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1.  Multiple Intramuscular Gouty Tophi Mimicking Deep Tissue Abscesses: A Case Report 
Introduction:
Gout is a common metabolic disorder resulting from supersaturation of uric acid in extracellular fluid and deposition of monosodium urate monohydrate crystals in tissues triggering inflammatory response. Depositions of uric acid crystal outside articular structures cause tophi and are commonly found at peripheral areas of the body which have a lower temperature. Deposition of uric acid crystals in the central area of the body is not uncommon and may be overlooked.
Case presentation:
A 55-year-old Pacific Islander man with a history of chronic tophaceous gout was admitted because of acute right knee pain. Physical examination revealed signs of inflammation over the right knee. Arthrocentesis was performed but no synovial fluid obtained. The patient was empirically treated with prednisone, colchicine, and febuxostat. On the next day, there was progression of inflammation up to the right mid-thigh. MRI of the right femur was obtained to exclude abscess and necrotizing faciitis. Multiple pockets of abscesses were identified within the vastus medialis and vastus intermedius adjacent to the femoral shaft. This prompted immediate surgical consultation and incision and drainage. Intraoperative findings revealed healthy muscles and deposition of soft-tan material in the vastus medialis and vastus intermedius along and above the shaft of the femur. Culture of the surgical aspirate was negative and pathology showed needle-shaped structures consistent with uric acid crystals. Empiric antibiotic was discontinued. The patient's condition improved after treatment for acute gout. Pegloticase was also added to the treatment regimen during an outpatient follow up visit with his rheumatologist. At six month follow up, the patient reported excellent improvements in clinical symptoms.
Discussion:
Atypical presentations of chronic tophaceous gout can be a great mimicker, causing diagnostic challenges for clinicians. Our patient who had multiple intramuscular tophi presented with abrupt signs and symptoms of inflammation of lower extremity resembling cellulitis, abscess, or necrotizing fasciitis. On MRI, tophi typically exhibit low signal on T1-weighted images and medium to high signal on T2-weighted images, indicating the presence of cellular tissues surrounding or infiltrating the crystalline mass. The vascularity of this tissue influences the degree of MRI post-contrast enhancement on T2-weighted images. With varying degrees of cellular response and vascularity, distinguishing tophi from abscesses by MRI is still difficult.
Conclusion:
Our report focuses on the fact that tophi can also trigger acute inflammatory responses mimicking those of acute infection. At atypical locations, it can lead to misdiagnosis and inappropriate treatment. MRI is not a sensitive tool to differentiate abscess from tophaceous gout. Tissue diagnosis obtained from biopsy or aspiration is warranted to guide appropriate treatment and distinguish these different entities.
PMCID: PMC4175947
2.  Paraspinal Abscess Communicated with Epidural Abscess after Extra-Articular Facet Joint Injection 
Yonsei Medical Journal  2007;48(4):711-714.
Facet joint injection is considered to be a safe procedure. There have been some reported cases of facet joint pyogenic infection and also 3 cases of facet joint infection spreading to paraspinal muscle and epidural space due to intra-articular injections. To the author's knowledge, paraspinal and epidural abscesses after facet joint injection without facet joint pyogenic infection have not been reported. Here we report a case in which extra-articular facet joint injection resulted in paraspinal and epidural abscesses without facet joint infection. A 50-year-old man presenting with acute back pain and fever was admitted to the hospital. He had the history of diabetes mellitus and had undergone the extra-articular facet joint injection due to a facet joint syndrome diagnosis at a private clinic 5 days earlier. Physical examination showed tenderness over the paraspinal region. Magnetic resonance image (MRI) demonstrated the paraspinal abscess around the fourth and fifth spinous processes with an additional epidural abscess compressing the thecal sac. The facet joints were preserved. The laboratory results showed a white blood cell count of 14.9 × 109 per liter, an erythrocyte sedimentation rate of 52mm/hour, and 10.88mg/dL of C-reactive protein. Laminectomy and drainage were performed. The pus was found in the paraspinal muscles, which was communicated with the epidural space through a hole in the ligamentum flavum. Cultures grew Staphylococcus aureus. Paraspinal abscess communicated with epidural abscess is a rare complication of extra-articular facet joint injection demonstrating an abscess formation after an invasive procedure near the spine is highly possible.
doi:10.3349/ymj.2007.48.4.711
PMCID: PMC2628056  PMID: 17722247
Complication; infection; injection; facet joint
3.  Tophaceous Gout of the Spine Causing Neural Compression 
Korean Journal of Spine  2013;10(3):185-188.
Gout is a common metabolic disease in which monosodium urate crystals called tophi develop. Spinal involvement in gout resulting in neural compression is unusual. We describe a case of a 64-year-old man with a history of gouty arthritis of the knee. The patient presented with thoracic myelopathy and radiculopathy. Imaging of the spine revealed an extradural mass lesion with bony erosion of the thoracic spine. A decompressive operation was performed, and a chalky white material was found. Histopathological examination confirmed a gouty tophus. The symptoms of spinal gout vary and its radiological features are not sufficiently specific to provide a definite diagnosis. Therefore, in patients with a history of gouty arthritis who present with neural compressive symptoms of the spine, spinal gout should be strongly suspected.
doi:10.14245/kjs.2013.10.3.185
PMCID: PMC3941767  PMID: 24757485
Gout; Spine; Myelopathy; Radiculopathy
4.  Gout, Have We Met before? No, Not Like This… 
LEARNING OBJECTIVES
Extra-articular symptoms could be the first manifestation of gouty arthritis (GA); polyarticular GA can mimic an infectious arthritis; infection can complicate GA.
