Abnormalities in synovial fluid of patients with septic arthritis detected by gas-liquid chromatography

Gas liquid chromatography was performed on synovial fluid of 94 patients with exudative arthritis. A relatively constant pattern of peaks was obtained in all synovial fluid samples. Lactic acid was increased in synovial fluid of patients with septic arthritis excluding gonococcal arthritis. In addition 2 constant peaks with retention time of 546 and 848 seconds in the chromatogram usually showed a significant increase in the synovial fluids of patients with septic arthritis (including gonococcal arthritis) but not in those from patients with sterile inflammatory or degenerative arthritis. In 1 patient with pseudomonas arthritis an increase in the peaks was noted with clinical and bacteriological relapse and subsequently there was a gradual return to normal levels during clinical improvement. Increase in synovial fluid lactic acid is useful in the diagnosis of septic arthritis. Identification of the compounds represented by the 2 peaks, which presumptively correspond to n-valeric and n-hexanoic acid, may provide further information on diagnosis, prognosis and pathogenesis of arthritis and may help in the differentiation between gonococcal and nongonococcal arthritis.