Impact of sonography in gouty arthritis: Comparison with conventional radiography, clinical examination, and laboratory findings

Ultrasonography in the prediction of gout flares: a 12-month prospective observational study

OBJECTIVES

To evaluate whether US findings indicating MSU deposits and US-detected inflammation (i.e. power Doppler signal) predict gout flares over 12 months.

METHODS

Gout patients on urate-lowering therapy for at least the preceding 6 months were enrolled consecutively in this 12-month prospective, observational, single-centre study. A nested case-control analysis was performed. Cases were participants with at least one flare in the follow-up period, while controls did not self-report any gout flare. The US assessment included elbows, wrists, second MCP joints, knees, ankles, and first MTP joints. The US findings indicating MSU deposits [i.e. aggregates, double contour (DC) sign and tophi] were identified as present/absent according to the Outcome Measure in Rheumatology definitions. Power Doppler signal was scored semiquantitatively. Summated scores were calculated for each US finding.

RESULTS

Eighty-one gout participants were enrolled, and 71 completed the study. Thirty (42.3%) of 71 participants experienced at least one flare over 12 months, with a median of 2.0 flares. Cases had a greater US burden of MSU deposits (6.7 ± 4.7 vs 2.9 ± 2.6, P = 0.01) and power Doppler signal (3.73 ± 3.53 vs 0.82 ± 1.44, P < 0.01) than controls, at baseline. The baseline US scores indicating MSU deposits and US-detected inflammation were significantly associated with the occurrence (total MSU score, adjusted odds ratio:1.75, 95% CI: 1.26, 2.43; power Doppler score, adjusted odds ratio: 1.63, 95% CI: 1.12, 2.40) and the number (total MSU score, adjusted incidence risk ratio: 1.17, 95% CI: 1.08, 1.26; power Doppler score, adjusted incidence risk ratio: 1.29, 95% CI: 1.19, 1.40) of flares over 12 months in multivariate analyses.

CONCLUSIONS

Baseline US findings indicating MSU deposits and US-detected inflammation are independent predictors of gout flares over 12 months.

The Role of Advanced Imaging in Gout Management

Gout is a common form of inflammatory arthritis where urate crystals deposit in joints and surrounding tissues. With the high prevalence of gout, the standardized and effective treatment of gout is very important, but the long-term treatment effect of gout is not satisfied because of the poor adherence in patients to the medicines. Recently, advanced imaging modalities, including ultrasonography (US), dual-energy computed tomography (DECT), and magnetic resonance imaging (MRI), attracted more and more attention for their role on gout as intuitive and non-invasive tools for early gout diagnosis and evaluation of therapeutic effect. This review summarized the role of US, DECT, and MRI in the management of gout from four perspectives: hyperuricemia, gout attacks, chronic gout, and gout complications described the scoring systems currently used to quantify disease severity and discussed the challenges and limitations of using these imaging tools to assess response to the gout treatment.

Dual-energy computed tomography for the diagnosis of acute gouty arthritis

AIMS

To investigate the diagnostic value of dual-energy computed tomography (DECT) in acute gouty arthritis (AGA) or patients presenting with suspected gouty arthritis.

METHODS

This retrospective study was performed in a single centre from May 2017 to August 2018. Two hundred and twenty-six patients with an initial diagnosis of AGA in the preceding 15 days were included. All patients were referred for a DECT scan of the affected joints. The diagnosis criteria of gout with the American College of Rheumatology Classification Standard were regarded as the reference standard.

RESULTS

Two hundred patients were included in the present study at last. The sensitivity, specificity, positive predictive value, and negative predictive value of DECT in the diagnosis of all AGA were 83.83%, 60.61%, 91.5% and 42.55% respectively. When AGA was subdivided according to the joint site, the sensitivity, specificity, positive predictive value, and negative predictive value were 80.68%, 61.11%, 91.03%, and 39.29% in feet, 93.55%, 40%, 93.55%, and 40% in knees and 87.5%, 71.43%, 91.3%, and 62.5% in ankles, respectively.

CONCLUSIONS

DECT had a high sensitivity for the diagnosis of AGA. However, the specificity was limited, particularly for the diagnosis of acute gouty knee arthritis. Prospective multicenter studies of large samples will enhance the application of DECT among the AGA patients in the future.

Unravelling the mysteries of gout by multimodality imaging

Gout is a common inflammatory arthritis that manifests as an aggregate of variably symptomatic monosodium urate crystals (MSU) in the joints and surrounding tissues in addition to multisystem involvement such as genitourinary and cardiovascular systems. In recent decades, there has been a documented increase in the prevalence and incidence of gout. Risk factors for gout include obesity, dietary influences, hypertension, renal impairment, and diuretic use. A prompt diagnosis followed by uric acid lowering treatment prior to the onset of bone destruction is the goal in any suspected case of gout. Advanced imaging modalities, such as dual energy computed tomography (DECT) and ultrasonography (US), employed for the diagnosis of gout are each accompanied by advantages and disadvantages. Conventional radiography (CR), although useful in visualizing joint erosions and mineralization, is limited in its ability to diagnose gout flare. Although synovial fluid aspiration remains the gold standard for MSU crystal visualization, less-invasive imaging modalities are preferred to avoid potential complications. DECT and US in particular are useful in the diagnosis of gout. In this review, we will discuss the current state and role of imaging in the detection of gout.

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.

Gout of ankle and foot: DECT versus US for crystal detection

OBJECTIVE

To compare dual-energy computed tomography (DECT) and ultrasound (US) in detecting monosodium urate (MSU) crystals in the ankle and foot in patients with acute gouty arthritis.

METHODS

Bilateral ankle and foot were examined by DECT and US and the differences between the findings were compared.

RESULTS

A total of 50 patients underwent DECT and US examinations. At the patient level, the overall positivity of crystal deposition detected by DECT was higher than that by US (92% vs 68%, P = 0.005). The agreement of detecting crystal deposition between DECT and US was not very strong (К = 0.44, P = 0.003). At different joint/area levels, there were significant differences between the two examinations in the area of the dorsum (36% vs 12%, P = 0.009) and metatarsal bone (34% vs 12%, P = 0.017), but the sensitivity of DECT and US was similar in the first metatarsophalangeal joint (MTP) and ankle areas (P>0.05). Agreement between the two examinations in the ankle and first MTP was very strong (К = 0.86, P < 0.001; К = 0.79, P < 0.001, respectively). However, agreement between the two examinations in other joints/areas was poor.

CONCLUSION

These findings indicated that DECT should be the first choice for acute gouty arthritis in patients with ankle and foot involvement. Key Points • There is little data regarding DECT and US in detecting MSU crystals in the ankle and foot in patients with acute gouty arthritis. • The overall positivity of crystal deposition detected by DECT was higher than that by US, but the sensitivity of DECT and US was similar in the first metatarsophalangeal joint (MTP) and ankle areas. • Agreement between the two examinations in the ankle and first MTP was very strong; however, agreement between the two examinations in other joints/areas was poor.

