痛风的影像学研究进展

影像学检查可以帮助临床医师评价痛风.X线成像只能显示慢性痛风进展期的典型变化.CT可能是评价痛风骨改变和痛风石的最好方法,双源CT可以评估全身周围关节的尿酸盐总沉积量.MRI适合评估软组织、滑膜厚度和炎性反应,对痛风的早期病变敏感性很高,也能够较好的显示痛风石.超声检查可以评价软骨、软组织、尿酸盐沉积和滑膜炎性反应.核医学有助于在细胞和分子层面理解痛风性关节炎的发病机制.     

痛风的影像学研究进展

影像学检查可以帮助临床医师评价痛风.X线成像只能显示慢性痛风进展期的典型变化.CT可能是评价痛风骨改变和痛风石的最好方法,双源CT可以评估全身周围关节的尿酸盐总沉积量.MRI适合评估软组织、滑膜厚度和炎性反应,对痛风的早期病变敏感性很高,也能够较好的显示痛风石.超声检查可以评价软骨、软组织、尿酸盐沉积和滑膜炎性反应.核医学有助于在细胞和分子层面理解痛风性关节炎的发病机制.

Abstract：

Imaging is a helpful tool for clinicians to evaluate gout. Plain radiographs show typical changes only in advanced chronic gout. Computed tomography may best evaluate bone changes and tophi. Dual energy CT can measure the total urate burden in general periphery joints. Magnetic resonance imaging is suitable to evaluate soft tissues,synovial membrane thickness,and inflammatory changes,which is also sensitive to early change of gout,and even well show the tophi. Ultrasonography may be used in evaluation of cartilage, soft tissues, urate crystal deposition, and synovial membrane inflammation. Nuclear medicine may be helpful to investigate the pathogenesis of gouty arthritis in the field of cell and molecule.     

Imaging of gout: New tools and biomarkers?

While joint aspiration and crystal identification by polarizing microscopy remain the gold standard for diagnosing tophaceous gout, agreement among medical and ancillary health personnel examining synovial fluid using polarizing microscopy for the detection of monosodium urate (MSU) crystals appears to be poor. Imaging modalities, including conventional radiography (CR), ultrasonography (US), magnetic resonance imaging (MRI), and dual-energy computed tomography (DECT), have been found to provide information on the deposition of MSU crystals in tissues, and the consequences of such deposition. CR can demonstrate typical “punched out lesions” with marginal overhangs, but the sensitivity for erosion detection is better for DECT and US. US is inexpensive and can identify tophus deposition in and around joints, erosions, and tissue inflammation if power Doppler US is used. MRI can show tophi, bone marrow edema, and inflammation, but MRI findings of tophi may be nonspecific. DECT can identify and color-code tophaceous material, and provide an overview of the tophus burden of a joint area. Because of the lower number of available studies, the strength of evidence for the newer imaging can be improved through further research.     

Treatment of hyperuricemia, gout and other crystalline arthritidies

Gout is a very common joint disease which is due to chronic hyperuricemia and its related articular involvements. Yet it can be cured when appropriately managed. Comprehensive management of gout involves correct identification and addressing all causes of hyperuricemia, treating and preventing attacks of gouty inflammation (using colchicine NSAIDs, and/or steroids), and lowering serum urate (SUA) to an appropriate target level indefinitely. The ideal SUA target is, at a minimum, less than 6 mg/dL (60 mg/L or 360 μmol/L), or even less than 5 mg/dL in patients with tophi. The SUA target should remain at less than 6 mg/dL for long in all gout patients, especially until tophi have resolved. Patient education and adherence to therapy are key point to the optimal management of gout, aspects which are often neglected. Adherence can be monitored in part by continuing, regular assessment of the SUA level. More difficult cases of gout often need a combination of urate lowering therapy (ULT) for both refractory hyperuricemia and chronic tophaceous arthritis. Chronic tophaceous gouty arthropathy which do not respond adequately to optimized oral ULT might benefit from the use of pegloticase, when this is available in, for example, Italy and other European countries. By contrast, in calcium pyrophosphate (CPP) crystal deposition disease (CPPD), as evidenced by pseudo gout attacks or chronic polyarthritis, similar anti-inflammatory strategies have been recommended, but there have as yet been no controlled trials. Of note, there is no treatment for the underlying metabolic disorders able to control the CPPD. Management of crystal-induced arthropathies (CIA) depends not only on clinical expression, namely acute attacks or chronic arthropathy, but also on the underlying metabolic disorder. We will mainly focus on gout as an archetype of CIA.     

