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CLINICAL MICROSCOPY > Microscopic Examination of Urine - Urinary Crystals > Flashcards

Microscopic Examination of Urine - Urinary Crystals Flashcards

1
Q

Crystals frequently found in the urine are rarely of clinical significance. True or False?

A

True

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2
Q

Appearance of urinary crystals

A

True geometrically formed structures or as amorphous material

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3
Q

The primary reason for the identification of urinary crystals

A

To detect the presence of the relatively few abnormal types that may represent such disorders

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4
Q

Manner of reporting for crystals

A

Rare, few, moderate, or many per hpf

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5
Q

How does urinary crystal forms?

A

Precipitation of urine solutes

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6
Q

Precipitation is subject to changes in

A

Temperature
Solute concentration
pH

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7
Q

Solutes precipitate more readily at high temperatures. True or False?

A

False; low temperature

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8
Q

As the concentration of urinary solutes increases, their ability to remain in solution decreases. True or False?

A

True

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9
Q

How does pH of the specimen aid in the identification of crystals?

A

It determines the type of chemicals precipitated

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10
Q

Organic and iatrogenic compounds crystallize more easily in acidic or alkaline pH?

A

Acidic

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11
Q

Inorganic salts are less soluble in

A

Neutral and alkaline solutions

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12
Q

Crystal that precipitates in both acidic and neutral urine

A

Calcium oxalate

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13
Q

All abnormal crystals are found in alkaline urine. True or False?

A

False; acidic urine

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14
Q

Microscopy technique that aids in the identification of crystals

A

Polarized microscopy

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15
Q

The geometric shape of a crystal determines its birefringence. True or False?

A

True

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16
Q

Slower crystallization produces smaller crystals. True or False?

A

False; larger crystals

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17
Q

Duration of crystallization alters the basic structure of crystals. True or False?

A

False; basic structure remains the same

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18
Q

Amorphous urates in refrigerated specimens may dissolve if the specimen is warmed. True or False?

A

True

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19
Q

Amorphous phosphates require acetic acid to dissolve. True or False?

A

True

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20
Q

The most common crystals seen in acidic urine

A

Urates

Consisting of amorphous urates, uric acid, acid urates, and sodium urates

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21
Q

Appearance of urates crystals

A

Yellow to reddish brown

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22
Q

The only normal crystals found in acidic urine that appear colored

A

Urates

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23
Q

Amorphous urates are similar to what casts?

A

Granular casts

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24
Q

Amorphous urates are frequently encountered in

A

Specimens that have been refrigerated and produce a very characteristic pink sediment due to accumulation of uroerythrin

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25
Q

Amorphous urates are found in acidic urine with a pH of

A

> 5.5

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26
Q

Amorphous urates are soluble in

A

Alkali and heat

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27
Q

Seen in a variety of shapes, including rhombic, four-sided flat plates (whetstones), wedges, and rosettes

A

Uric acid

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28
Q

They usually appear yellow-brown, but may be colorless and have a six-sided shape, similar to cystine crystals

A

Uric acid

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29
Q

How to distinguish uric acid from cystine crystals?

A

Uric acid is highly birefringent under polarize light

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30
Q

Increased amount of uric acid is associated with

A

Increased levels of purines and nucleic acids

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31
Q

Increased amount of uric acid in patients is associated with

A

Leukemia who are receiving chemotherapy
Lesch-Nyhan syndrome
Gout

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32
Q

Uric acid is soluble in

A

Alkali

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33
Q

Appear as larger granules and may have spicules similar to the ammonium biurate crystals seen in alkaline urine

A

Acid urates

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34
Q

Are needle-shaped and are seen in synovial fluid during episodes of gout, but may also appear in the urine

A

Sodium urates

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35
Q

Frequently seen in acidic urine, but they can be found in neutral urine and even rarely in alkaline urine

A

Calcium oxalate

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36
Q

2 forms of calcium oxalate

A

Dihydrate form (Weddellite)
Monohydrate form (Whewellite)

37
Q

Most common form (calcium oxalate) and is easily recognized as a colorless, octahedral envelope or as two pyramids joined at their bases

A

Dihydrate form (Weddellite)

38
Q

Oval/dumbbell/hourglass shape (calcium oxalate) and less frequently seen

A

Monohydrate form (Whewellite)

39
Q

How to distinguish monohydrate calcium oxalate from nonpolarizing RBCs?

A

Monohydrate forms are birefringent under polarized light

40
Q

Foods associated with calcium oxalate

A

Foods high in oxalic acid, such as tomatoes and asparagus, and ascorbic acid

41
Q

Primary pathologic significance of calcium oxalate

A

Presence of the monohydrate form in cases of ethylene glycol (antifreeze) poisoning

42
Q

Calcium oxalate is soluble in

A

Dilute HCl

43
Q

Majority of renal calculi are composed of

A

Calcium oxalate

44
Q

The finding of clumps of calcium oxalate crystals in fresh urine may be related to

A

Formation of renal calculi

45
Q

The majority of the crystals seen in alkaline urine

A

Phosphates

include amorphous phosphate, triple phosphate, calcium phosphate, calcium carbonate, and ammonium biurate

46
Q

Granular in appearance, similar to amorphous urates

A

Amorphous phosphates

47
Q

Appearance of amorphous phosphate following specimen refrigeration

A

White precipitate that does not dissolve on warming

48
Q

How to differentiate amorphous urates from amorphous phosphates?

