Chondrocalcinosis

Disc degeneration primarily contributes to chronic low back and neck pain. Consequently, there is an urgent need to understand the spectrum of disc degeneration phenotypes such as fibrosis, ectopic calcification, herniation, or mixed phenotypes. Amongst these phenotypes, disc calcification is the least studied. Ectopic calcification, by definition, is the pathological mineralization of soft tissues, widely studied in the context of conditions that afflict vasculature, skin, and cartilage. Clinically, disc calcification is associated with poor surgical outcomes and back pain refractory to conservative treatment. It is frequently seen as a consequence of disc aging and progressive degeneration but exhibits unique molecular and morphological characteristics: hypertrophic chondrocyte-like cell differentiation; TNAP, ENPP1, and ANK upregulation; cell death; altered Pi and PPi homeostasis; and local inflammation. Recent studies in mouse models have provided a better understanding of the mechanisms underlying this phenotype. It is essential to recognize that the presentation and nature of mineralization differ between AF, NP, and EP compartments. Moreover, the combination of anatomic location, genetics, and environmental stressors, such as aging or trauma, govern the predisposition to calcification. Lastly, the systemic regulation of calcium and Pi metabolism is less important than the local activity of PPi modulated by the ANK-ENPP1 axis, along with disc cell death and differentiation status. While there is limited understanding of this phenotype, understanding the molecular pathways governing local intervertebral disc calcification may lead to developing disease-modifying drugs and better clinical management of degeneration-related pathologies.

BackgroundCalcium pyrophosphate dihydrate (CPPD) crystals are commonly observed in osteoarthritic joints. The aim of our study was to investigate the efficacy of a dual-energy computed tomography (DECT) for detecting CPPD crystals in knee meniscus.MethodsTwenty-six patients undergoing primary total knee arthroplasty were included in the study. Radiographs of knee joint and synovial fluid specimens were analyzed for the presence of CPPD crystals. Meniscus extracted during surgery was scanned using DECT. Sensitivity and specificity of DECT and radiograph for detecting CPPD crystals were calculated against a reference standard (polarizing light microscopy of synovial fluid aspirate). Meniscus in which CPPD crystals were suspected with DECT was further examined to confirm the crystals using a polarized microscopy.ResultsCPPD crystals in synovial fluid were observed in 9 (36%) patients. The sensitivity and specificity of DECT in the detection of CPPD crystals, against microscopic identification, were 77.8 and 93.8%, respectively. The sensitivity and specificity of conventional radiography in the detection of CPPD crystals were 44.4 and 100%, respectively. DECT was able to detect the area where CPPD crystals were deposited in the meniscus.ConclusionDECT provides good diagnostic sensitivity and specificity for detection of CPPD crystals in knee meniscus as well as spatial information about CPPD crystals. DECT is currently a research tool, but we believe that DECT can be a useful instrument to diagnose CPPD deposition disease, especially for the regions where aspiration is difficult to be performed such as pubic symphysis, atlantoaxial joint, interphalangeal joint.

IntroductionCalcium pyrophosphate deposition (CPPD) may cause severe arthropathy, major joint destruction and treatment options are limited. The aim of this study was to test the therapeutic efficacy of methotrexate (MTX) in chronic or recurrent CPPD arthropathy.MethodsPatients with CPPD arthropathy were randomized to receive either weekly subcutaneous injections of 15 mg/week of MTX or placebo (PBO) for three months, in a double-blind, crossover randomized controlled trial. Inclusion criteria comprised definite CPPD disease, recurrent arthritis or persistent polyarthritis, and an insufficient response to NSAIDs, glucocorticoids or colchicine. The primary outcome was an improvement in the disease activity scores based on 44 joints (DAS44). The analysis was performed on an intent-to-treat basis.ResultsWe randomized 26 patients, and compared 25 treatment periods on MTX with 21 treatment periods on PBO. Baseline characteristics were balanced between the groups. The evolution of the DAS44 was not statistically significantly different between groups (median DAS44 decreased by -0.08 on MTX versus -0.13 on PBO, after three months, P = 0.44). Furthermore, pain levels remained stable in both groups (median change in VAS Pain -1 unit on MTX and 0 on PBO, P = 0.43), and none of the secondary outcomes was significantly different between the two groups. Minor adverse events (AE) did not differ in frequency between the groups, but the only serious AE occurred on MTX (bicytopenia).ConclusionsThe results of this trial with MTX in this older population with chronic or recurrent CPPD arthropathy suggest no strong effect of MTX on disease activity.Trial registrationEudraCT No: 2007-003479-37. Registered 26 April 2008.

RationaleThe wrist joint represents one of the most commonly affected anatomical sites in calcium pyrophosphate deposition disease, yet it remains underreported in the literature, frequently leading to diagnostic errors.Patient concernsWe present a case of acute pseudogout of the wrist whose symptoms mimicked cellulitis. Our patient presented with a swollen hand, which was initially treated as acute cellulitis with antibiotics, but without any improvement.DiagnosesA final diagnosis of acute chondrocalcinosis was made based on multiple intra-articular calcifications.OutcomesThe patient's symptoms were significantly relieved, and her inflammation markers were markedly reduced after glucocorticoid administration.LessonsPseudogout of the wrist can present with a pseudocellulitis appearance in the acute phase. Early accurate diagnosis can help physicians provide adequate treatment and avoid unnecessary antibiotic use.