Cls 1113 Introduction To Clinical Laboratory Practices

CLS 1113 Introduction to Clinical Laboratory Practices Microscopic Examination Formed Elements: 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

Urinary Crystals • 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

Urinary Crystals • 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

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

Amorphous Urates and Phosphates

Normal Acidic Crystals • Uric Acid – concentration depends on dietary intake of purines and breakdown of nucleic acids • seen in leukemia patients receiving chemotherapy

– when accompanies by increased serum uric acid may be associated with gout – pathologic only when seen in freshly voided urine – Most varied of morphologically

Uric Acid

Uric Acid

Uric Acid:

Polarized

Normal Acidic Crystals • Calcium oxalate – – – –

may also been seen in neutral or alkaline urine dihydrate form is easily recognized monohydrate uncommon - oval shape when present with symptoms of urinary calculi may indicate composition of stone (lithiasis) • 75% composed of CaOx

– Excess Oxalate • Spinach, rhubarb, ascorbic acid, ethylene glycol poisoning

Calcium Oxalate

CaOx cont...

Normal Alkaline Crystals • Amorphous Phosphates – ditto from amorphous urate...except it is alkaline urine – unable to distinguish...only by pH

• Triple Phosphate (ammonium magnesium) – Also referred to as struvite • 10-20% urinary calculi

– Coffin lid

Triple Phosphate

Triple Phosphate

Normal Alkaline Crystals • Ammonium Biurate – Rarely seen in freshly voided urine - common in old specimens – Dark yellow or brown

Ammonium Biurate

Abnormal Crystals of Metabolic Origin • Cystine – Cystinuria: metabolic disorder • inherited amino acid transport disorder affecting cystine • may form cystine stones - kidney damage - may fill renal collecting system, resulting in staghorn calculi causing stasis, etc.

– Colorless, refractile hexagonal plate

Cystine

Abnormal Crystals of Metabolic Origin • Cystine continued – May confuse with uric acid • both are acid pH crystals • confirmatory for cystine: Nitroprusside Reaction

• Tyrosine – Severe liver disease – Rarely seen – Colorless needles, acidic pH

Tyrosine

Abnormal Crystals of Metabolic Origin • Leucine (Rare) – Liver disease (with tyrosine) – Yellow, oily-looking spheres, acidic pH, birefringent (pseudo Maltese cross when polarized)

• Cholesterol – Seen as free fat, in renal epi’s, fatty casts in cases of nephrotic syndrome

Abnormal Crystals of Metabolic Origin • Cholesterol – Acidic pH, colorless, large, flat, rectangular plates with one or more corners notched. – May be mistaken for radiologic dyes • Specific gravity

Cholesterol

Abnormal Crystals of Iatrogenic Origin • Sulfonamides – Renal damage as these ppt out in nephron – Acidic pH, yellow to brown, needles in sheaves but have a variety of shapes

• Ampicillin – High dose – Acidic pH, thin colorless needles

Abnormal Crystals of Iatrogenic Origin • Radiologic Contrast Media – renografin, hypaque – Look like cholesterol (variety of shape)

Radiologic Dye

Sulfonamides

Bilirubin Crystals

Bilirubin Crystals Cont…