Tophus Size Research Articles

Musculoskeletal Ultrasound in Monitoring the Efficacy of Gout: A Prospective Study Based on Tophus and Double Contour Sign

In patients with gout receiving uric acid-lowering therapy, musculoskeletal ultrasound has the potential to observe changes in gout lesions. To analyze the effectiveness of uric acid-lowering therapy in patients with gout over one year using musculoskeletal ultrasound as a monitoring technique. Prospective cohort study. A total of 215 patients meeting the 1977 American College of Rheumatology gout classification criteria and treated with uric acid-lowering therapy were separated into two groups, treat-to-target and treat-to-non-target depending on the target serum urate levels. Lower extremity joints were evaluated by ultrasound before therapy (M0), as well as three (M3), six (M6), and twelve (M12) months after therapy. At various moments during uric acid-lowering therapy, the tophus size and the semiquantitative ultrasound scoring system of double contour sign were measured in the treat-to-target and treat-to-non-target groups. Ninety-five tophi (45 in treat-to-target and 50 in treat-to-non-target) and sixty-seven double contour sign (34 in treat-to-target and 33 in treat-to-non-target) were evaluated longitudinally. In both groups, the long diameter, short diameter, and area of tophus in treat-to-target decreased as the duration of uric acid-lowering treatment increased. Differences in the long diameter of tophus between M12 and M0, M3 and M6 were statistically significant (P < 0.05), while differences between the other time points were not significant (P > 0.05). No statistically significant differences were observed in the short diameter and the area of tophus between M0 and M3 (P > 0.05), while there were statistically significant differences between other periods (P < 0.05). In treat-to-non-target, the long diameter, short diameter, and area of tophus showed a slight increase at different uric acid-lowering therapy time points. The differences in the long diameter, short diameter, and area of tophus at different uric acid-lowering therapy time points were not significant (P > 0.05). The semiquantitative ultrasound scoring system of double contour sign of treat-to-target and treat-to-non-target showed a decreasing trend with increasing uric acid-lowering therapy time, with a more pronounced drop in treat-to-target than treat-to-non-target. In treat-to-target, the difference in the semiquantitative ultrasound scoring system of double contour sign at each uric acidlowering therapy time point was significant (P < 0.05). In treat-tonon- target, the difference in semiquantitative ultrasound scoring system of double contour sign scores between M0 and M3 was not statistically significant (P >0.05), but it was statistically significant for the remaining time points (P < 0.05). After one year of uric acid-lowering therapy in patients with gout, an ultrasound indicated that the size of tophus and the semiquantitative ultrasound scoring system of double contour sign score decreased dramatically in the treat-to-target group. Semiquantitative ultrasound scoring system of double contour sign score was dramatically reduced in the treat-to-non-target group, but the size of the tophus remained the same. Therefore, musculoskeletal ultrasound is an effective tool to monitor the efficacy of uric acid-lowering therapy.

Elevated serum CA72-4 predicts gout flares during urate lowering therapy initiation: a prospective cohort study.

Gout flares during urate-lowering therapy (ULT) initiation are common, but predictors of these flares are poorly understood. The aim of this study was to determine whether serum CA72-4 is an independent predictor for gout flares during ULT initiation. A prospective cohort study was conducted between March 2021 and January 2022. Men with gout, at least one gout flare in the past year, and at least three serum CA72-4 measurements in the previous six months were enrolled. Participants were grouped according to their highest recorded serum CA72-4 levels (above or within the normal range). All participants took oral febuxostat 20 mg daily without flare prophylaxis therapy, and attended face-to-face visits every four weeks until 24 weeks. The incidence of gout flare was compared between the two groups. Backward stepwise logistic regression analyses were used to identify risk factors associated with flares. Receiver operating characteristic curve analysis was used to evaluate prediction efficacy. A total of 193 completed the study (79 with high CA72-4; 114 with normal CA72-4). The cumulative incidence of at least one gout flare was 48.1% (62.1% in the high CA72-4 group, 38.4% in the normal CA72-4 group, P = 0.001), and recurrent (≥2) flares was 33.0% (47.1% in the high CA72-4 group, 23.2% in the normal CA72-4, P < 0.001). High CA72-4, disease duration, intra-articular tophus size, glucose, high-density lipoprotein-cholesterol and ESR were independent risk factors for gout flares. Serum CA72-4 alone predicted recurrent flares with an area under the curve of 0.63 (95%CI = 0.54, 0.71), and 0.78 (95%CI = 0.71, 0.85) when combined with other independent variables. High serum CA72-4 predicts the risk of gout flares during ULT initiation. ChiCTR; https://www.chictr.org.cn/; ChiCTR2100043573.

