TREATMENT OF REFRACTORY CRYSTAL-ASSOCIATED ARTHRITIS

The Utility of Ultrasound in Evaluating Joint Pain in Systemic Lupus Erythematosus: Looking beyond Fibromyalgia

BACKGROUND

Systemic lupus erythematosus (SLE) is a complex autoimmune condition with varied clinical presentations, and musculoskeletal pain is one of the most commonly associated symptoms. However, fibromyalgia (FM) is a prevalent co-existing condition in SLE patients that can also cause widespread pain, and in patients with both conditions, it is often difficult to distinguish the underlying cause of musculoskeletal pain and provide optimal therapy.

METHODS

A retrospective cohort study was conducted including all adult SLE patients who received musculoskeletal ultrasound (US) examinations for joint pain at the Ohio State University Wexner Medical Center between 1 July 2012, and 30 June 2022. Binary and multiple logistic regression analyses were performed to determine predictors of US-detected inflammatory arthritis as well as improved musculoskeletal pain.

RESULTS

A total of 31 of 72 SLE patients (43.1%) had a co-existing diagnosis of FM. In binary logistic regression, a co-existing diagnosis of FM was not significantly associated with US-detected inflammatory arthritis. In multiple logistic regression analysis, clinically detected synovitis was significantly associated with US-detected inflammatory arthritis (aOR, 142.35, p < 0.01), and there was also a weak association with erythrocyte sedimentation rate (ESR) (aOR 1.04, p = 0.05). In separate multiple logistic regression analysis, US-guided intra-articular steroid injection was the only predictor of improved joint pain at follow-up visit (aOR 18.43, p < 0.001).

CONCLUSIONS

Musculoskeletal US can be an effective modality to detect inflammatory arthritis as well as to guide targeted intra-articular steroid injection to alleviate joint pain in SLE patients with or without FM.

Febuxostat: A Novel, Non-Purine Xanthine Oxidase Inhibitor

Objective:

To review the pharmacology and clinical data for febuxostat in the treatment of gout and hyperuricemia.

Data Sources:

Articles on febuxostat published in English between 1966 and November 2006 were identified through a MEDLINE search using the key words febuxostat, TEI-6720, TMX-67, gout, and hyperuricemia. Additional articles were identified through search of the publications' reference lists. Abstracts from the 2005 proceedings of the American College of Rheumatology, American College of Clinical Pharmacology, and American Society for Clinical Pharmacology and Therapeutics were also searched for febuxostat studies.

Study Selection and Data Extraction:

All published febuxostat trials in humans were selected for this review. Clinical, pharmacokinetic, and pharmacodynamic data were evaluated.

Data Synthesis:

Febuxostat is a non-purine, selective inhibitor of xanthine oxidase that has demonstrated efficacy in lowering serum uric acid levels in patients with hyperuricemia associated with gout. Compared with allopurinol 300 mg/day, febuxostat 80 or 120 mg/day was more effective in lowering serum uric acid levels to less than 6 mg/dL. Febuxostat appears to be safe, with the majority of treatment-related adverse events reported being transient and mild-to-moderate in severity. However, abnormal elevation of liver enzyme levels has been reported with its use. There have been no documented major drug interactions with febuxostat.

Conclusions:

Febuxostat is a novel, non-purine xanthine oxidase inhibitor undergoing review by the FDA. It represents a potential advancement in the treatment of hyperuricemia associated with gout.

Comorbidity burden, healthcare resource utilization, and costs in chronic gout patients refractory to conventional urate-lowering therapy

Patients with chronic gout refractory to conventional urate-lowering therapy have high rates of flares and incidence of tophi, which impose a significant disease and potentially economic burden. This study examined healthcare resource use and costs stratified by disease burden. Adult patients diagnosed with gout (ICD-9-CM:274.xx) and having had ≥3 flares defined by clinical surrogates within a 12-month period were selected for the case cohort from the Thomson MarketScan databases (2003/Q3-2008/Q3). Only patients who had received allopurinol treatment and a diagnosis of tophi (ICD-9-CM:274.8x) at any time before the first flare (index date) or within 12 months postindex were included and were matched in a 1:1 ratio with control gout-free subjects. The comorbidity burden, healthcare resource use, and annual healthcare costs (2008 US$) in the 12-month postindex period were compared between both cohorts using regression models adjusted for demographic characteristic and stratified for patients with ≥6 flares. A total of 679 gout patients met the inclusion criteria for the study and had a higher prevalence of comorbidities than their matched controls. Gout cohort had a significantly higher incidence of emergency room, hospitalizations, outpatient visits, and other medical services than did their matched controls (all comparisons, uncorrected P < 0.01). After adjusting for baseline characteristics, the refractory gout cohort incurred an incremental total annual healthcare cost of $10,222 where 40% of the annual medical cost was for gout-related care compared with control cohort (P < 0.01). Patients with refractory gout have a significant economic burden compared with a gout-free population.

