Pyrophosphate Arthritis Research Articles

Prevalence and factors associated to calcium pyrophosphate arthritis in patients with gout

Aim: To ascertain the prevalence of calcium pyrophosphate arthritis (CPPA) at diagnosis and during follow-up of patients with gout. Methods: Inception cohort of patients with gout prospectively recruited and followed-up from 1994–2023. Gout-case was defined as crystal-proved tophus or arthritis, or the presence of tophus plus double contour with ultrasonography. CPPA was defined as the presence of intra-leukocyte calcium pyrophosphate (CPP) crystals in synovial fluid (SF) and neat chondrocalcinosis in plain radiographs. Age, gender, time from onset of symptoms, number of flares, joint distribution, previous and prescribed treatments, colchicine prophylaxis, comorbidities, alcohol intake, use of diuretics, renal function, and previous vascular disease were available for analysis. Results: A total of 1,544 patients with gout, with an average of 4-year follow-up, were available for analysis. CPPA was observed in 127/1,544 cases (8.2%). In 37/1,544 patients (2.4%) CPP and monosodium urate (MSU) crystals were observed in the same SF sample at gout diagnosis, and 90/1,544 (5.8%) showed CPP crystals apart from the diagnosis of gout. CPPA-gout cases had more flares per year, but no more frequent polyarticular distribution at baseline compared to non-CPPA-gout. CPPA-gout cases were older at baseline and showed lower renal function. Women, patients using diuretics, patients with hypertension, and those with previous vascular events showed CPPA more frequently. Multivariate analysis showed that only age and use of diuretics were independently associated with CPPA, as other variables apparently associated were dependent on aging. Interestingly, an analysis of the prevalence in the three decades available showed an increased CPPA diagnosis through time, probably associated with increased awareness of the association. Conclusions: (1) CPPA is not infrequent in patients with gout; (2) it is associated with aging and diuretic use; (3) awareness of this association may increase the rate of diagnosis.

A Narrative Review of Chondrocalcinosis: Clinical Presentation, Diagnosis, and Therapies.

Calcium pyrophosphate deposition disease is categorized into radiographic chondrocalcinosis, acute calcium pyrophosphate arthritis, chronic calcium pyrophosphate arthritis, and osteoarthritis with calcium pyrophosphate deposition. These entities collectively are characterized by the deposition of calcium into joints, which then may cause localized and systemic inflammation, resulting in pain and swelling in the affected joints. Patients with the ANKH gene are more susceptible to the development of CPP arthritis as are those with primary hyperparathyroidism, hypomagnesemia, and hemochromatosis. Radiographic chondrocalcinosis is asymptomatic. Acute calcium pyrophosphate arthritis results in self-limited periods of joint pain and swelling in the affected joint. Along with localized inflammation, there may also be systemic inflammation characterized by fever and elevated inflammatory markers. Chronic calcium pyrophosphate arthritis results in periods of quiescence interrupted by flares that are identical to acute periods of disease. Osteoarthritis associated calcium pyrophosphate arthritis presents with chronic pain well described in osteoarthritis with periods of acute flares. In 2023, a joint effort by the American College of Rheumatology and the European League Against Rheumatism developed guidelines meant to aid in the recognition of calcium pyrophosphate deposition diseases. The diagnosis is made if there is proof of either crowned dens syndrome or synovial fluid analysis demonstrating calcium pyrophosphate crystals or when more than 56 points are summed utilizing the criteria described in the guidelines. Radiographic chondrocalcinosis requires no therapy. Acute calcium pyrophosphate arthritis is treated with the goal of aborting the flare. Treatment options include nonsteroidal anti-inflammatory drugs (NSAIDs), colchicine, oral corticosteroids, parenteral corticosteroids, intraarticular corticosteroids, IL-1 inhibitors, or parenteral adrenocorticotropic hormone (ACTH). The goal in treatment for chronic calcium pyrophosphate arthritis is the suppression of acute flares. The drugs used for acute flare treatment may be given as maintenance therapy with the additional options of methotrexate and hydroxychloroquine.