CASE
A 66-year-old male with a history of gout presented with high fever and excruciating bilateral calf pain for 1 day. Examination revealed chronic knee effusions; range of motion in both knees was limited by calf pain. Joint aspiration showed negatively birefringent intracellular crystals and normal gram stain.
HOSPITAL COURSE
While receiving empiric antibiotics fever continued and he developed bilateral knee, right ankle, and shoulder pain. After demonstration of urate crystals and exclusion of infection, antibiotics were discontinued and steroids initiated. Fever, calf pain, and polyarthritis quickly resolved.
DISCUSSION
Polyarticular gouty attack is an uncommon presentation of gout, and can mimic several other conditions. An exceptional presentation of this entity is excruciating calf pain, probably caused by tenosynovitis or referred pain preceding an acute polyarticular gouty attack.
doi:10.1111/j.1525-1497.2006.00606.x
PMCID: PMC1924738  PMID: 17105518
gout; polyarticular; calf pain
5.  Frequency of chondrocalcinosis of the knees and avascular necrosis of the femoral heads in gout: a controlled study. 
An association between urate gout and chondrocalcinosis has been suggested in several studies, but the situation remains ill-defined because of lack of appropriate controls, small numbers of patients studied, or retrospective investigation. An association has also been claimed between gout and avascular necrosis of the femoral head. 138 patients with gout and 142 non-gouty control subjects were carefully matched for age and x-rays were taken of the knees and pelvis. Chondrocalcinosis of the knees was detected in 8 patients with gout (5.8%), no cases being found in the control group. The difference is significant (P less than 0.025). Deposits were linear or irregular. Six of the 8 patients gave a history of acute synovitis of the knees; fluid had been aspirated in 2 of them, urate crystals being found in one and no crystals in the other. Six of 8 patients showed evidence of chondrocalcinosis elsewhere. No association was apparent between chondrocalcinosis and the presence of tophaceous deposits or renal impairment, though the duration of gout appeared to be longer in the patients with chondrocalcinosis than in the other gout patients and osteoarthrosis of the knees commoner. There was no evidence of other metabolic disorders commonly associated with chondrocalcinosis. No cases of avascular necrosis of the femoral head were found.
Images
PMCID: PMC1000461  PMID: 7377863
6.  MicroRNA-155 as a proinflammatory regulator via SHIP-1 down-regulation in acute gouty arthritis 
Introduction
Gout is characterized by episodes of intense joint inflammation in response to intra-articular monosodium urate monohydrate (MSU) crystals. miR-155 is crucial for the proinflammatory activation of human myeloid cells and antigen-driven inflammatory arthritis. The functional role of miR-155 in acute gouty arthritis has not been defined. Therefore, the aim of this study was to examine the role of miR-155 in pathogenesis of acute gouty arthritis.
Methods
Samples from 14 patients with acute gouty arthritis and 10 healthy controls (HCs) were obtained. Peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) were cultured in vitro with MSU crystals, and gene expression (human miR-155 and SHIP-1) were assessed by real-time PCR. THP-1 cells were stimulated by MSU crystals and/or miR-155 transfection and then subjected to Western blot analysis. Levels of human tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-1β in cell culture supernatants were measured by Luminex. Immunohistochemistry was performed on formalin-fixed gout tissues with anti–SHIP-1 antibody. A C57BL/6 J male mouse model of gout was used to analyze the expressions of miR-155, SHIP-1, and inflammatory cytokines.
Results
The samples from gouty arthritis were highly enriched in miR-155, with levels of expression being higher than those found in PBMC from HC. Treatment of the cells with MSU crystals strongly induced miR-155. In addition, overexpression of miR-155 in the cells decreased levels of SHIP-1 and promoted production of MSU-induced proinflammatory cytokines, such as TNF-α and IL-1β. Consistent with in vitro observations, miR-155 expression was elevated in the mouse model of gout. The production of inflammatory cytokines was markedly increased in MSU crystal induced peritonitis mice.
Conclusions
Overexpression of miR-155 in the gouty SFMC leads to suppress SHIP-1 levels and enhance proinflammatory cytokines.
doi:10.1186/ar4531
PMCID: PMC4060367  PMID: 24708712
7.  Imaging Appearances in Gout 
Arthritis  2013;2013:673401.
Gout is an ancient disease. Last decade has brought about significant advancement in imaging technology and real scientific growth in the understanding of the pathophysiology of gout, leading to the availability of multiple effective noninvasive diagnostic imaging options for gout and treatment options fighting inflammation and controlling urate levels. Despite this, gout is still being sub-optimally treated, often by nonspecialists. Increased awareness of optimal treatment options and an increasing role of ultrasound and dual energy computed tomography (DECT) in the diagnosis and management of gout are expected to transform the management of gout and limit its morbidity. DECT gives an accurate assessment of the distribution of the deposited monosodium urate (MSU) crystals in gout and quantifies them. The presence of a combination of the ultrasound findings of an effusion, tophus, erosion and the double contour sign in conjunction with clinical presentation may be able to obviate the need for intervention and joint aspiration in a certain case population for the diagnosis of gout. The purpose of this paper is to review imaging appearances of gout and its clinical applications.
doi:10.1155/2013/673401
PMCID: PMC3621383  PMID: 23585966
8.  Psoriasis and gout 
Postgraduate Medical Journal  1982;58(682):477-480.
