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OBJECTIVE The coexistence of calcium pyrophosphate dihydrate (CPPD) and monosodium urate monohydrate crystals in gouty tophi has rarely been reported. We undertook this study to investigate CPPD crystal deposits in a series of surgically removed gouty tophi and to identify factors associated with these deposits. METHODS Twenty-five tophi from 22 gout patients were analyzed using polarized light microscopy, field emission scanning electron microscopy (FESEM), and μ Fourier transform infrared (μFTIR) spectroscopy. RESULTS Tophi consisted of multiple lobules separated by fibrous septa and surrounded by a foreign-body giant cell reaction. CPPD crystal aggregates were identified in 9 of 25 tophi from 6 patients. CPPD crystals were dispersed or highly compacted, localized at the edge or inside the tophus lobules, with some lobules completely filled with crystals. Both monoclinic and triclinic CPPD crystal phases were identified using FESEM and μFTIR. Compared to patients without CPPD, those with CPPD-containing tophi were older (mean 60.5 years versus 47.2 years; P = 0.009), and had longer-term gout duration (mean 17.0 years versus mean 9.0 years; P < 0.05) and tophi duration (mean 10.0 years versus mean 4.6 years; P < 0.01). None of the patients had radiographic chondrocalcinosis of the knee or wrist. CONCLUSION CPPD crystal formation seems to be a late and frequent event of tophus maturation, occurring more frequently with aging, and could contribute to the speed of tophus dissolution and the apparent persistence of tophus sometimes observed even after effective, long-lasting urate-lowering therapy.

International audience; Objectives: To determine whether changes in ultrasonography (US) features of monosodium urate crystal deposition is associated with the number of gouty flares after stopping gout flare prophylaxis.Methods: We performed a 1-year multicentre prospective study including patients with proven gout and US features of gout. The first phase of the study was a 6-month US follow-up after starting urate-lowering therapy (ULT) with gout flare prophylaxis. After 6 months of ULT, gout flare prophylaxis was stopped, followed by a clinical follow-up (M6 to 12) and ULT was maintained. Outcomes were the proportion of relapsing patients between M6 and M12 according to changes of US features of gout and determining a threshold decrease in tophus size according to the probability of relapse.Results: We included 79 gouty patients [mean (±SD) age 61.8±14 years, 91% males, median disease duration 4 (IQR 1.5;10) years]. Among the 49 completers at M12, 23 (47%) experienced relapse. Decrease in tophus size ≥50% at M6 was more frequent without than with relapse (54% vs. 26%, P=0.049). On ROC curve analysis, a threshold decrease of 50.8% in tophus size had the best sensitivity/specificity ratio to predict relapse [AUC 0.649 (95% confidence interval 0.488; 0.809)]. Probability of relapse was increased for patients with a decrease in tophus size

BACKGROUND: Gout is a condition characterized by abnormally elevated levels of uric crystals (gouty tophi). It is often to detect in the foot and ankle. Occasionally such tophus is found at rare sites and makes a challenge to the clinician where diagnosis and treatment are concerned. CASE REPORT: We present a patient who presented to our oncology department with pain on her right hip. It was diagnosed as a benign tumor by the clinical and radiological assessment but intraoperatively turned out to be gouty tophi. Excision surgery has performed, in the 1-year follow-up; there is no relapse of pain. CONCLUSIONS: Tophaceous gout in the hip joint is a rare case, which clinical and radiology assessments can detect erroneous diagnose. Tophaceous gout in the hip joint mimicked the bone tumor characteristics. It requires a better application and diagnosed for the mimicked tophaceous gout.

