title: Presence of crystals is not an evidence of absence of infection.
abstract: Acute monoarthritis is one of the most common rheumatologic presentations. However, it is clinically difficult to distinguish between an inflamed joint due to crystal-induced arthritis and an inflamed joint due to septic arthritis. Arthrocentesis and synovial fluid analysis are used to differentiate between these 2 conditions. The presence of crystals and positive synovial fluid culture confirm the diagnosis of crystal-induced arthritis and septic arthritis, respectively. Although uncommon, these 2 arthritides can coexist, and presence of crystal does not exclude bacterial arthritis. We reported a case of 85-year-old woman whose synovial fluid contained crystals and was initially diagnosed with crystal-induced arthritis. However, her joint fluid culture subsequently grew Staphylococcus aureus, and she was treated with arthroscopic debridement and antibiotics.
authors.affiliation: Department of Internal Medicine, Bassett Medical Center and Columbia University College of Physicians and Surgeons, Cooperstown, NY 13326, USA. Patompong.Ungprasert@bassett.org
authors.forename: Patompong
authors.initials: P
authors.lastname: Ungprasert
authors.forename: Quanhathai
authors.initials: Q
authors.lastname: Kaewpoowat
authors.forename: Supawat
authors.initials: S
authors.lastname: Ratapano
authors.forename: Narat
authors.initials: N
authors.lastname: Srivali
authors.forename: Edward F
authors.initials: EF
authors.lastname: Bischof
mesh_terms: D000369:Aged, 80 and over; D000843:Ankle Joint / Q000382:microbiology / Q000473:pathology; D001170:Arthritis, Infectious / Q000150:complications / Q000175:diagnosis*; D002805:Chondrocalcinosis / Q000150:complications / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D013203:Staphylococcal Infections / Q000150:complications / Q000175:diagnosis*; D013582:Synovial Fluid / Q000737:chemistry / Q000382:microbiology