Association of mutations in hemochromatosis genes with clinical severity of calcium pyrophosphate arthritis

Aims: To study factors associated with the development of calcium pyrophosphate (CPP) arthritis and the severity phenotype. Methods: Transversal case-control study. Cases had to be confirmed by both X-ray chondrocalcinosis and CPP crystals in synovial fluid. Controls had neither chondrocalcinosis nor CPP crystals in synovial fluid. Patients and controls with hemochromatosis or primary hyperparathyroidism were not included. Mutations of hemochromatosis genes (HFE), magnesium (Mg), calcium (Ca), phosphate, iron (Fe), transferrin saturation, ferritin, parathyroid hormone (PTH), and calcifediol levels were studied. Results: Three hundred patients and 300 sex and age matched controls were compared. Lower serum Mg (sMg) and higher ferritin levels were found among patients. Hypomagnesemia (HypoMg) and HFE mutations were more frequent among patients. Involvement of over one joint was observed in 199 (66.4%) patients whereas persistent joint inflammation was retrieved in 154 (51.4%) of the patients. Initial analysis showed that the frequency of polyarticular and inflammatory phenotypes seemed to be progressively overrepresented in patients with HFE mutations. Further bivariate and multivariate analysis adjusted for the time from onset disclosed that the presence of genotypes with C282Y mutations was associated with polyarticular disease (hazard risk 3.501, 95% confidence interval 1.862–6.581, P < 0.001). Although C282Y mutations also seemed to be associated with inflammatory patterns, the association did not reach statistical significance (P = 0.173). Conclusions: Low sMg and high ferritin levels are associated with CPP arthritis (CPPA). In patients without hemochromatosis, HFE mutations, and specifically C282Y mutations seem to associate with the polyarticular disease phenotype, and plausibly with the chronic inflammatory phenotype.

Prevalence and factors associated to diffuse idiopathic skeletal hyperostosis in gout

Aim: To evaluate the prevalence, associated factors, and the impact of diffuse idiopathic skeletal hyperostosis (DISH) in patients with gout. Methods: Patients with gout entering into an inception cohort were evaluated for either spinal or peripheral hyperostosis from January 2022 to April 2023. Age, gender, along with comorbid conditions associated to gout and DISH were analyzed, including the presence either axial or peripheral hyperostosis and associated calcium pyrophosphate arthritis (CPPA). Results: The prevalence of DISH was 25.6% (31/121) patients, neat peripheral joint hyperostosis affecting 51.6% (16/31). CPPA was also present in 11.6% (14/121) patients. Only older age and male gender were independently associated to the presence of DISH. The presence of hyperostosis in peripheral joints was not associated to a worse initial evaluation of the severity of gout. Conclusions: The presence of DISH in patients with gout seems to be related mostly to aging. Conditions apparently associated to DISH in gout patients seem therefore to be related to aging.

Acute Calcium Pyrophosphate Arthritis after Parathyroidectomy

Acute Calcium Pyrophosphate Arthritis after Parathyroidectomy

The complement system is activated in synovial fluid from subjects with knee injury and from patients with osteoarthritis.