Prevalence and Factors Associated With Bone Erosion in Patients With Gout

OBJECTIVE

To determine the prevalence, distribution, and factors associated with bone erosion detectable by ultrasound in patients with gout.

METHODS

Ultrasound scans were performed in 980 patients with gout, and bone erosion was detected. The prevalence and distribution of bone erosion in gout patients were calculated. Both clinical variables and ultrasound signs were entered into a multivariate logistic regression analysis to clarify the factors associated with bone erosion in patients with gout.

RESULTS

Bone erosion was found in 431 (44.0%) of the 980 patients with gout, and in 338 (78.4%) of these patients, the bone erosion was found in the first metatarsophalangeal (MTP) joint. A multivariable logistic regression analysis showed that age, duration of gout, the existence of tophi, ultrasound-detected synovial hypertrophy, and joint effusion were independently associated with bone erosion. A tophus was the most powerful factor associated with bone erosion, with an odds ratio (OR) of 4.218 (95% confidence interval 3.092-5.731). The risk for bone erosion also increased as the number of tophi increased (P < 0.001). However, after stratifying the size of tophi, the ORs did not increase significantly (P = 0.206).

CONCLUSION

A high percentage of gout patients had bone erosions; the first MTP joint was the most frequently involved site. Age, duration of gout, tophi, and synovial hypertrophy were factors associated with bone erosion in gout patients. The number of tophi, but not their size, was strongly associated with bone erosion in patients with gout.

Diagnostic value of ultrasound versus dual-energy computed tomography in patients with different stages of acute gouty arthritis

OBJECTIVE

Previous studies of the diagnostic accuracy of ultrasound (US) and dual-energy computed tomography (DECT) in patients with gout have reported different results. The aim of this study is to compare the diagnostic value of US and DECT in patients with different stages of acute gouty arthritis.

METHODS

Based on the presence of monosodium urate (MSU) crystals in the synovial fluid, patients (n = 37) were divided into three groups according to gout duration: early stage (within 1 year, n = 15), middle stage (1 to 3 years, n = 12), and late stage (more than 3 years, n = 10). All the affected joints were examined by US and DECT.

RESULTS

In the early-stage group, the sensitivity of US was significantly higher than DECT in identifying MSU deposition (66.7% vs 26.6%, p < 0.05), while in the middle- and late-stage groups, the sensitivity of US and DECT was similar. In the early-stage group, the US results in nine joints were positive (four with double contour sign, four with snowstorm sign, and one with both double contour sign and snowstorm sign), while DECT did not show any urate crystal deposits.

CONCLUSION

These findings indicate that US should be the first choice for acute gouty arthritis, especially in patients with early-stage disease.Key Points• Previous studies have compared DECT with US to evaluate the reliability of each method in diagnosing gout but have reported different results, which may be partly due to different gout duration.• In our study, the sensitivity of US was significantly higher than DECT in identifying MSU deposition in the early-stage group, while in the middle- and late-stage groups, the sensitivity of US and DECT was similar.• US should be the first choice for the diagnosis of acute gouty arthritis, especially in patients with early-stage disease.

The burden of subclinical intra-articular inflammation in gout

OBJECTIVE

To assess the burden of subclinical intra-articular inflammation using ultrasound in people with gout.

METHODS

A pilot, prospective longitudinal cohort of 28 participants with gout were examined twice, once during a gout flare (n = 25) and then during an inter-critical phase (n = 27). At each visit, a 52 joint count was done followed by ultrasound examination for detection of intra-articular power Doppler (PD) signal. Clinically active joints were defined as tender and swollen. Data was collected on patient reported gout pain - visual analog scale (VAS) (painVAS), physician global VAS (physicianVAS), Health Assessment Questionnaire (HAQ), serum uric acid, erythrocyte sedimentation rate (ESR), and high-sensitivity C-reactive protein (HsCRP).

RESULTS

At the flare visit, participants had a median of 1 clinically active joint (interquartile range [IQR] 1-2), and a median of 5 joints with a PD score ≥ 2 (IQR 4-10, P < .001). At the inter-critical visit, participants reported an median of 0 clinically active joints (IQR 0-0), and a median of 4 joints with a PD score ≥ 2 (IQR 3-7, P < .001). Physician VAS (5.69 vs 3.40, P < .001), painVAS (6 vs 0, P < .001), HAQ (0.75 vs 0.12, P = .032), and ESR (29 vs 13.5 mm/h, P = .02) were higher at the acute visit, but HsCRP levels were similar (8.88 vs 5.15 mg/L, P = .062).

CONCLUSION

This pilot study established the presence of subclinical intra-articular inflammation in gout at both acute and inter-critical phases. Despite the apparent resolution of symptoms after an acute flare, a relatively high proportion of joints had subclinical inflammation in the inter-critical visit. The long-term implications of untreated subclinical joint inflammation are not clear.

Gouty arthritis: Can we avoid unnecessary dual-energy CT examinations using prior radiographs?

OBJECTIVE

The dual-energy CT (DECT) algorithm for urate detection is feasible only if hyperdense deposits are present. Based on our experience, around half of the performed DECT examinations show no such deposits and thus were useless for this indication. Our diagnostic accuracy study investigates whether conventional radiographs can serve as gatekeeper test prior to DECT for reliable exclusion of such radiopaque deposits.

MATERIALS AND METHODS

In this retrospective study, 77 clinically indicated DECT examinations of the hand (n = 29), foot (n = 36) and ankle (n = 12) of 55 patients (13 female, mean age 62±15 years) with suspected gouty arthritis were included. Two blinded readers independently evaluated DECT, gray-scale CT images (reference standard) and corresponding standardized radiographs for the presence/location of dense soft tissue deposits.

RESULTS

Interreader agreement for detection of soft tissue deposits with DECT and radiographs was excellent (DECT: both readers, κ = 1; radiographs: both readers, κ = 0.94). DECT showed soft tissue deposits in 54/77 DECT (70%) scans. 30/54 scans (56%) showed deposits on the corresponding radiographs, while in 24 scans (44%) no deposits were seen on radiographs. Test performance of radiographs for soft tissue deposit detection: sensitivity 56%, specificity 100%, PPV 100%, NPV 48.9%, and accuracy 69%. Low density of the deposits was the main reasons for false-negative radiographs (19 cases, 79%), followed by superimposition of deposits by osseous structures (5 cases, 21%).

CONCLUSION

Conventional radiographs of the hand, foot and ankle cannot serve as a gatekeeper test for reliable exclusion of radiopaque soft tissue deposits prior to DECT.

Acute Gouty Knee Arthritis: Ultrasound Findings Compared With Dual-Energy CT Findings

OBJECTIVE

The purpose of this study was to compare findings of ultrasound (US) with dual-energy CT (DECT) findings in patients presenting with suspected gouty knee arthritis.

SUBJECTS AND METHODS

This prospective study included 65 patients (52 men and 13 women; median age, 61.7 years [range, 38-87 years]) with an initial clinical diagnosis of acute gouty knee arthritis who underwent DECT performed using a 128-MDCT scanner and US performed using a 5-18-MHz transducer. Both intra- and extraarticular findings obtained using each modality were tabulated.