Tophaceous hip gouty arthritis revealing asymptomatic axial gout

Background

Hip and axial involvement is uncommon during gout and may raise diagnostic challenges. We describe a rare case of tophaceous hip gout which lead to the diagnosis of asymptomatic axial tophaceous gout at a single rheumatology center.

Limited knee joint range of motion due to invisible gouty tophi

OBJECTIVES: Tophi deposits are a well-known cause of joint destruction, gouty nephropathy and spinal cord compression. This study reports another major complication of gout, namely tophi deposition causing limited knee joint excursion. METHODS: Seven gout patients with limited knee joint excursion owing to tophi deposition were studied to reveal clinical features and magnetic resonance imaging (MRI) findings. None of the patients were able to assume a full squatting posture. RESULTS: No patients had visible subcutaneous tophi over the knee joints, except for one case in which a pea-sized subcutaneous tophus was noted. Additionally, two patients even lacked visible tophi elsewhere. All knee problems in the study group were initially regarded as being due to degenerative or other internal derangements, but MRI unexpectedly revealed multiple tophaceous depositions within and around the joint. CONCLUSIONS: Intra-articular and periarticular tophi limiting knee joint range of motion are a rare but important cause of walking disability in gout patients. Although most patients do not display visible subcutaneous tophi over the knee on physical examination, the differential diagnosis should consider intra-articular tophi and MRI is valuable in this clinical setting.     

La maladie goutteuse

Gout is a chronic disease due to the deposition of monosodium urate microcrystals in joints and tissues. Its incidence and prevalence are increasing worldwide in close relation with the epidemic of obesity and metabolic syndrome. Gout is related to chronic hyperuricemia that should be treated to ensure the reduction or even the disappearance of acute attacks (“gout flares”) and to reduce the size and number of tophi. If arthritis of the first metatarsophalangeal joint is the most typical form, other joints may be affected, including the spine. Demonstration of urate microcrystals arthritis allows diagnosis of gout but, in the absence of possibility of performing joint puncture, imaging may be useful for providing complementary diagnostic elements. Appropriate care is essential to reduce the number of flares and the evolution towards gouty arthropathy but also in terms of public health in order to reduce costs related to this pathology.     

Role of Ultrasound and Other Advanced Imaging in the Diagnosis and Management of Gout

Imaging of gout with conventional radiography has been described since shortly after roentgenography was invented. Ultrasound (US) detects more erosions than conventional radiography in rheumatoid arthritis, and the same seems to be true for gout. MRI is being used to assess articular and periarticular masses, including gouty tophi. However, MRI findings in gout can lack specificity. Monosodium urate (MSU) tophi are very echogenic when US is used. Typical US features of gout include a double-contour sign or “urate icing.” The double-contour consists of the hyperechoic bony contour and a parallel hyperechoic line of MSU crystals that deposit on the hypoechoic or anechoic hyaline cartilage. Tophi can have a “wet clumps of sugar” appearance, often surrounded by an anechoic halo. Tophi are closely related to the formation of erosions. If serum urate levels are lowered consistently below 6.0 mg/dL, the disappearance of MSU crystals can be observed sonographically.     

Intra-articular tophus presenting as a loose body

In chronic tophaceous gout, tophi may occur in various tissues of the body. The joints are one of the main tissues of the tophaceous deposits. The articular surface may be coated by heavy deposits. We present a case of a patient with chronic tophaceous gout where the tophaceous deposits formed an intra-articular mass causing symptoms of a loose body.     

Ultrasonographic measurement of tophi as an outcome measure for chronic gout

OBJECTIVE: To validate the usefulness of measuring tophi with ultrasonography (US) as an outcome measure for chronic tophaceous gout. METHODS: Patients with crystal-proven gout were included. To evaluate validity, intraarticular and articular deep tophi were evaluated with both magnetic resonance imaging (MRI) and US. Tophi were punctured with US guidance to evaluate face validity. Interobserver and intraobserver measurement studies were done to evaluate reliability, and to estimate the smallest detectable difference. Sensitivity to change was evaluated with a 12-month followup observational study of urate-lowering therapy. RESULTS: US detected at least one tophus in all joints where MRI found nodules considered to be tophi. There was a good correlation, but just fair agreement between measurements with US and MRI. Puncture of nodules suspected of being tophi recovered urate crystals in 83% of the procedures. Intraobserver intraclass correlation was > 0.90 for diameters and volume, while it was 0.71 to 0.83 in the interobserver study. US was found to be sensitive to change, and there was an inverse correlation between serum urate concentrations and change from baseline measurement of tophi. CONCLUSION: US measurement of tophi fulfilled the OMERACT filter for an outcome measure, although it should be tested further in randomized clinical trials.     

