Association between specific ultrasound features of joints and impaired kidney function among gout patients

OBJECTIVE

To investigate the relationship between the specific ultrasonic manifestations of lower limb joints and impaired kidney function in gouty arthritis.

METHODS

In this cross-sectional study, 408 patients with gouty arthritis were divided into two groups based on the status of renal function: normal group (n = 240) and renal impairment (n = 168) group. All patients underwent ultrasound examination of the bilateral knee, ankle, and first metatarsophalangeal joints to detect ultrasound features of double-contour sign (DC) and tophus. Multiple logistic regression analysis was conducted to assess the association between kidney dysfunction and ultrasound features. A number of potential clinical confounders were adjusted in the model.

RESULTS

Univariable conditional logistic regression produces several significant risk factors of impaired kidney function which were the highest and current lever of serum urate acid, course of disease, frequency of attack, hyperlipidemia, hypertension, diabetes, coronary heart disease, presence of multiple tophus, and DC (P < 0.05). After correcting the course of disease and other risk factors, tophus was still an independent risk factor of impaired kidney function and the multivariable adjusted odds ratios (95% CI) was 1.789 (1.005-3.185, P = 0.05), however, the association was not significant in DC (OR = 1.098, 95% CI: 0.668-1.803, P = 0.71).

CONCLUSION

The ultrasound feature of tophus was associated with kidney dysfunction in patients with gout, independent of clinical risk factors, which may be helpful in guiding clinical practice.

Erosive Tophaceous Gouty Arthropathy of the Hand: A Case Report

The presence of tophaceous gout in the hand is a classic finding seen in uncontrolled gout. Occasionally gouty tophi can be the initial physical finding in asymptomatic hyperuricemia. Composed of monosodium urate (MSU) crystals, gouty tophi can cause significant soft tissue and joint pathology. In addition, tophaceous gout and hyperuricemia are associated with increased mortality. We present a patient with tophaceous gout causing erosive arthropathy of the proximal interphalangeal (PIP) joint. The diagnosis and treatment for tophaceous gout is reviewed.

Degenerative joint disease induced by repeated intra-articular injections of monosodium urate crystals in rats as investigated by translational imaging

The objective of this work was to assess the consequences of repeated intra-articular injection of monosodium urate (MSU) crystals with inflammasome priming by lipopolysaccharide (LPS) in order to simulate recurrent bouts of gout in rats. Translational imaging was applied to simultaneously detect and quantify injury in different areas of the knee joint. MSU/LPS induced joint swelling, synovial membrane thickening, fibrosis of the infrapatellar fat pad, tidemark breaching, and cartilage invasion by inflammatory cells. A higher sensitivity to mechanical stimulus was detected in paws of limbs receiving MSU/LPS compared to saline-injected limbs. In MSU/LPS-challenged joints, magnetic resonance imaging (MRI) revealed increased synovial fluid volume in the posterior region of the joint, alterations in the infrapatellar fat pad reflecting a progressive decrease of fat volume and fibrosis formation, and a significant increase in the relaxation time T2 in femoral cartilage, consistent with a reduction of proteoglycan content. MRI also showed cyst formation in the tibia, femur remodeling, and T2 reductions in extensor muscles consistent with fibrosis development. Repeated intra-articular MSU/LPS injections in the rat knee joint induced pathology in multiple tissues and may be a useful means to investigate the relationship between urate crystal deposition and the development of degenerative joint disease.

Differential Diagnosis of Acute and Chronic Gouty Arthritis by Multijoint Ultrasound

To investigate whether multi-joint ultrasound (US) findings in patients with gouty arthritis could be used to distinguish between acute and chronic stages, we performed a retrospective study with 129 enrolled patients from the Rheumatology Department of the First Affiliated Hospital of Chengdu Medical College from September 1, 2018 to June 12, 2019. Patients with acute or non-acute gout were categorized using clinical data, and US imaging findings of the knees, ankles and first metatarsophalangeal joints were analyzed and compared between groups. Notably, we found that the most prevalent sign detected by US was the hyperechoic spot in the synovium, followed by arthrosynovitis, aggregates, double contour signs and tophi; meanwhile, bone erosions were the least common. Additionally, synovitis was more frequently detected in the acute joints of gouty arthritis (49%) compared with the non-acute joints (35%), whereas grade 1 or 2 blood flow classifications (97%), tophi and bone lesions were more often seen in the latter. Overall, our data suggest that multi-joint US scanning might be used to evaluate disease severity and discriminate between stages of gouty arthritis.

