Crystal-Associated Arthropathies

Amorphous-mediated crystallization of calcium pyrophosphate tetrahydrate: the role of alkaline earth metal ions

Although calcium pyrophosphates are commonly involved in crystal arthropathies, their formation mechanisms remain largely underexplored. Here, we investigated the crystallization pathway of calcium pyrophosphate tetrahydrate in the absence and presence...

Gout Flare Burden, Diagnosis, and Management: Navigating Care in Older Patients with Comorbidity

Gout is the most common form of inflammatory arthritis, and its incidence is highest in middle-aged and older patients. Adding to the diagnostic complexity, up to 50% of patients aged > 65 years present atypically, with subacute oligo- or polyarticular flares. Comorbidity and polypharmacy, common in older populations, affect real-world treatment decisions in gout management, and no specific guidelines are available to address these issues in these at-risk groups. Despite the growing public health burden posed by gout, suboptimal management has led to increased morbidity and substantial healthcare utilization and cost burden, as reflected by an increased incidence of emergency department visits and hospitalizations in recent years. Colchicine, nonsteroidal anti-inflammatory drugs, or glucocorticoids (oral, intraarticular, or intramuscular) should be considered as first-line agents for gout flare management. Urate-lowering therapy, with the goal of lowering and maintaining serum urate concentrations at < 6 mg/dL (< 360 μmol/L), is recommended to achieve optimal outcomes, including regression of tophi, reduction (or elimination) of flares, and reductions in total urate burden. In this review, we summarize the current burden posed by gout and discuss best practices in its diagnosis and management, focusing on best practices in the context of gout flare in older patients with comorbid conditions.

[Synovial fluid analysis]

At present, the study of the synovial fluid (SF) is a tool that is used frequently in specialized laboratories because it allows the establishment of diagnosis of crystal associated arthropathies, supports the diagnosis of septic arthritis and helps establish other rheumatologic diagnoses such as monoarthritis or joint effusion. The complete study of the SF includes the following analyses: 1. Macroscopic; 2. Microscopic; and 3. Specific stains. Each one provides information of the joint's state and helps in the establishment of diagnosis and treatment. The characteristics that must be described in the macroscopic analysis are: color, volume and viscosity. Microscopic analysis of the SF confirms the presence of an inflammatory or infectious processes and allows for the detection and identification of crystals. Polarized light microscope is a fundamental tool for the analysis of SF and for the identification of the crystals present in the samples, which not only depend on the form, but also of their birefringence. It is important to mention that in the microscopic analysis, artifacts can confuse the inexperienced observer. A suitable interpretation of the analysis of SF requires the observation by at least two experienced observers. The information that the analysis of SF provides to the clinicians gives them the necessary elements to establish the diagnosis and to decide on treatment. Specific stains in the analysis of SF help in the identification of non-birefringent crystals as those of calcium hydroxypatite. In SF analysis, new fields are being explored that include quantification of cytokines, chemokines, immunoglobulins and the characterization of cell lineages.

Gout Induced by Intoxication of Sodium Bicarbonate in Korean Native Broilers

Gout is a metabolic disorder that results in hyperuricemia and the deposition of positively birefringent monosodium urate crystals in various parts of the body. Intoxication of sodium bicarbonate (SBC) for 35 days in Korean native broilers was investigated. Sixty birds, aged 2 weeks, divided into 5 groups were exposed to excess SBC: 2 g/L (group A), 7.5 g/L (group B), 20 g/L (group C), 40 g/L (group D). Toxicopathological examination of all exposed birds revealed the manifestation of visceral and articular gout in group C, while birds of group D showed acute kidney damage with manifestation of excessive visceral gout. Interestingly, few birds in group D also showed signs of rare condition of acute articular gout. Dose-dependent increments in erythrocytic count, hematocrit values, and hemoglobin levels of the exposed birds were observed. Hypernatremia, hyperuricemia, hypokalemia, and hypochloremia were common findings among exposed birds. Microscopic examination of birds that manifested visceral gout revealed significant urate deposit, tubular necrosis, and tophi formation in renal interstitium. These findings provide a pathophysiological link that SBC intoxication may support hyperuricemia, which is an independent risk factor for gout and other renal dysfunctions. Further study is required to delineate the effect of lowering uric acid on progression of gout and other renal diseases.