The Role of Ultrasound in Evaluating the Effect of Urate-lowering Drugs in Gout Patients.

Gout is one of the most common inflammatory arthritis, where identification of MSU crystals in synovial fluid is a widely used diagnostic measure. Ultrasonography has a great sensitivity in detecting signs of MSU deposits, such as tophi and double contour (DC), as mentioned in the latest gout criteria, allowing early clinical diagnosis and therapy. The objective of this study was to evaluate the changes in ultrasound of gout patients' knee and 1st metatarsophalangeal joint (MTP1) after initiation of urate-lowering therapy (ULT) drugs in the six-month period. Forty-three patients, fulfilling the ACR/EULAR 2015 criteria of gout with a score of >8, were enrolled; they were in between attacks and not on ULT for the last 6 months, or SUA concentration (SUA) of >6.0 mg/dL. Full examination, evaluation of joints pain by visual analog scale (VAS), ultrasonography (US) for tophus and DC at the knee, and MTP1 were performed at baseline and at 3 and 6 months (M3, M6) after starting ULT. After 6 months of treatment, patients reached the target SUA level showed higher disappearance of DC sign (p<0.05) and a decrease in tophus size (p<0.05). The percentage of tophus size at 6th month was 26.4% and 3% for DC sign disappearance, which was more at MTP1. Ultrasound examination in screening for gout tophi or DC sign before starting ULT and during follow-up is important and complements clinical examination.

Quantitative assessment of crystal dissolution in gout during urate-lowering therapy with computer-aided MicroPure imaging: a cohort study

BackgroundTo evaluate whether MicroPure imaging, an ultrasound (US) image-processing technique with computer-aided analysis, can quantitatively detect crystal dissolution during urate-lowering therapy (ULT) in gout.MethodsThis was a prospective study of gout patients requiring ULT. The first metatarsophalangeal joints were examined using US and MicroPure before and after 3 months of ULT. Elementary lesions of gout, including the double contour sign (DCS), aggregates, tophi, erosion, and other US features were recorded at baseline and 3 months. MicroPure imaging features were automatically calculated by a self-developed software. Patients were divided into goal-achieved and goal-not-achieved groups according to their urate levels at 3 months. The US and MicroPure imaging features of the two groups were analyzed at baseline and 3 months.ResultsA total of 55 consecutive patients were enrolled (25: goal-achieved group; 30: goal-not-achieved group). US findings demonstrated that the power Doppler signal grade decreased at 3 months, regardless of the group (both P<0.05). From baseline to 3 months, tophi size and the DCS reduced in the goal-achieved group (both P<0.05), while the US aggregate features showed no difference (P=0.250). However, on the MicroPure imaging, the number and density of aggregates at 3 months decreased in the goal-achieved group (both P<0.05). There were no significant changes at 3 months in any of the MicroPure imaging features in the goal-not-achieved group (all P>0.05).ConclusionsIn comparison with B-mode US, computer-aided MicroPure imaging can sensitively and quantitatively detect aggregate dissolution during effective ULT after only 3 months of treatment.

