Clinical and microbiological findings of septic arthritis caused by Haemophilus parainfluenzae.

OBJECTIVES: To report a case of septic arthritis due to H. parainfluenzae and to review the clinical and microbiological characteristics of published case patients.

PATIENTS AND METHODS: Data was collected on age, sex, infection localization, underlying risk factors, symptom onset-diagnosis interval, analytical findings, microbiological diagnosis, treatment, outcome, and follow-up of the present patient (presenting with septic arthritis of the pubic symphysis due to H. parainfluenzae) and those identified in a literature analysis.

RESULTS: Data of 18 patients, including 17 reported case patients, was collected. Mean age at presentation was 51±9 years. Underlying diseases for septic arthritis were recorded in 11 patients. The infection site was the knee in eight patients, hip and/or acromioclavicular joint in five. Pain was observed in 15 patients and fever in 10; the mean symptom onset-diagnosis interval was 9.4 days. Diagnosis was obtained from synovial fluid aspirate in 12 patients and from blood cultures in four. Susceptibility of H. parainfluenzae strains was reported in 12 cases. Eight patients were treated with cephalosporins and 10 with penicillins. A favorable outcome was observed in 13 patients.

CONCLUSIONS: Septic arthritis caused by H. parainfluenzae is a rare entity that requires a high level of suspicion before application of laboratory methods for rapid diagnosis and treatment.