Effect of intrathecal amikacin administration and repeated centesis on digital flexor tendon sheath synovial fluid in horses.
OBJECTIVE
To determine the effect of intrathecal amikacin administration and repeated tenovaginocentesis on the total nucleated cell count (TNCC), total protein (TP) concentration and cytologic characteristics of synovial fluid of the equine digital flexor tendon sheath (DFTS).


METHODS
Randomized, cross-over experimental design.


METHODS
Adult horses (n=8).


METHODS
Synovial fluid was aseptically collected from the DFTS and either 1 mL amikacin sulfate (250 mg/mL) or lactated Ringer's solution (LRS) was injected into the DFTS. Serial synovial fluid samples were obtained at 0, 12, 24, 48, and 72 hours. The opposite treatment was administered to the contralateral DFTS after a washout period of 2 weeks.


RESULTS
Treatment increased TP concentration, TNCC, percentage of neutrophils, and neutrophil counts from baseline levels. There was no difference between treatment of the DFTS with amikacin or LRS. Values peaked at 12-24 hours after the initial centesis and then declined toward baseline levels.


CONCLUSIONS
Injection and repeat centesis of the normal DFTS with 250 mg amikacin or an equivalent volume of LRS resulted in mild increases in synovial fluid analytes from baseline. Synovial inflammation in this study was not accompanied by lameness at the walk and measured analytes returned toward baseline levels within 12-24 hours of first injection.


CONCLUSIONS
The effect of tenovaginocentesis and intrathecal administration of amikacin or LRS on DFTS synovial fluid values are modest in most horses; however, some horses can develop marked increases in synovial fluid values that may be interpreted as sepsis.
Dykgraaf
Susanne
S
Veterinary Medical Teaching Hospital and the Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA. sdykgraaf@ucdavis.edu
Dechant
Julie E
JE
Johns
Jennifer L
JL
Christopher
Mary M
MM
Bolt
David M
DM
Snyder
Jack R
JR
D000583:Amikacin / Q000008:administration & dosage / Q000627:therapeutic use*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D019540:Area Under Curve; D018592:Cross-Over Studies; D005260:Female; D006734:Horse Diseases / Q000188:drug therapy*; D006736:Horses; D007442:Intubation, Intratracheal / Q000662:veterinary; D007794:Lameness, Animal / Q000188:drug therapy; D008297:Male; D009504:Neutrophils; D011506:Proteins / Q000032:analysis; D013582:Synovial Fluid / Q000737:chemistry / Q000166:cytology; D013708:Tendon Injuries; D013717:Tenosynovitis / Q000188:drug therapy / Q000662:veterinary*; D013997:Time Factors; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D011506:Proteins; D000583:Amikacin