Ten cases of gouty arthritis are described in association with psoriasis. Eight were receiving intensive inpatient treatment for their skin condition. Diagnosis was based on clinical grounds or, in 3 cases, by compensated polarizing microscopy (CPM) of synovial fluid. All patients were male and 5 of them had conditions other than psoriasis known to predispose to hyperuricaemia. The patients appeared to fit into three groups: five had typical lower limb gout occurring in conjunction with long-standing extensive psoriasis; 3 patients had preceding features of inflammatory synovitis, one of whom subsequently developed typical distal interphalangeal involvement of peripheral psoriatic arthritis; two patients appeared to have coincident gout and psoriasis.
We believe that an association of gout with extensive long-standing psoriasis may exist particularly in male patients with an additional cause for hyperuricaemia. Long-term studies of a large population of psoriatics are required. Previous reports may have underestimated the incidence of gout because of failure to examine synovial fluid for crystals particularly from those patients with a subacute large joint arthropathy.
PMCID: PMC2426549  PMID: 7134085
9.  Bone destruction by receptor activator of nuclear factor κB ligand-expressing T cells in chronic gouty arthritis 
Arthritis Research & Therapy  2011;13(5):R164.
Introduction
The purpose of this study was to analyze the cellular expressions of pro-resorptive cytokines in gouty tophus tissues, to determine the capacity of monosodium urate monohydrate (MSU) crystals to induce these cytokines, and to understand the mechanisms of bone destruction in chronic gout.
Methods
Fourteen fixed, paraffin-embedded, uninfected tophus samples were analyzed immunohistochemically. Peripheral blood mononuclear cells (PBMCs) were cultured in vitro with MSU crystals, and gene expression was assessed by reverse transcription-polymerase chain reaction. In vitro osteoclastogenesis was performed using PBMCs and synovial fluid mononuclear cells (SFMCs).
Results
CD4+ T cells, CD8+ T cells, CD20+ B cells and mast cells infiltrated tophus tissues. Tartrate-resistant acid phosphatase (TRAP)+ osteoclasts were present around tophi and in osteolytic lesions. Interleukin (IL)-1, IL-6 and tumor necrosis factor (TNF)-alpha were produced from infiltrated mononuclear cells, whereas receptor activator of nuclear factor κB ligand (RANKL) was strongly expressed in T cells. However, osteoprotegerin (OPG) was not or was weakly expressed in tophus tissues. MSU crystals induced the expressions of IL-1, IL-6, TNF-alpha and RANKL in PBMCs, but inhibited OPG expression. In addition, the pro-resorptive cytokines were highly expressed in SFMCs of gouty arthritis patients. Furthermore, in vitro osteoclastogenesis was enhanced in SFMC cultures, but inhibited in T cell-depleted SFMC cultures.
Conclusions
Our study demonstrates that RANKL-expressing T cells and TRAP+ osteoclasts are present within gouty tophus tissues, and that infiltrating cells express pro-resorptive cytokines. Furthermore, our data show that MSU crystals have the potential to induce pro-resorptive cytokines, and T cells are involved in osteoclastogenesis in chronic gout.
doi:10.1186/ar3483
PMCID: PMC3308097  PMID: 21992185
10.  Acute gouty bursitis: report of 15 cases. 
Annals of the Rheumatic Diseases  1979;38(4):326-328.
Fifteen cases of acute gouty bursitis were seen among 136 crystal-proved cases of gout. Bursal aspirate yielded yellow or pink fluid in 10, chalky white fluid in 1, and a small amount of bloody fluid in 4. Monosodium urate crystals were present in all. Bursal fluid leucocyte counts averaged 2.9 X 10(9)/1 compared with synovial fluid leucocyte counts that averaged 25.5 X 10(9)/1 in cases of articular gout (P less than 0.05). Gouty, septic, and idiopathic (traumatic) bursitis share clinical features, and detailed bursal fluid analysis is crucial for diagnosis.
PMCID: PMC1000363  PMID: 496446
11.  Imaging of tophaceous gout: computed tomography provides specific images compared with magnetic resonance imaging and ultrasonography 
Methods: Four male patients with chronic gout with tophi affecting the knee joints (three cases) or the olecranon processes of the elbows (one case) were assessed. Crystallographic analyses of the synovial fluid or tissue aspirates of the areas of interest were made with polarising light microscopy, alizarin red staining, and x ray diffraction. CT was performed with a GE scanner, MR imaging was obtained with a 1.5 T Magneton (Siemens), and ultrasonography with colour Doppler was carried out by standard technique.
Results: Crystallographic analyses showed monosodium urate (MSU) crystals in the specimens of the four patients; hydroxyapatite and calcium pyrophosphate dihydrate (CPPD) crystals were not found. A diffuse soft tissue thickening was seen on plain radiographs but no calcifications or ossifications of the tophi. CT disclosed lesions containing round and oval opacities, with a mean density of about 160 Hounsfield units (HU). With MRI, lesions were of low to intermediate signal intensity on T1 and T2 weighting. After contrast injection in two cases, enhancement of the tophus was seen in one. Colour Doppler US showed the tophi to be hypoechogenic with peripheral increase of the blood flow in three cases.
Conclusion: The MR and colour Doppler US images showed the tophi as masses surrounded by a hypervascular area, which cannot be considered as specific for gout. But on CT images, masses of about 160 HU density were clearly seen, which correspond to MSU crystal deposits.
doi:10.1136/ard.61.1.52
PMCID: PMC1753862  PMID: 11779759
12.  The relationship of apolipoprotein B and very low density lipoprotein triglyceride with hyperuricemia and gout 
Introduction
Gout results from an innate immune response to monosodium urate (MSU) crystals deposited in joints. Increased very low-density lipoprotein (VLDL) has been associated with gout. The apolipoprotein B (apo B), which is present on VLDL, regulates neutrophil response to MSU crystals and has been positively associated with gout. Furthermore, the gene (A1CF) encoding the complementation factor for the APOB mRNA-editing enzyme is associated with urate levels. However, the relationship of apo B and VLDL with gout and hyperuricaemia (HU) is still unclear. Therefore, we tested the association of VLDL and apo B with HU and with gout compared to HU.