Objective Dual-energy computed tomography (DECT), along with ultrasound (US), has been increasingly utilized for the diagnosis of gout because of its noninvasive advantages. However, the superiority of DECT over US remains controversial. This meta-analysis was performed to investigate whether DECT is superior to US in the diagnosis of gout. Methods A comprehensive search of PubMed, EMBASE, Cochrane, and Web of Science databases was conducted for potentially eligible articles. Studies that evaluated the utility of DECT or US for gout diagnosis were qualified. Two distinctive ultrasonographic features of gout, namely, the double contour sign and the presence of tophus, were also assessed. The methodological quality of the included studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 criteria. Besides, the subgroup analyses of early disease duration (≤ 2 years) was also performed. Results Twenty-eight studies were included in the meta-analysis. The pooled sensitivity and specificity of DECT were 0.89 (0.80–0.94) and 0.91 (0.88–0.94), respectively. The pooled sensitivity and specificity of US were 0.70 (0.58–0.79) and 0.95 (0.87–0.98), respectively, for double contour sign; 0.57 (0.38–0.74) and 0.99 (0.88–1.00), respectively, for tophus; and 0.84 (0.73–0.91) and 0.84 (0.78–0.89), respectively, for overall consideration of US signs. At the early disease duration (≤ 2 years), the pooled sensitivity and specificity were 0.75 (0.60–0.86) and 0.85 (0.75–0.91), respectively, for DECT; 0.93 (0.72–0.99) and 0.80 (0.71–0.86), respectively, for overall consideration of US signs. Conclusion DECT and US showed promising accuracy for gout diagnosis. DECT has higher sensitivity, specificity, and AUC than overall consideration of US signs and thus has a better diagnostic ability in diagnosing gout. Moreover, the diagnostic sensitivity of DECT is lower than that of overall consideration of US signs at less than 2 years’ disease duration.

Gout is currently the most frequent cause of inflammatory arthritis worldwide. It results from elevated serum urate and subsequent deposition of monosodium urate crystals in joints and other tissues. While many patients with gout can be managed with conventional agents (e.g., allopurinol, febuxostat), those with chronic refractory gout often fail to achieve treatment goals with these agents. Pegloticase is a recombinant, pegylated mammalian uricase developed for treatment of chronic refractory gout. Pegloticase is different than other urate lowering therapies in that it enzymatically degrades urate. Pegloticase has been evaluated in multiple studies, most importantly in two randomized controlled trials and a follow-up open-label extension. Extensive analysis of results from these studies has shown that pegloticase profoundly lowers serum urate, resolves tophi, reduces tender and swollen joint counts, decreases pain, and improves both patients' global assessments and quality of life. Pegloticase also significantly decreases blood pressure in patients with chronic refractory gout, but has no significant effect on renal function. Post hoc analyses of clinical results also indicated that chronic refractory gout patients not achieving sustained urate lowering still have significant clinical benefits with pegloticase treatment. The major limitation of pegloticase is immunogenicity and the emergence of anti-drug antibodies that result in increased drug clearance, loss of efficacy, and infusion reactions. However, these reactions can be avoided by stopping pegloticase when there is a loss of serum urate lowering. New dosing regimens and co-administration of immunosuppressive agents are also being employed to overcome this limitation and extend the benefits of pegloticase to a larger number of patients.

Objective: To explore the role of musculoskeletal ultrasound (MSUS) in the differential diagnosis of gouty arthritis (GA) and rheumatoid arthritis (RA) and to analyze the ultrasound imaging features of the two diseases. Methods: A retrospective study was carried out. A total of 66 patients who had been admitted to The First Medical Center of Chinese PLA General Hospital from May 2018 to March 2019 were enrolled. Among them, 34 patients were diagnosed with RA and were included in the RA group; 32 patients were diagnosed with gouty arthritis and were included in the GA group. The imaging features of musculoskeletal ultrasound were compared between the two groups of patients. Results: A total of 34 patients were included in the RA group, including 17 males and 17 females. A total of 32 patients were included in the GA group, including 14 males and 18 females. There were no significant differences in gender composition, age, and duration of disease between the two groups (P>0.05). In the RA group, there were joint bone erosions with a clear boundary in seven cases and with a blurred boundary in 27 cases; synovial hyperplasia was observed in 27 cases, and point-like hyperechoic masses were observed in four cases. In the GA group, there were joint bone erosions with a clear boundary in 27 cases and with a blurred boundary in five cases; synovial hyperplasia was observed in four cases, tophus was observed in 23 cases, point-like hyperechoic masses were observed in 27 cases, and the tram-track sign was observed in 23 cases. The differences in bone erosion boundaries (c2=26.854, P

