Tophi and carotid atherosclerosis in gout patients: Role of insulin resistance

BACKGROUND AND AIM

Gout and cardiovascular disease are closely related, but the mechanism linking them is still unknown. Gout may affect the insulin signaling pathway inducing insulin resistance (IR). The study aims to evaluate the association between tophi and carotid atherosclerosis, considering the potential role of IR.

METHODS AND RESULTS

A total of 595 patients with gout aged 18 to 80 were enrolled in this study. Carotid intima-media thickness, plaques and tophi were evaluated by B-mode ultrasonography. IR was assessed by the HOMA index (hepatic IR) and Gutt index (peripheral IR). Multivariable logistic regression and interaction analysis were used to examine the association between tophi and IR and its impact on carotid atherosclerosis. Among these participants, the average age was 55.4 (±12.54) years, and 94.6 % were male. Tophi were associated with increased odds of carotid atherosclerosis and burden after adjustment for confounders (P < 0.05). Tophi and IR synergically interacted for inducing carotid atherosclerosis. The interaction between peripheral IR with tophi was more pronounced than hepatic IR with tophi.

CONCLUSIONS

Tophi were independently associated with carotid atherosclerosis risk. IR mediated a significant amount of the effect of tophi on the development of carotid atherosclerosis. Peripheral IR probably plays a more important role than hepatic IR does.

Clinical characteristics and risk factors associated with bone erosion in patients with tophi

INTRODUCTION

If a large amount of urate crystals is deposited in a joint cavity for an extended period of time, bone erosion will occur and gradually cause skeletal muscle necrosis and joint deformity. The aim of this study was to describe the clinical characteristics and factors associated with bone erosion in gout patients with tophi.

METHODS

A total of 210 gout patients with tophi were enrolled and divided into a bone erosion group (n = 135) and a non-bone erosion group (n = 75). Digital radiography (DR) was performed to detect bone erosion in the elbow, wrist, knee, ankle joints, interphalangeal and metatarsophalangeal joints. The clinical characteristics were recorded and compared between the two groups. Multivariate logistic regression analysis was conducted to explore the factors associated with bone erosion.

RESULTS

Compared with the non-bone erosion group, the bone erosion group had an older age, longer disease duration of gout and tophi, higher level of serum creatinine (sCr), higher proportion of drinking history and ulceration, and a lower glomerular filtration rate (GFR). Univariate logistic regression analysis results showed that sex, age, body mass index (BMI), gout duration, tophi duration, GFR, white blood cell (WBC) count, sCr level, smoking history, drinking history, and presence of ulceration were associated with bone destruction. Multivariable logistic regression analysis results indicated that tophi duration, drinking history, ulceration and sCr were positively and independently related to bone erosion.

CONCLUSIONS

Tophi patients with bone erosion presented different clinical characteristics. Tophi duration, drinking history, ulceration and sCr were associated with bone erosion in gout patients with tophi.

Patient characteristics, surgical treatment, and outcomes in spinal gout: a systematic review of 315 cases

PURPOSE

To systematically investigate all published literature on spinal gout regarding location demographics, patient characteristics, treatment, and outcomes.

METHODS

We performed a systematic literature search of Medline and EMBASE from inception until April 15, 2023. Two investigators performed data extraction and quality assessment of location demographics and patient characteristics and outcomes of all article types describing spinal gout.

RESULTS

A total of 214 articles (204 case reports and 10 case series) were included, encompassing 315 subjects with spinal gout (81% male, mean age 58.1 years; range: 16-92). Most cases (36%) were between the age of 60-69 years. We observed an increase in publications and cases from 1950 to the present. Most patients were from institutions in Asia (n = 119, 37.8%) and North America (n = 96, 30.5%). Reported symptoms frequently included back pain (75%), radiating pain to extremities (27.3%), and weakness in the extremities (26.3%). The lumbar spine was most often affected. Pharmacological treatment was described for 108 (34.2%) patients. Surgery was performed for 146 (46.3%) of patients, of which 4.8% had postoperative complications. Three patients (2%) required secondary surgery for recurrence.