Primary care of the renal transplant patient

There has been a remarkable rise in the number of kidney transplant recipients (KTR) in the US over the last decade. Increasing use of potent immunosuppressants, which are also potentially diabetogenic and atherogenic, can result in worsening of pre-existing medical conditions as well as development of post-transplant disease. This, coupled with improving long-term survival, is putting tremendous pressure on transplant centers that were not designed to deliver primary care to KTR. Thus, increasing numbers of KTR will present to their primary care physicians (PCP) post-transplant for routine medical care. Similar to native chronic kidney disease patients, KTRs are vulnerable to cardiovascular disease as well as a host of other problems including bone disease, infections and malignancies. Deaths related to complications of cardiovascular disease and malignancies account for 60-65% of long-term mortality among KTRs. Guidelines from the National Kidney Foundation and the European Best Practice Guidelines Expert Group on the management of hypertension, dyslipidemia, smoking, diabetes and bone disease should be incorporated into the long-term care plan of the KTR to improve outcomes. A number of transplant centers do not supply PCPs with protocols and guidelines, making the task of the PCP more difficult. Despite this, PCPs are expected to continue to provide general preventive medicine, vaccinations and management of chronic medical problems. In this narrative review, we examine the common medical problems seen in KTR from the PCP's perspective. Medical management issues related to immunosuppressive medications are also briefly discussed.

Advances in the management of gout and hyperuricaemia

An acute attack of gouty arthritis is one of the most painful experiences reported throughout medical history. Therefore it is paramount to initiate appropriate therapy quickly in order to terminate the acute phase. This goal can be achieved with non-steroidal anti-inflammatory agents, colchicine, or corticosteroid-based therapies. Rarely, because of contraindications to these agents, only symptomatic treatment can be given until the attack subsides. The next step is to lower the serum urate level below the limit of solubility (i.e., below 40.8 mmol/L, or 6.8mg/dL) which reduces recurrences and begins to return the total body urate pool to normal. This equally important goal can be achieved by uricosuric agents or xanthine oxidase inhibitors, although the latter is generally favored. Allopurinol is the agent most commonly preferred because of its safety profile and ease of use, but there are known serious allergic reactions and untoward side effects that occasionally require discontinuation. Febuxostat, a xanthine oxidase inhibitor, and pegylated uricase are new agents under development and may be beneficial in these situations or when other comorbid conditions prevent the use of conventional treatments. Alcohol and dietary consumption are also related to hyperuricemia and acute gout. Recently beer, wine, and liquor were studied and the risk of gout varied according to the alcohol ingested. Furthermore, recent data sheds light on important dietary modifications that may help in the treatment of gout, and dispels certain beliefs about protein ingestion and the occurrence of acute gout. As we learn more about the associated conditions of hypertriglyceridemia, hypertension, and the metabolic syndrome, it may allow the tailoring of medical regimens that directly prevent or reduce recurrent attacks of gouty arthritis. There are specific approved treatments for these common comorbidities that have parallel effects of lowering serum urate levels. These recent findings may be especially important for treating refractory cases. While patient education remains a cornerstone to ensure compliance, other quality indicators for the management of this disease have been reported and should guide the clinician in the treatment of gout and result in improved care.