RESULTS

DECT identified gout as the final diagnosis for 52 of 65 patients (80.0%). An alternative diagnosis was confirmed for the remaining 13 patients. US detected gout in 31 of 52 patients (sensitivity, 59.6%) and produced findings negative for gout in seven of 13 patients (specificity, 53.8%). The double contour sign on US was positive for gout in 23 of 52 patients (44.2%) and negative in 12 of 13 patients (92.3%). Extraarticular urate deposition was identified by DECT in 44 of 52 patients, compared with identification by US in 11 of 52 patients (p < 0.001).

CONCLUSION

The sensitivity of US for the diagnosis of gouty knee arthritis is limited, particularly with respect to extraarticular urate deposition. The double contour sign is the single most valuable sign for the assessment of gouty knee arthritis by US.

Gout of hand and wrist: the value of US as compared with DECT

Objectives

The purpose of this study was to compare findings of ultrasound (US) with dual-energy CT (DECT) in patients presenting with suspected gouty hand and wrist arthritis.

Methods

This prospective study included 180 patients (136 men and 44 women, age range, 31– 94 years; mean age, 65.9 years) with an initial clinical diagnosis of acute gouty arthritis who underwent DECT and US examination. Intra- and extra-articular findings of each modality were tabulated and calculated with DECT as gold standard.

Results

The final diagnosis of gout was positive in 97/180 patients (53.9%) by DECT, an alternative diagnosis confirmed in 83 patients. US showed a sensitivity of 70.1% (extra-articular: 42.5%, p < 0.0001; intra-articular: 80.3%, p = 0.14) and specificity of 51%. The double contour sign (DCS) was present in 58/61 patients with a positive US study for intra-articular gout (95.1%).

Conclusions

Sensitivity of US for diagnosis of gouty arthritis in hand and wrist is limited, particularly with respect to extra-articular urate deposition. The DCS is the most sensitive sign for the assessment of gouty hand and wrist arthritis by US.

Key points

• Sensitivity of US for diagnosis of gouty arthritis in hand and wrist is limited, particularly with respect to extra-articular gouty deposits.

• The double contour sign is the most sensitive finding for the assessment of gouty hand and wrist arthritis by US.

• Although the sensitivity of US for diagnosis of gouty hand and wrist arthritis is limited, it can be used as a first-line imaging modality in the presence of the DCS.

Ultrasonographic detection of double contour sign and hyperechoic aggregates for diagnosis of gout: two sites examination is as good as six sites examination

OBJECTIVE

To compare ultrasound-detected abnormalities, namely double contour sign (DCS) and hyperechoic aggregates (HAGs), at two sites (knee and first metatarsophalangeal [1st MTP] joints) versus six sites (knee joint, 1st MTP joint, radiocarpal joint, talar joint, patellar tendon and triceps tendon) in gout patients.

METHODS

Forty-seven clinically diagnosed gout patients and 50 subjects (serum uric acid < 7 mg/dL) as controls were included. DCS was looked for at three articular cartilage sites (first metatarsal, tibiotalar and femoral condyle), whereas HAGs were looked for at one joint site (radiocarpal joint) and two tendon sites (patellar tendon and triceps tendon). Ultrasound findings of both the groups were compared.

RESULTS

Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and positive likelihood ratio (LR) of two sites ultrasound findings for gout were 87.2%, 84%, 83.7%, 85.6% and 5.5 respectively. Similar sensitivity, specificity, PPV, NPV and positive LR were observed with six sites ultrasound findings. Among controls, 16% were found to have these abnormal ultrasound findings by both two sites and six sites examinations.

CONCLUSION

Screening of two sites (knee and 1st MTP) has similar sensitivity, specificity, PPV, NPV and positive LR as compared to six sites in diagnosing gout.

Gout: an Asia-Pacific update

Even though, Hippocrates recognized gout as an affection of older men and a product of high living long back in 5th century BC, this painful condition promises to accompany humanity to the 21st century. The incidence is progressively rising and females are also affected in the modern era. There are also regional and ethnic variations in the incidence, the genetics of which is being studied. The recommended best therapy for the acute attacks and long term prophylaxis has improved remarkably in the recent years. However, patients are often treated inadequately and risk factors for their disease are not well explored in daily practice. Although well designed long term studies of current and newer treatment are welcomed, educating doctors especially the primary care physicians who manage majority of gout cases, in optimizing the currently available management options would improve the present care.

Are ultrasound features at the first metatarsophalangeal joint associated with clinically-assessed pain and function? A study of people with gout, asymptomatic hyperuricaemia and normouricaemia

Background

The first metatatarsophalangeal joint (1st MTP joint) is a common location for sonographic evidence of urate deposition in people with gout and asymptomatic hyperuricaemia. However, it is unclear whether these are related to clinically-assessed pain and function. This study aimed to determine the association between ultrasound features and clinical characteristics of the 1st MTP joint in people with gout, asymptomatic hyperuricaemia and age- and sex-matched normouricaemic individuals.

Methods

Twenty-three people with gout, 29 with asymptomatic hyperuricaemia and 34 with normouricaemia participated in a cross-sectional study. No participant had clinical evidence of acute inflammatory arthritis at the time of assessment. Four sonographic features at the 1st MTP joint were analysed: double contour sign, tophus, bone erosion and synovitis. Clinical characteristics included in the analysis were 1st MTP joint pain, overall foot pain and disability, 1st MTP joint temperature, 1st MTP joint range of motion and gait velocity. Statistical analyses adjusted for the diagnostic group of the participant.

Results

After accounting for the diagnostic group, double contour sign was associated with higher foot pain and disability scores (P < 0.001). Ultrasound tophus was associated with higher foot pain and disability scores (P < 0.001), increased temperature (P = 0.005), and reduced walking velocity (P = 0.001). No associations were observed between ultrasound synovitis or erosion and the clinical characteristics.

Conclusions

Ultrasound features of urate crystal deposition, rather than soft tissue inflammation or bone erosion, are associated with clinical measures of foot-related functional impairment and disability even in the absence of clinical evidence of current acute inflammatory arthritis. This association persisted regardless of the diagnosis of the participant as having gout or asymptomatic hyperuricaemia.

Ultrasound Features of the First Metatarsophalangeal Joint in Gout and Asymptomatic Hyperuricemia: Comparison With Normouricemic Individuals

OBJECTIVE

The first metatarsophalangeal (MTP1) joint is frequently affected in gout. The aim of this study was to identify ultrasound features of the MTP1 joint in people with gout and people with asymptomatic hyperuricemia compared with normouricemic controls.

METHODS

Participants with gout (n = 23) and asymptomatic hyperuricemia (n = 29), and age- and sex-matched normouricemic control participants (n = 34), underwent a gray-scale and power Doppler ultrasound assessment of bilateral MTP1 joints by a single musculoskeletal radiologist. No participants had clinical evidence of joint inflammation at the time of scanning. The static images were later read by 2 musculoskeletal radiologists for the presence of the double contour sign, tophus, erosion, effusion, synovial hypertrophy, synovitis, and cartilage thickness.