Ultrasound Evaluation of Three Outcome Domains in the Follow-up of Urate-Lowering Therapy in Gout: An Observational Study

This prospective study was aimed at observing the changes in three ultrasound (US) outcome domains (urate deposition, joint inflammation and bone erosion) in gout patients within the 1 y on urate-lowering therapy. The elementary lesions, including tophus, double-contour (DC) sign, aggregates, synovitis and bone erosion of the bilateral knee, ankle and first metatarsophalangeal joints, were evaluated repeatedly by US before and after 3, 6 and 12 mo of treatment, and the effective rates of clearance of tophus, DC sign and aggregates in different time groups were compared. A Global OMERACT–EULAR Synovitis Score (GLOESS) was calculated for these three paired joints to observe the inflammation. Bone erosion was also scored. The correlation between serum uric acid levels and tophus size changes was analyzed. Our results indicated that the decrease in serum uric acid levels was not completely parallel to the decrease in tophus size. For tophus, there was no significant difference in the clearance rate between different time groups (χ2 = 1.76, p = 0.392), while for DC sign and aggregates, there were significant differences (χ2 = 21.48, p < 0.001, χ2 = 7.75, p = 0.018). Meanwhile, GLOESS was significantly lower after 6 mo of therapy (χ2 = 32.316, p < 0.001). Additionally, bone erosion had not improved after 1 y of treatment (Z = –1.633, p = 0.102). Thus, US is crucial for assessing response to urate-lowering therapy in gout.

Development of a multivariable improvement measure for gout

BackgroundGout is a heterogeneous inflammatory disease with numerous clinical manifestations. A composite means to assess the impact of therapy on numerous aspects of gout could be useful.MethodsResults from patients treated with pegloticase or placebo in two randomized clinical trials and their open-label extension were assessed using a novel evidence-based Gout Multivariable Improvement Measure (GMIM) derived from previously reported criteria for remission and complete response. Improvement was defined as serum urate (sU) < 6 mg/dL and absence of flares during the preceding 3 months plus 20, 50, and 70% improvement in tophus size, patient global assessment, pain, and swollen and tender joints.ResultsPatients treated with pegloticase manifested a significantly greater GMIM20, 50, and 70 response vs those treated with placebo (GMIM20 at 6 months 37.1% vs 0%, respectively). Higher response rates were significantly more frequent in subjects with persistent urate lowering (GMIM 58.1% at 6 months) in response to pegloticase versus those with only transient urate lowering (GMIM 7.1% at 6 months). However, when the requirement for a decrease in sU to < 6 mg/dL was omitted, a substantial percentage of subjects with transient urate lowering met the GMIM clinical criteria. A sensitivity analysis indicated that gout flares contributed minimally to the model. The response measured by GMIM persisted into the open-level extension for as long as 2 years. Finally, subjects who received placebo in the randomized control trials, but pegloticase in the open-label extension, manifested GMIM responses comparable to that noted with pegloticase-treated subjects in the randomized controlled trials.ConclusionsGMIM captures changes in disease activity in response to treatment with pegloticase and may serve as an evidence-based tool for assessment of responses to other urate-lowering therapies in gout patients.

Predictive factors of tumour necrosis inhibitor treatment persistence for rheumatoid arthritis: An observational study in 8052 patients.

To determine whether changes in ultrasonography (US) features of monosodium urate crystal deposition is associated with the number of gouty flares after stopping gout flare prophylaxis. We performed a 1-year multicentre prospective study including patients with proven gout and US features of gout. The first phase of the study was a 6-month US follow-up after starting urate-lowering therapy (ULT) with gout flare prophylaxis. After 6 months of ULT, gout flare prophylaxis was stopped, followed by a clinical follow-up (M6 to 12) and ULT was maintained. Outcomes were the proportion of relapsing patients between M6 and M12 according to changes of US features of gout and determining a threshold decrease in tophus size according to the probability of relapse. We included 79 gouty patients (mean [±SD] age 61.8±14 years, 91% males, median disease duration 4 [IQR 1.5; 10] years). Among the 49 completers at M12, 23 (47%) experienced relapse. Decrease in tophus size≥50% at M6 was more frequent without than with relapse (54% vs. 26%, P=0.049). On ROC curve analysis, a threshold decrease of 50.8% in tophus size had the best sensitivity/specificity ratio to predict relapse. Probability of relapse was increased for patients with a decrease in tophus size <50% between M0 and M6 (OR 3.35 [95% confidence interval 0.98; 11.44]). A high reduction in US tophus size is associated with low probability of relapse after stopping gout prophylaxis. US follow-up may be useful for managing ULT and gout flare prophylaxis.