Colchicine: its mechanism of action and efficacy in crystal-induced inflammation

New light has been shed on the mechanisms of action of colchicine in crystal-associated arthropathies. Colchicine, long used to treat gout, arrests microtubule assembly and inhibits many cellular functions. At micromolar concentrations, it suppresses monosodium urate crystal-induced NACHT-LRR-PYD-containing protein-3 (NALP3) inflammasome-driven caspase-1 activation, IL-1beta processing and release, and L-selectin expression on neutrophils. At nanomolar concentrations, colchicine blocks the release of a crystal-derived chemotactic factor from neutrophil lysosomes, blocks neutrophil adhesion to endothelium by modulating the distribution of adhesion molecules on the endothelial cells, and inhibits monosodium urate crystal-induced production of superoxide anions from neutrophils. Cyto-chrome P450 3A4, the multidrug transporter P-glycoprotein, and the drugs that bind these proteins influence its pharmacokinetics and pharmacodynamics. Trial evidence supports its efficacy in acute gout and in preventing gout flares, but it has narrow therapeutic index, and overdosage is associated with gastrointestinal, hepatic, renal, neuromuscular, and cerebral toxicity; bone marrow damage; and high mortality.

Clinical trials in crystal arthropathy

A few clinical trials have evaluated therapeutic agents for crystal-associated arthropathy. Most of the studies are uncontrolled and observational. Management of patients who have acute crystal arthropathies usually is symptomatic with long-term management depending on crystal composition. In trials of gout, studies focus on acute symptomatic treatment, foregoing chronic management, which is aimed at reducing the concentration of serum urate. In those who have calcium crystals, however, there is no definitive or effective long-term treatment in chronic gout. The xanthine oxidase inhibitor and uricosurics are the agents used most commonly. Newer compounds in clinical trials show promise as effective and safe therapeutic options.

Treatment of crystal arthropathy--history and advances

The history of gout and the many distinguished historical figures who have suffered the agonies of this crystal deposition disorder have claimed the attention of medical historians like no other disease. Its treatment with uric acid lowering drugs became a twentieth century paradigm for the successful management and prevention of a chronic rheumatic disease, but the colorful history of the treatment of gout and crystal deposition disorders stretches back over 4,000 years.

High-level expression, purification, and characterization of non-tagged Aspergillus flavus urate oxidase in Escherichia coli

The entire encoding region for Aspergillus flavus uricase was cloned into pET-32a and expressed in Escherichia coli BL21 (DE3). The uricase was expressed in the E. coli cytoplasm in a completely soluble, biologically active form. A scalable process aimed to produce and purify multi-gram quantities of highly pure, recombinant urate oxidase (rUox) from E. coli was developed. The rUox protein was produced in a 30 L fermentor containing 25 L of 2x YT medium and purified to >99% purity using hydrophobic interaction, anion-exchange, and gel filtered chromatography. The final yield of purified rUox from fermentation resulted in approximately 27 g of highly pure, biologically active rUox per kg of cell paste (approximately 238 mg/8.8 g cell paste/L). The results presented here exhibit the ability to generate multi-gram quantities of rUox from E. coli that may be used for the development of pharmaceutics of reducing the hyperuricemia.

Calcium pyrophosphate dihydrate and hydroxyapatite crystal deposition in the joint: new developments relevant to the clinician

The major types of crystals containing calcium, which causes arthropathy and periarticular disease, are calcium pyrophosphate dihydrate and basic calcium phosphates, including hydroxyapatite. Exciting advances include the identification of mutations in the gene ANKH associated with disordered inorganic pyrophosphate (PPi) transport in some kindred with familial chondrocalcinosis linked to chromosome 5p. In addition, central basic mechanisms governing cartilage calcification and their relationship to aging and osteoarthritis have now been elucidated. These include the role of plasma cell glycoprotein-1, the PPi-generating ecto-enzyme, in chondrocalcinosis and the linkage of low- grade inflammation to expression and activation of two cartilage-expressed transglutaminase isoenzymes with direct calcification-stimulating activity. This review discusses clinically pertinent new information on pathogenesis. The authors also address, in detail, current diagnostic and therapeutic issues pertaining to calcium pyrophosphate dihydrate and hydroxyapatite crystal deposition in the joint, as well as possible therapeutic directions for the future.

Arthritis in the intensive care unit

Acute arthritis in critically ill patients may be caused by local or systemic infection, by a flare of chronic joint disease such as rheumatoid or crystal-associated arthritis, or by less common entities such as hemarthrosis. Diagnosis requires analysis of synovial fluid, and appropriate treatment is based on its findings. Prompt diagnosis and treatment are usually necessary to prevent the significant morbidity associated with these conditions.