Main Teaching Point: Dual-energy CT is a valuable asset in the detection of extra-articular manifestations of gout Extra-articular manifestations of gout are common. The Achilles tendon is a frequently affected site, and uric acid deposition may have harmful effects on tendon structure and function. Advanced imaging can aid in early diagnosis, follow-up of disease activity and therapy efficacy. This case series highlights the use of dual-energy CT as a tool in diagnosing gout and in detecting extra-articular manifestations.

Background Gout is a heterogeneous inflammatory disease with numerous clinical manifestations. A composite means to assess the impact of therapy on numerous aspects of gout could be useful. Methods Results from patients treated with pegloticase or placebo in two randomized clinical trials and their open-label extension were assessed using a novel evidence-based Gout Multivariable Improvement Measure (GMIM) derived from previously reported criteria for remission and complete response. Improvement was defined as serum urate (sU) Results Patients treated with pegloticase manifested a significantly greater GMIM20, 50, and 70 response vs those treated with placebo (GMIM20 at 6 months 37.1% vs 0%, respectively). Higher response rates were significantly more frequent in subjects with persistent urate lowering (GMIM 58.1% at 6 months) in response to pegloticase versus those with only transient urate lowering (GMIM 7.1% at 6 months). However, when the requirement for a decrease in sU to Conclusions GMIM captures changes in disease activity in response to treatment with pegloticase and may serve as an evidence-based tool for assessment of responses to other urate-lowering therapies in gout patients.

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

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

Objective To evaluate ultrasound for diagnosing gout using consensus-based Outcome Measures in Rheumatology ultrasound definitions of gout lesions. Methods Ultrasound was performed in patients with clinically suspected gout. Joints (28) and tendons (26) were binarily evaluated for the Outcome Measures in Rheumatology gout lesions—double contour (DC), tophus, aggregates and erosions. Ultrasound assessment was compared with two reference standards: (i) presence of MSU crystals in joint/tophus aspirate (primary outcome) and (ii) ACR/EULAR 2015 gout classification criteria (secondary outcome). Both reference standards were evaluated by rheumatologists blinded to ultrasound findings. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value of each ultrasound lesion against both reference standards were determined. Results Eighty-two patients (70 men), mean age 62.4 (range 19–88) years, were included. Fifty-seven patients were MSU-positive whereas 25 patients were MSU-negative (no MSU crystals: 23; aspiration unsuccessful: 2). Of these 25 patients, three patients were classified as ACR/EULAR-positive (i.e. totally 60 ACR/EULAR-positive patients). All ultrasound lesions had high sensitivities for gout (0.77–0.95). DC and tophus showed high specificities (0.88–0.95), positive predictive values (0.94–0.98) and accuracies (0.82–0.84) when both reference standards were used. In contrast, low specificities were found for aggregates and erosions (0.32–0.59). Ultrasound of MTP joints for DC or tophus, knee joint for DC and peroneus tendons for tophus was sufficient to identify all MSU-positive patients with ultrasound signs of gout at any location. Conclusion Ultrasound-visualized DC and tophus, as defined by the Outcome Measures in Rheumatology ultrasound group, show high specificities, positive predictive values and accuracies for diagnosing gout and are therefore valid tools in clinical practice.