Tophaceous joint disease strongly predicts hand function in patients with gout

OBJECTIVES: The functional impact of gout is poorly understood. The aim of this study was to determine predictors of hand function in gout. METHODS: Twenty unselected patients with gout were recruited from rheumatology clinics. No patient had an acute gout flare at assessment. Participants were assessed for clinical characteristics of gout, including the site and number of tophi. Hand function was assessed by the Sollerman hand function test. Fingertip to palm (FTP) distance measurement, grip strength and the Disability Assessment of Shoulder and Hand (DASH) questionnaire scores were also recorded. Data were analysed by simple and multiple linear regression models. RESULTS: The median Sollerman score was 75.5 (range 31-80). The median hand FTP distance was 2.91 (0.88-6.69) cm, grip strength was 31 (4-71) kg, and DASH score was 28.77 (0-76.47). Of the clinical characteristics measured, the number of joints of the hand with overlying tophi (hand tophus joint count) was the strongest single predictor of the Sollerman score (r2 = 0.59), and also predicted the other measures of hand mobility and function. A multiple regression model including hand tophus joint count, sex, number of gout flares in the preceding 6 months, gout disease duration and hand tender joint count was a better predictor of the Sollerman score than hand tophus joint count alone (r2 = 0.81, F(4,14) = 3.94, P = 0.024). CONCLUSIONS: Measures of chronic and poorly controlled disease predict hand function in patients with gout. In particular, tophaceous joint disease has a major impact on functional capacity in gout.     

Imaging modalities and monitoring measures of gout

PURPOSE OF REVIEW: Imaging modalities for gout have been mostly restrained to radiographs. Ultrasonography, computed tomography and magnetic resonance imaging are emerging techniques that could be used for diagnosis, evaluation, and monitoring acute and chronic gout. RECENT FINDINGS: Diagnosis of gout is based on urate crystal observation with microscopy. Recently, crystal deposition in the hyaline cartilage has been described to be different in gout from that of calcium pyrophosphate, but validation of the findings is pending. Severity of gout with simple radiographs may not disclose periarticular or intra-articular urate deposition. Ultrasonography, computed tomography and magnetic resonance imaging may improve the evaluation of tophi not apparent in clinical examination or simple radiographs. Monitoring urate deposition may be accomplished with imaging techniques. This would be of outstanding interest for clinical trials, but also for evaluating clinical response to urate-lowering therapy. Although preliminary results evaluating for validity and reliability have been very recently reported for magnetic resonance imaging, computed tomography and ultrasonography, sensitivity to change studies are still pending. Also, monitoring of chronic inflammation with imaging techniques, such as power-Doppler, deserve further studies. SUMMARY: Evidence exists regarding the usefulness of imaging techniques for diagnosis, evaluation of severity, and monitoring of gout, but further investigation is needed.     

Computed tomography of the knee joint as an indicator of intraarticular tophi in gout

Objective. To evaluate the utility of computed tomography (CT) of the knee joint for detecting intraarticular tophaceous deposits. Methods. A prospective study of 16 patients with gout affecting the knee was conducted. A condition for inclusion in the study was the presence of needle-shaped crystals with negative birefringence in the knee joint synovial fluid. Conventional radiography and CT were performed in each case. Results. Intraarticular opacities in the capsule and the synovium, consistent with the presence of tophaceous deposits, were found in 5 of the 16 patients (9 knee joints). The mean duration of gout was longer in the patients with intraarticular tophi than in those without tophi, and 2 of the patients with tophi had poor tolerance to antihyperuricemic therapy. Conclusion. Intraarticular opacities considered to represent tophi were observed in approximately one-third of the patients. The presence of tophi correlated with a longer duration of the disease and a poor tolerance to medication. We therefore suggest that CT of the knees could be useful in the assessment and followup of certain patients with gout.     

