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Flashcards in First test examination of crystals Deck (51):
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nephrolithiasis

kidney stone disease

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stones that are in the ureter

ureterolithiasis

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urinary bladder stones which form or havepassed into the bladder

cystolithiasis

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crystals can form before or after micturation

micturation=urination

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Crystal precipitation after micturition is most commonly dueto:

- changes in urinary temperature, as can occur if theurine is stored at room temperature or ina refrigerator;- changes in urinary pH, as can occur in thepresence of contamination of urea-splittingorganisms.

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abnormal crystals are usually seen in ___ urine

acidic

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Prerequisites for identification of crystals:

– pH of urine– morphology of crystals– crystals solubility– crystals polarization

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abnormal acidic crystals

metabolic origin

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abnormal alkaline crystals

Iatrogenic orgin

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In vitro factors of urinary crystal formation

-Temperature (solubilitydecreases withtemperature)- Evaporation (increasessolute concentration)- Urine pH (changes withstanding andbacterial overgrowth)

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In vivo (body) factors:

Solute concentration- Kidney filtration rate- Urine pH- Diet- Excretion of diagnosticimaging andtherapeutic agents

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most crystals are clinically

insignificant

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Generally, clinically significant crystals are present infreshly voided urine, or in cases of ______

metabolic disorders(e.g. gout)

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- Metabolic disorders may produce crystals (4)

• Cystine (inherited metabolic disease)• Leucine• Tyrosine• Cholesterol

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- Iatrogenic disorders-high doses of some drugs and supplements may cause formation of crystals:

• Salicilates (Aspirin)• Sulfonamides• Ascorbic Acid (vitamin C)

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_____ light is used for the identification of crystalsand other anisotropic substances.

Polarized

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The first lens is referred to as the “_____ filter” and itis nearest the light source, below the condenser

polarizing

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The second filtering lens is called the “______” and islocated between the objective and the eyepiece lenses

analyzer

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It is used for differential diagnosis between variouscrystals

Birefringence

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•Birefringence is a double refraction (or bending) of thelight into ___ rays, one is ____to the light axisand other is at angles to it

two, parallel, right

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Birefringence demonstrates crystal’s ability to split ____into the spectrum

light

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when examining with a polarizing filter and REDcompensator filter, the crystals are YELLOWwhen aligned parallel to the slow axis ofthe red compensatorbut they turn BLUE when aligned across thedirection of polarization

Negative birefringence: (Y-B)

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hen examining with a polarizing filter and redcompensator filter, the crystals are BLUEwhen aligned parallel to the slow axis ofthe red compensatorbut they turn YELLOW when aligned across thedirection of polarization

• Positive birefringence

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ACIDIC URINE CRYSTALS

Uric acid• Calcium Oxalates• Amorphous Urates

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Are usually formed when urine pH

uric acid crystals

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can look like barrels, rosettes, rhomboids, needlesor hexagonal plates. usually amber in color, irrespective of the sizeor shape of the individual crystal.

uric acid crystals

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Uric acid crystals are only pathogenic when in...

freshly voided urine.

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______ are much more common inpatients with urate urolithiasis or acute uratenephropathy.

Urate crystals

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A high uric acid level in the urine may be due to:

gout- high-purine diet- Lesch-Nyhan syndrome (when the body is not able toprocess purine due to lack an enzyme)- cancer metastases- rhabdomyolysis (due to breakdown of muscle fibers)- myeloproliferative disorders (e.g. multiple myeloma,leukemias)

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Low uric acid levels in the urine may be due to:

- inability of kidney to get rid of uric acid well,which can lead to gout with kidneydamage- chronic glomerulonephritis- lead poisoning- long-term (chronic) alcohol use

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May exhibit characteristic “lemon or football” shape appearing singly or in clusters, May also form into barrels, needles, rhomboids, and other shapes

Uric acid

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Dissolves in alkali• Insoluble in– alcohol– HCl– acetic acid

Uric Acid

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will re-solubilize when heated at 60° C

Amorphous urates

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often seen in:- acidic urine,- especially after refrigeration

Amorphous Urates

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formed in urine pH 6.8 - 7, Colorless or yellowish, Needles or slender prisms occurring insheaves or clusters.

sodium urates

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- are formed usually in acidic urine (pH 6)- may also been seen in neutral urine- they may occur as either:

• Calcium oxalate crystals:

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many small ones can be confused as amorphous

Calcium oxalate crystals

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patients with urolithiasis (___ of all urinary tract stonesconsists of oxalates or combination with calciumphosphate)

75%

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patients with acute renal failure due to ethylene glycol(antifreeze) intoxication (______ calcium oxalatecrystals are found)

monohydrate

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Dissolves in:– NaOH– HCl

calcium oxalate

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Insoluble in:– acetic acid

calcium oxalate

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Crystals CommonlyFound in Alkaline Urine

Triple PhosphatesCalcium Carbonates Ammonium biurate

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10-15% urinary calculi

Triple Phosphate crystals ( a.k.a. magnesium ammoniumphosphate, struvites)

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frequently seen in patientswith urinary tract infections, triple stones

Triple Phosphate crystals ( a.k.a. magnesium ammoniumphosphate, struvites)

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Exhibit distinct prism shape often termed “coffin-lid”

triple phosphate

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Polarizes light• Demonstrates birefringence (not all)• Dissolves in– Acetic acid

Triple Phosphate (cont.)

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Calcium carbonate crystals are _____ found in urine, inalkalinic pH

normally

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A unique feature of _____ _____ is that thecrystals bubbling with hydrochloric acid or acetic acid. Thiscan help to confirm the presence of calcium carbonate inthe urine.

calcium carbonate

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Found in alkaline urine pH 9• Common seen in old specimens• Abnormal only if found in freshly voided urine

Ammonium Biurate

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Dissolves in

Acetic acid– NaOH– And when heated (60oC)

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Abnormal Crystals of Metabolic Origin

• Cystine• Tyrosine• Leucine• Cholesterol