Can Blood Serum Amyloid A Concentrations In Horses Differentiate Synovial Sepsis From Extrasynovial Inflammation And Determine Response To Treatment?

Background Serum amyloid A (SAA) concentrations in blood and synovial fluid of horses with synovial sepsis have diagnostic value. Studies suggest serial blood SAA measurements could act as a prognostic indicator. This study evaluated the use of serial blood SAA concentrations for monitoring of horses with synovial sepsis.Methods A prospective clinical trial was performed of horses referred to a single hospital with synovial sepsis that survived (n=17), synovial sepsis that were euthanised (n=5), non-septic intrasynovial pathologies (n=14) or extensive extrasynovial lacerations (n=5). SAA concentrations were determined on admission and every 24 hours thereafter. The area under the concentration-time curve from 0 to 144 hours of each group was compared by Kruskal-Wallis and post hoc Dunn's tests (P<0.05).Results Significant difference in mean blood concentration of SAA was found between synovial sepsis that survived and non-septic pathologies in the first 48 hours, as well as between non-septic intrasynovial pathologies and non-responsive sepsis requiring euthanasia. No difference was found between extensive extrasynovial lacerations and any septic group.Conclusions While serial blood SAA is useful for monitoring clinical response of intrasynovial septic pathologies, interpretation should consider other clinical findings since blood SAA is not a specific marker for synovial sepsis.