Treatment of atypical gouty arthritis of the hip using total hip arthroplasty: A case report

RATIONALE

Gout and gouty arthritis typically involve peripheral and monoarticular joints, especially the first metatarsophalangeal joint and knees. Hip involvement in patients with gout is rare, and its diagnosis is very difficult, especially in the late stages of the disease. Total hip arthroplasty could be a surgical treatment for atypical gouty arthritis of the hip; however, few cases have been reported.

PATIENT CONCERNS

We reported an uncommon case of a 74-year-old man without typical symptoms of hip gout arthritis whom was misdiagnosed as having avascular necrosis of the femoral head.

DIAGNOSES

Clinical examination and imaging revealed bilateral avascular necrosis of the femoral head. However, the final pathology report revealed left hip gout arthritis.

INTERVENTIONS

The patient underwent left total hip arthroplasty and was followed up for 3years.

OUTCOMES

The outcome was favorable. The function of the left hip was almost normal.

LESSONS

Our case indicated the difficulty of the diagnosis of hip gout arthritis. Due to the lower rates of hip gout arthritis and lack of typical clinical examination, it is easy to misdiagnose. Furthermore, surgical treatment for the late stage of hip gout arthritis has not previously been reported. In our case, total hip arthroplasty proved to be a good option.

Acute Gout Attack Immediately After Total Knee Arthroplasty: A Case Report

CASE

We report a case of acute gouty arthritis-mimicking infection that occurred immediately after right total knee arthroplasty in a 73-year-old man. Repetitive laboratory tests showed acute inflammation and did not easily distinguish acute gout from bacterial infection. Surgical treatment was undertaken for diagnostic and therapeutic purposes. A large amount of chalky whitish crystals suggestive of acute gout was found in both knees without the suspicion of bacterial infection, and thorough irrigation and debridement were performed.

CONCLUSIONS

Although conservative treatment is generally administered for acute gouty arthritis, early surgical intervention may ensure a good clinical result in a prosthetic joint.

Imaging of gout: findings and pitfalls. A pictorial review

Gout is the most common crystal arthropathy, accounting for up to 5% of all arthritis. The hallmark of the disease is hyperuricemia with the subsequent deposition of monosodium urate (MSU) crystals in the intra- and extra-articular soft tissues and bones, leading to inflammation of these tissues. Recurrent intermittent flares can result in chronic gouty arthritis leading to cartilage and bone destruction. The most sensitive and specific imaging methods for diagnosing acute gout are ultrasound and dual energy computed tomography (DECT). In the chronic or tophaceous gout, imaging may depict tophi and their local destructive effect on surrounding tissues with characteristic findings on radiographs. In this pictorial review the imaging features of acute and chronic gout on radiographs, ultrasound, and DECT are presented, as well as imaging pitfalls that one needs to be aware.

Size matters: observations regarding the sonographic double contour sign in different joint sizes in acute gouty arthritis

OBJECTIVE

In distinguishing urate arthritis (UA) from non-crystal-related arthritides, joint sonography including the detection of the double contour sign (DCS) and hypervascularization using power Doppler ultrasound (PDUS) is an important step in the diagnostic process. But are these sonographic features equally reliable in every accessible joint under real-life conditions?

METHODS

We retrospectively analyzed 362 patients with acute arthritis and evaluated the DCS and the degree of PDUS hypervascularization in patients with gout and in those with arthritis other than urate arthritis (non-UA). We classified all joints into the groups small, medium, and large. Sensitivities, specificities, positive and negative predictive values (PPV/NPV), and a binary regression model were calculated. We also evaluated the influence of serum uric acid levels (SUA) on the presence of a DCS in each joint category.

RESULTS

Sensitivity of the DCS in gout was 72.5% in the entire cohort, 66.0% in large, 78.8% in medium, and 72.3% in small joints. In wrist joints the DCS sensitivity maxed at 83.3%, with a specificity of 81.8%. The lowest rates of DCS sensitivity were found in gout patients with elbow joint involvement (42.9%). In all joints except metatarsophalangeal joint 1 (MTP-1), the incidence of a DCS increased by the increment of SUA levels above 7.5 mg/dl (p < 0.001). PDUS signals were most commonly found in medium and small joints and were only scarce in large joints, independent of the underlying diagnosis.

CONCLUSIONS

In our study we detected different rates of accuracy regarding DCS and PDUS in patients with acute arthritis. The best results were seen in medium-size joints, especially wrists.