CONCLUSION

Published cases of spinal gout have increased over the last decades. Patient characteristics of spinal gout were similar to findings in systemic gout. Trends identified in patient characteristics and treatment outcomes may help guide patient management and improve our understanding of spinal gout.

Case of lumbar spinal stenosis and chronic tophaceous gout

Background

Rarely, chronic tophaceous gout can result in lumbar spinal stenosis and neural compression.

Case Description

A 67-year-old male presented with the radiographic and magnetic resonance findings of gout involving and causing compression of the lumbar spine that responded to surgical decompression.

Conclusion

It is difficult to diagnose lumbar spinal stenosis secondary to tophaceous gout. Notably, the treatment, based on the clinical presentation, may include both medication and surgical decompression.

WHEN TOPHACEOUS GOUT INVOLVES MULTIPLE ORGANS: CHALLENGES AND SOLUTIONS

Uncontrolled chronic gout can lead to deposition of monosodium urate crystals, better known as tophi. Such depositions can involve several organ systems, including unusual locations such as the vertebrae. Nevertheless, certain complications, such as hypercalcemia, can arise because of tophi. Despite an aggressive intervention, hypercalcemia might not resolve spontaneously, as long as an ongoing inflammatory process secondary to gouty tophi is taking place. Herein, we present the case of a 62-year-old man with a long history of gouty tophi who presented for back pain and was found to have spinal cord involvement with PTH-independent hypercalcemia which only resolved with pegloticase therapy.

Palpable tophi and more comorbidities associated with adherence to urate-lowering medical therapy in a Chinese gout cohort

OBJECTIVE

Urate-lowering therapy (ULT) nonadherence is common and problematic in gout. Since, sociocultural factors affect adherence, we analyzed a Chinese cohort.

METHODS

We studied 903 Chinese gout patients aged 46.4±14.7 years (mean±SD), uniquely extending to assay of 2-year medication possession ratio (MPR) ≥80% defined as high adherence. Multivariable logistic regression analyses evaluated factors linked with adherence and ULT target attainment.

RESULTS

Characterization of ULT outcomes in this cohort revealed that after 2 years ULT, MPR ≥80% patients had better target serum urate (SU) achievement (from 23.3% to 71.0%, P <0.001), lower flare frequency and palpable tophi compared to MPR <80%. However, only 44.7% of cohort subjects had MPR ≥80%. Male sex (OR 3.68), gout onset age >60 years (OR 3.51), disease duration >5 years (OR 1.70), more comorbidities (OR 1.74), baseline palpable tophi (OR 1.53), SU <6mg/dL (360μmol/L) (OR 1.92) and more frequent follow-up visits (OR 1.98) were significantly associated with high adherence. Nevertheless, significant independent risk factors for failed SU target achievement included male sex (OR 0.36) and more comorbidities (OR 0.85).

CONCLUSION

Despite adherence to ULT linked to better outcomes for flares and tophi, the more adherent Chinese male patients and those with more comorbidities had decreased target SU attainment. Differences in adherence of Chinese gout patients compared to several primarily Western studies emphasize the importance of not stereotyping gout patients for projected nonadherence. Results underline the dual importance of identifying gout patients more likely to be ULT-adherent and leveraging adherence to drive treatment to SU target.

A multicentre, efficacy and safety study of methotrexate to increase response rates in patients with uncontrolled gout receiving pegloticase (MIRROR): 12-month efficacy, safety, immunogenicity, and pharmacokinetic findings during long-term extension of an open-label study

Background

Publications suggest immunomodulation co-therapy improves responder rates in uncontrolled/refractory gout patients undergoing pegloticase treatment. The MIRROR open-label trial showed a 6-month pegloticase + methotrexate co-therapy responder rate of 79%, compared to an established 42% pegloticase monotherapy responder rate. Longer-term efficacy/safety data are presented here.