BackgroundThe complement system is suggested to be involved in the pathogenesis of osteoarthritis (OA), and proinflammatory cytokines may play a role in OA development by inducing proteases. The association between complement factors, cytokines and OA has not been investigated. The aim of the present study was to explore the involvement of the complement system after knee trauma and in OA.MethodsC4d, C3bBbP and soluble terminal complement complex (sTCC) resulting from complement activation were immunoassayed in synovial fluid from subjects with healthy knees (reference), OA, rheumatoid arthritis (RA; positive control), pyrophosphate arthritis (PPA; positive control) and knee injury; other biomarkers were previously assessed. Magnetic resonance imaging was used to assess joint injuries.ResultsCompared with levels in the reference group, the median concentrations of C4d, C3bBbP and sTCC in the OA, RA, PPA and knee injury groups were 2- to 34-fold increased (p < 0.001 to p = 0.044). For the knee injury group, the median concentrations of C4d, C3bBbP and sTCC were 5- to 12-fold increased (p < 0.001) at the day of injury; after 3–12 weeks, C3bBbP and sTCC concentrations were similar to reference levels; and C4d was still increased several years after injury. In the 0–12 weeks period after injury, the concentrations of C4d, C3bBbP and sTCC correlated positively with levels of interleukin (IL)-1β, IL-6 and tumour necrosis factor α (r s range 0.232–0.547); none of the measured complement factors correlated with proteolytic fragments of aggrecan or cartilage oligomeric matrix protein. Knees with osteochondral fracture, with or without disrupted cortical bone, had higher concentrations of C4d (p = 0.014, p = 0.004) and sTCC (p = 0.004, p < 0.001) compared with knees without fractures.ConclusionsThe complement system is activated in OA and after knee injury. Following knee injury, this activation is instant and associated with inflammation as well as with the presence of osteochondral fractures.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-016-1123-x) contains supplementary material, which is available to authorized users.

A prospective evaluation of ultrasound as a diagnostic tool in acute microcrystalline arthritis.

IntroductionThe performance of ultrasound (US) in the diagnosis of acute gouty (MSU) arthritis and calcium pyrophosphate (CPP) arthritis is not yet well defined. Most studies evaluated US as the basis for diagnosing crystal arthritis in already diagnosed cases of gout and few prospective studies have been performed.MethodsOne hundred nine consecutive patients who presented an acute arthritis of suspected microcrystalline arthritis were prospectively included. All underwent an US of the symptomatic joints(s) and of knees, ankles and 1st metatarsopalangeal (MTP) joints by a rheumatologist “blinded” to the clinical history. 92 also had standard X-rays. Crystal identification was the gold standard.ResultsFifty-one patients had MSU, 28 CPP and 9 had both crystals by microscopic analysis. No crystals were detected in 21. One had septic arthritis. Based on US signs in the symptomatic joint, the sensitivity of US for both gout and CPP was low (60 % for both). In gout, the presence of US signs in the symptomatic joint was highly predictive of the diagnosis (PPV = 92 %). When US diagnosis was based on an examination of multiple joints, the sensitivity for both gout and CPP rose significantly but the specificity and the PPV decreased. In the absence of US signs in all the joints studied, CPP arthritis was unlikely (NPV = 87 %) particularly in patients with no previous crisis (NPV = 94 %). X-ray of the symptomatic joints was confirmed to be not useful in diagnosing gout and was equally sensitive or specific as US in CPP arthritis.ConclusionsArthrocenthesis remains the key investigation for the diagnosis of microcrystalline acute arthritis. Although US can help in the diagnostic process, its diagnostic performance is only moderate. US should not be limited to the symptomatic joint. Examination of multiple joints gives a better diagnostic sensitivity but lower specificity.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-015-0701-7) contains supplementary material, which is available to authorized users.

SAT0508 Coexistence of Gout and Pyrophosphate Arthritis in Two Large Cohorts: Hyperuricemia as A Factor for Clinical Misdiagnosis

Backgrounda definite diagnosis for gout and pyrophosphate arthritis require identification of urate and pyrophosphate crystals in biolόgica samples. That might explain why databases do not capture with acuracy the coexistence...

SP0178 Gout and Crystal-Induced Diseases: Year in Review 2013-2014

In recent times, increasing interest has been raised on crystal-induced arthritis, especially regarding gout and the development of new medications to treat hyperuricaemia and inflammation, what has been nicely demonstrated...

THU0508 Incidence of Inflammatory Joint Diseases in Northern Savo Area in Finland in 2010

BackgroundMonitoring of the incidence of inflammatory joint diseases may provide new insight into the etiology of these diseases.ObjectivesAll rheumatologists practising in the Northern Savo rheumatological outpatient departments collected data on...