Better understanding of acute gouty attack using CT perfusion in a rabbit model

OBJECTIVE

To assess hemodynamic changes related to acute gouty knee arthritis in a rabbit with CT perfusion (CTP) METHODS: Forty-two rabbits were randomly separated into two groups: the treated group of 30 and the control group of 12. The right knee was injected with monosodium urate solution and polymyxin in the treated group and saline and polymyxin in the control group. At 2, 16, 32, 48, 60, and 72 h after injection, five rabbits from the treated group and two rabbits from the control group were selected for CTP. At each time point, blood flow (BF), blood volume (BV), and clearance rate (CL) were measured, and microvessel density (MVD) was evaluated with a microscope.

RESULTS

In the treated group, BF, BV, CL, and MVD were significantly higher than in the control group (p < 0.001). Differences within paired comparison of BV, BF, CL, and MVD were all significant (all p < 0.001). Peak time of BV, BF, and MVD was 32 h and 48 h for CL. After multivariate stepwise linear regression analysis, BV was linearly associated with MVD and vice versa, which also applied to BF with MVD and BF with CL, separately. The ascending rate of MVD was the highest among that of all parameters; so was the descending rate of CL.

CONCLUSION

CTP in this rabbit knee model accurately detected hemodynamic changes during a gouty attack.

KEY POINTS

• Acute gouty arthritis can be evaluated with CTP in a rabbit knee model. • Following injection of MSU crystals, producing an acute gouty attack, CTP successfully assessed hemodynamic changes. • The ascending rate of MVD was the highest among that of all parameters; so was the descending rate of CL.

Diagnostic accuracy of dual-energy computed tomography and joint aspiration: a prospective study in patients with suspected gouty arthritis

OBJECTIVES

To validate the diagnostic benefit of dual-energy computed tomography (DECT) and synovial fluid aspiration in suspected gout.

METHODS

A total of 43 patients with suspected gout underwent aspiration and DECT (320-row CT; Canon Medical Systems, Japan). The patients were assessed (gout vs. non-gout) based on the 2015 ACR/EULAR gout classification criteria using clinical and laboratory findings. The results were analysed by comparing two scenarios using McNemar test: Scenario A: ACR/EULAR criteria, followed by DECT results and aspiration findings. Scenario B: ACR/EULAR criteria, followed by aspiration and DECT results.

RESULTS

15/43 patients (34.9%) were positive for MSU crystals, and 16/43 patients (37.2%) for gouty tophi (DECT). 26/43 patients (60.5%) were diagnosed with gout and fulfilled the ACR/EULAR criteria. The diagnostic performance of either synovial fluid aspiration or DECT was similar with sensitivity of 58% and specificity of 100% and 94%, respectively. Combination of both modalities (at least one of them positive), resulted in increased sensitivity of 85% and unchanged specificity (94%). Based only on clinical and laboratory findings, 13/43 patients (30.2%) were classified as gout according to ACR/EULAR criteria. In scenario A, additional 8 out of 30 (26.7%) patients were diagnosed as gout by DECT findings, and another 5/22 (22.7%) patients by aspiration findings. In scenario B, initial consideration of aspiration findings resulted in 10 out of 30 (33.3%) additionally identified patients, and another 3 (15%) patients by DECT findings. There was no relevant difference between scenarios A and B (p=0.508).

CONCLUSIONS

Combination of joint aspiration and DECT improves the diagnostic algorithm for gout. In our attempt to establish an optimal sequence of diagnostic tests, we did not identify an advantage for either synovial fluid analysis or DECT as the initially better modality after clinical examination and analysis of blood tests.

Detection of uric acid crystal deposition by ultrasonography and dual-energy computed tomography: A cross-sectional study in patients with clinically diagnosed gout

The aim of our study was to compare the performance of ultrasonography (US) and dual-energy computed tomography (DECT) in detecting the crystal deposition at lower extremity joints in patients with gout. The correlation of imaging findings with microscopic findings was further assessed whenever aspiration is available.We recruited consecutive patients who were presented with arthritis of lower extremity from January 2012 to December 2014. All the patients underwent DECT and US scan of bilateral knees, ankles, and feet. Synovial fluid was obtained by aspiration from an acute inflammatory joint if possible.Finally, 60 patients fulfilling the 1977 gout classification criteria were included in our study. We found that US can detect significantly more patients with crystal deposition than DECT (81.7% vs 56.7%, by US and DECT, respectively, P < .001). The frequency of urate crystal deposition detected by US at MTP1, knee, and ankle joints regions was 56.7%, 63.3%, and 51.7%, respectively. The percentage of positivity of double contour sign on US was 33.3%, 48.3%, and 41.7% at the joints mentioned above, respectively. There was a good correlation between ultrasound and synovial fluid analysis in detecting crystal deposition (κ = 0.87, P = .001), while the agreement between DECT and synovial fluid analysis was just fair (κ = 0.28, P = .02).The sensitivity of US in detecting urate crystal deposition in lower extremity joints was higher than DECT. The superiority was more obvious in knee and MTP1 joints. US should be considered as the first choice of image examinations when diagnosing gout.