Methods
New Zealand European (n = 90) and Māori and Pacific Island (Polynesian) (n = 90) male gout case and control sample sets were divided into normouricaemia (NU), asymptomatic HU and gout groups. Size exclusion chromatography and enzyme-linked immunosorbant assay was used to measure VLDL and apo B. Multivariate logistic regression was used to assess the risk of gout and HU per unit change in VLDL and apo B.
Results
Increased levels of VLDL triglycerides (Tg) were observed in the gout sample set compared to NU and HU in Europeans (P = 1.8 × 10-6 and 1 × 10-3, respectively), but only compared to NU in Polynesians (P = 0.023). This increase was driven by increased number of VLDL particles in the European participants and by the Tg-enrichment of existing VLDL particles in the Polynesian participants. Each mmol/L increase in VLDL Tg was significantly associated with gout in the presence of HU in Europeans, with a similar trend in Polynesians (OR = 7.61, P = 0.011 and 2.84, P = 0.069, respectively). Each μmol/L increase in total apo B trended towards decreased risk of HU (OR = 0.47; P = 0.062) and, conversely, with increased risk of gout compared to HU (OR = 5.60; P = 0.004).
Conclusions
Increased VLDL Tg is associated with the risk of gout compared to HU. A genetic approach should be taken to investigate the possibility for causality of VLDL in gout. Apolipoprotein B may have pleiotropic effects in determining HU and gout.
doi:10.1186/s13075-014-0495-z
PMCID: PMC4265487  PMID: 25432151
13.  Time required for disappearance of urate crystals from synovial fluid after successful hypouricaemic treatment relates to the duration of gout 
Annals of the Rheumatic Diseases  2007;66(8):1056-1058.
Objectives
To determine whether hypouricaemic treatment results in the disappearance of urate crystals from gouty joints and to define the time required.
Methods
In 18 patients with monosodium urate (MSU) crystal proven gout, and after the initiation of successful serum uric acid (SUA)‐lowering treatment, an arthrocentesis of the asymptomatic signal joint (11 knees, 7 first metatarsophalangeal joints) was performed every 3 months to obtain a synovial fluid (SF) sample. The sample was then analysed for the presence of MSU crystals, and the number of crystals/400× field was noted. SUA levels and the duration of gout were also noted.
Results
MSU crystals disappeared from the SF of all 18 joints after reduction of SUA to normal levels. The time required for disappearance ranged from 3 to 33 months; disappearance time correlated with the duration of gout (rs = 0.71; p<0.01). The median number of MSU crystals in the SF samples before urate‐lowering treatment was 7.5 (2.5–11) crystals/400× field, reducing to 3 (1–6.5) crystals/400× field (p<0.05) at 3 months. Crystal counts continued to decrease after 3 months.
Conclusions
In gout, reduction of SUA to normal levels results in disappearance of urate crystals from SF, requiring a longer time in those patients with gout of longer duration. This indicates that urate crystal deposition in joints is reversible. Normalisation of SUA levels results in a decrease in the concentration of MSU crystals in SF in the asymptomatic gouty joints. This may partially explain the reduced frequency of gouty attacks when a patient has been treated with SUA‐lowering drugs.
doi:10.1136/ard.2006.060368
PMCID: PMC1954685  PMID: 17223663
gout; monosodium urate crystals; synovial fluid; gout treatment
14.  A case of gouty arthritis following percutaneous radiofrequency ablation for hepatocellular carcinoma 
Percutaneous radiofrequency thermal ablation (RFA) is considered an effective technique for providing local control in the majority of Hepatocellular carcinoma (HCC) patients. Although RFA is generally well tolerated, recent studies have reported complications associated with RFA. We describe a case of acute gouty arthritis in a 71-year-old man with chronic renal failure who was treated with RFA for a HCC lesion and who had hepatitis B-associated cirrhosis and mild renal insufficiency. Regular surveillance of the patient detected a 3.5 cm HCC lesion. Because the patient had declined surgery, RFA was chosen for therapy. On the third post-procedural day, the laboratory results showed increases in his uric acid and potassium levels, which were compatible with a tumor lysis syndrome. On the 6th post-procedural day, the patient complained of new right knee pain. Subsequent joint aspiration revealed monosodium urate monohydrate crystals. We made the diagnosis of acute gouty arthritis arising from tumor lysis and liver infarction caused by HCC ablation, which was aggravated by acute renal insufficiency. After adequate hydration and administration of oral colchicines, the patient’s right knee pain subsided and the uric acid serum level returned to normal. This is the first described case of acute gouty arthritis after RFA for a HCC lesion in a patient with underlying chronic renal insufficiency. To avoid hyperuricemia and an acute attack of gout after RFA therapy for HCC, early identification of patients at risk is warranted, such as those with a large tumor, rapid tumor growth, and renal insufficiency, and preventative measures should be considered.
doi:10.3748/wjg.v16.i6.778
PMCID: PMC2817069  PMID: 20135729
Radiofrequency thermal ablation; Hepatocellular carcinoma; Gout; Tumor lysis syndrome; Complications
15.  Veterans Affairs databases are accurate for gout-related health care utilization: a validation study 
Arthritis Research & Therapy  2013;15(6):R224.