Methods

Uncontrolled gout patients (serum urate [SU] ≥ 6 mg/dL and SU ≥ 6 mg/dL despite urate-lowering therapy [ULT], ULT intolerance, or functionally-limiting tophi) were included. Patients with immunocompromised status, G6PD deficiency, severe kidney disease, or methotrexate contraindication were excluded. Oral methotrexate (15 mg/week) and folic acid (1 mg/day) were administered 4 weeks before and during pegloticase therapy. Twelve-month responder rate (SU < 6 mg/dL for ≥ 80% during month 12), 52-week change from baseline in SU, and extended safety were examined. Efficacy analyses were performed for patients receiving ≥ 1 pegloticase infusion. Pharmacokinetics (PK)/anti-drug antibodies (ADAs) were examined and related to efficacy/safety findings.

Results

Fourteen patients were included (all male, 49.3 ± 8.7 years, 13.8 ± 7.4-year gout history, pre-therapy SU 9.2 ± 2.5 mg/dL). Three patients were non-responders and discontinued study treatment before 24 weeks, one patient exited the study per protocol at 24 weeks (enrolled prior to treatment extension amendment), and 10 remained in the study through week 52. Of the 10, 8 completed 52 weeks of pegloticase + methotrexate and were 12-month responders. The remaining two discontinued pegloticase + methotrexate at week 24 (met treatment goals) and stayed in the study under observation (allopurinol prescribed at physicians’ discretion); one remained a responder at 12 months. At 52 weeks, change from baseline in SU was − 8.2 ± 4.1 mg/dL (SU 1.1 ± 2.4 mg/dL, n = 10). Gout flares were common early in treatment but progressively decreased while on therapy (weeks 1–12, 13/14 [92.9%]; weeks 36–52, 2/8 [25.0%]). One patient recovered from sepsis (serious AE). Two non-responders developed high ADA titers; fewer patients had trough concentrations (C_min) below the quantitation limit (BQL), and the median C_min was higher (1.03 µg/mL vs. BQL) than pegloticase monotherapy trials.

Conclusions

Pegloticase + methotrexate co-therapy was well-tolerated over 12 months, with sustained SU lowering, progressive gout flare reduction, and no new safety concerns. Antibody/PK findings suggest methotrexate attenuates ADA formation, coincident with higher treatment response rates.

Trial registration

ClinicalTrials.gov, NCT03635957. Registered on 17 August 2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02865-z.

Simple metabolic markers associated with tophaceous gout

INTRODUCTION

The relationship between tophaceous gout and metabolic markers is not well understood. The aim of this study was to compare the correlations between different metabolic markers and tophi and evaluate their potential predictive values for tophus.

METHOD

We analysed the data of gout patients in Beijing Jishuitan Hospital from 2013 to 2020. Ten laboratory indicators (UA, eGFR, underexcretion, GLU, TRIG, HDL-C, ALT, TBIL, γ-GT and UPH) were included to evaluate the relationship between tophaceous gout and metabolic markers.

RESULTS

Tophi was present in 14.7% (119/808) of gout patients. UA, eGFR, ALT and γ-GT were independently related to the development of tophi; UA and γ-GT were positively correlated. The γ-GT/ALT ratio and UA/eGFR ratio showed a positive correlation with tophi, with (rho, P) of (0.305, < 0.001) and (0.195, < 0.001), respectively. The γ-GT/ALT ratio showed the best classificatory performance (AUC = 0.749, P < 0.001) for tophi among the four positive correlation indicators. With increasing integer γ-GT/ALT ratio, the incidence of tophi (4.9%, 9.7%, 22.3% and 38.4%, P < 0.001), chronic kidney disease (2.5%, 5.2%, 12.3% and 19.2%, P < 0.001) and hyperuricemia over 10 years (6.6%, 10.7%, 18.5% and 26.4%, P < 0.001) showed a progressive increase. The γ-GT/ALT ratio was positively correlated with the number of tophi and duration of hyperuricemia, negatively correlated with eGFR.

CONCLUSIONS

UA, eGFR, γ-GT and ALT were independently associated with tophi. The γ-GT/ALT ratio may be used as a predictor or monitor of tophi.