Rheumatoid and pyrophosphate arthritis synovial fibroblasts induce osteoclastogenesis independently of RANKL, TNF and IL-6

Bone destruction is a common feature of inflammatory arthritis and is mediated by osteoclasts, the only specialized cells to carry out bone resorption. Aberrant expression of receptor activator of nuclear factor kappa β ligand (RANKL), an inducer of osteoclast differentiation has been linked with bone pathology and the synovial fibroblast in rheumatoid arthritis (RA). In this manuscript, we challenge the current concept that an increase in RANKL expression governs osteoclastogenesis and bone destruction in autoimmune arthritis.We isolated human fibroblasts from RA, pyrophosphate arthropathy (PPA) and osteoarthritis (OA) patients and analyzed their RANKL/OPG expression profile and the capacity of their secreted factors to induce osteoclastogenesis. We determined a 10-fold increase of RANKL mRNA and protein in fibroblasts isolated from RA relative to PPA and OA patients. Peripheral blood mononuclear cells (PBMC) from healthy volunteers were cultured in the presence of RA, PPA and OA synovial fibroblast conditioned medium. Osteoclast differentiation was assessed by expression of tartrate-resistant acid phosphatase (TRAP), vitronectin receptor (VNR), F-actin ring formation and bone resorption assays. The formation of TRAP+, VNR+ multinucleated cells, capable of F-actin ring formation and lacunar resorption in synovial fibroblast conditioned medium cultures occured in the presence of osteoprotegerin (OPG) a RANKL antagonist. Osteoclasts did not form in these cultures in the absence of macrophage colony stimulating factor (M-CSF).Our data suggest that the conditioned medium of pure synovial fibroblast cultures contain inflammatory mediators that can induce osteoclast formation in human PBMC independently of RANKL. Moreover inhibition of the TNF or IL-6 pathway was not sufficient to abolish osteoclastogenic signals derived from arthritic synovial fibroblasts. Collectively, our data clearly show that alternate osteoclastogenic pathways exist in inflammatory arthritis and place the synovial fibroblast as a key regulatory cell in bone and joint destruction, which is a hallmark of autoimmune arthritis.

Ankylosing Spondylitis, Late Osteoarthritis, Vascular Calcification, Chondrocalcinosis and Pseudo Gout: Toward a Possible Drug Therapy

In this review we consider diseases associated with pathological mineralization/ossification, namely, ankylosing spondylitis (AS), osteoarthritis (OA), generalized artery calcification of infancy (GACI), vascular calcification as well as chondrocalcinosis (CC) and pseudo gout. Deciphering the key enzymes implicated in the calcification process is an objective of prime importance and the ultimate goal is to synthesize inhibitors of these enzymes in order to provide efficient alternate therapeutic strategies that will slow down the pathologic mineralization and complement the arsenal of anti-inflammatory drugs. One of the difficulties in the definition of diseases associated with pathologic mineralization/ossification lies in the controversial relationship between the type of calcification and the nature of the disease. Here, we propose to clarify this relationship by making a distinction between diseases associated with hydroxyapatite (HA) and calcium pyrophosphate dihydrate (CPPD) deposits. AS, OA, GACI and vascular calcification are usually characterized by mineralization/ossification associated with HA deposits, while CC and pseudo gout are mostly characterized by CPPD deposits. Although both HA and CPPD deposits may occur concomitantly, as in chronic pyrophosphate arthritis or in OA with CPPD, they are formed as a result of two antagonistic processes indicating that treatment of distinct diseases can be only achieved by disease-specific drug therapies. The hydrolysis of PPi, an inhibitor of HA formation, is mostly controlled by tissue non-specific alkaline phosphatase TNAP, while PPi production in the extracellular medium is controlled by ANK, a PPi transporter, and/or NPP1 which generates PPi from nucleotide triphosphates. Low PPi concentration may lead to a preferential deposition of HA while high PPi concentration will favor the formation of CPPD deposits. Thus, HA and CCPD deposition cannot occur concomitantly because they are determined by the Pi/PPi ratio which, in turn, depends on the relative activities of antagonistic enzymes, TNAP hydrolyzing PPi or ANK and NPP1 producing PPi. TNAP inhibitors could prevent HA formation in AS, in late OA, in GACI, as well as in vascular calcifications, while ANK or NPP1 inhibitors could slow down CCPD deposition in CC and pseudo gout.