Introduction
The aim of this study was to assess the accuracy of Veterans Affairs (VA) databases for gout-related health care utilization.
Methods
This retrospective study utilized VA administrative and clinical databases. A random sample of gout patients with visits (outpatient, inpatient or emergent/urgent care) with or without the diagnosis of gout (International Classification of Diseases, ninth revision, common modification ICD-9-CM code of 274.x or 274.xx) at the Birmingham VA hospital was selected. A blinded abstractor performed a review of VA electronic health records for the documentation of gout or gout-related terms (gouty arthritis, tophaceous gout, tophus/tophi, acute gout, chronic gout, podagra, urate stones, urate or uric acid crystals and so on) in the chief complaint, history of present illness or assessment and plan for the visit; this constituted the gold standard for gout-related utilization. The accuracy of database-derived gout-related claims was assessed by calculating sensitivity, specificity, and positive and negative predictive values (PPV and NPV).
Results
Of 108 potential visits, 85 outpatient, inpatient or urgent care/emergency room visits to a health care provider (85 patients: 84 men and 1 woman with a mean age of 63 years) and retrievable data from medical records constituted the analyzed dataset. Administrative claims for gout-related utilization with ICD-9 code for gout were accurate with a PPV of 86%, specificity of 95%, sensitivity of 86% and NPV of 95%.
Conclusions
VA databases are accurate for gout-related visits. These findings support their use for studies of health services and outcome studies. It remains to be seen if these findings are generalizable to other settings and databases.
doi:10.1186/ar4425
PMCID: PMC3979008  PMID: 24377421
16.  Neutrophil Extracellular Trap Formation Is Associated with IL-1β and Autophagy-Related Signaling in Gout 
PLoS ONE  2011;6(12):e29318.
Background
Gout is a prevalent inflammatory arthritis affecting 1–2% of adults characterized by activation of innate immune cells by monosodium urate (MSU) crystals resulting in the secretion of interleukin-1β (IL-1β). Since neutrophils play a major role in gout we sought to determine whether their activation may involve the formation of proinflammatory neutrophil extracellular traps (NETs) in relation to autophagy and IL-1β.
Methodology/Principal Findings
Synovial fluid neutrophils from six patients with gout crisis and peripheral blood neutrophils from six patients with acute gout and six control subjects were isolated. MSU crystals, as well as synovial fluid or serum obtained from patients with acute gout, were used for the treatment of control neutrophils. NET formation was assessed using immunofluorescence microscopy. MSU crystals or synovial fluid or serum from patients induced NET formation in control neutrophils. Importantly, NET production was observed in neutrophils isolated from synovial fluid or peripheral blood from patients with acute gout. NETs contained the alarmin high mobility group box 1 (HMGB1) supporting their pro-inflammatory potential. Inhibition of phosphatidylinositol 3-kinase signaling or phagolysosomal fusion prevented NET formation, implicating autophagy in this process. NET formation was driven at least in part by IL-1β as demonstrated by experiments involving IL-1β and its inhibitor anakinra.
Conclusions/Significance
These findings document for the first time that activation of neutrophils in gout is associated with the formation of proinflammatory NETs and links this process to both autophagy and IL-1β. Modulation of the autophagic machinery may represent an additional therapeutic study in crystalline arthritides.
doi:10.1371/journal.pone.0029318
PMCID: PMC3241704  PMID: 22195044
17.  Acute camptocormia induced by olanzapine: a case report 
Introduction
Camptocormia refers to an abnormal posture with flexion of the thoraco-lumbar spine which increases during walking and resolves in supine position. This symptom is an increasingly recognized feature of parkinsonian and dystonic disorders, but may also be caused by neuromuscular diseases. There is recent evidence that both central and peripheral mechanisms may be involved in the pathogenesis of camptocormia. We report a case of acute onset of camptocormia, a rare side effect induced by olanzapine, a second-generation atypical anti-psychotic drug with fewer extra-pyramidal side-effects, increasingly used as first line therapy for schizophrenia, delusional disorders and bipolar disorder.
Case presentation
A 73-year-old Caucasian woman with no history of neuromuscular disorder, treated for chronic delusional disorder for the last ten years, received two injections of long-acting haloperidol. She was then referred for fatigue. Physical examination showed a frank parkinsonism without other abnormalities. Routine laboratory tests showed normal results, notably concerning creatine kinase level. Fatigue was attributed to haloperidol which was substituted for olanzapine. Our patient left the hospital after five days without complaint. She was admitted again three days later with acute back pain. Examination showed camptocormia and tenderness in paraspinal muscles. Creatine kinase level was elevated (2986 UI/L). Magnetic resonance imaging showed necrosis and edema in paraspinal muscles. Olanzapine was discontinued. Pain resolved quickly and muscle enzymes were normalized within ten days. Risperidone was later introduced without significant side-effect. The camptocormic posture had disappeared when the patient was seen as an out-patient one year later.
Conclusions
Camptocormia is a heterogeneous syndrome of various causes. We believe that our case illustrates the need to search for paraspinal muscle damage, including drug-induced rhabdomyolysis, in patients presenting with acute-onset bent spine syndrome. Although rare, the occurrence of camptocormia induced by olanzapine must be considered.
doi:10.1186/1752-1947-4-192
PMCID: PMC2904791  PMID: 20579377
18.  Functional Polymorphisms of the ABCG2 Gene Are Associated with Gout Disease in the Chinese Han Male Population 
Background
Gout is a common type of arthritis that is characterized by hyperuricemia, tophi and joint inflammation. Genetic variations in the ABCG2 gene have been reported to influence serum uric acid levels and to participate in the pathogenesis of gout, but no further data have been reported in the Han Chinese population.
