Course of serum amyloid A (SAA) plasma concentrations in horses undergoing surgery for injuries penetrating synovial structures, an observational clinical study

Abstract

BackgroundInjuries penetrating synovial structures are common in equine practice and often result in septic synovitis. Significantly increased plasma levels of serum amyloid A (SAA) have been found in various infectious conditions in horses including wounds and septic arthritis. Plasma SAA levels were found to decrease rapidly once the infectious stimulus was eliminated. The purpose of the current study was to investigate the usefulness of serial measurements of plasma SAA as a monitoring tool for the response to treatment of horses presented with injuries penetrating synovial structures. In the current study plasma SAA concentrations were measured every 48 hours (h) during the course of treatment.ResultsA total of 19 horses with a wound penetrating a synovial structure were included in the current study. Horses in Group 1 (n = 12) (injuries older than 24 h) only needed one surgical intervention. Patients in this group had significantly lower median plasma SAA levels (P = 0.001) between 48 h (median 776 mg/L) and 96 h (median 202 mg/L) after surgery. A significant decrease (P = 0.004) in plasma SAA levels was also observed between 96 h after surgery (median 270 mg/L) and 6 days (d) after surgery (median 3 mg/L). Four horses (Group 2) required more than one surgical intervention. In contrast to Group 1 patients in Group 2 had either very high initial plasma concentrations (3378 mg/L), an increase or persistently high concentrations of plasma SAA after the first surgery (median 2525 mg/L). A small group of patients (n = 3) (Group 3) were admitted less than 24 h after sustaining a wound. In this group low SAA values at admission (median 23 mg/L) and peak concentrations at 48 h after surgery (median 1016 mg/L) were observed followed by a decrease in plasma SAA concentration over time.ConclusionsA decrease in plasma SAA concentrations between two consecutive time points could be associated with positive response to treatment in the current study. Therefore, serial measurements of plasma SAA could potentially be used as an additional inexpensive, quick and easy tool for monitoring the treatment response in otherwise healthy horses presented with injuries penetrating synovial structures. However further studies will be necessary to ascertain its clinical utility.

Serum amyloid A and plasma fibrinogen concentrations in horses following emergency exploratory celiotomy

“…Similar findings are reported in horses, where increases in [SAA] occur as early as 12 h after elective surgical procedures [3]. [SAA] peaks at 48 h after lavage of septic synovial structures [11], and is increased at 72 h after castration, returning to preoperative values at 192 h in non-complicated cases [12]. Additionally, [SAA] and [fibrinogen] were significantly higher after more invasive procedures (ovariectomy, celiotomy), compared with arthroscopy or laryngoplasty [13].…”

Validation of an equine serum amyloid A assay with an unusually broad working range

“…This is a highly undesirable feature, as it results in falsely low concentration outputs that goes unnoticed unless samples are analysed in several dilutions. Particularly when working with equine SAA, where markedly high concentrations are observed frequently [10,20,21], it is of great importance to ascertain that the assay does not have prozone issues. Within the concentration range of 0 to more than 6000 mg/L SAA the VET-SAA assay did not show prozone effect, similar to a previously validated multi-species SAA assay from the Eiken Chemical Co. [4].…”

Equine Inflammatory Markers in the Twenty-First Century

“…74 Horses with penetrating wounds to a synovial structure that presented within 24 hours after the initial injury had lower plasma SAA concentrations at admission (median, 23 mg/L) and a faster decrease following surgery, compared with horses requiring multiple surgeries, which had a median SAA concentration of 3378 mg/L at admission, with persistent increases 48 hours postoperatively (median, 2525 mg/L). 75…”