Clinical factors and treatment outcomes associated with failure in the detection of urate crystal in patients with acute gouty arthritis

BACKGROUND/AIMS: To investigate the rate of detection of monosodium urate (MSU) crystals in the synovial fluid (SF) of patients with acute gouty arthritis and factors associated with false-negative results. METHODS: A total of 179 patients with acute gouty arthritis who had undergone SF crystal examination were identified from the data warehouse of two university hospitals. Clinical and laboratory data were obtained from the medical records. RESULTS: The overall rate of detection of MSU crystals was 78.8%. In univariate analyses, the only significant differences between the variables of crystal-negative and crystal-positive patients were a lower C-reactive protein level (p = 0.040) and fewer patients undergoing emergent surgery in the crystal-positive group (p = 4.5 x 10(-6)). In logistic regression analyses, MSU crystal-negative results were significantly associated with the interval from arthritis onset to crystal examination (p = 0.042), and this was the most significant risk factor for arthroscopic surgery (p = 2.1 x 10(-4)). Seventeen patients who underwent arthroscopic surgery had a significantly longer hospital stay (p = 0.007) and a significant delay in gout treatment (p = 8.74 x 10(-5)). The distribution of crystal-negative patients differed significantly between the SF samples that were evaluated by both the laboratory medicine and the rheumatology departments (p = 1.2 x 10(-14)), and the kappa value was 0.108. CONCLUSIONS: Although several clinical features were associated with detection failure, SF MSU crystal identification was critically dependent on the observer. Considering the impact on the treatment outcomes, implementation of a quality control program is essential.

A Case of Relapsing Polychondritis Improved by Infliximab Treatment

Relapsing polychondritis is an episodic, systemic inflammation of the cartilage with unknown autoimmune etiology. It leads to the destruction of cartilaginous structures of the ear, eye, nose, respiratory tract, joints, skin, and heart valve, and its presented symptoms are diverse. It can be improved mainly by corticosteroid or immunosuppressive agents. Recently, the use of biologic agents (TNF inhibitors, rituximab, tocilizumab et al) was reported from abroad. However, there is no reported case of relapsing polychondritis, which is treated by biologic agents in Korea. We report this first case of refractory relapsing polychondritis, which was improved with a treatment of Infliximab.

Rituximab Treatment for the Patients with Refractory Inflammatory Myopathy

OBJECTIVE: To assess the efficacy and safety of rituximab (RTX) on disease activity and muscle strength in patients with inflammatory myopathies refractory to conventional therapy. METHODS: Four inflammatory myopathy patients who had been refractory to glucocorticoids, one or more immunosuppressive therapies and intravenous immunoglobulin were treated on an open-label basis. Each patient received two 500 mg doses of RTX 2 weeks apart in one cycle. In one patient who did not respond after the first cycle of RTX, the infusion schedule was modified by the physician. We measured muscle enzyme including CPK, LDH and assessed muscle strength individually to evaluate RTX response. Additionally anti-CD19 antibody was measured. RESULTS: Three patients responded to the first cycle of RTX treatment with improvements in muscle enzyme and muscle strength, and then maintained physical function over the duration of several infusion cycles. In one patient, muscle enzyme did not decrease after the first cycle of RTX, and a high dose glucocorticoid was given. After modifying the treatment schedule with monthly RTX infusion, his muscle enzyme level and muscle strength improved. Anti-CD19 antibody decreased after RTX generally, but responses were variable. Herpes zoster infection occurred in two patients. CONCLUSION: Rituximab may be a therapeutic choice in refractory inflammatory myopathy. However a further trial is needed to confirm the efficacy and prove the safety.