Methods
Peripheral blood DNA was isolated from 352 male patients with gout and 350 gout-free normal male controls. High-resolution melting analysis and Sanger sequencing were performed to identify the genetic polymorphisms V12M, Q141K and Q126X in the ABCG2 gene. Genotype and haplotype analyses were utilized to determine the disease odds ratios (ORs). A prediction model for gout risk using ABCG2 protein function was established based on the genotype combination of Q126X and Q141K.
Results
For Q141K, the A allele frequency was 49.6% in the gout patients and 30.9% in the controls (OR 2.20, 95% confidence interval (CI): 1.77–2.74, p = 8.99 × 10−13). Regarding Q126X, the T allele frequency was 4.7% in the gout patients and 1.7% in the controls (OR 2.91, 95% CI: 1.49–5.68, p = 1.57 × 10−3). The A allele frequency for V12M was lower (18.3%) in the gout patients than in the controls (29%) (OR 0.55, 95% CI 0.43–0.71, p = 2.55 × 10−6). In the order of V12M, Q126X and Q141K, the GCA and GTC haplotypes indicated increased disease risk (OR = 2.30 and 2.71, respectively). Patients with mild to severe ABCG2 dysfunction accounted for 78.4% of gout cases.
Conclusion
The ABCG2 126X and 141K alleles are associated with an increased risk of gout, whereas 12M has a protective effect on gout susceptibility in the Han Chinese population. ABCG2 dysfunction can be used to evaluate gout risk.
doi:10.3390/ijms15059149
PMCID: PMC4057780  PMID: 24857923
gout; uric acid; polymorphism; ABCG2
19.  Tophaceous Gout and Renal Insufficiency: A New Solution for an Old Therapeutic Dilemma 
Case Reports in Medicine  2011;2011:397646.
The prevalence of gout is increasing with increased life expectancy. Approximately half of the patients with gout have some degree of renal impairment. If both conditions persistently coexist, and in severe tophaceous gout, in particular, treatment has been difficult. We here report on the case of an 87-year-old woman, who had been suffering from recurrent gouty arthritis over 4 years. Monthly polyarthritis attacks were accompanied by subcutaneous tophi. Serum uric acid levels were constantly above 600 μmol/L (10 mg/dL). Allopurinol was no option because of intolerance, while benzbromarone was ineffective because of renal impairment. Therefore, the novel xanthin oxidase inhibitor febuxostat was started, achieving rapid control of serum urate levels (<360 μmol/L). After initial worsening of inflammation in the first weeks, gouty attacks stopped and all tophi resolved within the following 10 months. Renal function remained stable.
doi:10.1155/2011/397646
PMCID: PMC3099210  PMID: 21629805
20.  Crystal deposition in the knee and great toe joints of asymptomatic gout patients. 
Crystal deposition in asymptomatic knee and first metatarsophalangeal (MTP) joints has been studied in 31 patients with previously proven gout. All had had clinical gout in their MTP joints but their knee joints had never been the site of acute gout. Knee arthroscopy was performed permitting synovial membrane inspection, photography and biopsy. Crystalline material was seen in 9 knees (28%) and confirmed histologically as monosodium urate (MSU) in 4 (12.5%). Synovial fluid analysis on 26 samples using a polarizing light microscope demonstrated MSU crystals in 4 (12.5%) and calcium pyrophosphate dihydrate (CPPD) in 2 (6%). Fluid aspirated from 27 of the metatarsophalangeal joints revealed MSU crystals in 14 (52%) and no CPPD crystals.
Images
PMCID: PMC1440018  PMID: 6481756
21.  Association analysis of the SLC22A11 (organic anion transporter 4) and SLC22A12 (urate transporter 1) urate transporter locus with gout in New Zealand case-control sample sets reveals multiple ancestral-specific effects 
Arthritis Research & Therapy  2013;15(6):R220.
Introduction
There is inconsistent association between urate transporters SLC22A11 (organic anion transporter 4 (OAT4)) and SLC22A12 (urate transporter 1 (URAT1)) and risk of gout. New Zealand (NZ) Māori and Pacific Island people have higher serum urate and more severe gout than European people. The aim of this study was to test genetic variation across the SLC22A11/SLC22A12 locus for association with risk of gout in NZ sample sets.
Methods
A total of 12 single nucleotide polymorphism (SNP) variants in four haplotype blocks were genotyped using TaqMan® and Sequenom MassArray in 1003 gout cases and 1156 controls. All cases had gout according to the 1977 American Rheumatism Association criteria. Association analysis of single markers and haplotypes was performed using PLINK and Stata.
Results
A haplotype block 1 SNP (rs17299124) (upstream of SLC22A11) was associated with gout in less admixed Polynesian sample sets, but not European Caucasian (odds ratio; OR = 3.38, P = 6.1 × 10-4; OR = 0.91, P = 0.40, respectively) sample sets. A protective block 1 haplotype caused the rs17299124 association (OR = 0.28, P = 6.0 × 10-4). Within haplotype block 2 (SLC22A11) we could not replicate previous reports of association of rs2078267 with gout in European Caucasian (OR = 0.98, P = 0.82) sample sets, however this SNP was associated with gout in Polynesian (OR = 1.51, P = 0.022) sample sets. Within haplotype block 3 (including SLC22A12) analysis of haplotypes revealed a haplotype with trans-ancestral protective effects (OR = 0.80, P = 0.004), and a second haplotype conferring protection in less admixed Polynesian sample sets (OR = 0.63, P = 0.028) but risk in European Caucasian samples (OR = 1.33, P = 0.039).