Gouty Involvement of Foot and Ankle: Beyond Flares

The foot and ankle are common locations of deposition of monosodium urate (MSU) crystals, as indicated by the clinical manifestations presented by patients with gout, which are not limited to the acute inflammation of the big toe. We present a narrative literature review aimed to update the gout involvement of foot and ankle and how it affects the quality of life. Cumulative reports indicate that gout, even at the non-tophaceous stage, could cause pain, gait impairment and limit the mobility at lower limbs. These patients may present difficulties in some activities of daily living such as choosing footwear, thus leading to an impaired quality of life. Gout is a curable disease by dissolving MSU crystals but remains unclear how this could modify some of these foot and ankle manifestations, especially when structural damage has already occurred. Furthermore, a collaboration between rheumatologists and podiatrists seems helpful to understand, relieve these symptoms and improve the quality of life in gouty patients.

Osteochondral lesion of talus with gout tophi deposition: A case report

BACKGROUND

Osteochondral lesion of talus is a broad term used to describe an injury or abnormality of the talar articular cartilage and adjacent bone. It arises from diverse causes, and although trauma is implicated in many cases, it does not account for the etiology of every lesion. Gout is a chronic arthritic disease caused by excess levels of uric acid in blood. Intraosseous deposition of monosodium urate in the clavicle, femur, patella and calcaneus was reported previously. Gout is common disease but rare at a young age, especially during teenage years. Osteochondral lesion caused by intra-articular gouty invasion is very rare.

CASE SUMMARY

We encountered a rare case of a 16-year-old male who has osteochondral lesion of the talus (OLT) with gout. He had fluctuating pain for more than 2 years. We could see intra-articular tophi with magnetic resonance image (MRI) and arthroscopy. We performed arthroscopic exploration, debridement and microfracture. Symptoms were resolved after operation, and bony coverage at the lesion was seen on postoperative images. We had checked image and uric acid levels for 18 mo.

CONCLUSION

It is rare to see OLT with gouty tophi in young adults. While it is challenging, the accuracy of diagnosis can be improved through history taking, MRI and arthroscopy.

Risk factors of ultrasound-detected tophi in patients with gout

INTRODUCTION

Tophus is a characteristic manifestation of advanced gout, the clinical significance of which is often underestimated. This study aimed to compare the difference of clinical and ultrasound features between gout patients with and without ultrasound-detected tophus and identify risk factors associated with the presence of ultrasonographic tophus in gout patients.

MATERIALS AND METHODS

A total of 85 gout patients were divided into tophaceous (n = 54) and non-tophaceous group (n = 31) according to the presence of ultrasound-detected tophus. All patients underwent ultrasound examination of the bilateral knee, ankle, and first metatarsophalangeal joint (MTP1). Clinical information and ultrasound findings were compared between the groups. A multivariate logistic regression analysis to determine possible risk factors is associated with the number of ultrasound-detected tophaceous joints.

RESULTS

Older age, longer gout duration, higher gout flare frequency, lower estimated glomerular filtration rate (eGFR), and higher prevalence of hypertension, hyperlipidemia, and ultrasound manifestations including double contour sign (DCS) and erosion were observed in tophaceous patients from the univariate analysis. Multivariable logistic regression analysis showed that eGFR and disease duration were independently associated with the number of tophaceous joints. Lower eGFR and longer course duration were associated with a higher risk of tophi (B = -0.020, 0.141; P = 0.009, 0.010, respectively).

CONCLUSIONS

The main factors that may influence the formation of tophi are disease duration and eGFR.Key Points• Lower eGFR and longer course duration are independent risk factors of tophi formation in gout patients.• The incidence of ultrasound manifestations including double contour sign (DCS) and erosion in patients with tophi were higher than those without tophi.

[Lesion clearance combined with Ilizarov technique for treatment of tophi in first metatarsophalangeal joint with bone defect]

Objective

To evaluate the effectiveness of lesion clearance combined with Ilizarov technique for the treatment of tophi in first metatarsophalangeal (MTP) joint with bone defect.

