Pyelonephritis

Question 32

Where are the granules of granular casts derived from?

Answer 32

Lysosomes of RTE cells during normal metabolism (nonpathologic)

Question 33

What is the appearance of a fine granular cast?

Answer 33

Sandpaper

Question 34

What possible casts are seen in pyelonephritis?

Answer 34

Bacterial, WBC casts, Granular Cast (Coarse and Fine)

Question 35

What is the significance of granular casts?

Answer 35

Glomerulonephritis, pyelonephritis, stress, strenuous exercise

Question 36

What does the Sternheimer-Malbin stain?

Answer 36

Cast matrix (not fat globules)

Question 37

How is cholesterol seen in casts?

Answer 37

Polarizing microscope

Question 38

What is the significance of fatty casts?

Answer 38

Nephrotic syndrome, toxic tubular necrosis, diabetes mellitus, crush injuries

Question 39

What is the final degenerative form of all types of casts?

Answer 39

Waxy casts

Question 40

What is the appearance of waxy casts?

Answer 40

Ground glass

Question 41

What is the significance of waxy casts?

Answer 41

Urinary stasis, chronic renal failure, ESRD

Question 42

What is often referred to as a Renal Failure Cast?

Answer 42

Broad cast

Question 43

What does a broad cast indicate?

Answer 43

Destruction (widening) of the tubular walls

Question 44

What is the appearance of broad casts compared to ordinary casts?

Answer 44

2-6x wider than ordinary casts

Question 45

What is the significance of broad casts?

Answer 45

Extreme urine stasis, renal failure

Question 46

What is the appearance of a miscellaneous cast that incorporates bilirubin color?

Answer 46

Golden-brown

Question 47

What is the appearance of a miscellaneous cast that incorporates hemoglobin or myoglobin color?

Answer 47

Yellow to red-brown

Question 48

What is a cast containing multiple cell types called?

Answer 48

Mixed cellular casts

Question 49

What is the composition of a mixed cellular cast in glomerulonephritis?

Answer 49

RBC and WBC casts

Question 50

What is the composition of a mixed cellular cast in pyelonephritis?

Answer 50

WBC and RTE casts or WBC and bacterial casts

Question 51

What types of casts contain urates, calcium oxalate, and sulfonamides?

Answer 51

Crystal casts

Question 52

Where are crystal casts formed?

Answer 52

Tubule or collecting duct