title: Prevalence of calcium pyrophosphate and monosodium urate crystals in synovial fluid of patients with previously diagnosed joint diseases.
abstract: OBJECTIVE
  The main aim of this study was to investigate the frequency of monosodium urate (MSU) and calcium pyrophosphate (CPP) crystals in synovial fluid (SF) obtained from patients with previously diagnosed joint diseases.
  
  
  METHODS
  We reviewed the results of SF analysis of 5020 samples identifying those collected from patients with a previously definite diagnosis (2370 samples). SF analysis results, age, sex, diagnosis and disease duration were recorded from computerized records of patients' archives.
  
  
  RESULTS
  The prevalence of CPP crystals in SF was 22.28% in osteoarthritis (OA), 8.28% in rheumatoid arthritis (RA), 3.82% in psoriatic arthritis (PsA), 2.79% in other spondyloarthropathies (SpA), 10% in septic arthritis (SeA), 0.66% in gout and 9.18% in the miscellanea of joint diseases, respectively. The prevalence of MSU crystals in SF was 0.30% in RA, 3.34% in PsA, 0.70% in other SpA, 0.80% in acute CPP crystal arthritis (CPP-CA), 0% in OA, reactive arthritis (ReA), SeA, juvenile idiopathic arthritis (JIA) and miscellanea. In OA group, we observed that age and SF inflammatory indices were higher in SF positive to CPP crystals with respect to those without crystals (P<0.0001). In RA, we found that the group of patients with CPP crystals was significantly older (P=0.001) and had a SF less inflammatory (P=0.022) with respect to that without crystals but with a higher disease duration than those without crystals.
  
  
  CONCLUSIONS
  Crystals can be detected more frequently than expected in SF from joint diseases with a previous established diagnosis. This highlights the importance of SF analysis for the diagnosis of possible comorbidities linked to the presence of crystals.
authors.affiliation: Rheumatology Unit, Department of Medicine, University of Padova, Via Giustiniani, 2, 35128 Padova, Italy. francesca.oliviero@unipd.it
authors.forename: Francesca
authors.initials: F
authors.lastname: Oliviero
authors.forename: Anna
authors.initials: A
authors.lastname: Scanu
authors.forename: Paola
authors.initials: P
authors.lastname: Galozzi
authors.forename: Alessandra
authors.initials: A
authors.lastname: Gava
authors.forename: Paola
authors.initials: P
authors.lastname: Frallonardo
authors.forename: Roberta
authors.initials: R
authors.lastname: Ramonda
authors.forename: Leonardo
authors.initials: L
authors.lastname: Punzi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001170:Arthritis, Infectious / Q000175:diagnosis / Q000453:epidemiology / Q000378:metabolism; D015535:Arthritis, Psoriatic / Q000175:diagnosis / Q000453:epidemiology / Q000378:metabolism; D001172:Arthritis, Rheumatoid / Q000175:diagnosis / Q000453:epidemiology / Q000378:metabolism; D002131:Calcium Pyrophosphate / Q000737:chemistry / Q000378:metabolism*; D003460:Crystallization; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000175:diagnosis / Q000453:epidemiology / Q000378:metabolism; D015995:Prevalence; D000091402:Prohibitins; D012189:Retrospective Studies; D012307:Risk Factors; D013582:Synovial Fluid / Q000737:chemistry / Q000378:metabolism*; D014527:Uric Acid / Q000737:chemistry / Q000378:metabolism*
chemical_list: C000717331:PHB2 protein, human; D000091402:Prohibitins; D014527:Uric Acid; D002131:Calcium Pyrophosphate