Methods

Between July 2016 and June 2018, 14 cases of tophi in the first MTP joint with bone defect were treated by lesion clearance combined with Ilizarov technique. There were 12 males and 2 females. The average age was 39.3 years (range, 22-60 years). The disease duration ranged from 5 to 15 years, with an average of 11.2 years. The tophi volume ranged from 2.5 cm×2.7 cm×2.2 cm to 5.2 cm×2.9 cm×2.4 cm. The X-ray films showed that the length of the bone defect ranged from 2.0 to 4.6 cm, with an average of 3.4 cm. Preoperative visual analogue scale (VAS) score was 7.6±0.9; American Orthopaedic Foot and Ankle Society (AOFAS) score was 47.5±4.3; short-form 36 health survey scale (SF-36) score was 79.7±4.7.

Results

The incision primarily healed in 13 patients after operation. The skin necrosis at the edge of the incision occurred in 1 patient and recovered after symptomatic treatment. All 14 patients were followed up 12-16 months, with an average of 13.6 months. X-ray films showed that the first metatarsal column defects were repaired. The time of bone extension ranged from 2 to 6 weeks, with an average of 3.6 weeks. The time of bone healing ranged from 9 to 16 weeks, with an average of 11.2 weeks. During follow-up, no complication such as nerve, blood vessel, or tendon injury, needle tract infection, or stress fracture occurred. At last follow-up, VAS score was 1.4±0.5, AOFAS score was 86.6±4.8, and SF-36 score was 89.1±3.3, all of which were superior to preoperative scores, with significant differences ( t=22.532, P=0.000; t=22.702, P=0.000; t=6.124, P=0.000).

Conclusion

Lesion clearance combined with Ilizarov technique is a safe and effective method for the treatment of tophi in the first MTP joint with bone defect.

Multilevel Lumbar Stenosis Caused by Large Tophi Involving Both Spinal Canal and Posterior Spinal Elements: A Rare Case Report and Literature Review

Tophus is a characteristic manifestation of gout entering the chronic phase, which usually deposits in the joints of the extremities, skin mucosa, etc. A gout tophus that involves the spine causing spinal stenosis is rare and it can be misdiagnosed as a spinal tumor preoperatively. We report the case of a 35-year-old man who presented with lumbar stenosis symptoms, and suffered multiple-site gout tophi involvement throughout his body. Radiographic examinations showed that the large tophi infiltrated the posterior elements of the spine and encroached the lumbar spinal canal, resulting in neurologic compression from the second to the fifth lumbar level. Urate could be observed on a dual-energy computed tomography. A posterior-based procedure was performed to eradicate the tophi and stabilize the spine. Finally, urate crystal was confirmed by postoperative pathological examination. Here, the clinical manifestations, radiological, pathological and surgical features for this case are reported.

Risk factors for the formation of double-contour sign and tophi in gout

Background

This study aimed to confirm the diagnostic accuracy of ultrasound (US) on gout and explore the potential risk factors for double-contour sign and tophi formation in gout patients.

Methods

The US analyses were performed on all knee, ankle, and first metatarsophalangeal (MTP 1) joints to reveal the type and location of lesions. While a questionnaire and blood biochemical index were used to explore the potential risk factors for double-contour sign and tophi in gout, the SPSS17.0 software was used for statistical analysis in the present study.

Results

Totally, 117 gout patients with 702 joints (38 lesions in knee joint, 93 lesions in ankle joint, and 112 lesions in MTP 1 joint) were enrolled in current analyses. Double-contour sign and joint effusion were the two most outstanding lesion manifestations in knee joints and ankle joints. Tophi and double-contour sign were the two most outstanding lesion manifestations in TMP 1 joints. Moreover, factors including uric acid (UA) level and the highest blood UA were potential risk factors of the double-contour sign, while age and history of US were potential risk factors for tophi.

Conclusion

US was effective on the joints of gout patients. There was US sensitivity for tophi and double-contour sign in MTP 1 joints. The double-contour sign was a potential specific manifestation in knee joints and ankle joints. Furthermore, UA and highest blood UA level were potential risk factors for double-contour sign, while age and US history were potential risk factors for tophi.