Treat-to-Target urate-lowering therapy in primary gout patients: A real-world retrospective study at a dedicated gout clinic in China

Gout is the most common inflammatory arthritis affecting 1.1% of the population in mainland China with a higher prevalence in coastal areas. The purpose of the study was to investigate the clinical outcomes following urate-lowering therapy (ULT) in a real-world group study of primary gout patients in China. Electronic medical records of all the gout patients (n= 1588) that visited the Clinical Medical Center of Gout of the Affiliated Hospital of Qingdao University from September 2016 to February 2018 were analyzed in this study. The patients were treated with a standard treat-to-target (T2T) ULT strategy according to the 2016 EULAR Guidelines. Clinical data were collected in the first visit and one-month (defined as the baseline of ULT), 7-month, and 13-month follow-ups were completed. Amongst the patients in the study, 92.70% accepted ULT and 82.93% completed ULT for 3months, 63.54% for 6months, and 40.49% (n= 643) for 12months. Further analysis of the 643 patients included the following data: the sUA level reduced at month 7 and reduced further at month 13. The gout flares, patient global pain visual analogue score, and health assessment questionnaire score improved at month 7 but did not improve further at month 13, and the index tophus size did not.

Impact of Dual-Energy CT Postprocessing Protocol for the Detection of Gouty Arthritis and Quantification of Tophi in Patients Presenting With Podagra: Comparison With Ultrasound.

OBJECTIVE. The objective of our study was to compare ultrasound (US) tophus and monosodium urate (MSU) deposit detection and US tophus size in the metatarsophalangeal (MTP) 1 joint with dual-energy CT (DECT) using two DECT postprocessing protocols in patients presenting with podagra. SUBJECTS AND METHODS. Seventy-five consecutive patients with podagra (66 men and nine women; mean age, 65.6 years; age range, 33-88 years) and 75 control subjects with MTP 1 joint osteoarthritis (49 men and 26 women; mean age, 63.0 years; age range, 35-87 years) prospectively underwent US and DECT between 2016 and 2018 to assess the MTP 1 joint. Two Syngovia postprocessing DECT protocols with different minimum attenuation thresholds of 150 HU (DECT 150 protocol) versus 120 HU (DECT 120 protocol) and the same maximum attenuation threshold (500 HU) and constant kilovoltage setting of tubes A and B at 80 and 140 kVp were evaluated. Interobserver variability of the two DECT protocols was calculated and compared with that of US. RESULTS. The postprocessing DECT 150 protocol was positive for tophus detection in 55 of 75 patients (73.3%) with podagra, whereas the postprocessing DECT 120 protocol detected MSU deposits in all 75 patients (100%). Tophus size assessed using the DECT 120 protocol showed an improved correlation with tophus size detected on US (p < 0.01). Interobserver variability of DECT was improved when using the DECT 120 protocol (p < 0.01). CONCLUSION. The postprocessing DECT 120 protocol enables improved visualization of MSU deposits and provides more accurate information about tophus size that better correlates with tophus size on US compared with the standard postprocessing DECT 150 protocol.

Tophi reduction: ultrasound imaging and correlation with plasma levels of uric acid in patients undergoing treatment for tophaceous gout.

The objective was to determine the reduction of tophi in patients undergoing drug therapy in correlation with urate serum levels through ultrasound examination. A total of 31 male patients, between the ages of 33 to 77 years, with tophaceous gout were evaluated between 2005 and 2009, 11 of which were selected. Ultrasound examinations of visible tophi and evaluations of serum uric acids levels were performed annually on each patient. There was a statistically significant difference between measurements 1, 2, 3 and measurement 4 and between measurements 4 and 5. A strong significant positive association was seen between variation of tophus size and the reduction of serum uric acid levels.