RESULTS

Compared to normouricemic control participants, participants with gout and participants with asymptomatic hyperuricemia had more frequent double contour sign (odds ratio [OR] 3.91, P = 0.011 and OR 3.81, P = 0.009, respectively). Participants with gout also had more erosion (OR 10.13, P = 0.001) and synovitis (OR 9.00, P < 0.001) and had greater tophus and erosion diameters (P = 0.035 and P < 0.001, respectively). More severe erosion and synovitis grades and a less severe effusion grade were independently associated with gout compared with asymptomatic hyperuricemia (R²  = 0.65, P < 0.001).

CONCLUSION

Urate deposition, synovitis, and bone erosion are common at the MTP1 joint in people with gout, even in the absence of flare. Although individuals with asymptomatic hyperuricemia lack ultrasound features of inflammation or structural joint changes, they demonstrate a similar frequency of urate deposition.

Imaging as a potential outcome measure in gout studies: A systematic literature review

OBJECTIVE

Despite major progress in the imaging of gout, it is unclear which domains these techniques can evaluate and whether imaging modalities have the potential to provide valid outcome measures. The aim of this study was to assess the use of imaging instruments in gout according to the Outcomes in Rheumatology Clinical Trials (OMERACT) filter to inform the development of imaging as an outcome measure.

METHODS

A systematic literature search of imaging modalities for gout was undertaken. Articles were assessed by two reviewers to identify imaging domains and summarize information according to the OMERACT filter.

RESULTS

The search identified 78 articles (one abstract). Modalities included were conventional radiography (CR) (16 articles), ultrasound (US) (29), conventional computed tomography (CT) (11), dual energy computed tomography (DECT) (20), and magnetic resonance imaging (MRI) (16). Three domains were identified as follows: urate deposition, joint damage, and inflammation. Although sufficient data were available to assess feasibility, validity, and reliability, comprehensive assessment of discrimination was not possible due to the paucity of prospective imaging studies. CR is widely accessible, inexpensive with a validated damage scoring system. US and MRI offer radiation-free methods of evaluating urate deposition, damage and inflammation, but may be limited by accessibility. DECT provides excellent definition of urate deposition and bone damage, but has restricted availability and requires radiation.

CONCLUSIONS

Imaging methods can detect urate deposition, damage, and inflammation in gout. More than one modality may be required depending on the domains and therapeutic agent of interest. No single imaging method currently fulfils all aspects of the OMERACT filter for any domain.

Presence of gout is associated with increased prevalence and severity of knee osteoarthritis among older men: results of a pilot study

BACKGROUND

Gout and osteoarthritis (OA) are the most prevalent arthritides, but their relationship is neither well established nor well understood.

OBJECTIVES

We assessed whether a diagnosis of gout or asymptomatic hyperuricemia (AH) is associated with increased prevalence/severity of knee OA.

METHODS

One hundred nineteen male patients aged 55 to 85 years were sequentially enrolled from the primary care clinics of an urban Veterans Affairs hospital, assessed and categorized into 3 groups: gout (American College of Rheumatology Classification Criteria), AH (serum urate ≥6.8 mg/dL, no gout), and control (serum urate <6.8 mg/dL, no gout). Twenty-five patients from each group subsequently underwent formal assessment of knee OA presence and severity (American College of Rheumatology Clinical/Radiographic Criteria, Kellgren-Lawrence grade). Musculoskeletal ultrasound was used to detect monosodium urate deposition at the knees and first metatarsophalangeal joints.

RESULTS

The study showed 68.0% of gout, 52.0% of AH, and 28.0% of age-matched control subjects had knee OA (gout vs control, P = 0.017). Odds ratio for knee OA in gout versus control subjects was 5.46 prior to and 3.80 after adjusting for body mass index. Gout subjects also had higher Kellgren-Lawrence grades than did the control subjects (P = 0.001). Subjects with sonographically detected monosodium urate crystal deposition on cartilage were more likely to have OA than those without (60.0 vs 27.5%, P = 0.037), with crystal deposition at the first metatarsophalangeal joints correlating most closely with OA knee involvement.

CONCLUSIONS

Knee OA was more prevalent in gout patients versus control subjects and intermediate in AH. Knee OA was more severe in gout patients versus control subjects.

Use of ultrasound for diagnosis and monitoring of outcomes in crystal arthropathies

PURPOSE OF REVIEW

In the latest recommendations for the diagnosis and management of gout and calcium pyrophosphate dihydrate (CPPD) crystal deposition disease, the diagnostic potential of ultrasound has been recognized. This review highlights the recent advances of research on ultrasound in gout and CPPD crystal deposition disease.

RECENT FINDINGS

Ultrasound allows highly sensitive, noninvasive and quick detection of microcrystal aggregates in multiple anatomic areas. Ultrasound can be used as a safe and reliable guide to aspirate even minimal fluid collections suitable for microscopic analysis, and as a tool for monitoring monosodium urate crystal dissolution induced by urate-lowering therapy. The first metatarsophalangeal joint and the knee should be regarded as the anatomic regions with the highest probability of being respectively positive for monosodium urate and CPPD crystal aggregates.

SUMMARY

The detection of highly evocative signs in patients with equivocal clinical findings may have a deep impact on the clinical decision-making process, narrowing the differential diagnostic spectrum and avoiding time-consuming and expensive diagnostic procedures. Ultrasound differential diagnosis between gout and CPPD crystal deposition disease is based on the characteristics of crystal aggregates and their preferential localization in different anatomical areas.

Characteristics of the first metatarsophalangeal joint in gout and asymptomatic hyperuricaemia: a cross-sectional observational study

Background

This study aimed to identify patient-reported outcomes and clinician-assessed characteristics of the first metatarsophalangeal joint (1MTPJ) in people with gout and with asymptomatic hyperuricaemia by comparing them to normouricaemic controls.

Methods

Twenty four people with gout (without current symptoms of acute arthritis), 29 with asymptomatic hyperuricaemia and 34 age- and sex-matched controls participated in this cross-sectional observational study. Patient-reported outcomes included 1MTPJ pain, foot pain and disability, body pain, lower limb function, activity limitation and overall wellbeing. Clinician-assessed characteristics of the 1MTPJ included range of motion (ROM), plantar- and dorsi-flexion force, foot posture, temperature and hallux valgus severity.