Potential Dangers of Serum Urate-Lowering Therapy

In observational studies, high serum urate levels are associated with adverse outcomes, including mortality. However, the hypothesis that urate-lowering may improve nongout outcomes has not been confirmed by placebo-controlled clinical trials. On the contrary, 7 recent placebo-controlled trials of urate-lowering drugs with different mechanisms of action (uricosuric: lesinurad; xanthine oxidase inhibition: febuxostat; uricase: pegloticase) have observed higher mortality or trends to higher mortality in gout patients, with the largest decreases in serum urate. Because all urate-lowering mechanisms were implicated, this raises safety concerns about urate-lowering itself. Far from unexpected, the higher mortality associated with more intense urate-lowering is in line with the U-shaped association of urate with mortality in some observational studies. Urate accounts for most of the antioxidant capacity of plasma, and strategies to increase urate are undergoing clinical trials in neurological disease. Post hoc analysis of recent trials should explore whether the magnitude of urate-lowering is associated with adverse outcomes, and safety trials are needed before guidelines recommend lowering serum urate below certain thresholds.

Risk factors for ulceration over tophi in patients with gout

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

Clinically-evident tophi are associated with reduced muscle force in the foot and ankle in people with gout: a cross-sectional study

Background

The foot and ankle represent a common site for tophi in people with gout, yet it is unclear whether the presence of tophi is related to impaired muscle function. This study aimed to determine the association between foot and ankle tophi and muscle force in people with gout.

Methods

Participants with gout were stratified into two groups based on the presence of clinically-evident tophi affecting the foot or ankle on physical examination. Isometric muscle force for plantarflexion, dorsiflexion, inversion and eversion was measured using static dynamometry. Mixed-models regression was used to determine the difference in muscle force between the two groups while adjusting for age, disease duration and foot pain. This model was also used to determine the difference in muscle force between presence and absence of tophi at specific locations within the foot and ankle. In addition, Pearson’s correlations were used to determine the association between total foot tophus count and muscle force.

Results

Fifty-seven participants were included (22 with foot or ankle tophi and 35 without foot or ankle tophi). Foot and ankle tophi were most often seen at the Achilles tendon. After adjusting for age, disease duration and foot pain, participants with tophi had significantly reduced muscle force during plantarflexion (P < 0.001), dorsiflexion (P = 0.003), inversion (P = 0.003) and eversion (P = 0.001) when compared to participants without tophi. Those with Achilles tophi had significantly reduced force during plantarflexion (P < 0.001), inversion (P = 0.008) and eversion (P = 0.001). No significant differences in muscle force were observed between the presence and absence of tophi at other foot or ankle locations. There were also no significant correlations between total foot tophus count and muscle force (all P > 0.05).

Conclusion

In people with gout, clinically-evident foot or ankle tophi are associated with muscle force deficits during foot plantarflexion, dorsiflexion, inversion and eversion, which persist despite adjusting for age, disease duration and foot pain. Tophi at the Achilles tendon, which associate with force deficits, may contribute to reduced muscular activation and consequent disuse muscle atrophy.

Metabolic characteristics and renal dysfunction in 65 patients with tophi prior to gout

Tophi typically occur many years after uncontrolled gout. Therefore, their development before gout remains unusual. Such patients might exhibit some characteristic differences compared with typical tophaceous gout patients. In this study, 65 tophaceous gout patients with tophi as the first sign of gout (tophi-first group) were enrolled. Their clinical characteristics were compared with those of 1421 patients whose tophi occurred after gout (tophi-after group). Compared with the tophi-after group, the tophi-first group had a significantly higher percentage of female patients and patients with elderly onset of disease and a lower percentage of patients with a positive family history; these patients had lower body mass indices, serum urate levels, and estimated glomerular filtration rates (eGFRs). Female sex and negative family history were identified as the principal determinants of tophi development before gout. The decreasing eGFR among the tophi-first group was not due to the group per se but was a result of older age, longer tophi duration, and hyperuricemia. The most common site of initial tophi occurrence in both groups was the toe. In the tophi-first group, the occurrence rates for initial tophi sites were significantly higher at the finger but were lower at the ankle. The tophi-first group exhibited distinct characteristics of age, gender, family history, BMI, serum urate levels, and initial tophi site. This group had fewer comorbidities but similar renal dysfunction compared with the tophi-after group. Thus, patients presenting with tophi should be treated promptly, even if they have no history of gout symptoms.

