Pseudosepsis in rheumatoid arthritis due to cellular and lipid abnormalities in synovial fluid

Pseudoseptic arthritis resulting in joint destruction

Pseudoseptic arthritis is an increasingly recognised entity. It is an inflammatory arthritis that mimics septic arthritis; however, Gram stain and cultures are persistently negative. It is a diagnosis of exclusion. We present the first case, to date, in which pseudoseptic arthritis led to such severe joint degeneration that joint replacement surgery was required. A 54-year-old truck driver with rheumatoid arthritis, on immunosuppressive therapy, presented with acute onset severe left hip pain. He was given a clinical diagnosis of septic arthritis and treated with two prolonged courses of antibiotics despite persistently negative synovial fluid cultures. He experienced progressive joint destruction necessitating a two-stage total hip replacement. A retrospective diagnosis of pseudoseptic arthritis was made. This case demonstrates the difficulties inherent in differentiating between septic and pseudoseptic arthritis. This case also highlights the importance of accurate diagnosis and treatment for pseudoseptic arthritis to avoid accelerated joint destruction.

Pyarthrosis in patients with rheumatoid arthritis: a detailed analysis of 10 cases and literature review

OBJECTIVES

1) To analyze the clinical features and outcome of patients with rheumatoid arthritis and pyarthrosis seen in a rheumatology department during a 9-year period; 2) To review the available literature about this association in the last decade.

METHODS

From the database of our department, we collected all hospitalized cases of infectious arthritis in native joints between January 1990 and December 1998. In 10 cases (27%), pyarthrosis occurred in patients with rheumatoid arthritis. A detailed analysis of each patient was performed. The literature was reviewed by using MEDLINE from 1990 to 1999.

RESULTS

The mean age of patients was 63.2 years; six were female. Most patients had long-standing disease and poor functional class, and all received glucocorticoid treatment. Mean diagnostic delay was 7.3 days. Causative organisms were Staphylococcus aureus (4 cases), gram-negative bacilli (3 cases), anaerobic bacteria (2 cases), and Streptococcus pneumoniae (n = 1). Two patients died. In all but two patients who survived, joint function worsened.

CONCLUSIONS

Rheumatoid arthritis is a relevant host-related risk factor for septic arthritis. Pyarthrosis in these patients is associated with considerable morbidity and mortality.