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.

Radiculopathy in a patient with chronic tophaceus gout: vertebral imaging

INTRODUCTION

Spinal involvement is infrequent in chronic gout. However, some cases of back pain with radiculopathy secondary to this etiology have been reported.

CASE REPORT

56-year old male patient, with history of arterial hypertension, hypertriglyceridemia, obesity, glucose intolerance and alcohol abuse, diagnosed with gout in his fifth decade of life. The patient was started on urate lowering therapy, with poor compliance, and evolved with sustained hyperuricemia, recurrent episodes of arthritis, and growth of gouty tophi on the elbows, wrists, hands and knees. In 2011, the patient presented with radiculopathy. When pain recurred, a Computed Tomography was performed and it showed alterations compatible with spinal tophi formation and nerve root involvement.

DISCUSSION/CONCLUSIONS

Our clinical case is another example of how gout can produce spinal inflammation and nerve damage and superimpose on previously damaged joints and how patients' compliance to therapeutics may have an important impact on prognosis.

Knee Extension Loss Secondary to a "Cyclops-Like" Gouty Tophus A Case Report and Literature Review

While gouty arthritis of the knee is not uncommon, associated mechanical block to extension is a rarely seen complication. This report presents a unique case of extension loss due to a single, isolated intra-articular gouty tophus. Only a few similar reports have been described in the literature involving cases that are often initially suspected to be related to inherent structural knee pathology as opposed to a systemic condition or illness.

Value and Progress of Ultrasound in Diagnosis and Treatment of Hyperuricemia

Uric acid is the final end-product of purine metabolism and 70% of it is excreted through the kidneys. Chronic hyperuricemia can easily cause gout and meanwhile may affect the kidneys and cardiovascular system. In recent years,the incidences of hyperuricemia and gout have gradually increased. This article summarizes the correlation of hyperuricemia with hyperuricemic nephropathy,gouty arthritis,non-alcoholic fatty liver disease,and carotid atherosclerosis and the role of color Doppler ultrasound in the diagnosis of these lesions.

Multiple Gouty Tophi with Bone Erosion and Destruction: A Report of an Early-onset Case in an Obese Patient

A 27 year-old severely obese man (BMI, 35.1) had hyperuricemia and multiple gouty tophi with bone erosion and destruction, resulting in gait disturbance for 6 years after the early onset of gout at 21 years of age. His hyperuricemia was associated with hyperinsulinemia in obesity and a genetic variant of the ABCG2 gene. In addition, multiple gouty tophi with bone erosion and destruction might have been caused by hypoadiponectinemia and the elevation of the patient' s pro-inflammatory cytokine (IL-1β) level with the accumulation of visceral fat. In this case, bone and Ga-67 scintigraphy were useful for detecting the location and magnitude of gouty tophi.

A 52-year-old man with gouty arthritis and erosive lesion in the hip

The case study of peripheral and axial gouty arthritis is described in a 52-year-old man without concomitant clinical evidence of tophaceus gout on physical evaluation on admission. Gout is a metabolic disorder related to excess of uric acid in the extracellular compartment, and deposition of monosodium urate crystals in the joints and other sites. Arthritis and tophi are major manifestations, which more often involve the peripheral joints asymmetrically. Chronic tophaceous gout commonly develops after a decade of recurrent polyarticular gout. With lower frequency, the axial skeleton (spine and sacroiliac region) may be affected, condition sometimes associated with additional concerns, diagnostic challenges and pitfalls. Higher suspicion index and utilization of novel radiographic tools can settle these matters. Radiographic imaging exams include plain radiography, computed tomography (CT), magnetic resonance imaging (MRI), and bone scintigraphy to show bone erosion and joint lesions characterizing the spectrum of gouty osteoarthropathy.