Background: Gout is a modern-day chronic disease seen in 4·62% of Taiwan’s general population. Although the current treatment of urate lowering therapy (ULT) is effective, there remains 10% of patients who do not response well for this treatment. This paper reviews the effectiveness of the shaver technique, which not only increases efficacy when coupled with ULT but can also be used individually to treat the 10% subset that suffer from chronic tophaceous lesions. Method: Using PubMed, all available series of surgery for tophaceous gout were reviewed. Statistical analysis was performed on our surgical outcomes of patients treated by the shaver technique over a sixteen-year (2002 to 2018) period. Finding: The key to shaver technique is early intervention to prevent joint function deterioration. Statistical analysis showed that infection and surgery sites directly correlate to the prognosis of gout patients. Moreover, 6 published surgical articles were identified. All 6 articles were published between 2009 and 2019. The reported outcome of surgical intervention for gout was positive with satisfactory cosmetic outcome and faster recovery period. Interpretation: Although ULT is currently used as the first-line approach to tophaceous gout, we believe the shaver technique should be implemented at the early phase of tophaceous gout lesions, thereby preventing excessive damage in the joints, but also the complication of the shaver technique is minor compared to other available surgical options. Funding: This study was authors’ own work. Declaration of Interests: No conflicts of interests to be disclosed. Ethics Approval Statement: The study was approved by Institutional Review Board at Kaohsiung Medical University.

Gout is a systemic metabolic disorder characterized by hyperuricemia and deposition of monosodium urate crystals in joints and other extra-articular tissues. Poorly controlled cases progress to chronic gout with tophi, which can sometimes assume massive sizes. We report one such case of a 39-year-old male with poorly controlled polyarticular tophaceous gout presenting with a massive swelling of the left elbow simulating a soft tissue tumor. Subsequent investigations confirmed it to be a massive tophus which was then surgically excised, as the mass was not responding to the medical management. At the latest follow-up after two years, the patient has full function of the elbow and gout is well controlled with medications.

ObjectivesTo evaluate the sensitivity to change of ultrasound structural gout lesions, as defined by the Outcome Measures in Rheumatology (OMERACT) ultrasound group, in patients with gout during urate-lowering therapy (ULT).MethodsUltrasound (28 joints, 26 tendons) was performed in patients with microscopically verified gout initiating or increasing ULT and repeated after 3 and 6 months. Joints and tendons were evaluated by ultrasound for presence of the OMERACT structural gout lesions—double contour sign (DC), tophus, aggregates and erosion—scored binarily. A sum score was calculated at patient and lesion level. Changes at 3 and 6 months in patient sum scores and lesion scores at different locations were evaluated.Results50 patients (48 men), mean age 68.9 (range, 30–88) years, were included. Ultrasound showed a statistically significant decrease in DC and tophus sum scores from 0 months (3.16 and 2.68, respectively) to 3 months (2.33 and 2.43) and 6 months (1.34 and 1.83) (all p1 lesions bilaterally), and furthermore MTP2–4 and knee joints were common sites especially for DC. Likewise, these regions were the locations with most pronounced changes in scores.ConclusionUltrasound assessment of the OMERACT structural gout lesions scored binarily seems to be a useful tool for monitoring urate depositions during ULT. Particularly DC and tophus showed sensitivity to change after only 3 months of treatment.

The objective: to study and systematize own clinical observations and management of gout cases and atypical gout manifestations and literature data on this item. Clarification of main characteristics of atypical manifestations of this pathological condition. Scientific and practical base of the investigation was Kiev City Clinical Hospital № 8, which admits patients by the reference of primary care physicians in general practice – family medicine. Clinically gout is preferably a male disease. The condition is more often seen in men, than in women, but in women it is more obvious in postmenopausal period. Women with gout are more proun to have atypical manifestation (for example, disease on fingers and ankle joint), which becomes at atypical age, making efficiency of treatment problematic because of coexisting comorbidities. Gout is a common and exclusively painful form of inflammatory arthritis, which typically involves first metatarsophalangeal joint (and terminologically this is gout). Atypical signs of the gout are described now with increasing rate in definite populational groups, such as elder people, people with genetic predispositions, enzyme deficiencies, prosthetic implants and those receiving immunosuppressive therapy. Gout can mimic other conditions, such as septic arthritis, osrteoarthritis, rheumatoid arthritis, pseudogout (accumulation of calcium pyrophosphates) and even periarticular tumors. Gout can coexist with other arthropaties, making diagnosis more difficult. Article contains the description of authors own observations of patient with multiple gout atypical manifestations during 35 years. Lower extremities were not involved in the process for a long period of time, and only near 2,5-3 last years patient noted, that tophuses start to appear ass well on both legs. Atypical features differ from “classical” gout, which is found in men of middle age with different aspects: there is no prevalence of men, but there is more uniform gender distribution, polyarthicular involvement with upper extremity, less of acute gout episodes, not intensive clinical picture and increase rate of tophuses formation.