Management of acute and chronic gouty arthritis: present state-of-the-art

There are three stages in the management of gout: (i) treating the acute attack; (ii) lowering excess stores of uric acid to prevent flares of gouty arthritis and to prevent tissue deposition of urate; and (iii) providing prophylaxis to prevent acute flares. It is important to distinguish between therapy to reduce acute inflammation in acute gout and therapy to manage hyperuricaemia in patients with chronic gouty arthritis. During the acute gouty attack nonpharmacological treatments such as topical ice and rest of the inflamed joint are useful. NSAIDs are the preferred treatment in acute gout. The most important determinant of therapeutic success is not which NSAID is chosen, but rather how soon NSAID therapy is initiated. Other treatments include oral and intravenous colchicine, intra-articular and systemic corticosteroids, and intramuscular corticotropin. Optimal treatment of chronic gout requires long-standing reduction in serum uric acid. The urate-lowering drugs used to treat chronic gout are the uricosuric drugs, the uricostatic drugs, which are xanthine oxidase inhibitors, and the uricolytic drugs. Xanthine oxidase inhibitors such as allopurinol, oxipurinol and febuxastat should be used as first-line treatment in patients with renal calculi, renal insufficiency, concomitant diuretic therapy and ciclosporin (cyclosporine) therapy, and urate overproduction. Uricosuric drugs include probenecid, benzbromarone, micronised fenofibrate and losartan. They are the urate-lowering drugs of choice in allopurinol-allergic patients and underexcretors with normal renal function and no history of urolithiasis. The use of recombinant urate oxidase in patients with chronic gout is limited by the need for parenteral administration, the potential antigenicity and production of anti-urate oxidase antibodies, and declining efficacy. The effectiveness of colchicine prophylaxis as an isolated therapy is still to be confirmed by placebo-controlled trials. Another issue is prophylaxis with NSAIDs. There are no comparative studies with colchicine.

A literature review of the epidemiology and treatment of acute gout

BACKGROUND

Gout is the most common cause of inflammatory arthritis in men aged >40 years and is frequently encountered in clinical practice.

OBJECTIVE

The goal of this article was to review the published literature on the epidemiology, treatment, and estimated burden of illness of acute gout.

METHODS

Articles on gout published in English between 1980 and June 2002 were identified through a MEDLINE search. Relevant clinical studies and review articles were found using the text- and keyword-search term gout alone and in combination with epidemiology, prevalence, incidence, complications, outcome, quality of life, economics, cost, prevention or drug therapy. The reference lists of identified articles, especially review articles, were checked for any additional studies that might have been missed in the original MEDLINE search.

RESULTS

The epidemiology of gout in various geographic regions has been well documented. Data suggest that environmental, racial, and hereditary factors may influence the development of gout, and that the prevalence of gout appears to be on the rise worldwide. Evidence from well-designed clinical studies evaluating drug therapies for gout is limited. Therapies for acute gout include corticotropin, corticosteroids, colchicine or, more often, nonsteroidal anti-inflammatory drugs (NSAIDs), which have shown comparable efficacy. A recent study suggests that etoricoxib, a new cyclooxygenase-2-selective inhibitor, may be as effective as and better tolerated than traditional NSAIDs in the treatment of gout. Urate-lowering therapy, prophylactic colchicine, and low-dose NSAIDs are used for the long-term prophylaxis of gout. However, all acute and prophylactic therapies are associated with adverse events. Using an economic model for gout, the annual direct burden of illness for new cases of acute gout can be estimated at 27,378,494 US dollars in the United States.

CONCLUSIONS

Gout is an increasingly prevalent condition worldwide and creates a heavy economic burden. Available treatments are generally effective; however, they are not devoid of adverse events. Well-designed, long-term, controlled clinical trials evaluating the comparative efficacy and tolerability of treatments for gout are needed.

Crystal-induced arthritis: an overview

The most common crystal-related arthropathies-gout, calcium pyrophosphate dihydrate disease or "pseudogout," and calcific periarthritis/tendinitis-may be appropriately diagnosed and managed by the primary care physician. Definitive diagnosis via synovial tap is recommended, as the clinical picture may not identify some cases. The acute pain and swelling of attacks, regardless of etiology, generally respond to treatment with nonsteroidal anti-inflammatory drugs and local or occasionally systemic corticosteroids. Once a causative crystal has been identified and a diagnosis established, a plan for long-term management and prevention of recurrences may be devised. Thus, uric-acid-lowering therapy may be indicated in a patient who has experienced recurrent attacks of gout, whereas control of serum phosphate levels might be effective in some individuals with hyperphosphatemia and hydroxyapatite-associated periarthritis or arthritis. Crystal deposits in joints can be destructive as well as painful. Treatment, therefore, has two objectives: To relieve the pain of the acute attack, thus restoring normal function, and to prevent the accumulation of crystals that can lead to degenerative disease. Identification and subsequent treatment of preventable or correctable underlying disorders may be one of the most gratifying aspects of managing crystal-induced arthropathies.