Sonographic Findings in Gouty Arthritis: Diagnostic Value and Association with Disease Duration

The objective of this work was to evaluate the sonographic features of gouty arthritis and correlate findings with disease duration. The study was conducted on 100 patients in ambulatory care aged ≥40 y. Inclusion criteria included mono- or oligo-arthritis with effusion of the knee or the first metatarsophalangeal (MTP) joint and no known history of gout. A complete medical history was obtained with emphasis on the known risk factors or causes of gouty arthritis. A 12-MHz Medison linear probe was used for ultrasonography (US). Synovial fluid analysis with polarizing light microscopy was performed on all patients. Ninety-eight knee joints and 33 first MTP joints were examined. Gouty arthritis was found by US in four forms: (i) floating echogenic foci in effusion fluid or Baker cysts, (ii) deposits on the cartilage surface (double contour sign), (iii) erosions and (iv) mature tophus/tophi. These were found in 78.9%, 42.3%, 39.4% and 28.2% of patients, respectively. The overall sensitivity and specificity of US in detecting gout (as defined by the clinical gold standard, i.e., detection of urate crystals by polarizing light microscopy) were 85.9% and 86.7%, respectively. Detection of echogenic foci in effusion fluid was associated with the shortest duration of symptoms (median duration 2 y) followed by double contour sign (3.5 y), erosions (4 y) and tophus (12.5 y). Sonographic findings in gout can be assigned a temporal pattern, with echogenic foci being associated with the shortest and full tophus formation with the longest disease duration.

Simplified Radiographic Damage Index for Affected Joints in Chronic Gouty Arthritis

The aim of this study was to develop and validate a new radiographic damage scoring method (DAmagE index of GoUt; DAEGU) in chronic gout using plain radiography. Two independent observers scored foot x-rays from 15 patients with chronic gout according to the DAEGU method and the modified Sharp/van der Heijde (SvdH) method. The 10 metatarsophalangeal (MTP) and 2 interphalangeal (IP) joints of the first toes of both feet were scored to assess the degrees of erosion and joint space narrowing (JSN). The intraobserver and interobserver reliabilities were analyzed by calculating the intraclass correlation coefficient (ICC) and minimal detectable change (MDC). The correlation between the DAEGU and SvdH methods was analyzed by calculating the Spearman's rho correlation coefficients and Kappa coefficients. The DAEGU method was found to be highly reproducible (0.945-0.987 for the intraobserver and 0.993-0.996 for the interobserver ICC values). The erosion, JSN, and total scores exhibited strong positive correlations between the DAEGU and SvdH methods and also within each method (r = 0.860-0.969, P < 0.001 for all parameters). The DAEGU and SvdH methods were in very good agreement as determined by Kappa coefficient analysis [0.732 (0.387-1.000) for erosion and 1.000 (1.000-1.000) for JSN]. In conclusion, this study revealed that DAEGU method was a reliable and feasible tool in the assessment of radiographic damage in chronic gout. The DAEGU method may provide a more easy assessment of structural damage in chronic gout in the real clinical practice.

Dual-Energy CT in Patients with Suspected Gouty Arthritis: Effects on Treatment Regimen and Clinical Outcome

RATIONALE AND OBJECTIVES

This investigation aimed to evaluate the impact on treatment regimen and clinical outcome of dual-energy computed tomography (DECT) in patients with suspected gouty arthritis.

MATERIALS AND METHODS

We retrospectively analyzed electronic medical records (EMR) of 39 patients (36 male, 3 female; age range, 36-85 years) who underwent DECT of peripheral joints because of suspected gouty arthritis. We assessed the prior medical history, lab results, treatment regimen, and medications before and after DECT, and changes in subjective severity of symptoms as stated by patients in the EMR. The presence of monosodium urate (MSU) crystals in the index joint was verified with DECT.

RESULTS

Several patients had a prior diagnosis of gout (n = 9), hyperuricemia (n = 6), rheumatoid arthritis (n = 3), or psoriatic arthritis (n = 3). Elevated uric acid blood levels were detected in 32 patients (82%) before DECT. On DECT, MSU crystals were detected in 23 patients (59%). Of the 36 cases, the current treatment regimen was modified after DECT to gout-specific therapy in 22 cases and other rheumatic diseases were targeted in 14 cases. Several medications were prescribed more frequently based after DECT compared to before DECT imaging, including steroids (n = 20 vs. n = 12, respectively), colchicine (n = 13 vs. n = 4, respectively), and urate-lowering medication (n = 18 vs. n = 11, respectively). A subjective reduction of clinical symptoms during cumulative follow-up was reported by 34 patients (87.2%).