Efficacy and safety during extended treatment of lesinurad in combination with febuxostat in patients with tophaceous gout: CRYSTAL extension study

BackgroundIn gout, long-term urate-lowering therapy (ULT) promotes dissolution of tissue urate crystal deposits. However, no studies using combined xanthine oxidase inhibition and uricosuric ULT have focused on clinical outcomes or adverse events (AEs) beyond 12 months of therapy. Our objective in the present study was to examine efficacy and long-term safety in patients with tophaceous gout receiving febuxostat plus lesinurad as combination therapy.MethodsPatients receiving combined lesinurad and febuxostat in the 12-month core CRYSTAL study continued at the same doses in the extension study (“200CONT”, “400CONT”), whereas those receiving only febuxostat 80 mg were randomized to lesinurad 200 or 400 mg with febuxostat (“200CROSS”, “400CROSS”). The primary endpoint was the proportion of patients experiencing complete resolution (CR) of at least one target tophus by extension month (EM) 12. The key secondary endpoint was mean rate of gout flares requiring treatment from the end of EM 2 to the end of EM 12. Secondary endpoints included reduction in the sum of areas for all target tophi. Safety assessments included AEs and laboratory data for the entire extension study (median length of lesinurad exposure, 800 days).ResultsOf 235 patients completing the core study, 196 (83.4%) enrolled in the extension: 200CONT (n = 64), 200CROSS (n = 33), 400CONT (n = 65), and 400CROSS (n = 34). At EM 12, 59.6%, 43.5%, 66.7%, and 50.0% of patients, respectively, had CR of at least one target tophus. The sum of areas for all target tophi was reduced by 76.4%, 58.1%, 77.5%, and 62.8%, respectively. The adjusted mean (SE) rates of gout flares requiring treatment from the end of EM 2 to the end of EM 12 were 0.6 (0.19), 1.3 (0.48), 0.2 (0.08), and 1.9 (0.93), respectively. Target sUA < 5.0 mg/dl was achieved by 77.1%, 79.2%, 88.5%, and 71.4% of patients, respectively. Exposure-adjusted incidence rates of treatment-emergent adverse events (TEAEs) and renal-related TEAEs in the core study were not increased with prolonged lesinurad exposure in the extension study.ConclusionsPatients receiving lesinurad plus febuxostat therapy for 2 years continued to be at sUA target. Patients exhibited a progressive increase in CR of at least one target tophus, progressive reduction in tophus size, and reduction of gout flares requiring treatment over the second year, with AEs consistent with those observed in the core study.Trial registrationClinicalTrials.gov, NCT01510769. Registered on 13 January 2012.

Recent advances in gout: pathogenesis, diagnosis, comorbidities, treatment

After a "silence" period for decades, a great body of new information has become available about the pathogenesis, diagnosis and treatment of gout. New data on purine metabolism and urate transporters have been published. It has become evident that gout is an autoinflammatory disease involving the inflammasome and interleukin-1. With respect to diagnosis, microscopic evaluation of the urate crystal is still the gold standard, however, sensitive imaging techniques (ultrasound, modern computed tomography methods) are able to visualize crystal deposition and tophus formation. Tophus size may also be monitored over time. We see a renaissance of non-pharmacological, lifestyle-related treatment modalities. Pharmacotherapy includes the resolution of attacks and urate-lowering maintenance therapy. In 2016, two recent series of recommendations have been published. Treat-to-target therapy aiming at urate levels ≤360 μmol/l is crucial. Urate-lowering therapy includes xanthine oxidase inhibitors (allopurinol, febuxostat). However, a number of novel compounds (urate transporter inhibitors, recombinant uricase, interleukin-1 inhibitors) are under development or before introduction to gout treatment. Comorbidites should be considered throughout the follow-up of gout patients. Orv Hetil. 2018; 159(40): 1625-1636.

Improvement in OMERACT domains and renal function with regular treatment for gout: a 12-month follow-up cohort study.