Conclusions
Our analysis provides evidence for multiple ancestral-specific effects across the SLC22A11/SLC22A12 locus that presumably influence the activity of OAT4 and URAT1 and risk of gout. Further fine mapping of the association signal is needed using trans-ancestral re-sequence data.
doi:10.1186/ar4417
PMCID: PMC3978909  PMID: 24360580
22.  Enhanced interleukin-1β production of PBMCs from patients with gout after stimulation with Toll-like receptor-2 ligands and urate crystals 
Arthritis Research & Therapy  2012;14(4):R158.
Introduction
Monosodium urate monohydrate (MSU) crystals synergize with various toll-like receptor (TLR) ligands to induce cytokine production via activation of the NOD-like receptor (NLR) family, pyrin domain-containing 3 (NLPR3) inflammasome. This has been demonstrated in vitro using human cell lines or monocytes of healthy volunteers. In the present study, we have investigated the effect of MSU crystals and of their combination with TLR ligands in peripheral blood mononuclear cells (PBMC) of patients with gout.
Methods
PBMCs from 18 patients with primary gout and 12 healthy donors were exposed to MSU crystals in the presence or absence of saturated fatty acid C18:0 (free fatty acid, TLR2 ligand), palmitoyl-3-cystein (Pam3Cys, TLR1/2 ligand) and fibroblast stimulating factor-1 (FSL-1, TLR 2/6 ligand). Production of IL-1β, IL-6, IL-8, IL-17 and tumor necrosis factor alpha (TNFα) was determined by ELISA. mRNA transcripts of IL-1β were measured by real-time PCR.
Results
MSU crystals alone failed to induce IL-1β, IL-6 or TNFα in both patients and control groups, but a stronger synergy between MSU/Pam3Cys and MSU/C18:0 for the induction of IL-1β was found in patients with gout compared to healthy controls. IL-6, but not IL-8, followed the kinetics of IL-1β. No production of the neutrophil-recruiting IL-17 was detectable after stimulation of the patients' PBMCs with MSU in both the presence or absence of TLR ligands. No change of gene transcripts of IL-1β after stimulation with MSU and Pam3Cys or with MSU and C18:0 was found. A positive correlation was found between synergy in IL-1β production from PBMCs of patients between C18:0 and MSU crystals, as well as the annual number of attacks of acute gouty arthritis (rs: +0.649, P: 0.022).
Conclusions
The synergy between MSU crystals and TLR-2 ligands is more prominent in patients with gout than in controls. This is likely mediated by the enhanced maturation of pro-IL-1β into IL-1β.
doi:10.1186/ar3898
PMCID: PMC3580550  PMID: 22762240
23.  Spinal gout tophus: a very rare cause of radiculopathy 
European Spine Journal  2011;21(Suppl 4):400-403.
Gout is a common metabolic disease characterized by the development of arthritis and nephropathy related to the deposition of monosodium urate crystals within the joints, periarticular tissues, skin and kidneys. Tophus formation seen around the spinal column is very rare, while occurrences of spinal gout tophus without systemic gout disease are much more unique. In our study, we report a spinal gout case that presented with right sciatica without previous history of systemic gout disease.
doi:10.1007/s00586-011-1847-x
PMCID: PMC3369051  PMID: 21594750
Gout tophus; Radiculopathy; Spinal column; Management
24.  Spondyloarthritis: A Gouty Display 
Gout is a systemic, metabolic disease that typically affects the peripheral joints. We describe an unusual presentation of gout affecting the facet joints and costovertebral joints in the thoracic and lumbar spine. A 54-year old man presents to the emergency department with increasing swelling and pain at the left elbow for one week and difficulty ambulating. The imaging work-up included plain radiographs of the left elbow, left wrist, and chest with subsequent admission for possible septic arthritis. MRI of the elbow showed olecranon bursitis and an erosion of the lateral epicondyle. CT scan demonstrated lytic cloud-like lesions localized to the facet joints and costovertebral joints of the thoracic and lumbar spine as well as bilateral medullary nephrocalcinosis. Possible hyperparathyroidism manifestations (including Brown tumors and medullary nephrocalcinosis) were evaluated with plains films of the hands; x-rays instead showed classic gouty arthritis. Our report reviews the disease, epidemiology, classic radiologic findings, and treatment of gout.
doi:10.3941/jrcr.v4i5.378
PMCID: PMC3303407  PMID: 22470729
Chronic Tophaceous Gout; Spondyloarthritis; Gout
25.  SLC2A9 Is a High-Capacity Urate Transporter in Humans 
PLoS Medicine  2008;5(10):e197.
Background
Serum uric acid levels in humans are influenced by diet, cellular breakdown, and renal elimination, and correlate with blood pressure, metabolic syndrome, diabetes, gout, and cardiovascular disease. Recent genome-wide association scans have found common genetic variants of SLC2A9 to be associated with increased serum urate level and gout. The SLC2A9 gene encodes a facilitative glucose transporter, and it has two splice variants that are highly expressed in the proximal nephron, a key site for urate handling in the kidney. We investigated whether SLC2A9 is a functional urate transporter that contributes to the longstanding association between urate and blood pressure in man.