CONCLUSIONS

Both positive and negative findings of MSU crystals on DECT have a significant impact on the treatment regimen and clinical outcome of patients with suspected gouty arthritis and facilitate differentiation from other rheumatic diseases.

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

INTRODUCTION

The performance of ultrasound (US) in the diagnosis of acute gouty (MSU) arthritis and calcium pyrophosphate (CPP) arthritis is not yet well defined. Most studies evaluated US as the basis for diagnosing crystal arthritis in already diagnosed cases of gout and few prospective studies have been performed.

METHODS

One hundred nine consecutive patients who presented an acute arthritis of suspected microcrystalline arthritis were prospectively included. All underwent an US of the symptomatic joints(s) and of knees, ankles and 1(st) metatarsopalangeal (MTP) joints by a rheumatologist "blinded" to the clinical history. 92 also had standard X-rays. Crystal identification was the gold standard.

RESULTS

Fifty-one patients had MSU, 28 CPP and 9 had both crystals by microscopic analysis. No crystals were detected in 21. One had septic arthritis. Based on US signs in the symptomatic joint, the sensitivity of US for both gout and CPP was low (60% for both). In gout, the presence of US signs in the symptomatic joint was highly predictive of the diagnosis (PPV = 92%). When US diagnosis was based on an examination of multiple joints, the sensitivity for both gout and CPP rose significantly but the specificity and the PPV decreased. In the absence of US signs in all the joints studied, CPP arthritis was unlikely (NPV = 87%) particularly in patients with no previous crisis (NPV = 94%). X-ray of the symptomatic joints was confirmed to be not useful in diagnosing gout and was equally sensitive or specific as US in CPP arthritis.

CONCLUSIONS

Arthrocenthesis remains the key investigation for the diagnosis of microcrystalline acute arthritis. Although US can help in the diagnostic process, its diagnostic performance is only moderate. US should not be limited to the symptomatic joint. Examination of multiple joints gives a better diagnostic sensitivity but lower specificity.

Animal model of acute gout reproduces the inflammatory and ultrasonographic joint changes of human gout

INTRODUCTION

Gout is an inflammatory condition induced by the deposition of monosodium urate (MSU) crystals in the joints and soft tissues that can produce acute or chronic arthritis. Several animal models of crystal-induced inflammation have been proposed that involve direct injection of MSU-crystals into different anatomical structures; however, only a few of these models reflect a true diarthrodial joint microenvironment in which an acute gouty attack takes place. The aim of this study was to assess the inflammatory and structural joint changes in a rabbit model of acute gout attack by ultrasound (US), synovial fluid (SF) and histopathological analyses.

METHODS

Under US guidance, 42 rabbit knees were randomly injected with a suspension of 50 mg/ml of either MSU or allopurinol synthetic crystals. The control group received intra-articular vehicle of phosphate-buffered saline (PBS). US evaluation, SF and histopathological analyses were performed at days 1, 3, and 7.

RESULTS

A total of 21 rabbit knees were assigned to the control group, 12 to the MSU-crystals group, and 9 to the allopurinol crystals group. By US, the MSU crystals group displayed the double contour sign and bright stippled aggregates in 67% and 75% of joints, respectively. Neither control knees nor allopurinol crystals group displayed these US signs. Power Doppler (PD) signal was moderate to intense in the MSU-crystals group and greater than both the allopurinol crystal and control groups at day 1 (P<0.001) and 3 (P<0.05), with its practical disappearance by day 7. SF leukocyte count was 40,312±6,369 cells/mm3 in the MSU-crystals group, higher than in controls (P=0.004) and allopurinol crystal group (P=0.006). At day 7, SF leukocyte count decreased in both MSU and allopurinol crystal groups reaching the non-inflammatory range. Histologically, at day 3 intense synovial polymorphonuclear cells infiltration and MSU aggregates were identified.

CONCLUSION

The rabbit model of MSU crystal-induced acute arthritis efficiently reproduces the inflammatory, US, SF and histopathological changes of the human acute gouty attack.

[Diagnostic value of ultrasound imaging in chronic gouty arthritis]

OBJECTIVE

To determine the diagnostic value of ultrasound imaging in chronic gouty arthritis.

METHODS

Ultrasound imaging of 32 patients with chronic gouty arthritis were compared with those of 36 patients with non-gouty joint diseases. A logistic model was obtained to establish the associations between ultrasound appereances and gouty arthritis. Receiver operator characteristic (ROC) curve was constructed to evaluate the performance of the logistic model.