Results

Compared to controls, participants with gout reported greater 1MTPJ pain (p = 0.014), greater foot pain and disability (p < 0.001), increased odds of having disabling foot pain (odds ratio (OR) 13.4, p < 0.001), decreased lower limb function for daily living (p = 0.002) and recreational (p < 0.001) activities, increased activity limitation (p = 0.002), reduced overall wellbeing (p = 0.034), reduced ROM (p < 0.001), reduced plantarflexion force (p = 0.012), increased 1MTPJ plantar (p = 0.004), dorsal (p = 0.003) and medial (p = 0.004) temperature and had increased odds of having more severe hallux valgus (OR 0.3 p = 0.041). Compared to controls, participants with asymptomatic hyperuricaemia had increased odds of having disabling foot pain (OR 4.2, p = 0.013), increased activity limitation (p = 0.033), decreased lower limb function for daily living (p = 0.026) and recreational (p = 0.010) activities, increased 1MTPJ plantarflexion force (p = 0.004) and a more pronated foot type (p = 0.036).

Conclusions

People with gout demonstrate 1MTPJ-specific changes indicative of subclinical inflammation, even in the absence of acute arthritis. People with asymptomatic hyperuricaemia, who exhibit no features or symptoms of gout, also report high levels of foot- and lower limb-related pain and disability.

The assessment of lesions of the Achilles tendon by ultrasound imaging in inflammatory arthritis: A systematic review and meta-analysis

OBJECTIVE

Ultrasound (US) is a highly sensitive, reliable and non-invasive tool, which allows for the assessment of lesions of tendons and entheseal sites. The aim of this systematic review and meta-analysis is to identify differences in US lesions of the Achilles tendon (AT) between people with inflammatory arthritis (IA) and healthy controls.

METHODS

An electronic literature search was performed on Medline, CINAHL, SportDiscus and The Cochrane Library. Methodological quality was assessed using a modified Quality Index. Odds ratios with 95% confidence intervals (CI) were determined. Meta-analysis was conducted on those studies that were considered to be homogenous.

RESULTS

A total of 13 high-to-medium quality studies met the inclusion criteria. The majority of studies reported US lesions in spondyloarthropathy (SpA), with limited evidence for other forms of IA. US lesions were not consistently defined with regard to Outcome Measures in Rheumatology Clinical Trials (OMERACT) definitions, and numerous scoring systems were used across the majority of studies. The mean AT thickness at the enthesis in people with SpA was 0.54mm thicker (95% CI: 0.10-0.97mm) with more frequent erosions in people with SpA (odds ratio = 7.43, 95% CI: 1.99-27.77, P = 0.003) and rheumatoid arthritis (RA) (odds ratio = 9.60, 95% CI: 1.23-74.94, P = 0.03), compared to controls. There was no significant difference in the frequency of enthesophyte formation in people with SpA compared to the controls (odds ratio = 2.48, 95% CI: 0.64-9.70, P = 0.19).

CONCLUSIONS

The systematic review identified that a majority of studies reporting US lesions were in SpA, but limited evidence relating to other forms of IA. Consistent application of the OMERACT US definitions and scoring of US lesions is required in future studies of AT disease in IA. Further work is also required to distinguish between US lesions reflective of inflammation and structural damage.

Sonography of the first metatarsophalangeal joint and sonographically guided intraarticular injection of corticosteroid in acute gout attack

OBJECTIVE

The aims of this study were to identify the characteristic ultrasound (US) findings of the first metatarsophalangeal joint (MTPJ1) in acute gout attack and to evaluate the efficacy and safety of US-guided intraarticular corticosteroid injection of the MTPJ1.

METHODS

We enrolled 21 patients with acute gout attack involving the MTPJ1 unilaterally. US evaluation of each affected MTPJ1 was compared with radiographic features. US-guided intraarticular corticosteroid (0.5 ml [20 mg] of triamcinolone mixed with 0.5 ml of 2% lidocaine) was injected into the affected MTPJ1s. Pain, general disability, and walking disability were assessed at baseline, 24 hours, 48 hours, and 7 days after injection with visual analog scales.

RESULTS

The characteristic US findings of MTPJ1 were erosion, joint effusion, synovial hypertrophy, tophus-like lesion, double contour, hyperechoic spots, and increased power Doppler signal in acute gout attack. US was more sensitive than conventional radiograph in detecting erosion and tophus-like lesion. The reductions of mean visual analog scale scores in pain, general disability, and walking disability were 48 mm (SD, 27), 35 mm (SD, 26) and 39 mm (SD, 26), respectively, 48 hours after US-guided intraarticular corticosteroid injection. There were no adverse events.

CONCLUSIONS

US is a sensitive tool to evaluate joint abnormality of the MTPJ1 in acute gout attack and US-guided intraarticular corticosteroid injection to this joint is effective and safe.

Imaging in gout: A review of the recent developments

Gout is a common inflammatory arthritis and is caused by accumulation of monosodium urate crystals in joints and soft tissues. Apart from joint damage, untreated gout is associated with cardiovascular and renal morbidity. Gout, whilst in principle considered to be well understood and simple to treat, often presents diagnostic and management challenges, with evidence to suggest that it is often inadequately treated and poor compliance is a major issue. Imaging tools can aid clinicians in establishing the correct diagnosis, when histological crystal diagnosis is unable to be established, and also assess the burden of inflammatory and structural disease. Imaging can also be used to monitor treatment response. The imaging techniques that currently have a role in the imaging of gout include conventional radiography, ultrasound, computed tomography, dual energy computed tomography, magnetic resonance imaging and nuclear medicine. Despite the lack of major technological advances in imaging of gout in recent years, scientific studies of existing imaging modalities have improved our understanding of the disease, and how to best utilize imaging techniques in the clinical setting.

An old disease with new insights: Update on diagnosis and treatment of gout

Gout is an acute and chronic inflammatory disorder associated with high morbidity and impaired quality of life. There has been a substantial increase in the prevalence and incidence of gout in recent years. Novel diagnostic and therapeutic options have provided new insights into the pathogenesis and management of hyperuricemia and gout in the last decade. This clinical review aims to summarize the diagnostic process and management of acute and chronic gout.

Advanced imaging in gout

OBJECTIVE

The purpose of this article is to describe the role of advanced imaging using ultrasound, CT, and MRI in the assessment and diagnosis of gout.

CONCLUSION

Dual-energy CT can quantitatively identify monosodium urate crystal deposits with high sensitivity and specificity within joints, tendons, and periarticular soft tissues. There are several characteristic ultrasound imaging findings, which include visualization of echogenic monosodium urate crystal deposition, tophus, and adjacent erosions. MRI is sensitive in showing soft-tissue and osseous abnormalities of gout, although the imaging findings are not specific. Gout commonly involves specific joints and anatomic structures, and knowledge of these sites and imaging appearances are clues to the correct diagnosis.

Systematic review of the value of ultrasound and magnetic resonance musculoskeletal imaging in the evaluation of response to treatment of gout

BACKGROUND

Imaging may be useful for monitoring response to therapy. Within the OMERACT proposal for the core set domains for outcome measures in chronic gout, serum urate levels, recurrence of gouty flares, tophus regression, and joint damage imaging have been included, among other proposed issues.

OBJECTIVES

To perform a systematic literature review of the usefulness of magnetic resonance imaging (MRI) and ultrasound (US) on assessment of treatment response in patients with gout.

