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 afflicts the big toe - known as podagra.

Etiology:[4]

  • Overproduction of uric acid ~ 10% of cases.
  • Reduced excretion of uric acid ~ 90% of cases.
    • May be genetic, e.g. 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

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

General

  • Classically found in the knee.
  • Associated with low bone mineral density and vascular calcification.[10]

Radiology

Findings suggestive of CPPD:[11]

  • Subchondral cysts (large) - important.
  • Intra-articular bodies, several.
  • Increased narrowing of patellofemoral joint.

Microscopic

Features:

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

Notes:

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

Images

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KNEE - BONE AND SOFT TISSUE, RIGHT, KNEE ARTHROPLASTY:
- DEGENERATIVE JOINT DISEASE WITH SYNOVIAL HYPERPLASIA AND MINIMAL INFLAMMATION.
- CRYSTALLINE DEPOSITS CONSISTENT WITH PSEUDOGOUT.
- BONE WITH THIN TRABECULAE.

Micro

The soft tissue section shows readily apparent rhomboid-shaped crystalline deposits (compatible with pseudogout). The crystals polarize and have a light blue hue under polarized light. Synovial hyperplasia is present. No lymphoid aggregates are apparent.

The bony section show thin bony trabeculae and cartilage with degenerative changes (surface fibrillation, thinning).

See also

References

  1. Yeung, J.C.; Leonard, Blair J. N. (2005). The Toronto Notes 2005 - Review for the MCCQE and Comprehensive Medical Reference (2005 ed.). The Toronto Notes Inc. for Medical Students Inc.. pp. RH6. ISBN 978-0968592854.
  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.
  10. Abhishek, A.; Doherty, S.; Maciewicz, R.; Muir, K.; Zhang, W.; Doherty, M. (Aug 2013). "Association between low cortical bone mineral density, soft-tissue calcification, vascular calcification and chondrocalcinosis: a case-control study.". Ann Rheum Dis. doi:10.1136/annrheumdis-2013-203400. PMID 23912799.
  11. 11.0 11.1 URL: http://www.learningradiology.com/archives04/COW%20102-CPPD/cppdcorrectpage.htm. Accessed on: 9 October 2013.
  12. Dieppe, P.; Swan, A. (May 1999). "Identification of crystals in synovial fluid.". Ann Rheum Dis 58 (5): 261-3. PMC 1752883. PMID 10225806. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1752883/.

External links