THU0300 Septic Arthritis in the Central Part of Denmark

Background Septic arthritis (SA) is a serious condition which can lead to rapid cartilage destruction and irreversible joint damage and is asociated with a significant mortality. SA is an uncommon condition with an incidence of 4-10/100.000/year. Risk factors for SA are age >60 years, recent bacteremia, diabetes mellitus, rheumatoid arthritis, gout, recent joint surgery, degenerative joint disease and joint prosthesis [1]. An accurate diagnosis can be difficult to state for patients with an underlying inflammatory joint disease. Intra-articular corticosteroid injections are widely used in aseptic arthritis and reduce the manifestations of inflammation. However, iatrogenic infection can be a complication to joint puncture, of which septic arthritis (SA) is the most serious[2] Objectives The aim of this study is to describe the microbiological etiology and co-morbidity in patients with SA and to register how many who had received an intra-articular steroid injection prior to the diagnosis Methods In this descriptive cross-sectional study all patients older >18 years diagnosed with SA at all hospitals in the central part of Denmark in the period January 2006 through December 2013 were registered. SA was defined as clinically inflamed joint and positive synovial fluid culture. The department of microbiology at Odense University Hospital identified the microbiological agents. Patients who had received an intra-articular steroid injection in a period of up to one month earlier they were diagnosed with SA and co-morbidities were registered Results We identified 215 patients diagnosed with SA (male:142, female: 73) given an average incidence at 6,9 cases/100.000 inhibitants [3]. Mean age was 64,8 years (21-94) 97% were monoarticular and 3% were polyarticular. Mean C-reactive protein 204 mg/l (2-523), mean leuc 11,9*10 9 /L (0,7-30,6). Nearly half of the patients had a prosthetic joint (47%) followed in frequency by pre-existing inflammatory joint or connective tissue disease (21%), 11% had diabetes mellitus and 5,6% (n=12) had an intra-articular steroid injection prior to the diagnosis. The average time from injection to diagnosis was 9 days.Twenty patients died within four weeks after SA was diagnosed, corresponding to a mortality of 9,3%. Bacterial agents: Staphylococcus aureus (n=104) 48% Coagulase negative staphylococcus (n=25) 12% Streptococcus pyogenes group (n=24) 11% Streptococcus mitis group (n=19) 9% Gram-negative rod shape bacteria (n=23) 11% other less common bacteria (n=20) 9% Conclusions In accordense with earlier studies we found staphylococcus aureus to be the most common bacterial microorganism in patients with SA. The highest isolated risk factor was joint prosthesis followed by inflammatory joint and connective tissue diseases. We did not find an increasing incidence of SA even though the numbers of therapeutic steroid injections had markedly increased in recent years. Despite the rarity of SA following intra-articular injections, patients should be informed of the risk of septic arthritis and the possible consequences A strict aseptic technique is important. References Shirtliff M.E. and Mader J. Acute Septic Arthritis, Clinical Microbiology Reviews, Oct 2002, 527-544 Geirsson Ά.J. et al, Septic arthritis in Iceland 1990-2002: increasing incidence due to iatrogenic infections, Ann Rheum Dis 2008; 67: 638-643 Denmark statistical demographic data (http://statistikbanken.dk) Disclosure of Interest : None declared DOI 10.1136/annrheumdis-2014-eular.3263