Spinal gout: A review with case illustration

AIM

To summarize clinical presentations and treatment options of spinal gout in the literature from 2000 to 2014, and present theories for possible mechanism of spinal gout formation.

METHODS

The authors reviewed 68 published cases of spinal gout, which were collected by searching “spinal gout” on PubMed from 2000 to 2014. The data were analyzed for clinical features, anatomical location of spinal gout, laboratory studies, imaging studies, and treatment choices.

RESULTS

Of the 68 patients reviewed, the most common clinical presentation was back or neck pain in 69.1% of patients. The most common laboratory study was elevated uric acid levels in 66.2% of patients. The most common diagnostic image finding was hypointense lesion of the gout tophi on the T1-weighted magnetic resonance imaging scan. The most common surgical treatment performed was a laminectomy in 51.5% and non-surgical treatment was performed in 29.4% of patients.

CONCLUSION

Spinal gout most commonly present as back or neck pain with majority of reported patients with elevated uric acid. The diagnosis of spinal gout is confirmed with the presence of negatively birefringent monosodium urate crystals in tissue. Treatment for spinal gout involves medication for the reduction of uric acid level and surgery if patient symptoms failed to respond to medical treatment.

Genetic background of uric acid metabolism in a patient with severe chronic tophaceous gout

Hyperuricemia depends on the balance of endogenous production and renal excretion of uric acid. Transporters for urate are located in the proximal tubule where uric acid is secreted and extensively reabsorbed: secretion is principally ensured by the highly variable ABCG2 gene. Enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT) plays a central role in purine metabolism and its deficiency is an X-linked inherited metabolic disorder associated with clinical manifestations of purine overproduction. Here we report the case of a middle-aged man with severe chronic tophaceous gout with a poor response to allopurinol and requiring repeated surgical intervention. We identified the causal mutations in the HPRT1 gene, variant c.481G>T (p.A161S), and in the crucial urate transporter ABCG2, a heterozygous variant c.421C>A (p.Q141K). This case shows the value of an analysis of the genetic background of serum uric acid.

Treatment of tophaceous gout: When medication is not enough

OBJECTIVES

To review the literature concerning surgical intervention of tophaeceous gout and propose clinical circumstances for when it may be considered.

INTRODUCTION

Tophi develop in approximately 12-35% of patients with gout. Tophaceous disease is usually preventable given the availability of effective urate lowering therapies (ULT) including allopurinol, febuxostat, probenecid, lesinurad, and pegloticase. Despite medical therapy, there remains a subset of patients who develop significant complications of tophi including infection, ulceration, and entrapment neuropathy. Tophi in close proximity to joints can cause joint instability, severely limited range of motion, and significant functional impairment. For the rare circumstance when a tophus is causing an urgent complication or if a patient has a contraindication to all available ULTs, surgery may be an appropriate option. This review summarizes the published experience with surgical interventions for tophaceous gout and offers recommendations for its consideration.

METHODS

Using Medline and Google Scholar, all available series of surgery for tophaceous gout were reviewed.

RESULTS

Overall, 7 published surgical series were identified. In all, 6 of these 7 series were published between 2002 and 2014. The reported outcomes of surgical interventions for tophaceous gout were generally positive without major post-surgical complications.

CONCLUSION

Although medical therapy with ULTs should be the first-line approach to tophaceous gout, surgery should be considered for the rare patient with impending or severe, debilitating complications including infections, entrapment neuropathy or those at risk for permanent joint destruction. In these selected clinical circumstances, surgical intervention for tophaceous gout may be appropriate.

A world of hurt: failure to achieve treatment goals in patients with gout requires a paradigm shift

BACKGROUND

Gout continues to be underdiagnosed and poorly managed despite the potential for cure. US and European management guidelines recommend treating to target serum urate (sUA) levels of <6 mg/dL (or <5 mg/dL to durably improve severe symptoms), with use of regular sUA monitoring, but studies suggest relatively poor adherence to these recommendations. This study investigates the real-world state of gout management in the United States by describing the characteristics of a large patient population treated in primary care and rheumatology settings.

