From the Research
Immunodeficiency should be considered in a patient with septic arthritis when there are unusual clinical presentations or treatment responses, as identified in the most recent study 1. Specifically, suspect immunodeficiency when septic arthritis involves unusual or multiple organisms, particularly opportunistic pathogens like fungi or mycobacteria; when infection recurs despite appropriate treatment; when the patient has septic arthritis at multiple sites simultaneously; or when the infection fails to respond to standard antibiotic therapy. Additional red flags include septic arthritis in the absence of typical risk factors, concurrent unusual infections at other sites, or a history of recurrent serious infections of any type. A thorough immune workup should be initiated in these cases, including complete blood count with differential, immunoglobulin levels (IgG, IgA, IgM), complement studies, HIV testing, and potentially more specialized testing like lymphocyte subset analysis or neutrophil function tests depending on the clinical scenario, as suggested by earlier studies 2, 3, 4, 5. Early identification of underlying immunodeficiency is crucial as it may require specific management beyond treating the acute infection, such as immunoglobulin replacement therapy, prophylactic antibiotics, or treatment of underlying conditions like HIV. Some key points to consider in the diagnosis and management of septic arthritis include:
- Prompt diagnosis and treatment to prevent permanent morbidity and mortality 1
- Consideration of risk factors such as age, diabetes mellitus, rheumatoid arthritis, recent joint surgery, and immunosuppressive medication use 1
- The importance of synovial fluid studies in confirming the diagnosis 1
- The need for empiric antibiotic therapy if there is clinical concern for septic arthritis, with consideration of microorganisms such as Neisseria gonorrhoeae, Borrelia burgdorferi, and fungal infections based on history and laboratory results 1.