OMERACT proposed a set of mandatory and discretionary domains to evaluate the effect of treatment in patients with gout. To determine the percentage of improvement and the effect size 6 and 12months after starting a proper treatment in patients with gout from our cohort (GRESGO) based on the OMERACT proposal for chronic gout. GRESGO is a cohort of consecutive, new patients with gout attending either of two dedicated clinics. This report includes 141 patients evaluated at baseline and 6months plus 101 of them completing a 12-month follow-up in 2012. Clinical data including the OMERACT domains for chronic gout were collected at baseline and every 6months. Treatment was prescribed by their attending physician with the purpose of getting < 6mg/dL of seric uric acid (sUA). Most patients were males (96%) with inappropriate treatment (95%); 66% had tophi, 30% metabolic syndrome, and 32% low renal function. Mean dose of allopurinol at baseline and throughout the study went from 344 ± 168mg/day to 453 ± 198 at 12months. Most OMERACT domains and renal function improved significantly; 73% improved > 20% from 6 to 12months. Greater improvement was observed in the domains: flares, index tophus size, pain, general health assessment, and HAQ score, all of them associated to lower sUA values. Chronic gout patients improve significantly in most OMERACT domains when conventional and regular treatment is indicated. sUA < 6mg/dL is associated with greater improvement.

Tophus size is associated with hallux valgus deformity in gout.

Hallux valgus (HV) and gout are common pathologies of the first metatarsophalangeal joint (MTP1) leading to pain and deformation. In this study, we aimed to determine the correlation between tophus size and characteristics of HV in gouty patients. In this case-control study, we included patients with gout (the presence of monosodium urate crystals in synovial fluid) and control patients with spondyloarthritis, without crystal disease disorders. Radiographic assessment and ultrasound (US) assessment were performed by two blinded operators. US features of gout (double contour [DC] sign and/or tophus) were collected. HV was defined by hallux abductus (HA) angle ≥20° and/or intermetatarsal angle (IM) ≥10°. Correlation between US findings and HV angles was estimated by Spearman correlation coefficient. We included 56 gouty patients (87.5% males, mean age of 63.9±12.2years) and 41 control patients (90% males, mean age of 59.0±12.8years). HV was more frequent in patients with gout than controls (62% vs 37%, P=.0007). Regardless of HV status, correlations were found between the size of US tophi and IM (r=.3381, P=.003) and HA angles (r=.2344, P=.043). Our results confirm a high prevalence of HV in gouty patients. We also observed a correlation between the size of the US tophus and the angles defining HV, which suggests a link between urate deposition load and HV. Early urate-lowering therapy for gout could limit the occurrence of HV.

Allopurinol dose escalation to achieve serum urate below 6 mg/dL: an open-label extension study

ObjectivesTo determine the long-term safety and efficacy of allopurinol dose escalation (DE) to achieve target serum urate (SU) in gout.MethodsPeople, including those with chronic kidney disease, who completed the first...

Risk factors for ulceration over tophi in patients with gout.

Ulceration over tophi in patients with gout usually causes a number of clinical problems. The aim of this study was to investigate the risk factors for ulceration of tophi in patients with gout. Patients with gout who had tophi with or without ulceration were prospectively recruited and underwent a comprehensive clinical assessment. Clinical factors independently associated with the presence of ulceration were analysed using logistic regression models. Of the 113 participants, 18 (13·7%) had clinically apparent ulceration over tophi. In univariate analysis, ulceration over tophi correlated with age, tophus duration, size, location and lack of protective sensation. In logistic regression analysis, age, tophus size and lack of protective sensation were associated with ulceration over tophi. These findings indicate that old age, large tophus size and lack of protective sensation were independent risk factors for ulceration over tophi.

Using serum urate as a validated surrogate end point for flares in patients with gout: protocol for a systematic review and meta-regression analysis