METHODS

A retrospective chart audit, conducted among 124 primary care physicians and 125 rheumatologists, included 1245 patients with gout. Physicians completed structured case report forms capturing 12 months of sUA laboratory values, flare counts, comorbidities, types and doses of treatment, treatment duration, diagnosis date, physician specialty and socio-demographic factors. Focusing on the xanthine oxidase inhibitors (n = 858), descriptive statistics and multivariate models characterized relationships between patient characteristics, disease control, and treatment.

RESULTS

Only 83 (11%) patients achieved disease control, defined as a 12-month average sUA ≤6 mg/dL, no flares, and no tophi. Patients with greatest disease severity (defined as sUA >6 mg/dL, ≥2 flares per year, and tophi) were more likely to have kidney disease and other comorbidities. In a multivariate model, predictors of more severe gout were rheumatologist (vs primary care) management, febuxostat (vs allopurinol) use and presence of comorbid conditions.

CONCLUSION

Our findings confirm the inadequacy of gout management in the real-world setting. Regular monitoring, including sUA measurement as recommended in guidelines, is important to assess gout control. Our analyses also demonstrate that patients with more severe gout are more likely to have comorbid conditions, be treated by a specialist and use newer therapies.

Clinical utility of dual-energy CT for gout diagnosis

OBJECTIVE

The present study was to evaluate the clinical value of dual-energy computed tomography (DECT) for detecting monosodium urate crystals in patients with gouty arthritis.

METHODS

Two hundred and two patients, who experienced arthrocele and (or) joint pain, were enrolled into our study. DECT scans of upper or lower extremity were performed. One hundred and sixty one patients who conformed to the American College of Rheumatology classification standard were defined as the gout group. The rest (41) of the patients were regarded as the without-gout group. DE (80kV/140kV) datasets were reconstructed via DE gout software. Images were reviewed independently by two senior radiologists.

RESULTS

In the gout group, DECT scans revealed a total of 379 areas of urate deposition in 121 patients. In the without-gout group, 3 areas of green urate deposition were detected. The sensitivity and specificity were 75.2% and 92.7%, respectively; when we increased the ratio to 1.32 and decreased the range to 3, the number of patients with green urate deposition increased, and the areas of urate deposition were more extensive. The sensitivity and specificity were 91.9% and 85.4%. DECT images could illustrate the palpable reduction in the tissue urate deposits compared to baseline images before and after treatment.

CONCLUSIONS

DECT has comparable sensitivity and specificity for the detection of gouty arthritis in a clinical setting, and DECT can monitor the clinical treatment. However, DECT results should be interpreted carefully because there could be some false-negative or false-positive findings.

Clinical manifestations and diagnosis of gout

Gout has been academically considered to be a step-up disease consisting of different stages: acute gout, intercritical gout, and chronic gout. This simple approach may lead to misinterpretation and misdiagnosis. In clinical practice, we should consider gout as a single disease with either or both acute (most commonly, episodes of acute inflammation) and persistent clinical manifestations, but not restricted to chronic synovitis. In this article, an innovative, practical, and rational approach to the clinical manifestations and diagnosis of gout is presented, which may be supportive for clinicians involved in everyday care and management of patients with gout.

Gout tophus detection-a comparison of dual-energy CT (DECT) and histology

OBJECTIVES

To compare dual-energy CT images (DECT) directly with gold standard histology.

METHODS

A 85-year-old woman with chronic recurrent gouty arthritis and macroscopically visible tophi was assessed with DECT-scans of her feet. When she died 7 days later, three tophi in different regions and in different tissues of her left foot were processed for histological examination.

RESULTS

Of the selected tophi, two were almost completely missed by the color-coding DECT sequences. The tophi remained in most of their volume below the detection threshold value of 150HU (default value).

CONCLUSIONS

It could be demonstrated that DECT only highlights the dense tophi (corresponding of approximately 15-20vol% urate in the tophus). Less dense tophi, despite considerable size, will be missed in the color-coded images.