[Diagnostic approach and differential diagnosis of mon- and oligoarthritis]. / Wichtige Differenzialdiagnosen von Mon- und Oligoarthritiden.

Reasons of mon- and oligoarthritis are heterogeneous. The diagnostic approach includes a detailed medical anamnesis, physical examination and imaging (conventional X-ray, sonography, MRI and, CT). Analysis of the synovial fluid is required in suspected septic arthritis and frequently helps in diagnosis and differential diagnosis of crystal arthropathies. Dual-energy-CT (DECT) detects sodium urate crystals and can replace joint puncture in some cases. In addition to crystal arthropathies and septic arthritis, differential diagnosis of mon-/oligoarthritis includes reactive arthritis, arthrosis and monarthritic courses of SpA/PsA. A rheumatologist should be consulted particularly in the case of persistent monarthritides, in order to initiate a specific therapy to prevent secondary damage.

Synovial Biopsy in the Diagnosis of Crystal-Associated Arthropathies.

BACKGROUND/ OBJECTIVE: This study seeks to assess the utility of synovial biopsy in the diagnosis of crystal-associated arthropathies (CAAs) in a clinical setting. METHODS: In this retrospective study, we reviewed biopsy reports involving synovial tissue between 1988 and 2015. We then reviewed the records of patients where the biopsy was performed for a clinical suspicion of CAA-the clinical group-and calculated the frequency of a positive diagnosis. The t test, Mann-Whitney-Wilcoxon test, and Fisher test were used to compare clinical characteristics of patients with and without a tissue diagnosis of CAA. We also reviewed cases of unexpected detection of crystalline disease involving synovial tissue-the incidental group. RESULTS: Among 2786 biopsies involving the synovium, we identified 65 cases in the clinical group and 33 cases in the incidental group. In the clinical group, a relevant diagnosis was obtained from synovial tissue in 36.9%, and a CAA was diagnosed in 20%. Restricting analysis to clinical biopsies performed for a primary suspicion of CAA, a relevant diagnosis was obtained in 61.3%, and a CAA was diagnosed in 38.7%. The incidental group comprised 1.2% of all synovial biopsies and included 7 mass lesions. Basic calcium phosphate was not reported on any biopsy in the study period. CONCLUSIONS: Synovial biopsy is a diagnostic option when suspected CAA is resistant to conventional modes of diagnosis. Crystalline diseases should be considered in the differential diagnosis of musculoskeletal mass lesions mimicking neoplasms.

[Crystal arthropathies]. / Kristallarthritiden.

Crystals are one of the commonest reasons for acute joint inflammation. The most relevant types of crystals are those of monosodium urate (MSU) and calcium pyrophosphates (CPP). To get proven diagnosis of a crystal arthropathy the microscopic identification of those crystals in synovial fluid is still recommended by the actual guidelines. Whenever arthrocentesis is not feasible, ultrasound or dual-energy-computed tomography might help to visualize specific changes induced especially by MSU crystals. Both types of crystals act as danger signals inducing flares of immediate inflammatory response via activation of the innate immune system. Therefore crystal arthropathies could be seen as an auto-inflammatory condition. As neutrophils, monocytes and macrophages are the key cells and Interleukin 1ß is one of the dominant cytokines the way of blocking inflammation by colchicine and override IL-1ß are specific options in treating inflammation due to the crystals. For gout, causal treatment with urate lowering therapy can result in clearance of urate crystals. Unfortunately, to date there is no causal therapy for CPPD available. The present article summarises the recent knowledge highlighting the news regarding the crystal arthropathies gout and CPPD.

Disease-Associated Particulates and Joint Inflammation; Mechanistic Insights and Potential Therapeutic Targets.

It is now well established that intra-articular deposition of endogenous particulates, such as osteoarthritis-associated basic calcium phosphate crystals, gout-associated monosodium urate crystals, and calcium deposition disease-associated calcium pyrophosphate crystals, contributes to joint destruction through the production of cartilage-degrading enzymes and pro-inflammatory cytokines. Furthermore, exogenous wear-debris particles, generated from prosthetic implants, drive periprosthetic osteolysis which impacts on the longevity of total joint replacements. Over the last few years, significant insight has been gained into the mechanisms through which these particulates exert their effects. Not only has this increased our understanding of the pathological processes associated with crystal deposition but it has also led to the identification of a number of therapeutic targets to treat particulate-associated disease. In this review, we discuss recent developments regarding the cellular events triggered by joint-associated particulates, as well as future directions in therapy for particulate-related arthropathies.

[The analysis of synovial fluid: clinical significance of derived results].

The review presents modern data concerning characteristics of drawing of synovial fluid and also informativeness of its particular indices for resolving main clinical differential diagnostic task namely - selection group of septic and micro-crystal arthritis. It is demonstrated that minimal generally available span of analysis of synovial fluid is to include: finding number of leukocytes (threshold level for diagnostic of septic arthritis is 50 000 - 100 000 kl/mkl) and percentage of ploymorpho-nuclear cells (threshold level is 90%); analysis of content of crystals, Gram's stain and culture analysis of synovial fluid using light microscopy; and all this with mandatory registration of clinical data. The common evaluation of content of glucose and protein in synovialfluid is not enough informative. The detection of concentration of procalcitonin and lactate in synovial fluid is perspective for establishing septic genesis of arthritis. The sensitivity and specificity of light microscopy are quite high. Because of it absence of polarized microscope is no obstacle for implementation of crystallographic analysis of synovial fluid.