Crystals in body fluids

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This article deals with crystals in body fluids.

Crystals

Joint crystals

Types:[1]

  • Gout = needle-shaped, negatively birefringent, yellow when aligned.
  • Pseudogout = rhomboid-shaped, positively birefringent, blue when aligned.

Notes:

  • Pseudogout also known as CPPD = calcium pyrophosphate dehydrogenase.
  • Memory device: ABC+ = aligned blue is calcium & cuboid - positively birefringent.

Urine crystals

Types - morphology:

  • Envelope shape (calcium oxalate).
  • Diamond shape (uric acid).
  • Coffin-lid shape (struvite).
  • Hexagonal shape (cysteine).

Notes:

  • Memory devices:
    • Diamonds are see-through; ergo, uric acid stones not seen on KUB.
    • Calcium oxalate = envelope, uric acid = diamond.
  • Uric acid crystals: usually dissolve in formalin... but do not dissolve in alcohol.[2]
  • Calcium oxalate crystals are seen in the context of ethylene glycol poisoning.[3]

Diseases

Gout

General

  • Classically big toe.

Etiology:[4]

  • Overproduction of uric acid ~ 10% of cases.
  • Reduced excretion of uric acid ~ 90% of cases.
    • May be genetic - URAT1 mutation.[5][6]
    • Renal failure.

Gross/radiology

  • Radiologically may mimic anconeus epitrochlearis muscle.[7]

Microscopic

Features:[8]

  • Tophi (advanced)
    • Reactive granulomatous inflammation.
      • Surrounds fluffy (cotton candy-like) material.
    • Fibrotic synovium.
    • Aggregates of urate crystals.

Images:

Pseudogout

  • AKA Calcium pyrophosphate dihydrate deposition disease,[9] abbreviated CPPD.

General

  • Classically found in the knee.

Microscopic

Features:

  • Crystals with a rhomboid-shape.
    • Positively birefringent, blue when aligned.

Notes:

  • Memory device: ABC+ = aligned blue is calcium & cuboid - positively birefringent.

Images:

See also

References

  1. TN05 RH6
  2. WG. 8 January 2010.
  3. Saukko, Pekka; Knight, Bernard (2004). Knight's Forensic Pathology (3rd ed.). A Hodder Arnold Publication. pp. 589. ISBN 978-0340760444.
  4. Mitchell, Richard; Kumar, Vinay; Fausto, Nelson; Abbas, Abul K.; Aster, Jon (2011). Pocket Companion to Robbins & Cotran Pathologic Basis of Disease (8th ed.). Elsevier Saunders. pp. 634. ISBN 978-1416054542.
  5. Online 'Mendelian Inheritance in Man' (OMIM) 607096
  6. Tin, A.; Woodward, OM.; Kao, WH.; Liu, CT.; Lu, X.; Nalls, MA.; Shriner, D.; Semmo, M. et al. (Oct 2011). "Genome-wide association study for serum urate concentrations and gout among African Americans identifies genomic risk loci and a novel URAT1 loss-of-function allele.". Hum Mol Genet 20 (20): 4056-68. doi:10.1093/hmg/ddr307. PMID 21768215.
  7. URL: http://radiology.casereports.net/index.php/rcr/article/viewArticle/57/213. Accessed on: 7 August 2011.
  8. URL: http://pathologyoutlines.com/joints.html#gout. Accessed on: 5 August 2011.
  9. URL: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001458/. Accessed on: 28 October 2011.

External links