RESULTS

A double contour sign of articular cartilage, a snowstorm appearance of the joint fluid, and a hyperecho around the periarticular tendon had diagnostic value for chronic gouty arthritis. According to the logistic regression analysis, the accuracy of predicting chronic gouty arthritis was 95.59% (65/ 68), and the area under curve of ROC was 3.987 +/- 0.011 (P < 0.05).

CONCLUSION

A double contour sign of articular cartilage, a snowstorm appearance of the joint fluid, and a hyperecho around the periarticular tendon have diagnostic value. The combination of these appearances can improve diagnosis of chronic gouty arthritis.

Pseudorheumatoid disability man with chronic tophaceous gout: a case report

Gout is a type of inflammatory arthropathy that affects the peripheral joints and results from the accumulation of monosodium urate (MSU) crystals in the synovial fluid and other tissues. This disease is the most common form of inflammatory arthritis in men over 40 years of age. The fundamental biochemical abnormality in gout is an increase in serum urate (SU) concentration. These needle-like crystals induce not only acute episodes of inflammatory process into the surrounding area, but also, in the long-term history of the disease, chronic inflammation that is associated with changes in articular and periarticular structures. The next step caused by deposited MSU crystals is represented by the tophus formation and chronic gouty synovitis. The presence of tophi has been associated with greater physical functional disability in gout patients. We presented a case of severe chronic tophaceous gout in a 48-year-old man with chronic hand arthritis and urolithiasis, to point the significance of complex assessment (clinical, functional, imagistic and histological exams) in the diagnosis of a soft tissue lesion, especially in hands.

Gouty wrist arthritis causing carpal tunnel syndrome--a case report

A 63 year old male with a history of gout and hypertension presented with carpal tunnel syndrome. He gave history of bilateral wrist pain associated with numbness over the median nerve distribution of the hand. Tinels sign and Phalens test were positive with no obvious thenar muscle wasting on examination. Tophaceous deposits in the flexor tendons and within the synovium of the wrist joint was seen during surgery and this established gout as the cause of median nerve entrapment in this patient.

[The diagnostic value of musculoskeletal ultrasound in gouty arthritis]

OBJECTIVE

To observe the characteristic features of musculoskeletal ultrasound (MSUS) in gouty arthritis (GA) and to assess its value in GA diagnosis.

METHODS

Patients with GA and non-GA who underwent MSUS examination in Chinese PLA General Hospital were enrolled in this study. The synovitis, tenosynovitis, soft tissue swelling, bone erosion, bursitis and ossification were measured by grey-scale ultrasound, and the synovial vascularity was measured by power Doppler ultrasound to evaluate the degree of inflammation.

RESULTS

The ultrasound images of GA were intended to have specific features like tophus, hyperechoic deposition on the surface of the articular hyaline cartilage (double contour sign), hyperechoic deposition in the synovium appearing as bright stippled foci, and bright strap in tendons with a significant difference when compared with non-GA group (P < 0.05). The percentage of tenosynovitis and bone erosion in non-GA group was higher than that in the GA group with a significant difference (P < 0.05). Tophus, double contour sign, bright stippled foci or bright stippled foci in tendons together suggested gout with a specificity of 92.4% and a sensitivity of 60.3%, the AUC of ROC was 0.764 (P < 0.05).

CONCLUSION

Tophus, double contour sign, bright foci and bright strap detected by MSUS are of diagnostic value on GA and MSUS may be a promising tool in diagnosing GA.

[Radiologic imaging of crystalline arthritides]

Gout is a group of diseases characterized by arthritis and is a result of urate metabolism disturbance with the deposition of monosodium urate crystals in the joint and soft tissues. Clinical manifestations include acute and chronic arthritis, tophaceous deposits, interstitial renal disease and uric acid nephrolithiasis. The diagnosis is based on the identification of uric acid crystals in joint or body fluids.

[Musculoskeletal ultrasound I - «pearls and crystals»]

This article reviews the applications of high resolution ultrasound (HRUS) which were discussed at the SGUM congress in Davos in the talk «pearls and crystals». Sonography is an excellent and validated tool in the diagnostics and assessment e.g. of spondylo-arthritis and crystal deposition diseases. Enthesitis is a typical feature of SpA. The Sensitivity of HRUS diagnosing enthesitis is higher compared to the clinical examination. High frequency US probes allow furthermore an accurate assessment in crystal deposition diseases. Sonography is able to detect various typical pathologies in gout, pseudogout and apatite deposition disease. Will HRUS in the near future be able to replace microscopy in the diagnostics of crystal deposition diseases?