A

Color of the sediment and the urine pH

49
Q

Amorphous phosphate is soluble in

A

Dilute acetic acid

50
Q

Easily identified by their prism shape that frequently resembles a “coffin lid”

A

Triple phosphate/Ammonium magnesium phosphate/struvite crystals

51
Q

Shape of triple phosphate crystals

A

Feathery appearance when they disintegrate, Fern-leaf shape, sheets or flake

52
Q

Appearance of triple phosphate crystals under polarized light

A

Birefringent

53
Q

Crystal often seen in highly alkaline urine associated with the presence of urea-splitting bacteria

A

Triple phosphate

54
Q

Triple phosphate is soluble in

A

Dilute acetic acid

55
Q

Crystal that appear as colorless, flat rectangular plates or thin prisms often in rosette formations

A

Calcium phosphate/Apatite crystals

56
Q

How to differentiate calcium phosphate from sulfonamide crystals?

A

Calcium phosphate crystals dissolve in dilute acetic acid and sulfonamides do not

57
Q

Crystals that are small and colorless, with dumbbell or spherical shapes

A

Calcium carbonate

58
Q

How to differentiate calcium carbonate from amorphous materials?

A

Formation of gas after the addition of acetic acid

59
Q

Crystals frequently described as “thorny apples” because of their appearance as spicule-covered spheres

A

Ammonium biurate

60
Q

Crystals that are almost always encountered in old specimens

A

Ammonium biurate

61
Q

Ammonium biurate is soluble in

A

Acetic acid with heat

62
Q

Abnormal urine crystals are found in

A

Acidic urine or rarely in neutral urine

63
Q

Crystals found in the urine of persons who inherit a metabolic disorder that prevents reabsorption of cystine by the renal tubules (cystinuria)

A

Cystine crystals

64
Q

Appearance of cystine crystals

A

Colorless, hexagonal plates and may be thick or thin

65
Q

How to differentiate uric acid crystals from cystine crystals?

A

Uric acid crystals are very birefringent under polarized microscopy, whereas only thick cystine crystals have polarizing capability

66
Q

Test for the positive confirmation of cystine crystals

A

Cyanide-nitroprusside test

67
Q

Cystine crystal is soluble in

A

Acetic ammonia, dilute HCl

68
Q

Crystal resembling a rectangular plate with a notch in one or more corners (staircase pattern)

A

Cholesterol crystals

69
Q

Crystal with most characteristic appearance

A

Cholesterol crystal

70
Q

Cholesterol crystals are soluble in

A

Chloroform

71
Q

Crystals that have a very similar appearance to cholesterol crystals and also are highly birefringent

A

Radiographic dye crystals

72
Q

How to differentiate cholesterol crystals from radiographic dye crystals?

A

Comparison of the other urinalysis results
Patient history

73
Q

Cholesterol crystals should be accompanied by

A

Other lipid elements and heavy proteinuria

74
Q

Crystals associated with liver disease

A

Tyrosine
Leucine
Bilirubin

75
Q

Crystals appear as fine colorless to yellow needles that frequently form clumps or rosettes

A

Tyrosine crystals

76
Q

Tyrosine crystals are usually seen in conjunction with bilirubin crystals in specimens with positive chemical test results for leucine. True or False?

A

False; leucine crystals, positive chemical test results for bilirubin

77
Q

Tyrosine crystal is soluble in

A

Alkali or heat

78
Q

Yellow-brown spheres that demonstrate concentric circles and radial striations

79
Q

Leucine crystals when present, should be accompanied by

A

Tyrosine crystals

80
Q

Leucine crystal is soluble in

A

Hot alkali or alcohol

81
Q

Crystals that appear as clumped needles or granules with the characteristic bright yellow color of bilirubin

A

Bilirubin crystals

82
Q

The presence of bilirubin crystals gives positive result for bilirubin when using reagent strip. True or False?

83
Q

Bilirubin crystal is soluble in

A

Acetic acid, HCl, NaOH, ether, chloroform, and alkali

84
Q

Primary cause of sulfonamide crystallization

A

Inadequate patient hydration

85
Q

The appearance of sulfonamide crystals in fresh urine can suggest the possibility of

A

Tubular damage

86
Q

Most frequently encountered shapes of sulfonamide crystals

A

Needles, rhombics, whetstones, sheaves of wheat, and rosettes with colors ranging from colorless to yellow-brown

87
Q

Sulfonamide crystals is soluble in

88
Q

Crystal that appear as colorless needles that tend to form bundles following refrigeration

A

Ampicillin crystals

89
Q

Ampicillin crystals are seen in

A

High doses of penicillin compound without adequate hydration

CLINICAL MICROSCOPY (20 decks)

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