METHODS

MEDLINE, EMBASE, Cochrane Library (up to February 2012), and abstracts presented at the 2010 and 2011 meetings of the American College of Rheumatology and European League Against Rheumatism, were searched for treatment studies of any duration and therapeutic options, examining the ability of MRI/US to assess treatment response in gouty patients. Meta-analyses, systematic reviews, randomized clinical trials, cohort and case-control studies and validation studies were included. Quality was appraised using validated scales.

RESULTS

There were only 3 US published studies in the literature that analysed US utility on assessment of response to treatment in patients with gout. All of them were prospective case studies with a small number of patients and they were reviewed in detailed. A total of 36 patients with gout were examined with US. All of them had a baseline serum urate >6mg/dL. US features of gout (double contour sign, hyperechoic spots in synovial fluid, hyperechoic cloudy areas, tophus diameter and volume) achieved significant reduction in patients who reached the objective of uricemia ≤6mg/dL in all the studies; however, patients in whom levels did not drop below 6mg/dL had no change of US features of gout. Other parameters evaluated in one study included ESR, CRP, number of tender joints (TRN), number of swollen joints, and pain score (SP). All of them decreased with uricemia reduction, but only TRN and SP were statistically significant. No data was found on the value of MRI on treatment response assessment in patients with gout.

CONCLUSIONS

The improvement in ultrasound features shows concurrent validity with uric acid reduction. According to the published evidence, US can be a useful tool for monitoring treatment of gouty patients, although more research is needed. The value of MRI on treatment response assessment in patients with gout remains to be determined.

Dual-energy computed tomography compared with ultrasound in the diagnosis of gout

OBJECTIVES

The aim of our study was to compare dual-energy CT (DECT) with US for the diagnosis of gouty arthritis and to correlate the imaging findings with results from synovial fluid aspiration whenever possible.

METHODS

We recruited 21 patients (17 male and 4 female) who presented with a clinical suspicion of acute or chronic gout in 37 joints. DECT scans of the hands, wrists, feet, ankles, knees and elbows were performed. For post-processing, a colour-coding gout software protocol was used. US examinations of the same joints were performed. In addition, joint fluid aspiration was performed in a total of 14 joints.

RESULTS

DECT images were positive for urate crystal deposits in 25 of 37 joints. US findings were positive in 24 of 37 examined joints. In 12 of 14 joints the synovial fluid aspiration was positive. CT and US findings correlated in 32 of 37 joints (86.5%; κ = 0.698, P < 0.001). CT and synovial fluid results correlated in 12 of 14 joints (85.7%; κ = 0.417, P = 0.119). US and cytology findings correlated in 14 of 14 joints (100%; κ = 1, P < 0.001).

CONCLUSION

DECT and US have comparable sensitivity for the detection of gouty arthritis in a clinical setting. However, DECT results should be interpreted carefully, as there could be some false-negative findings.

Imaging of gout: an overview

The diverse clinical states and sites of pathology in gout provide challenges when considering the features apparent on imaging. Ideally, an imaging modality should capture all aspects of disease including monosodium urate crystal deposition, acute inflammation, tophus, tissue remodelling and complications of disease. The modalities used in gout include conventional radiography, ultrasonography, magnetic resonance imaging, computed tomography and dual-energy computed tomography. This review discusses the role of each of these imaging modalities in gout, focussing on the imaging characteristics, role in gout diagnosis and role for disease monitoring. Ultrasonography and dual-energy computed tomography are particularly promising methods for both non-invasive diagnosis and monitoring of disease. The observation that ultrasonographic appearances of monosodium urate crystal deposition can be observed in patients with hyperuricaemia but no other clinical features of gout raises important questions about disease definitions.

Ultrasound applications for the practicing rheumatologist

Musculoskeletal ultrasound is an increasingly used tool for the evaluation and management of rheumatologic diseases. Its utilisation by rheumatologists is varied around the world and is dependent upon training and local expertise. Its applications can be broadly categorised into three main areas; for the education of patients, to aid the rheumatologist in the diagnosis and monitoring of disease, and therapeutically for joint aspiration and injection. Ultrasound is a safe, portable, easily repeatable, dynamic images in multiple planes and cheap form of imaging. Ultrasound however, is operator dependent and has a number of artefacts that can result in misinterpretation. Musculoskeletal Ultrasound uses a number of modes to characterise joint pathology, including grey scale, colour and power Doppler, spectral Doppler, 3D imaging, elastography. Musculoskeletal ultrasound can detect and monitor multiple joint pathologies including synovitis, tenosynovitis, and tendon pathologies, entheseal processes, bone erosions and osteophytes, cartilage changes and bursal pathologies.

Polyarticular sonographic assessment of gout: a hospital-based cross-sectional study

OBJECTIVE

To assess the sonographic frequency of synovial effusion, synovial hypertrophy, synovitis, and double contour sign at joints commonly affected by gout and whether these features differ according to serum urate levels, disease duration, and use of urate-lowering therapy.

METHODS

Participants with gout were recruited from rheumatology clinics. A detailed clinical assessment was undertaken of gout history, co-morbidities, medication, alcohol consumption, height, weight, clinical synovitis, tophi, and serum urate. Sonographic examination of the metatarsophalangeal joints, ankles, knees, metacarpophalangeal joints, wrists and elbows for synovial effusion, synovial hypertrophy, synovitis and double contour sign was undertaken. The mean number of joints affected were compared according to serum urate (<360 μmol/L versus ≥360 μmol/L), urate-lowering therapy (yes/no), and disease duration (≤5 years versus>5 years).

RESULTS

Forty patients participated in the study. Synovial effusion, synovial hypertrophy, synovitis, and double contour sign were identified in 36 (90%), 38 (95%), 24 (62%) and 37 (93%) participants respectively. Synovial effusion was seen most frequently at the knee (right 70%, left 68%) followed by the first metatarsophalangeal (right 48%, left 40%) and lesser metatarsophalangeal joints (right 45%, left 35%). Synovial hypertrophy, synovitis, and double contour sign were seen most frequently at the first metatarsophalangeal joint (hypertrophy: right 65%, left 60%; synovitis: right 18%, left 18%; double contour: right 60%, left 68%). These findings did not differ according to serum urate, disease duration, or use of urate-lowering therapy.

CONCLUSION

Polyarticular sonography frequently identifies synovial effusion, synovial hypertrophy, synovitis and double contour sign in patients with gout, particularly at the metatarsophalangeal joints and knees.

[Gout as a systemic disease. Manifestations, complications and comorbidities of hyperuricaemia]

Of all inflammatory rheumatic diseases gout has the highest prevalence. Patients with intermittent acute gout attacks are usually treated by primary care physicians. However, in cases of insufficient long-term control of serum uric acid levels, complications or atypical clinical manifestations may necessitate consultation with a rheumatologist in the further course of the disease. An oligoarticular or polyarticular presentation can give rise to the initial suspicion of rheumatoid or psoriatic arthritis. In these cases a careful clinical work-up supported by laboratory and imaging investigations is necessary and synovial fluid analysis is usually required. As in other rheumatic diseases extra-articular manifestations are of utmost importance for morbidity and mortality. Gout is a complex metabolic and inflammatory disease and besides articular symptoms the renal and cardiovascular effects of hyperuricemia are particularly relevant for the overall prognosis.