Familial and clinical aspects of calcium pyrophosphate deposition disease

The mechanisms involved in calcium pyrophosphate dehydrated deposition disease (CPPDD) are unknown and those families with the disease, described in different countries, provide a fertile file for genomic research. Genomic DNA studies in these kindred with secondary or primary form of CPPDD provide a shortcut for trying to investigate the biomolecular basis of the disease. Mutations in the COL2A1 gene have been identified in one family with spondyloepiphyseal dysplasia and secondary deposits of pyrophosphate and apatite crystalline deposits. In another kindred with CPPDD due to precocious osteoarthritis, the phenotype was linked to markers of chromosome 8p. In four other kindreds (British, Argentinean, French, and the United States), the phenotypes were linked to a precise region of chromosome 5p. Two possible genes located in this region that are expressed in the articular cartilage, but of unknown articular physiologic role are being investigated as possible CPPDD genes. From the clinical point of view, CPPDD spectrum of clinical and radiographic manifestations is enlarging, especially those related to spine involvement or pseudo tumoral forms. At the end, the present review of a current therapeutic approach for CPPDD is discussed.

Stopping progression to tophaceous gout. When and how to use urate-lowering therapy

Although the prevalence of tophaceous gout has decreased in the past few years, the disease still exists, and without accurate diagnosis and therapy, it can still result in destructive arthritis. However, use of urate-lowering drugs may reduce plasma urate concentrations enough to allow resorption of tophi and prevent painful tophaceous gout. Some patients may have mechanical problems from tophi, despite adequate control of acute arthritis; in such situations, joint replacement or surgical excision of tophi may be necessary.

Diagnosis and Treatment of Gout in the Intensive Care Unit

Gout is a common cause of arthritis resulting from formation of monosodium urate crystals in synovial tissues. The incidence of this condition in the critically ill population is unknown, but gout can result in short-term morbidity and it can occasionally complicate management of a patient's primary condition. The diagnosis of gout should be considered in any patient in whom acute arthritis or bursitis develops. Aspiration of the involved joint or bursa and identification of crystals using either polarized or light microscopy are mandatory. Treatment options in critically ill patients differ from the usual treatment of gout because most critically ill patients have or are at risk for renal dysfunction and gastrointestinal bleeding, thus making use of nonsteroidal anti-inflammatory agents and colchicine hazardous. Intravenous colchicine in critically ill patients should be used with extreme caution, if at all, because the risk of bone marrow toxicity and other complications are well described in this patient population. Initial regimens should include use of adrenocorticotropic hormone, intra-articular corticosteroids, or systemic steroids. Analgesics may be beneficial as primary therapy in minor cases of acute gout, and they may be useful as adjunctive therapy in more severe cases. The role of colchicine as a prophylactic agent is discussed, as are treatment options in the allograft transplant population, in which rapidly progressive gout is increasingly common.

Periodontoid calcium pyrophosphate dihydrate deposition disease: "pseudogout" mass lesions of the craniocervical junction

Between 1984 and 1996, seven patients with symptomatic masses located posterior to the odontoid process and containing calcium pyrophosphate dihydrate crystals were evaluated by the senior author (A.H.M). All patients presented with distal paresthesias and myelopathy and underwent transoral-transpharyngeal resection of the anterior arch of C-I, the odontoid process, and the compressing mass. Histological examination revealed the characteristic changes of calcium pyrophosphate dihydrate (CPPD) deposition disease, with nodular deposits of birefringent rhomboid crystals. On magnetic resonance imaging, the masses appeared predominantly isointense with neural tissue on T1-weighted images and iso-to hyperintense on T2-weighted images. On computerized tomography scans, small area of calcifications within the masses were apparent in all cases. All patients improved postoperatively, with six of seven patients requiring posterior fixation for instability as a second procedure. Calcium pyrophosphate dihydrate deposition causing periodontoid mass lesions is a distinct clinical disease entity that probably is underdiagnosed. In the authors' l opinion, the diagnosis can often be established preoperatively by the distinctive neuroradiological appearance of the masses. Therefore, CPPD deposition disease should be considered in the differential diagnosis of masses of the craniocervical junction, because it is amenable to early surgical intervention. The consulting neuropathologist should be made aware of this diagnostic possibility at the time of surgery.