2005 Abstract : Cl 9

Authors: Charalampos Zalavras, M.D., Ph.D., Ryan Dellamaggiora, M.D., Michael Patzakis, M.D, Paul Holtom, M.D.

Title: Septic Arthritis In HIV Positive Patients

Addresses:

Purpose: The purpose of this study was to describe the microbiological features of septic arthritis in HIV-infected patients.

Methods: This is a retrospective review of 19 HIV-infected patients treated at our musculoskeletal infection ward for septic arthritis. All patients were male with a mean age of 42 years (range, 25 to 56 years). Eleven of these patients were diagnosed with AIDS. The mean CD4 count was 154/mm3 (range, 7 to 482/mm3) and 11 patients (58%) had a CD4 count < 200/mm3.

Results: Septic arthritis was monoarticular in 14 patients (74%) and involved the knee in 8 patients, the hip in 3 patients, and the wrist in 3 patients. Five patients (26%) presented with septic arthritis of more than one joints and in 4 of these cases the knee was one of the involved joints. Overall, the knee was involved in 63% of patients. The infection was monomicrobial in 18 patients (95%) and polymicrobial in 1 patient (5%). The most common pathogens were Staphylococcus aureus, present in 7 cases (37%); in 6 of these cases (32% of total cases) the organism was oxacillin-resistant. Mycobacterial infections were present in 3 patients (16%) and no fungal pathogens were identified. All mycobacterial infections as well as 4 of 5 polyarticular infections occurred in patients with a CD4 count < 200/mm3.

Discussion: Septic arthritis rarely develops in patients infected with the human immunodeficiency virus, despite their immunosuppression, and the role of opportunistic organisms appears controversial. In our series, Staphylococcus aureus was the most common pathogen, with an increased prevalence of ORSA. However, mycobacterial infections occurred in patients with a low CD4 count.

Significance: A high-index of suspicion for septic arthritis of multiple joints and mycobacterial infections is necessary in HIV-infected patients with a CD4 count < 200/mm3. However, the predominant pathogen is Staphylococcus aureus and should be covered with initial empiric antibiotic therapy.