Recent advances in management of gout

Incidence and prevalence of gout have markedly increased over the last few decades in keeping with the rise in prevalence of obesity and metabolic syndrome. Until recently, management of gout in patients with associated metabolic syndrome and comorbid illnesses such as renal impairment was difficult because of limited treatment options. However, significant progress has been made in the last few years, with introduction of new treatments such as interleukin-1 antagonists for management of acute gout, and febuxostat and pegloticase for chronic gout. The association of gout with alcohol, dietary purines and fructose ingestion has been confirmed in large prospective studies, thus enabling the clinician to now provide evidence-based advice to patients. Recent efficacy and safety data favour lower over higher doses of colchicine, and oral corticosteroids over non-steroidal anti-inflammatory drugs for patients with acute gout. Local ice therapy might help to differentiate gout from other forms of inflammatory arthritis, and supplementation with vitamin C help to reduce risk of gout. Several other drugs with rational mechanisms of action are in the pipeline, and likely to be introduced over the next few years. A new era has thus begun in the field of gout.

Usefulness of ultrasonography for gout

Gout is a common arthritis caused by deposition of monosodium urate (MSU) crystals within joints secondary to chronic hyperuricemia. Joint damage can occur during evolution of the disease. The identification of MSU crystals in synovial fluid is the gold standard to diagnose gout. However, the diagnosis is sometimes difficult to do, particularly in atypical clinical presentations or when small joints are involved. Radiography is often normal at the early stage of gout. MRI and CT-scan are costly and availability of these imaging techniques may be problematic in clinical practice. Ultrasonography (US) appears useful for diagnosis and management of the disease. Several ultrasound features evocating gout have been described with different sensitivity and specificity. We reviewed the literature for evidence of the ability and usefulness of US for diagnosis of early-stage and established gout.

Reproducibility of musculoskeletal ultrasound for determining monosodium urate deposition: concordance between readers

OBJECTIVE

Criteria for sonographic diagnosis of monosodium urate (MSU) crystal deposition have been developed, but the interreader reproducibility of this modality is not well established. We therefore assessed agreement using a systematic approach.

METHODS

Fifty male subjects ages 55-85 years were recruited during primary care visits to an urban Veterans Affairs hospital, and were assessed by musculoskeletal ultrasound (US) of the knees and first metatarsophalangeal (MTP) joints to evaluate for the double contour sign and tophi as evidence of MSU crystal deposition. Images were read by 2 blinded rheumatologists trained in musculoskeletal US, and the degree of concordance was determined for individual subjects, total joints, femoral articular cartilage (FAC), and first MTP joints. Subjects were further categorized into 3 diagnostic groups: gout, asymptomatic hyperuricemia (no gout, serum uric acid [UA] ≥6.9 mg/dl), and controls (no gout, serum UA ≤6.8 mg/dl), and reader concordance within these 3 groups was assessed.

RESULTS

We observed almost perfect agreement between readers for 1) individual subjects (yes/no; n = 50, 100% agreement, κ = 1.000), 2) total joints (n = 200, 99% agreement, κ = 0.942), 3) FAC (n = 100, 99% agreement, κ = 0.942), and 4) first MTP joints (n = 100, 99% agreement, κ = 0.942). Furthermore, findings by side (right/left) and diagnostic group (gout, asymptomatic hyperuricemia, control) showed substantial to almost perfect concordance for all measures. MSU deposition was seen most commonly in gout patients, and deposition was also seen in some subjects with asymptomatic hyperuricemia, but in only 1 control.

CONCLUSION

Musculoskeletal US is reliable for detecting MSU deposition in FAC and first MTP joints in gout and asymptomatic hyperuricemia.

Imaging in gout--what can we learn from MRI, CT, DECT and US?

There are many exciting new applications for advanced imaging in gout. These modalities employ multiplanar imaging and allow computerized three-dimensional rendering of bone and joints (including tophi) and have the advantage of electronic data storage for later retrieval. High-resolution computed tomography has been particularly helpful in exploring the pathology of gout by investigating the relationship between bone erosions and tophi. Magnetic resonance imaging and ultrasonography can image the inflammatory nature of gouty arthropathy, revealing synovial and soft tissue inflammation, and can provide information about the composition and vascularity of tophi. Dual-energy computerized tomography is a new modality that is able to identify tophi by their chemical composition and reveal even small occult tophaceous deposits. All modalities are being investigated for their potential roles in diagnosis and could have important clinical applications in the patient for whom aspiration of monosodium urate crystals from the joint is not possible. Imaging can also provide outcome measures, such as change in tophus volume, for monitoring the response to urate-lowering therapy and this is an important application in the clinical trial setting.

2011 recommendations for the diagnosis and management of gout and hyperuricemia

Gout is a major health problem in the United States; it affects 8.3 million people, which is approximately 4% of the adult population. Gout is most often diagnosed and managed in primary care practices; thus, primary care physicians have a significant opportunity to improve patient outcomes. Following publication of the 2006 European League Against Rheumatism (EULAR) gout guidelines, significant new evidence has accumulated, and new treatments for patients with gout have become available. It is the objective of these 2011 recommendations to update the 2006 EULAR guidelines, paying special attention to the needs of primary care physicians. The revised 2011 recommendations are based on the Grading of Recommendations Assessment, Development, and Evaluation approach as an evidence-based strategy for rating quality of evidence and grading the strength of recommendation formulated for use in clinical practice. A total of 26 key recommendations, 10 for diagnosis and 16 for management, of patients with gout were evaluated, resulting in important updates for patient care. The presence of monosodium urate crystals and/or tophus and response to colchicine have the highest clinical diagnostic value. The key aspect of effective management of an acute gout attack is initiation of treatment within hours of symptom onset. Low-dose colchicine is better tolerated and is as effective as a high dose. When urate-lowering therapy (ULT) is indicated, the xanthine oxidase inhibitors allopurinol and febuxostat are the options of choice. Febuxostat can be prescribed at unchanged doses for patients with mild-to-moderate renal or hepatic impairment. The target of ULT should be a serum uric acid level that is ≤ 6 mg/dL. For patients with refractory and tophaceous gout, intravenous pegloticase is a new treatment option. This article is a summary of the 2011 clinical guidelines published in Postgraduate Medicine. This article provides a streamlined, accessible overview intended for quick review by primary care physicians, with the full guidelines being a resource for those seeking additional background information and expanded discussion.

Joint and tendon subclinical involvement suggestive of gouty arthritis in asymptomatic hyperuricemia: an ultrasound controlled study

Introduction

In this study, we aimed to investigate ultrasonographic (US) changes suggestive of gouty arthritis in the hyaline cartilage, joints and tendons from asymptomatic individuals with hyperuricemia.