Can ultrasonography make identification of asymptomatic hyperuricemic individuals at risk for developing gouty arthritis more crystal clear?

Hyperuricemia is the most important risk factor for gouty arthritis. The quandary is how to predict which patient with asymptomatic hyperuricemia will develop gouty arthritis. Can ultrasonography help identify hyperuricemic individuals at risk for developing gouty arthritis? In the previous issue of Arthritis Research & Therapy, Pineda and colleagues found ultrasonography changes suggestive of gouty arthritis in 25% of hyperuricemic individuals. These were found exclusively in hyperuricemic individuals but not in normouricemic patients. Ultrasonography may serve as a noninvasive means to diagnose gouty arthritis in hyperuricemic individuals who have yet to develop symptomatic gouty arthritis.

Wrist gouty arthritis presenting as scaphoid erosions with scapholunate ligament disruption

We report a 43-year-old man who presented with features of acute wrist inflammation with scapholunate dissociation. Radiologically, erosions were noted in the proximal pole of the scaphoid. The patient underwent wrist arthrotomy, exploration and washout with intraoperative bacterial cultures and histology specimens were obtained. Histological analysis revealed the diagnosis of gout. We discuss the clinical presentation and literature review of this topic. This case illustrates that gout may mimic infection.

Crystal-associated synovitis- ultrasonographic feature and clinical correlation

The aim of this paper is to describe the ultrasonographic findings in rheumatologic pathology due to crystal deposition. There are four main types of crystals involved: monosodium urate, calcium pyrophosphate dihydrate, basic calcium phosphate (hydroxyapatite), and calcium oxalate. In gout the joint fluid is anechoic only at the first gouty attack; afterwards the synovium begins to proliferate. Double contuour sign, a focal or diffuse enhancement of the superficial margin of the articular cartilage is a specific finding. Bursitis has chronic features from the beginning. The ultrasonographic aspect of tophi depends on their age and size (at first small, hypoechoic and homogenous nodules, then echoic with hyperechoic edges and finally pseudotumoral, inhomogeneous). The depositions in the superficial layer are hyperechoic, well delimited only in the absence of inflammatory reaction. The depositions at the entheseal level are leading to the gouty enthesopathy. In knee involvement irregularities of the anterior surface of patella are found. In chondrocalcinosis the most important ultrasonographic signs are the thin hyperechoic band, parallel to the surface of the hyaline cartilage and the punctuated pattern of the fibrocartilage. In hydroxyapatite associated disease, calcifications are frequent in the shoulder or in the great trochanter of the hip, with aspects depending of the calcification phase. Milwakee shoulder is an advanced form of this pathology, associated with rotator cuff arthropathy. Oxalate crystal deposition disease is seen rarely, in patients with primary hyperoxaluria and in patients with end-stage renal disease. Therefore ultrasonography is useful in characterize the articular and juxta-articular alterations in crystal related diseases.

“Crystal Clear”—Sonographic Assessment of Gout and Calcium Pyrophosphate Deposition Disease

OBJECTIVES

To date, high-resolution ultrasound (US) has not been fully exploited in the field of crystalline arthropathy. Both gout and calcium pyrophosphate deposition (CPPD) disease are significant diseases within the purview of the rheumatologist. The aim of this pictorial review was to present the principal findings in patients with crystal deposition in gout and CPPD.

METHODS

US pictures were obtained from 60 consecutive patients, 34 with CPPD disease and 26 with gout, whose diagnosis was confirmed by synovial fluid analysis. The US examinations were performed using the following US systems: Diasus (Dynamic Imaging, Livingstone, UK) and Logiq 9 (General Electric Medical Systems, Milwaukee, WI).

RESULTS

Pictorial evidence of the principal US findings in gout includes monosodium urate (MSU) deposition on the surface of articular cartilage, various patterns within synovial fluid ranging from completely anechoic fluid to collections filled with aggregates of variable shape and echogenicity, microdeposition within tendons, and tophus formation. In CPPD, the hallmark US features include crystal deposition within articular cartilage, calcification of fibrocartilage, together with focal crystal deposition within tendons.

CONCLUSION

US is an impressive imaging modality in crystalline arthropathy. The anatomical location of the crystal deposits, clearly depictable by US, allows differentiation between MSU and CPPD aggregates.