Changes in joint cartilage aggrecan after knee injury and in osteoarthritis.

To determine the concentrations of aggrecan fragments in synovial fluid from patients with knee joint injury, osteoarthritis (OA), or acute pyrophosphate arthritis (PPA; pseudogout), and to test their relative reactivity with the 846 epitope, a putative marker of cartilage aggrecan synthesis. Samples of knee joint fluid from 385 patients and 9 healthy-knee volunteers were obtained in a cross-sectional study. Study groups were acute PPA/ pseudogout (n = 60), anterior cruciate ligament (ACL) rupture (n = 159), meniscus lesion (n = 129), and primary knee OA (n = 37). The 846 epitope on aggrecan was assayed by competitive solution-phase radioimmunoassay. Aggrecan fragments were assayed by enzyme-linked immunosorbent assay using a monoclonal antibody (1-F21). Cartilage oligomeric matrix protein (COMP), C-propeptide of type II collagen (CPII), bone sialoprotein, matrix metalloproteinases 1 and 3, and tissue inhibitor of metalloproteinases 1 were previously quantified by immunoassays. Reactivity of the 846 epitope was increased in all study groups compared with the reference group, and was highest in patients with primary OA. The median levels (in microg fetal aggrecan equivalents/ml) of the epitope were 0.28 (range 0.24-0.47) in the reference group, 0.48 (range 0.26-1.32) in PPA/pseudogout, 0.61 (range 0.12-2.87) in ACL rupture, 0.53 (range 0.22-3.02) in meniscus lesion, and 0.68 (range 0.31-4.31) in primary OA. The 846 epitope reactivity per microg aggrecan fragments in the joint fluid was higher in late-stage OA than in early-stage OA. Epitope 846 reactivity correlated positively with several markers of matrix turnover, particularly with COMP (r(s) = 0.421) and CPII (r(s) = 0.307). The observed differences in 846 epitope reactivity in synovial fluid, and its concentration in relation to aggrecan and other markers of matrix turnover, were consistent with marked ongoing changes in aggrecan turnover after joint injury and in the development of OA. OA is thus a disease characterized by dynamic changes in tissue macromolecule turnover, which is reflected by measurable changes in aggrecan epitopes in the synovial fluid.

Calcium pyrophosphate crystal deposition disease and other crystal deposition diseases

"Tumoral" calcium pyrophosphate dihydrate (CPPD) crystal deposition in the ligamentum flavum is rare and can lead to compression myeloradiculopathy in the cervical spine and to spinal canal stenosis in the lumbar spine. CPPD crystal deposition disease is rarely associated with Bartter's syndrome and hypomagnesemia. Intramuscular corticotropin has proved effective in the treatment of acute episodes of pyrophosphate arthritis in patients with multiple medical illnesses in whom nonsteroidal anti-inflammatory drugs are contraindicated. IgG binding to CPPD crystals enhances neutrophil activation (by increasing intracellular cytoplasmic calcium levels) and seems to play a greater role in pyrophosphate than in urate crystal-induced inflammation. Transforming growth factor-beta 1 stimulates intracellular pyrophosphate generation by articular chondrocytes. The effect is inhibited by probenecid, an anion transport blocker, through interfering with the active transport of intracellular pyrophosphate to cartilage matrix where crystals form. Calcific tendinitis associated with underlying cortical bone erosions is an uncommon manifestation of apatite crystal deposition disease. Closed-needle tidal irrigation proved beneficial in two patients with Milwaukee shoulder syndrome. Two patients with nodular subcutaneous cholesterol crystal deposition are described.