Gout is a condition that commonly affects the foot and ankle, and practitioners who treat these structures should be aware of the methods to diagnose and treat this form of arthritis. Practitioners also need to recognize extra-articular manifestations of the disease. Although the acutely red, hot, swollen joint is a common presentation, chronic tophaceous gout can be associated with pain, nodule formation, and cutaneous compromise. Since the underlying causes that lead to excessive monosodium urate deposition may be treatable, early and accurate diagnosis can be very beneficial and may even prevent articular degeneration.

Up to 90% of gout patients experience low uric acid (UA) excretion rather than high UA production. The selective UA reabsorption inhibitor lesinurad (Zurampic®) is an effective and generally well tolerated option for the adjunctive treatment of hyperuricaemia in patients with gout who have not achieved target serum uric acid (sUA) levels with monotherapy with an adequate dosage of a xanthine oxidase inhibitor, a class of drugs that acts on UA production. In phase 3 trials of lesinurad + allopurinol in adults with gout inadequately responsive to allopurinol, and lesinurad + febuxostat in adults with tophaceous gout, the addition of once-daily oral lesinurad enabled many patients to achieve target sUA levels, and improved clinical parameters (e.g. tophus number/size) in the long term.

Introduction: Febuxostat is a potent non-purine selective xanthine oxidase inhibitor approved by the FDA in 2009 for management of hyperuricemia in people with gout.Areas covered: The authors summarize the pre-clinical studies and pivotal randomized controlled trials of febuxostat when used as a treatment for hyperuricaemia in goutExpert opinion: Febuxostat has clinical efficacy in serum urate lowering, and long-term use leads to improved outcomes such as gout flare frequency and tophus burden. Recently published post-approval placebo-controlled trials have demonstrated urate-lowering efficacy and safety of febuxostat in patients with chronic kidney disease, and reduced frequency of gout flares in people with early onset of gout. In November 2017, the FDA issued a drug safety communication based on the preliminary results of the CARES trial. This cardiovascular safety study of 6190 patients with gout and established cardiovascular disease comparing febuxostat and allopurinol showed no difference in the primary endpoint (a composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or unstable angina with urgent revascularization), but did report higher all-cause mortality (hazard ratio 1.22) and cardiovascular mortality (hazard ratio 1.34) with febuxostat. Based on currently available data, it seems likely that allopurinol, rather than febuxostat, will remain first line urate-lowering therapy for people with gout.

Objective To improve neurologists’ awareness of spine gout by showing a rare case of tophaceous gout in thoracic spine and a summary of vertebral gout in order. Material and methods We reported a case of a 36-year-old male with a 2-year-history of hyperuricemia. Neurological examination suggested that the strength of his lower limbs decreased. Bilateral Babinski's sign and ankle clonus were positive. He had no bladder or bowel dysfunction. Computed tomography of the thoracic spine showed occupied lesions at the T9, T10 levels which led to the spinal stenosis. Magnetic resonance imaging of the thoracic spine revealed epidural disease at T9, T10 levels. A resection of the occupying lesion in the thoracic spinal canal was performed, tophaceous gout was diagnosed by the pathological examination. We also provide a brief review of literature on 30 cases of spine tophaceous gout. Result Spinal tophaceous gout is rare, gout can involved in any spine level, but the probability of occurrence of thoracic spine is the least. Most patients had a history of hyperuricemia or peripheral tophus, the most common symptoms are back pain, when the pain stone compression spinal cord or nerve root, there will be the corresponding neurological symptoms or signs. Conclusions The spinal gout should be considered when a patient has chronic or acute back pain and/or neurological symptoms, with mass on sides of the vertebras on MRI, especially when the patient has a history of hyperuricemia, the pathology examination can confirm the diagnosis.

