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International Journal of Rheumatology
Volume 2009, Article ID 286951, 7 pages
http://dx.doi.org/10.1155/2009/286951
Research Article

Differentiation of PSRA due to Group A and due to Nongroup A Streptococci in Patients with Early Arthritis and Elevated Antisteptolysin-O at Presentation

Department of Rheumatology, Medical Centre Leeuwarden, P.O. Box 888, 8901 BR Leeuwarden, The Netherlands

Received 20 August 2008; Revised 10 December 2008; Accepted 28 January 2009

Academic Editor: Ronald F. van Vollenhoven

Copyright © 2009 T. L. Th. A. Jansen. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A study was performed of consecutive patients presenting to a Dutch early arthritis clinic with a primary suggested diagnosis of reactive arthritis due to streptococci between April 1998 and January 2003, in a well-defined reference population consisting of 600 000 inhabitants. At 1 year after presentation out of 45 acute arthritis patients with initially an elevated antistreptolysin-O and without an alternative rheumatic diagnosis only 9 patients (20%) were not diagnosed as PSRA; 16 cases (36%) were due to NGAS, 20 cases (44%) due to GAS. The estimate of the annual incidence rate of PSRA in the Netherlands during the study was 1.26 per 100 000: 0.70 GAS-related. A diagnostic set of criteria was formulated based on the original Ayoub&Ahmed criteria by adding a serological criterium ASO/antiDNaseB ratio <1.4 and excluding a clinical criterium on chronicity/recurrency of arthritis: likelihood ratio for a positive test 7.9 [95% confidence interval (95%CI: 2.7–22.7)], for a negative test 0.06 [95%CI: 0.009–0.39].