The structure of aggrecan fragments in human synovial fluid. evidence that aggrecanase mediates cartilage degradation in inflammatory joint disease, joint injury, and osteoarthritis

To determine the proteolytic fragmentation patterns and N-terminal sequence of aggrecan fragments in human synovial fluid from patients with inflammatory arthritides, joint injury, or osteoarthritis (OA). Knee synovial fluid was obtained from patients with joint injury, OA, acute pyrophosphate arthritis (pseudogout), reactive arthritis, psoriatic arthritis, or juvenile rheumatoid arthritis. Chondroitin sulfate-substituted aggrecan fragments present in the fluid were purified by cesium chloride gradient centrifugation and enzymatically deglycosylated. Core protein species were determined by N-terminal analysis and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with electroblotting and detection with monoclonal antibody 3B3. Samples from patients with joint injury, OA, and inflammatory joint disease all showed a similar 3-band pattern, with core sizes of approximately 200 kd, 170 kd, and 135 kd. In all samples, diffuse immunoreactive products were also seen, with an apparent size of > 250 kd. N-terminal analysis of core preparations of all samples showed a consistent single predominant sequence, beginning at alanine 374 of the human aggrecan core protein. The aggrecan fragments present in joint fluids from patients with various inflammatory arthritides, joint injury, or OA result from a predominant cleavage of the human aggrecan core protein at the glutamate 373-alanine 374 bond within the interglobular domain, between the G1 and G2 domains. The consistent pattern of fragments seen on SDS-PAGE and the single predominant N-terminal sequence suggest a common degradative mechanism of aggrecan in these different joint conditions. The identity of the proteolytic agent (aggrecanase), however, remains unknown. These results appear to have important implications with regard to the development of therapies to protect cartilage from degradation in patients with joint disease.

Increased concentrations of proteoglycan components in the synovial fluids of patients with acute but not chronic joint disease.

Synovial fluid samples (139) from 121 patients with rheumatoid arthritis, osteoarthritis, pseudogout, chronic pyrophosphate arthritis, gout, and reactive arthritis were analysed for cartilage proteoglycan components. Keratan sulphate (KS) epitope was determined by a competitive radioimmunoassay, and total sulphated glycosaminoglycans (S-GAG) were determined after papain digestion by a specific dye binding assay. Increased concentration of both KS epitope and S-GAG were found in synovial fluid from joints with acute inflammatory arthropathy (gout, pseudogout, and reactive arthritis). Analysis of consecutive samples from the same joint at different stages showed that the concentration of KS epitope or total S-GAG varied with acute inflammatory activity. In samples from patients with chronic conditions during active and inactive inflammatory phases concentrations were much lower and not distinguishable among these disease groups. The detection of raised concentration of proteoglycan components may reflect the rapid depletion or greatly increased turnover of proteoglycan in the articular cartilage during acute inflammation in the joint. This did not appear to be sustained in most patients with chronic joint diseases.

Pyrophosphate arthritis with local amyloid deposition.

Pyrophosphate and capsular chondromatosis were demonstrated histologically in 15 cases, 14 of which also exhibited local deposition of amyloid. A systematic examination of the joint capsule in 57 consecutive hip replacement operations for osteoarthritis revealed these changes in 6 of the cases (10.5 per cent). Microscopic examination which was done if intraarticular calcifications were grossly visible at operation, showed the same changes in 8 knees, 4 with osteoarthritis and 4 with meniscal disease. The changes were also seen in the menisci. Only one patient was suffering from chronic, polyarticular pyrophosphate arthritis. In the other cases neither change had been expected a priori, and the patients had no signs of systemic articular disease or amyloidosis. Most of them were elderly, but in good health.

LOCAL ARTICULAR AMYLOID DEPOSITION IN PYROPHOSPHATE ARTHRITIS

A material of 15 cases of histologically examined pyrophosphate arthritis (hip-joint: 7 cases, knee joint: 8 cases) is presented. Amyloid deposits were found in 14 cases and chondromatosis in the subsynovial connective tissue of all the cases. The significance of this high, not previously reported, coincidence is discussed, together with various pathogenetic possibilities, as related to the theories of the genesis of amyloid substance.