The foot and ankle are frequently affected in tophaceous gout, yet kinematic and kinetic changes in this region during gait are unknown. The aim of the study was to evaluate ankle biomechanical characteristics in people with tophaceous gout using three-dimensional gait analysis.Twenty-four participants with tophaceous gout were compared with 24 age-and sex-matched control participants. A 9-camera motion analysis system and two floor-mounted force plates were used to calculate kinematic and kinetic parameters.Peak ankle joint angular velocity was significantly decreased in participants with gout (P 0.01). No differences were found for ankle ROM in either the sagittal (P = 0.43) or frontal planes (P = 0.08). No differences were observed between groups for peak ankle joint power (P = 0.41), peak ankle joint force (P = 0.25), peak ankle joint moment (P = 0.16), timing for peak ankle joint force (P = 0.81), or timing for peak ankle joint moment (P = 0.16).Three dimensional gait analysis demonstrated that ankle joint function does not change in people with gout. People with gout demonstrated a reduced peak ankle joint angular velocity which may reflect gait-limiting factors and adaptations from the high levels of foot pain, impairment and disability experienced by this population.

Gout is a disabling and common arthritis with increasing prevalence. Without treatment the disease can cause permanent joint damage. It is commonly associated with the metabolic syndrome but can also be related to a number of life-threatening diseases and their treatments. Gout is often misdiagnosed and its long-term management is suboptimal despite the availability of effective treatments. Recently The American College of Rheumatology (ACR) and European League against Rheumatism (EULAR) released common guidelines for the diagnosis of gout and EULAR updated their guidelines for management. There is increased emphasis on preventive treatment, both with lifestyle modifications and pharmacotherapy. It is important to educate patients about the disease and the existence of effective treatment options, how to manage an acutely inflamed joint and why it is important to lower serum urate. When a patient is diagnosed with gout he should be screened for associated comorbidities. It is important to treat-to-target and lower serum urate over a long period of time to induce permanent remission of gouty arthritis.

Objective This study aimed to evaluate the diagnostic performance of ultrasound (US) for patients with gout. Methods We searched the Medline, Embase, Pubmed, and Cochrane Library databases, and performed a meta-analysis of the diagnostic accuracy of US according to the double contour sign, tophus, snowstorm, or bony erosion in patients with gout. Results In total, 11 studies including 938 patients with gout, and 788 controls (patients with nongout inflammatory arthritis) were available for the meta-analysis. The pooled sensitivity and specificity of US were 65.1% ([95% confidence interval (CI): 62.0–68.2] and 89.0% (96.6–91.1), respectively. The positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 5.889 (3.365–10.30), 0.359 (0.266–0.485), and 17.61 (11.11–17.92), respectively. The area under the curve of US was 0.858 and the Q ⁎ index was 0.789, indicating good diagnostic accuracy. Some between-study heterogeneity was found in the meta-analyses. Meta-regression showed that the sample size, study design, and diagnostic criteria were not sources of heterogeneity, and subgroup meta-analyses did not change the overall diagnostic accuracy. US signs of tophus, snowstorm, or bony erosion besides the double contour sign were not sensitive (54.3%, 30.8%, and 51.6%), but specific (93.2%, 90.6%, and 93.3%) enough as a diagnostic tool. Conclusions Our meta-analysis of published studies demonstrates that US offers good diagnostic accuracy with high specificity and can play an important role in the diagnosis of gout.

The paper describes a rare case of thoracic spine involvement in a 28-year-old patient with gout that was manifested by acute neurologic symptoms (lower extremity paresis with pelvic organ dysfunction) and that required emergency surgery. Similar cases that are previously described, including the possible variants of the clinical manifestations, tophus localization, surgical treatment, risk factors for axial tophus formation, are separately discussed.