Crystals

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Urinary Crystals

• Most crystals form after urine sits– urinary solutes precipitate(ppt) out of solution

• Clinical Significance– MOST are clinically INsignificant– Generally clinically significant crystals are present

on freshly voided urine (body temp.)– Crystal composition may imply urinary calculi

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Urinary Crystals• Clinical Significance Continued

– May indicate metabolic disorder• Cystinuria - inherited metabolic condition

– Crystals of some drugs may precipitate(ppt) out, especially in high doses

• Sulfonamides

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• Formation – crystals ppt out of solution when the

concentration in solution is greater than the solubility threshold for that solute

– Factors that affect crystal formation• pH, solute concentration, filtrate volume passing

through kidneys

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• Classification– Normal and Abnormal

• Normal Acidic crystals

• Normal Alkaline crystals

• Abnormal crystals - metabolic origin or iatrogenic origin

– Morphology• Based on pH

• Generally reported based on morphology alone

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Normal Acidic Crystals

• Amorphous urates– amorphous:– salt of uric acid (Na, Mg, Ca or K)– yellow/red to red/brown

• Uric Acid– along with amorphous urates, most common– pH <6.0

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Uric Acid

Acid urineYellowish Brown Ovals with pointed Ends

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Uric Acid

Birefringence under polarized light

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Uric Acid

Sometimes associated with gout

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Uric Acid Rosette Form

Many Forms

“Great Imposters”

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Normal Acidic Crystals

• Calcium oxalate– may also been seen in neutral or alkaline urine– dihydrate form is easily recognized

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Calcium Oxalate

• Common• pH acid or neutral• Envelope or dumb

bell shaped• Oval May be

mistaken for RBC• Ca Ox soluble in

HCl Insoluble in acetic acid

• RBC lyse in acetic acid

15Calcium Oxalate and Epi

16Calcium Oxalate

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Calcium oxalate dihydrate and monohydrate (dumbbell and ring forms)

- x400 magnification.

18Calcium Oxalate

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Amorphous Urates

Brown or colorless granulesNa or KSediment in spin down tube may have brick red color

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Amorphous Phosphates• Ca or Mg • Found in Basic

urine• Dissolves in

Acetic Acid

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Normal Alkaline Crystals

• Amorphous Phosphates

• Triple Phosphate (ammonium magnesium)

• Ammonium Biurate

• Calcium Phosphate Crystals

• Calcium Carbonate

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Triple Phosphate

Coffin Lid

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Triple Phosphate

AKA Ammonium Magnesium Phosphate

Found in Basic or Neutral urine

Soluble in Acetic Acid

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Calcium Phosphate Crystals

Alkaline urine

Irregular plates

“Sheets of Ice”

Rosettes

Associated with Cystitis and Urine retention

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Calcium Carbonate Crystals

Alkaline urine

Spheres or Dumb-bell forms

Birefringent

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Ammonium Biurate

– Rarely seen in freshly voided urine - common in old specimens

– Dark yellow or brown

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Calcium Carbonate

• Rhombohedral form

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Calcium Carbonate

• Dumbbell form

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Abnormal Crystals

• All are found in acidic urine

• Indicate pathologic condition

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Tyrosine

Acid pH

Needle shaped fine and silky appearance

Liver disease due to hepatitis, hepatocellular poisons

Leukemia's Typhoid fever and smallpox

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LeucineAcid pH

Spheres, Yellow-brown concentric rings

Birefringence

Pseudo Maltese Cross

Maple syrup disease

Liver Disease

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CystineAcid pH

Thin colorless hexagonal plates

Birefringent in polarized light

Hereditary metabolic disorders involving renal transport of various amino acieds

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Cystine

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Cystine

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CholesterolAcid Urine

Regular or irregular plate with Notched corner

Birefringent under polarized light

Various renal diseases

Nephrotic Syndrome or other condition where there is a deposition of lipids in Kidney

36Cholesterol

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Fiber

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Bilirubin Crystals

• Acidic Urine

• Pigmented yellowish Brown Granules

• Pathologic appear in a wide variety of hepatobiliary and hematopoietic diseases

39Bilirubin Crystals

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