IntroductionGout is the most common inflammatory arthritis in men over 40 years of age. Long-term urate-lowering therapy is considered a key strategy for effective gout management. The primary outcome measure for efficacy in clinical trials of urate-lowering therapy is serum urate levels, effectively acting as a surrogate for patient-centred outcomes such as frequency of gout attacks or pain. Yet it is not clearly demonstrated that the strength of the relationship between serum urate and clinically relevant outcomes is sufficiently strong for serum urate to be considered an adequate surrogate. Our objective is to investigate the strength of the relationship between changes in serum urate in randomised controlled trials and changes in clinically relevant outcomes according to the ‘Biomarker-Surrogacy Evaluation Schema version 3’ (BSES3), documenting the validity of selected instruments by applying the ‘OMERACT Filter 2.0’.Methods and analysisA systematic review described in terms of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines will identify all relevant studies. Standardised data elements will be extracted from each study by 2 independent reviewers and disagreements are resolved by discussion. The data will be analysed by meta-regression of the between-arm differences in the change in serum urate level (independent variable) from baseline to 3 months (or 6 and 12 months if 3-month values are not available) against flare rate, tophus size and number and pain at the final study visit (dependent variables).Ethics and disseminationThis study will not require specific ethics approval since it is based on analysis of published (aggregated) data. The intended audience will include healthcare researchers, policymakers and clinicians. Results of the study will be disseminated by peer-reviewed publications.Trial registration numberCRD42016026991.

FRI0230 Exploring Cartilage Damage in Gout Using 3T Mri: Developing A Scoring System

BackgroundFew imaging studies have investigated cartilage damage in gout. Magnetic Resonance Imaging (MRI) can produce high quality images of cartilage damage in this disease and also reveal other features of...

Exploring cartilage damage in gout using 3-T MRI: distribution and associations with joint inflammation and tophus deposition

Few imaging studies have investigated cartilage in gout. Magnetic resonance imaging (MRI) can image cartilage damage and also reveals other features of gouty arthropathy. The objective was to develop and validate a system for quantifying cartilage damage in gout. 3-T MRI scans of the wrist were obtained in 40 gout patients. MRI cartilage damage was quantified using an adaptation of the radiographic Sharp van der Heijde score. Two readers scored cartilage loss at 7 wrist joints: 0 (normal), 1 (partial narrowing), 2 (complete narrowing) and concomitant osteoarthritis was recorded. Bone erosion, bone oedema and synovitis were scored (RAMRIS) and tophi were assessed. Correlations between radiographic and MRI cartilage scores were investigated, as was the reliability of the MRI cartilage score and its associations. The GOut MRI Cartilage Score (GOMRICS) was highly correlated with the total Sharp van der Heijde (SvdH) score and the joint space narrowing component (R = 0.8 and 0.71 respectively, p < 0.001). Reliability was high (intraobserver, interobserver ICCs = 0.87 [0.57-0.97], 0.64 [0.41-0.79] respectively), and improved on unenhanced scans; interobserver ICC = 0.82 [0.49-0.95]. Cartilage damage was predominantly focal (82% of lesions) and identified in 40 out of 280 (14%) of joints. Cartilage scores correlated with bone erosion (R = 0.57), tophus size (R = 0.52), and synovitis (R = 0.55), but not bone oedema scores. Magnetic resonance imaging can be used to investigate cartilage in gout. Cartilage damage was relatively uncommon, focal, and associated with bone erosions, tophi and synovitis, but not bone oedema. This emphasises the unique pathophysiology of gout.

Untreated tophaceous gout

Gout is associated with hyperuricemia and characterized by inflammatory arthritis induced by monosodium urate crystal deposition in synovial fluid and other tissues. Tophi can occur in soft and osseous tissue, ligaments, and different organs, either in presence or absence of gouty arthritis. If left untreated, hyperuricemic patients (serum urate level = 6.8 mg/dL or 400 mol/L) can evolve from intermittent arthritis to polyarticular tophaceous gout with symptoms between attacks. Lowering serum urate levels with xanthine oxidase inhibitors or uricosuric agents prevents acute flares and tophi development. Synovial fluid crystals slowly dissolve and can disappear after normalization of serum urate levels. Uricosuric agents are, generally, ineffective in patients with renal impairment. The recommended target serum uric acid concentration is <6 mg/dL (357 mol/L). Although controversial, recommendations have been made to achieve a target serum urate level <5 mg/dL (297 mmol/L) in severe chronic gout patients, as this concentration may be associated with greater depletion of synovial fluid crystals and a reduction in tophus size. Therapy is usually continued indefinitely. Several urate-lowering agents are currently under clinical investigation. These include uricase agents and inhibitors of renal urate transporter proteins. Interventions which enhance patient education and treatment adherence are considered important in improving gout management.