Crystals

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

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

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

Classification Normal and Abnormal Morphology Normal Acidic crystals Normal Alkaline crystals Abnormal crystals - metabolic origin or iatrogenic origin Morphology Based on pH Generally reported based on morphology alone

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

Uric Acid Acid urine Yellowish Brown Ovals with pointed Ends

Uric Acid Birefringence under polarized light Acid urine Yellowish Brown Ovals with pointed Ends Birefringence under polarized light

Uric Acid Sometimes associated with gout Acid urine Yellowish Brown Ovals with pointed Ends

Uric Acid Rosette Form Many Forms “Great Imposters”

Normal Acidic Crystals Calcium oxalate may also been seen in neutral or alkaline urine dihydrate form is easily recognized

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 Tomatoes

Calcium Oxalate and Epi

Calcium Oxalate

Calcium oxalate dihydrate and monohydrate (dumbbell and ring forms) - x400 magnification.

Calcium Oxalate

Amorphous Urates Brown or colorless granules Na or K Sediment in spin down tube may have brick red color Brown or colorless granules Na or K Sediment in spin down tube may have brick red color

Amorphous Phosphates Ca or Mg Found in Basic urine Dissolves in Acetic Acid

Normal Alkaline Crystals Amorphous Phosphates Triple Phosphate (ammonium magnesium) Ammonium Biurate Calcium Phosphate Crystals Calcium Carbonate

Triple Phosphate Coffin Lid Looks like a Coffin Lid

Triple Phosphate AKA Ammonium Magnesium Phosphate Found in Basic or Neutral urine Soluble in Acetic Acid

Calcium Phosphate Crystals Alkaline urine Irregular plates “Sheets of Ice” Rosettes Associated with Cystitis and Urine retention

Calcium Carbonate Crystals Alkaline urine Spheres or Dumb-bell forms Birefringent

Ammonium Biurate Rarely seen in freshly voided urine - common in old specimens Dark yellow or brown

Calcium Carbonate Rhombohedral form

Calcium Carbonate Dumbbell form

Abnormal Crystals All are found in acidic urine Indicate pathologic condition

Tyrosine Acid pH Needle shaped fine and silky appearance Liver disease due to hepatitis, hepatocellular poisons Leukemia's Typhoid fever and smallpox

Leucine Acid pH Spheres, Yellow-brown concentric rings Birefringence Pseudo Maltese Cross Maple syrup disease Liver Disease

Cystine Acid pH Thin colorless hexagonal plates Birefringent in polarized light Hereditary metabolic disorders involving renal transport of various amino acieds

Cystine

Cystine

Cholesterol Acid 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 Acid Urine Regular or irregular plate with Notched corner Birefringent under polarized light Various renal diseases Nephrotic Syndrome or other condition where there is a depositio of lipids in Kidney

Cholesterol

Fiber

Bilirubin Crystals Acidic Urine Pigmented yellowish Brown Granules Pathologic appear in a wide variety of hepatobiliary and hematopoietic diseases

Bilirubin Crystals

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