Crystal ua

the value of detected crystals in urine analysis

1. Crystalluria in Urinalysis
Dr. Afshin GhalehgolabBehbahan
Pediatric Nephrologist
Tabriz Children’s Hospital

2. Crystalluria in Urinalysis
• It is commonto find crystals on microscopic
examination of the urine (about 8%).
• the presence of crystals may benormal or
pathologic.
• Usually, the presence of crystals in the urine is
of limited clinical significance.

3. Supersaturationof the solute components of the
crystals must occur for crystallization to initiate.
• Factors affecting supersaturation, include;
–Solute concentration,
–Ionic strength (solubility),
–Urine pH,
–The presence of promoters or inhibitors.
• Causes of Supersaturation:
• Low fluid intake (dehydration),
• Hi dietary intake –Drug ingestion,
• Body metabolism,
• Prolonged interval between urine collection and urine
examination.

4. Crystalluria -Supersaturation
• In most instances, crystalluriais an occasional
finding without clinical importance because it
reflects transient supersaturation of urine, these
are called Common Crystals.
• Some crystals that almost always correlate with
a known pathology if they are seen in a child’s
urine, are called Pathological Crystals.

5. Urinary Crystals Classification:
Common (Normal) Crystals -Pathological (Abnormal) Crystals

6. Urinary Crystals Classification:
Common Crystals vs Pathological Crystals
Common Crystals

7. Urinary Crystals Classification:
Common Crystals vs Pathological Crystals
Pathological Crystals
Other Pathological Crystals include:
Tyrosine, Leucine, Bilirubin
& Cholesterol
Crystals.

8. However, Common Crystals May Be Seen In
Some Pathologic Situations As Well !
• persistent Calcium Oxalate crystalluria in repeated
samples of the same subject should raise the suspicion
of a possible disorder:
• Hypercalciuria,
• Hyperoxaluria,
• Hypocitraturia,
– Citrate is a crystallization inhibitor
• Ethylene Glycol Intoxication,
• Ingestion of the Exotic Star Fruit,
• Drug ingestion (
Vitamin C, NaftidrofurylOxalate, & Orlistat
)
Envelope or pyramid shaped
crystals

9. However, Common Crystals May Be Seen In
Some Pathologic Situations As Well !
• Persistent Uric Acid crystalluria in repeated
samples of the same subject should raise the
suspicion of a possible disorder:
• Hyperuricosuria (
with or without Hyperuricemia
)
• Acute Uric Acid Nephropathy,
• Persistent Dehydration

10. However, Common Crystals May Be Seen In
Some Pathologic Situations As Well !
• Persistent Triple phosphate, or Struvite crystalluria in
repeated samples of the same subject should raise the
suspicion of a possible disorder:
• Infections due to urease-producing bacteria
–typically associated with Proteus species
• Alkaline Urine
Triple phosphate crystals have the shape of
“coffin lids”: 3 to 4 to 6 – sided prism ,
composed of magnesium ammonium phosphate

11. Pathologic Crystals Seen in Pathologic Situations
• Cystine crystals are always abnormal and are
pathognomonic of the inherited disease: Cystinuria,
patients often have kidney stones.
• Found only in fresh urine, because if there is delay,
they are soluble and not seen.
• May also be seen in transient acute phase of
pyelonephritis
Flat, hexagonal plates with well-defined
edges, colorless, and highly retractile.

12. Pathologic Crystals Seen in Pathologic Situations
• Tyrosine and leucine crystals are also abnormal and
suggest liver disease.
• Bilirubin crystals are seen in All conditions associated
with Conjugated Hyperbilirubinemia and
Hyperbilirubinuria, such as Cholestasis.
Leucine crystalTyrosine crystals Bilirubin crystals

13. Pathologic Crystals Seen in Pathologic Situations
• Cholesterol crystals
–are found in patients with marked proteinuria.

14. Pathologic Crystals Seen in Pathologic Situations
• 2,8-dihydroxyadenine crystals
– are a highly sensitive marker of homozygotic deficiency of
the enzyme adenine phosphoribosyltransferase(APRT),
found in about 96% of untreated patients.

15. Association between Urine pH & Crystals
•
I. Acidic urine crystals
• -Amorphous Urates,
• -Uric acid crystals,
• -Cystine crystals
• -Calcium Phosphate
• -Cholesterol
• -Ammonium Biurates
• -Tyrosine, Leucien, Bilirubin,
• -Calcium sulfates
• -Calcium urates
• -Calcium carbonate
•II.
Acidic, Neutral, or slightly
alkaline Urine crystals
• -Calcium Oxalate crystals
•III.
Alkaline, Neutral, or Slightly
acidic urine
• -Triple phosphates (Struvite)
•
IV. Alkaline Urine Crystals
• -Amorphous phosphate
• -Calcium carbonate
• -Calcium phosphate

16. Drug Crystals in Urine
• As a general rule:
–one should always suspect drug crystalluria
when finds Atypical Crystals, because:
Most drugs cause atypical and/or
pleomorphic crystals, which differ remarkably
from common or pathological crystals

17. Drug Crystals in Urine
• Factors causing Drug-crystals precipitation in urine:
–Drug overdose,
–Rapid intravenous bolus administration,
–Hypoalbuminemia,
–Dehydration,
–Urine pH:
• Indinavir at pH > 6.0,
• Amoxicillin at pH ≤ 4.0 or >7.0
with “U” shaped behavior,
• Ciprofloxacin at pH>7.3

18. Drug Crystals in Urine
• If confirmed, this should always prompt the check of
renal functionbecause acute renal failure can occur,
especially in patients with impaired renal function.
• When crystalluria is caused by drugs, this may be the
only urinary abnormality or it may be associated with:
–Hematuria (either gross or microscopic),
–Acute Tubular Necrosis caused by precipitation of
crystals within renal tubules,
–Obstructive uropathy caused by drug stones.

19. Drug Crystals in Urine

20. Drug Crystals in Urine
• If confirmed, this should always prompt the check of
renal functionbecause acute renal failure can occur,
especially in patients with impaired renal function.
• It is advisable to:
–Withdraw the drug or decrease the dosage,
–Reestablish euvolemia,
–Stimulate a high urine flow,
–Manipulate urine pH in reverse direction

21. Drug Crystals in Urine