Management of gout and hyperuricemia: Multidisciplinary consensus in Taiwan

Gout is an inflammatory disease manifested by the deposition of monosodium urate (MSU) crystals in joints, cartilage, synovial bursa, tendons or soft tissues. Gout is not a new disease, which was first documented nearly 5,000 years ago. The prevalence of gout has increased globally in recent years, imposing great disease burden worldwide. Moreover, gout or hyperuricemia is clearly associated with a variety of comorbidities, including cardiovascular diseases, chronic kidney disease, urolithiasis, metabolic syndrome, diabetes mellitus, thyroid dysfunction, and psoriasis. To prevent acute arthritis attacks and complications, earlier use of pharmacotherapeutic treatment should be considered, and patients with hyperuricemia and previous episodes of acute gouty arthritis should receive long‐term urate‐lowering treatment. Urate‐lowering drugs should be used during the inter‐critical and chronic stages to prevent recurrent gout attacks, which may elicit gradual resolution of tophi. The goal of urate‐lowering therapy should aim to maintain serum uric acid (sUA) level <6.0 mg/dL. For patients with tophi, the initial goal can be set at lowering sUA to <5.0 mg/dL to promote tophi dissolution. The goal of this consensus paper was to improve gout and hyperuricemia management at a more comprehensive level. The content of this consensus paper was developed based on local epidemiology and current clinical practice, as well as consensuses from two multidisciplinary meetings and recommendations from Taiwan Guideline for the Management of Gout and Hyperuricemia.     

Effect of urate-lowering therapy on the velocity of size reduction of tophi in chronic gout

OBJECTIVE: The optimal serum urate levels necessary for elimination of tissue deposits of monosodium urate in patients with chronic gout is controversial. This observational, prospective study evaluates the relationship between serum urate levels during therapy and the velocity of reduction of tophi in patients with chronic tophaceous gout. METHOD: Sixty-three patients with crystal-confirmed tophaceous gout were treated with allopurinol, benzbromarone, or combined therapy to achieve serum uric acid levels less than the threshold for saturation of urate in tissues. The tophi targeted for evaluation during followup were the largest in diameter found during physical examination. RESULTS: Patients taking benzbromarone alone or combined allopurinol and benzbromarone therapy achieved faster velocity of reduction of tophi than patients taking allopurinol alone. The velocity of tophi reduction was linearly related to the mean serum urate level during therapy. The lower the serum urate levels, the faster the velocity of tophi reduction. CONCLUSION: Serum urate levels should be lowered enough to promote dissolution of urate deposits in patients with tophaceous gout. Allopurinol and benzbromarone are equally effective when optimal serum urate levels are achieved during therapy. Combined therapy may be useful in patients who do not show enough reduction in serum urate levels with single-drug therapy.     

EULAR evidence based recommendations for gout. Part I: Diagnosis. Report of a task force of the Standing Committee for International Clinical Studies Including Therapeutics (ESCISIT)

OBJECTIVE: To develop evidence based recommendations for the diagnosis of gout. METHODS: The multidisciplinary guideline development group comprised 19 rheumatologists and one evidence based medicine expert, representing 13 European countries. Ten key propositions regarding diagnosis were generated using a Delphi consensus approach. Research evidence was searched systematically for each proposition. Wherever possible the sensitivity, specificity, likelihood ratio (LR), and incremental cost-effectiveness ratio were calculated for diagnostic tests. Relative risk and odds ratios were estimated for risk factors and co-morbidities associated with gout. The quality of evidence was categorised according to the evidence hierarchy. The strength of recommendation (SOR) was assessed using the EULAR visual analogue and ordinal scales. RESULTS: 10 key propositions were generated though three Delphi rounds including diagnostic topics in clinical manifestations, urate crystal identification, biochemical tests, radiographs, and risk factors/co-morbidities. Urate crystal identification varies according to symptoms and observer skill but is very likely to be positive in symptomatic gout (LR = 567 (95% confidence interval (CI), 35.5 to 9053)). Classic podagra and presence of tophi have the highest clinical diagnostic value for gout (LR = 30.64 (95% CI, 20.51 to 45.77), and LR = 39.95 (21.06 to 75.79), respectively). Hyperuricaemia is a major risk factor for gout and may be a useful diagnostic marker when defined by the normal range of the local population (LR = 9.74 (7.45 to 12.72)), although some gouty patients may have normal serum uric acid concentrations at the time of investigation. Radiographs have little role in diagnosis, though in late or severe gout radiographic changes of asymmetrical swelling (LR = 4.13 (2.97 to 5.74)) and subcortical cysts without erosion (LR = 6.39 (3.00 to 13.57)) may be useful to differentiate chronic gout from other joint conditions. In addition, risk factors (sex, diuretics, purine-rich foods, alcohol, lead) and co-morbidities (cardiovascular diseases, hypertension, diabetes, obesity, and chronic renal failure) are associated with gout. SOR for each proposition varied according to both the research evidence and expert opinion. CONCLUSIONS: 10 key recommendations for diagnosis of gout were developed using a combination of research based evidence and expert consensus. The evidence for diagnostic tests, risk factors, and co-morbidities was evaluated and the strength of recommendation was provided.     

