title: Gout and coexisting pseudogout in the knee joint.
abstract: OBJECTIVE
  We report the unusual case of a 63-year-old man with gout and coexisting pseudogout (calcium pyrophosphate dihydrate crystal deposition disease) affecting the same joint. In this report, we describe the clinical features of the patient in addition to the characteristics of the crystals extracted from his affected joint, examined using compensated polarized microscopy.
  
  
  METHODS
  Synovial fluid and specimens of the lateral meniscus of the patient's knee joint taken during arthroscopy were analyzed using compensated polarized microscopy to evaluate the presence and type of crystals.
  
  
  RESULTS
  Compensated polarized microscopy revealed both monosodium urate (MSU) and calcium pyrophosphate dihydrate (CPPD) crystals extracted from the knee joint.
  
  
  CONCLUSIONS
  Our findings suggest that the coexistence of gout and pseudogout should be considered in the diagnosis of crystal-induced arthritis. Careful crystal evaluation using compensated polarized microscopy may reveal similar cases with MSU and CPPD crystals in the same joint.
authors.affiliation: Center for Arthroscopy, Department of Orthopaedic Surgery, Hallym University Hangang Sacred Heart Hospital, 94-200 Youngdeungpo-Dong, Youngdeungpo-Ku, 150-719, Seoul, Korea.
authors.forename: Yonsik
authors.initials: Y
authors.lastname: Yoo
authors.forename: Young-Jin
authors.initials: YJ
authors.lastname: Seo
authors.forename: Mina
authors.initials: M
authors.lastname: Huh
authors.forename: Je Hyun
authors.initials: JH
authors.lastname: Yoo
authors.forename: Kyu Ho
authors.initials: KH
authors.lastname: Yun
authors.forename: Sung-Jae
authors.initials: SJ
authors.lastname: Kim
mesh_terms: D001182:Arthroscopy / Q000379:methods*; D002131:Calcium Pyrophosphate / Q000032:analysis; D002805:Chondrocalcinosis / Q000150:complications* / Q000175:diagnosis / Q000601:surgery; D003646:Debridement / Q000379:methods; D004636:Emergency Service, Hospital; D005500:Follow-Up Studies; D006073:Gout / Q000150:complications* / Q000175:diagnosis / Q000601:surgery; D006801:Humans; D007719:Knee Joint; D008297:Male; D008875:Middle Aged; D010808:Physical Examination / Q000379:methods; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014527:Uric Acid / Q000032:analysis
chemical_list: D014527:Uric Acid; D002131:Calcium Pyrophosphate
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