Definitive Diagnosis of Gout by Identification of Urate Crystals in Asymptomatic Metatarsophalangeal Joints.код для вставкиСкачать
BRIEF REPORTS 559 DEFINITIVE DIAGNOSIS OF GOUT BY IDENTIFICATION OF URATE CRYSTALS IN ASYMPTOMATIC METATARSOPHALANGEAL JOINTS CARLOS A. AGUDELO, MD, ABRAHAM WEINBERGER, MD, H. RALPH SCHUMACHER, MD, ROBERT TURNER, MD, and JAVIER MOLINA, MD Since McCarty and Hollander (1) in 1961 demonstrated monosodium urate cystals in synovial fluids, crystal identification has come to be regarded as the major diagnostic criterion for acute gouty arthritis (2). In the interim period between attacks, the diagnosis of gout is based on either aspiration of visible tophaceous material that has been reported to exist in about 30% of patients or suggested criteria (2) that include hyperuricemia and a variety of clinical features. Thirteen of 14 consecutive patients with a classic history of gout but without signs of inflammation at the time of aspiration of the first metatarsophalangeal (MTP) joint have been found to have monosodium urate crystals in these aspirates on compensated polarized light microscopic examination (3). One MTP joint not previously clinically involved was also found to contain crystals. These findings suggest that this simple procedure may be of great help in definitively establishing the diagnosis of gout in patients not experiencing acute attacks at the time of examination. Patients and Methods. Fourteen patients (13 men and 1 woman) ages 40-80 with typical histories of podagra without apparent tophaceous deposits were studied. Ten patients had had diagnosis confirmed previously by demonstration of monosodium urate crystals by compensated polarized light microscopy during attacks involving other lower extremity joints. Two patients had been asymptomatic for l year while on colchicine and allopurinol therapy (0.6 mg twice daily and 300 mg/daily, respectively) with serum uric acids of 6.0 and 6.8 mg% (normal 2.5-8 mg). Twelve patients had documented hyperuricemia in the past; 6 were normouricemic at the time of study. From the Rheumatology Unit, Department of Medicine, Bowman Gray School of Medicine, Winston-Salem, North Carolina; Arthritis Section, University of Pennsylvania School of Medicine and Veterans Administration Hospital, Philadelphia, Pennsylvania; Instituto de Seguros Sociales, Medellin, Colombia. Address reprint requests to Carlos A. Agudelo, MD, Rheumatology Unit, Department of Medicine, Bowman Gray School of Medicine, Winston-Salem, North Carolina 27103. Submitted for publication January 1 1 , 1979; accepted January 19, 1979. The first MTP joint was aspirated under aseptic technique using a dorsolateral approach and topical anesthesia with chloroethane. The joint was entered with a 20 or 21 gauge needle attached to a 10 cc syringe. The minute amount of material that usually included 12 drops of synovial fluid thus obtained was then placed on a glass slide, a coverslip was applied, and the slide was examined immediately for the presence of crystals under regular light and compensated polarized light microscopy. In l patient with a l-year history of gout, both first MTP joints were aspirated although his left MTP joint had never been acutely inflamed. Roentgenograms of the feet were done in 6 patients; 5 of these were normal and 1 showed a MTP cyst. Results. Fourteen of 15joints aspirated yielded strongly negative birefringent crystals typical of monosodium urate and were often intermingled with erythrocytes. All crystals seen were extracellular; in 2 cases the crystals were the long ( 15-2Op) needles seen frequently in tophi but are rarely found in joint fluid. In the patient in whom both MTP joints were aspirated, crystals were demonstrated in each aspirate. Discussion. Although a history of acute arthritis of the first metatarsophalangeal joint is typical of gout, a variety of other diseases including osteoarthritis, Reiter’s syndrome, trauma, and infection can also involve this joint. The best way to classify a patient as having gouty arthritis is to demonstrate characteristic sodium urate monohydrate crystals in the joint aspirate (2). It has been known from the postmortem studies of Garrod that urate tophi can occasionally be found in apparently asymptomatic joints (4). Our demonstration that crystals are almost invariably present in first MTP joints in the interim between attacks suggests a simple and useful method for diagnosis of gout in patients not experiencing active arthritis. Since crystals were still found in two asymptomatic patients after a year of allopurinol therapy despite normal serum uric acids, it will be of interest to determine how much therapy is needed to deplete joints of the crystals. BRIEF REPORTS 5 60 The presence of urate deposits in asymptomatic joints and in an apparently previously uninvolved joint raises the question of what factors must change to allow the crystals to be phlogistic (4,5). REFERENCES I. McCarty DJ, Hollander JL: Identification of urate crystals in gouty synovial fluid. Ann Intern Med 54:452-460, 1961 2. Wallace SL, Robinson H, Masi AT, Decker JL, McCarty DJ, Yu T: Preliminary criteria for the classification of the acute arthritis of primary gout. Arthritis Rheum 20:895900, 1977 3. Phelps P, Steele AD, McCarty DJ: Compensated polarized light microscopy: identification of crystals in synovial fluids from gout and pseudogout. JAMA 203:508-5 12, 1968 4. McCarty DJ: The gouty toe-A multifactorial condition (editorial). Ann Intern Med 86:234-236, 1977 5. Schumacher HR: Pathogenesis of crystal induced synovitis. Clin Rheum Dis 3:105-131, 1977 ERATTUM In Table 1 on page 85 of the article, “Coexistent Gout and Rheumatoid Arthritis,” by Daniel Wallace et al, the correct numbers should be: Women with rheumatoid arthritis Men and women with rheumatoid arthritis 3,360.000 5,145.000 If 3.2% of gouty women had rheumatoid arthritis (52,500 x 3.2%), 1680 concurrent cases would be expected.