Radiographic imaging: the 'gold standard' for assessment of disease progression in rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by a chronic inflammation of the joints, which leads to the destruction of articular cartilage and bone. The degree of joint damage assessed by radiographic imaging represents a key outcome in RA. There are several methods for scoring the joint damage associated with RA. The most widely used are the Sharp and Larsen systems, as well as more recent modifications of each method. Radiographic imaging has several advantages compared with other outcome measures in RA, specifically: X-rays reflect the history of joint pathology, provide a permanent record for serial evaluation, and can be randomized and blinded for objective scoring. Several modifications of these methods have been proposed and employed in the investigation of disease progression. A review of the radiographic progression of RA is presented, as well as a simplified scoring system useful for the evaluation of joint damage in RA in a clinical setting.     

Severe tophaceous gout. Characterization of low socioeconomic level patients from México

OBJECTIVE: To describe a group of patients with frequent tophaceous gout, the variables associated with severe tophaceous gout and to compare them with other patients with gout described elsewhere. METHODS: We looked for 65 demographic clinical and paraclinical variables from patients with gout who attended our gout clinic from 1995-2000 and were evaluated by the same group of physicians. RESULTS: Three hundred and sixteen patients were included, 98% males, 82% live in México city, the mean age at onset, educational level and disease duration were 37.5 +/- 12.4, 6.3 +/- 3.9 and 12.6 +/- 10.3 years respectively. Tophaceous gout was present in 62% of the patients with a mean tophi number of 4.7 +/- 6.3 and mean HAQ score 0.13 +/- 0.37. Severe tophaceous gout (>or= 5 tophi) was found in 34% and these patients had significantly: earlier age at onset, longer duration of the disease, lesser frequency of obesity and higher frequency of: intradermal tophi, HAQ > 0.5, hospitalizations, radiographic score III/IV, uric acid under-excretion, renal function impairment and previous (oral and parenteral) auto-prescribed chronic glucocorticoid treatment compared with patients with non-severe tophaceous gout. In the multiple logistic regression the significant variables were renal function impairment (p = 0.000) and previous chronic parenteral glucocorticoid treatment (p = 0.011) . CONCLUSION: Our patients compared with those from other countries who have earlier age at onset, very low frequency of gout among females, frequent tophaceous gout and severe tophaceous gout. Severe tophaceous gout in this group is associated with renal function impairment and previous chronic parenteral glucocorticoid treatment.     

Factors associated with musculoskeletal disability and chronic renal failure in clinically diagnosed primary gout

OBJECTIVE:. To assess the association between a set of sociodemographic, clinical, and biochemical variables and the presence of musculoskeletal (MSK) disability and chronic renal failure in patients with primary gout defined using Wallace criteria. METHODS: Subjects were 90 patients with primary gout (98% male, age 54 +/- 12 years, 11.3 +/- 9.8 years with gout). A cohort nested case-control design was used. Analysis was done of the association between MSK disability or renal failure and a series of variables: age; duration of gout; body mass index; education level; income; serum glucose, cholesterol, triglycerides, and uric acid; Health Assessment Questionnaire score; obesity; family history of gout; high blood pressure; alcoholism; smoking habit; presence of tophi; ischemic cardiopathy; and use of colchicine, glucocorticoids, nonsteroidal antiinflammatory drug, or allopurinol. RESULTS: Forty-two patients (47%) had MSK disability, and 25/80 (31%) had renal failure. On logistic regression, presence of tophi (relative risk 4.3, 95% confidence interval 1.2-15.1), hypertriglyceridemia (RR 3.4, 95% CI 1.1-10), and history of ischemic heart disease (RR 8.3, 95% CI 1.6-41) were associated with MSK disability. Patient age was the only variable associated with renal failure. CONCLUSION: Optimal medical control of gout and its comorbidities may improve prognosis of gout, as suggested by our findings, in which a marker for poorly controlled gout such as presence of tophi in addition to high blood triglyceride levels and ischemic heart disease were associated with MSK disability. Older age was the only factor associated with renal failure, although this may only reflect declining renal function in the elderly.     

Multiple microcrystal deposition disease in a patient with systemic lupus erythematosus.

A 17-year-old female patient with systemic lupus erythematosus (SLE) developed chronic tophaceous gout, chondrocalcinosis and articular capsule calcification in several joints. Analysis of synovial fluid and tophi revealed the coexistence of monosodium urate, calcium pyrophosphate, hydroxyapatite, and cholesterol crystals.