Methods and Findings
We expressed both SLC2A9 splice variants in Xenopus laevis oocytes and found both isoforms mediate rapid urate fluxes at concentration ranges similar to physiological serum levels (200–500 μM). Because SLC2A9 is a known facilitative glucose transporter, we also tested whether glucose or fructose influenced urate transport. We found that urate is transported by SLC2A9 at rates 45- to 60-fold faster than glucose, and demonstrated that SLC2A9-mediated urate transport is facilitated by glucose and, to a lesser extent, fructose. In addition, transport is inhibited by the uricosuric benzbromarone in a dose-dependent manner (Ki = 27 μM). Furthermore, we found urate uptake was at least 2-fold greater in human embryonic kidney (HEK) cells overexpressing SLC2A9 splice variants than nontransfected kidney cells. To confirm that our findings were due to SLC2A9, and not another urate transporter, we showed that urate transport was diminished by SLC2A9-targeted siRNA in a second mammalian cell line. In a cohort of men we showed that genetic variants of SLC2A9 are associated with reduced urinary urate clearance, which fits with common variation at SLC2A9 leading to increased serum urate. We found no evidence of association with hypertension (odds ratio 0.98, 95% confidence interval [CI] 0.9 to 1.05, p > 0.33) by meta-analysis of an SLC2A9 variant in six case–control studies including 11,897 participants. In a separate meta-analysis of four population studies including 11,629 participants we found no association of SLC2A9 with systolic (effect size −0.12 mm Hg, 95% CI −0.68 to 0.43, p = 0.664) or diastolic blood pressure (effect size −0.03 mm Hg, 95% CI −0.39 to 0.31, p = 0.82).
Conclusions
This study provides evidence that SLC2A9 splice variants act as high-capacity urate transporters and is one of the first functional characterisations of findings from genome-wide association scans. We did not find an association of the SLC2A9 gene with blood pressure in this study. Our findings suggest potential pathogenic mechanisms that could offer a new drug target for gout.
Editors' Summary
Background.
Blood is continually pumped around the human body to deliver the chemicals needed to keep the body's cells alive and to take cellular waste products to the kidneys where they are filtered out of the blood and excreted in the urine. In healthy people, the levels of nutrients and waste products in serum (the liquid part of blood) fall within “normal” ranges but in ill people these levels can be very different. For example, serum uric acid (urate) levels are usually increased in people with gout. In this arthritic condition, uric acid crystallizes in the joints (often those in the big toe) and causes swelling and intense pain. Increased serum urate levels, which are also associated with high blood pressure, diabetes, and several other important conditions, can be caused by eating food that is rich in chemicals called purines (for example, liver, dried beans, and port). The body also converts its own purines into uric acid so genetic variations in the enzymes involved in purine breakdown can alter serum urate levels, as can variations in the rate of urate removal from the body by the kidneys. Urinary urate excretion is controlled by urate transporters, proteins that carry urate into and out of the kidney cells. Uricosuric drugs, which are used to treat gout, reduce serum urate levels by inhibiting a urate transporter that reabsorbs urate from urine.
Why Was This Study Done?
Several urate transporters have already been identified but recently, using an approach called genome-wide association scanning, scientists found that some genetic variants of a human gene called SLC2A9 are more common in people with high serum urate levels than in people with normal levels. SLC2A9 encodes a glucose transporter (a protein that helps to move the sugar glucose through cell membranes) and is highly expressed in the kidney's main urate handling site. Given these facts, could SLC2A9 (the protein made from SLC2A9) be a urate transporter as well as a glucose transporter? In this study, the researchers investigate this possibility and also ask whether genetic variations in SLC2A9 might be responsible for the association between serum urate levels and high blood pressure.
What Did the Researchers Do and Find?
The researchers first expressed SLC2A9 in frog eggs, a type of cell that does not have its own urate transporter. They found that urate rapidly moved into eggs expressing SLC2A9 but not into control eggs, that SLC2A9 transported urate about 50 times faster than glucose, and that glucose stimulated SLC2A9-mediated urate transport. Similarly, overexpression of SLC2A9 in human embryonic kidney cells more than doubled their urate uptake. Conversely, when the researchers used a technique called RNA interference to reduce the expression of mouse SLC2A9 in mouse cells that normally makes this protein, urate transport was reduced. Next, the researchers looked at two small parts of SLC2A9 that vary between individuals (so-called single polynucleotide polymorphisms) in nearly 900 men who had had their serum urate levels and urinary urate excretion rates measured. They found that certain genetic variations at these two sites were associated with increased serum urate levels and decreased urinary urate excretion. Finally, the researchers used a statistical technique called meta-analysis to look for an association between one of the SLC2A9 gene variants and blood pressure. In two separate meta-analyses that together involved more than 20, 000 participants in several studies, there was no association between this gene variant and blood pressure.
What Do These Findings Mean?
Overall, these findings indicate that SLCA9 is a high capacity urate transporter and suggest that this protein plays an important part in controlling serum urate levels. They provide confirmation that common genetic variants in SLC2A9 affect serum urate levels to a marked degree, although they do not show exactly which genetic variant is responsible for increasing serum urate levels. They also provide important new insights into how the kidneys normally handle urate and suggest ways in which this essential process may sometimes go wrong. Thus, these findings could eventually lead to new treatments for gout and possibly for other diseases that are associated with increased serum urate levels.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050197.
The UK National Health Service Direct health encyclopedia provides detailed information for patients about gout
MedlinePlus provides links to many sources of information about gout (in English and Spanish), including “What is gout?”, an easy-to-read guide from the US National Institutes of Arthritis and Musculoskeletal and Skin Diseases
Wikipedia also has pages on gout, uric acid, and SCL2A9 (note: Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
The Arthritis Research Campaign also has information on gout
Mark Caulfield and colleagues show that theSLC2A9 gene, which encodes a facilitative glucose transporter, is also a high-capacity urate transporter.
doi:10.1371/journal.pmed.0050197
PMCID: PMC2561076  PMID: 18842065

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