Methods

We conducted a cross-sectional, controlled study including US examinations of the knees and first metatarsal-phalangeal joints (first MTPJs), as well as of the tendons and enthesis of the lower limbs. Differences were estimated by χ² or unpaired t-tests as appropriate. Associations were calculated using the Spearman's correlation coefficient rank test.

Results

Fifty asymptomatic individuals with hyperuricemia and 52 normouricemic subjects were included. Hyperechoic enhancement of the superficial margin of the hyaline cartilage (double contour sign) was found in 25% of the first MTPJs from hyperuricemic individuals, in contrast to none in the control group (P < 0.0001). Similar results were found on the femoral cartilage (17% versus 0; P < 0.0001). Patellar enthesopathy (12% versus 2.9%; P = 0.01) and tophi (6% versus 0; P = 0.01) as well as Achilles enthesopathy (15% versus 1.9%; P = 0.0007) were more frequent in hyperuricemic than in normouricemic individuals. Intra-articular tophi were found in eight hyperuricemic individuals but in none of the normouricemic subjects (P = 0.003).

Conclusions

These data demonstrate that morphostructural changes suggestive of gouty arthritis induced by chronic hyperuricemia frequently occur in both intra- and extra-articular structures of clinically asymptomatic individuals.

The role of uric acid and other crystals in osteoarthritis

Clinicians have long assumed that an association exists between crystal arthropathies and the presence of osteoarthritis (OA). However, studies establishing an independent association between calcium pyrophosphate or uric acid crystal disease and OA are sparse. Even less is known about a possible pathogenic relationship. Whereas some studies suggest that the relationships between crystals and OA may not be incidental and that crystal deposition may contribute to the onset and/or acceleration of OA joint damage, other authors have challenged this assertion. In this review, we provide an overview of past and current research elucidating the role of crystal deposition, including monosodium urate, calcium pyrophosphate, and other crystals, in OA. Given the clinical frequency of gout and that agents exist to modulate serum UA levels, special attention is given to the role of monosodium urate crystals.

Enthesiopathy of the flexor carpi ulnaris at the pisiform: findings of high-frequency sonography

OBJECTIVES

Acute or chronic pain at the pisiform may be due to tendinopathy of the flexor carpi ulnaris tendon (FCU) insertion, mechanical overuse, bony fractures, and osteoarthritis of the pisiform-triquetral joint. Enthesiopathy of the FCU at the pisiform might exhibit abnormalities assessable for sonographic characterization. This study aimed to determine the most relevant sonographic features of tendinopathy of the FCU insertion at the pisiform.

MATERIALS AND METHODS

We retrospectively analyzed radiological findings of 9 patients admitted for high-frequency sonographic evaluation of a painful pisiform FCU insertion. The FCU insertion was assessed for active enthesiopathy in terms of tendon thickening and hyperemia, peritendinous effusion, peritendinous hyperemia, peritendinous soft tissue thickening, cystic fluid collections, erosive cortical irregularities, and osteoproliferative alterations at the pisiform.

RESULTS

Of all patients, 5 had inflammatory rheumatic disorders and the remainder had a painful pisiform FCU insertion related to overuse. While peritendinous effusion, pisiform erosive cortical irregularities, and peritendinous soft tissue thickening at the FCU insertion were exclusively found in rheumatic patients, active enthesiopathy of the FCU tendon, pisiform osteoproliferative alterations, and hyperemia of the peritendinous soft tissue were inconsistent and found in both groups. Cystic fluid collections from the pisiform-triquetral joint were only seen in patients with overuse.

CONCLUSIONS

In this small case series of patients with pain at the pisiform FCU insertion, we could reveal several typical sonographic features for insertion tendinopathy. Further studies should prove if these sonographic features could impact on the management of patients with pain at the pisiform.

Ultrasonographic evidence of inflammation is frequent in hands of patients with erosive osteoarthritis

OBJECTIVE

Erosive osteoarthritis (OA) (EOA) is considered an aggressive form of primary OA that is defined radiographically by intra-articular erosions of the inter-phalangeal joints of the hand and characteristic deformities. The aim of the present study was the sonographic investigation of hand small joints in patients with EOA and comparison of the imaging findings with conventional radiography (CR).

METHOD

Twenty-two patients (20 women, mean age 62.5 years) with clinical and radiographic diagnosis of EOA formed our study group. A total of 660 joints were assessed by both radiographs and ultrasound (US). US and plain films were evaluated by two different physicians on a blinded fashion. Erosions, osteophytes and deformities were evaluated by both US and plain films. Synovial thickening, effusion, and power Doppler signal indicative of abnormal vascularity were recorded in each joint during US scanning.

RESULTS

Erosions were detected in 231/660 (35%) small joints by US and in 115/660 (17.4%) small joints by conventional radiographs (P<0.05). Osteophytes were detected in 360/660 (54.5%) small joints by US, and in 310/660 (47.0%) small joints by conventional radiographs (P<0.05). Thickened synovium was detected in 19 of 22 patients and increased intra-articular power Doppler signal, indicative of active inflammation, was detected in 18 of 22 patients. Thickened synovium was found in 159/660 (24.1%), effusion in 119/660 (18%) and increased power Doppler in 148/660 (22.4%) small joints. Intra-observer kappa value for agreement regarding US was 0.81 and plain films 0.86. In 31 instances extensive finger tenosynovitis was also evident.

CONCLUSION

In patients with EOA, US is a reliable and a more sensitive imaging modality than CR in detecting erosions and osteophytes. US detects inflammatory changes in small hand joints in the vast majority of patients with EOA and suggests that current treatment modalities are inadequate treatment for this disease.

Gout--current diagnosis and treatment

BACKGROUND

Because of the changing dietary habits of an aging population, hyperuricemia is frequently found in combination with other metabolic disorders. Longstanding elevation of the serum uric acid level can lead to the deposition of monosodium urate crystals, causing gout (arthritis, urate nephropathy, tophi). In Germany, the prevalence of gouty arthritis is estimated at 1.4%, higher than that of rheumatoid arthritis. There are no German guidelines to date for the treatment of gout. Its current treatment is based largely on expert opinion.

METHODS

Selective literature review on the diagnosis and treatment of gout.

RESULTS AND CONCLUSIONS

Asymptomatic hyperuricemia is generally not an indication for pharmacological intervention to lower the uric acid level. When gout is clinically manifest, however, acute treatment of gouty arthritis should be followed by determination of the cause of hyperuricemia, and long-term treatment to lower the uric acid level is usually necessary. The goal of treatment is to diminish the body's stores of uric acid crystal deposits (the intrinsic uric acid pool) and thereby to prevent the inflammatory processes that they cause, which lead to structural alterations. In the long term, serum uric acid levels should be kept below 360 micromol/L (6 mg/dL). The available medications for this purpose are allopurinol and various uricosuric agents, e.g., benzbromarone. There is good evidence to support the treatment of gouty attacks by the timely, short-term use of non-steroidal anti-inflammatory drugs (NSAID), colchicine, and glucocorticosteroids.