Arthritis diagnosis based upon the near-infrared spectrum of synovial fluid

Synovial fluid aspirates have been characterized by measuring their visible/near-infrared spectra (400-2500 nm). The hypothesis tested in this study is that the spectra contain sufficient information to serve as an aid in the diagnosis and/or staging of arthritic disorders. The concentrations of all major constituents are carried implicitly in the spectra, and in this sense this approach is similar in spirit to conventional synovial fluid analysis. The distinguishing feature of this method is that we have not converted the raw data (spectra) explicitly to analytical information. Rather, we have used automated pattern recognition methods to identify significant characteristics of the spectra themselves. A total of 109 spectra were measured and split into three classes according to the disease (osteoarthritis, rheumatoid arthritis, or spondyloarthropathy) affecting the patient from whom the synovial fluid sample was taken. An automated classification method was then trained by correlating features derived from these spectra to the clinical diagnoses. The robustness of the classification was validated using the leave-one-out cross-validation method, i.e., by training on all but one of the spectra and using the resulting model to predict the classification for the spectrum that is left out. The result derived by following this procedure for each of the spectra was that 105 of the 109 predicted classifications correctly matched the clinical diagnosis. These results suggest that the near-infrared spectrum of synovial fluid is sufficient to allow diagnosis of the disease affecting the joint from which the aspirate is drawn.

Managing rheumatologic disease in nursing home patients

Precise diagnosis and treatment are essential when dealing with rheumatologic complaints in elderly nursing home patients. National surveys suggest that for every nursing home resident, there are two equally frail elders living in the community. The same principles of diagnosis and management apply to this latter group of patients, including use of multidisciplinary input from nurses and physical and occupational therapists, who are becoming increasingly available in the rapidly expanding and accessible home healthcare system. However, the therapeutic value of the physician's thoughtful and empathic history taking and careful hands-on examination should not be underestimated.

Supravital staining of synovial fluid with Testsimplets

We explored the use of Testsimplet (TS) in synovial fluid (SF) analysis. TS is a glass slide coated with a dry mixture of methylene blue and cresyl violet, which in contact with one drop of SF provides a stained fresh preparation. We applied the TS to the study of 159 SFs of patients with different rheumatic diseases. In those SFs of patients with crystal-associated diseases, the crystal search was performed both on unstained preparations and with TS. TS was as good as the Wright's and Papanicolaou stain in characterizing SF cells, lupus erythematosus cells, and detection of occasional bacteria. TS allowed a better visualization of Reiter's cells, cartilage fragments, synovial villi, fat droplets, and fibrin. Crystals were identified in every TS of those patients with crystal-associated diseases. TS is a rapid and reproducible method of SF supravital staining. Crystals are well preserved for simultaneous examination with compensated polarized light.

Effectiveness of etodolac ('Lodine') compared with naproxen in patients with acute gout

A double-blind, parallel group study was carried out in 61 patients suffering from acute gouty arthritis to compare the effectiveness of etodolac and naproxen in the relief of symptoms. Patients were allocated at random to receive either 300 mg etodolac twice daily (31 patients) or 500 mg naproxen twice daily (30 patients) for 7 days. Both groups were comparable for sex, age and weight of patients, but there was a tendency for patients in the etodolac group to have more severe gout as shown by baseline clinical assessment scores. The variables assessed on entry and on Days 2, 4 and 7 of treatment were pain intensity, swelling, tenderness, erythema, joint heat, range of motion, and physician's and patients' overall evaluation of the condition. The results showed that there was a significant improvement from baseline in all of the variables at each time point in both treatment groups. However, more etodolac-treated patients (81%) than naproxen-treated patients (53%) showed overall improvement at Day 2, and etodolac was significantly better than naproxen on the Day 2 evaluation of joint swelling and at the Day 4 evaluations of joint tenderness, range of motion and the physician's global assessment. At the final evaluation on Day 7, 97% of the etodolac group reported that their condition had improved as compared to 93% of the naproxen group. Both drugs were well tolerated and only a few mild side-effects were reported.