Neopterin in Septic Arthritis

Abstract

Despite its low incidence septic arthritis remains a serious problem in orthopaedic practice. General or local immunosuppression predisposes for septic arthritis. Thus we see an increasing incidence in elderly patients, in patients suffering from rheumatic diseases and after alloplastic arthroplasty of the hip and of the knee. In septic arthritis the first line of host defense mechanisms is overwhelmed and bacterial multiplication proceeds within the joint. The pathogens found are in 50% to 75% of cases Staphylococci and in 15% to 20% Streptococci. Histologically we initially find an edema of the synovial membrane and a dramatic polymorph-nuclear-cell infiltration. After developing all signs of inflammation, a persistent purulent effusion accumulates and cartilage and bone destruction ensues as a result of proteolytic enzyme activity released from the bacteria and the polymorph nuclear leukocytes. Modern therapy consists of early surgical intervention (synovectomy, debridement) combined with local and systemic antibiotic treatment. The early intervention is one of the main factors for successful management. Thus the interest of early detection of septic arthritis is obvious. The production of neopterin can be related to the activity of the specific antibacterial cell mediated immune response. In the current, study weexamined neopterin levels in 12 patients with septic arthrits and in 8 patients with an infected prosthesis. The results were related to a new inflammation marker (PMN-elastase) and to 4 other 'classical' inflammation markers (ESR, leukocytes, fibrinogen and C-reactive protein). All markers showed a high sensitivity in the detection of septic arthritis. 10 patients with septic arthritis and 5 patients with an infected prosthesis showed pathological neopterin levels > 10 nmol/l.

Keywords

• septic arthritis
• inflammation markers