EQUINE VETERINARY EDUCATION / AE / MAY 2015


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impregnated adhesive drape (Ioban)3 was applied to the shoulder region and the horse recovered uneventfully from anaesthesia.


Antimicrobial therapy (enrofloxacin 5 mg/kg bwt i.v. s.i.d.)


and phenylbutazone (4.4 mg/kg bwt i.v. s.i.d.) were continued post operatively. Five days post operatively, comfort levels had improved considerably (grade 2/5: AAEP at walk) and the phenylbutazone dose was reduced to 2.2 mg/kg bwt s.i.d. for a further 5 days, at which point it was stopped. Sutures were removed 10 days post operatively and the patient was discharged with instructions for box rest with 2 min handwalking twice daily. Oral enrofloxacin was continued at 7.5 mg/kg bwt s.i.d. for a further 14 days.


Outcome


Walking exercise was gradually increased from one month post operatively. Repeat examination 2 months post operatively identified no evidence of lameness at walk or trot and no pain was elicited by palpation of the infraspinatus or biceps structures. The patient was allowed free turnout at 2 months post surgery and returned to exercise at 5 months post surgery. At the time of writing, the horse has been in full race training for 4 months with no recurrence of lameness reported.


Discussion


In this case report we describe the successful diagnosis and treatment of synovial sepsis of the ITB and ISB. Sepsis developed within 48 h of treatment for subsolar abscessation and therefore haematogenous localisation of bacteria from this focus of infection was considered the most likely aetiology. There was no history of trauma or a penetrating wound affecting the scapulohumeral region, ruling out the most common causes of synovial sepsis in an adult equine (Schneider et al. 1992). Because the horse had been kept stabled, pressure injury from a racing harness was also excluded. Consideration must be given to the species of bacteria isolated from the ITB, Staphyloccus intermedius. Although environmental bacteria are often cultured from hoof abscesses, Staphylococcus and other Gram-positive bacteria have been cultured from diseased hoof tissue (Onishi 2012). Synovial and osseous infection as a result of haematogenous spread and localisation is a well recognised condition in equine neonates (Waterhouse and Marr 1997; Steel et al. 1999; Neil et al. 2010). Septic tenosynovitis has also been reported in an adult Arabian subsequent to bacterial peritonitis (Archer et al. 2004) but the incidence of septic localisation from minor infectious processes in adult equines is less common. We are not aware of any reports of multicentric synovial sepsis arising from a foot abscess. In human dentistry and medicine reports exist of haematogenous bacterial spread following endodontic procedures (Murray and Sanders 2000). We feel that this is an interesting parallel, given that those affected are often immunocompetent adult patients. Ultrasound imaging protocols for examination of the scapulohumeral region have been described (Tnibar et al. 1999; Pasquet et al. 2008). Ultrasound examination proved very useful in the diagnosis and management of this case. In this case, the turbidity of the fluid and amount of free fibrin prevented needle centesis of the ISB. Distention of the ISB under ultrasonographic guidance (Schneeweiss et al. 2012) facilitated endoscopic access to this structure (Whitcomb et al. 2006). The small size of the bursa necessitated having the


arthroscopic and instrument portals close together, limiting mobility. However, manipulation of the limb can result in improved access but should be performed carefully as manipulation can result in damage to the scope or adjacent structures. Based on the absence of an osteolytic lesion in the ITB


during endoscopic examination, there was no indication for tenotomy or tenectomy (Fugaro and Adams 2002). The outcome of this case seems to be in agreement with the recent literature review (Koch andWitte 2013) suggesting that aggressive debridement of osseous lesions may not be mandatory as a first step procedure and achievement of adequate local concentration of an appropriate antimicrobial can result in a successful treatment outcome. Case reports by Neil et al. (2010) and Kay et al. (2012) support this. In these reports, osteolytic lesions of the distal phalanx and patella, respectively were not debrided because of anatomic inaccessibility or choice of surgical approach with no significant effect on treatment outcome noted. Whitcomb et al. (2006) described a fibrocartilaginous lesion underlying the ISB similar to that noted in our patient. This lesion was also inaccessible for debridement and this did not appear to negatively influence the outcome in either case. Intra-articular medication of the synovial structures with enrofloxacin was performed intraoperatively with 250 mg in the ITB and 150 mg in the ISB. This is not a routinely used intra-articular medication; however, the results of culture and sensitivity supported its use. Enrofloxacin has been shown to result in aberrations in cartilage metabolism (Davenport et al. 2001) and we would not routinely recommend its use in high motion synovial structures. In summary, in an adult horse with a septic focus such as a


foot abscess, the potential exists for development of synovial sepsis due to haematogenous localisation of bacteria. In this case of synovial sepsis of the ISB and ITB endoscopic examination, debridement and lavage with appropriate antimicrobial treatment proved curative.


Authors’ declaration of interests No conflicts of interest have been declared.


Acknowledgement


The authors wish to thank Dr. Padraig Kelly of Liverpool University for assistance in reviewing the manuscript.


Manufacturers’ addresses 1Bayer Ltd, Leverkusen, Germany. 2Advanced Sterilisation Products, Irvine, California, USA. 33M Ltd, Rosedale, Auckland, New Zealand.


References


Adams, S.B. and Blevins,W.E. (1989) Shoulder lameness in horses - part II. Comp. Cont. Educ. Pract. Vet. 11, 190-196.


Adams, M.N. and Turner, T.A. (1999) Endoscopy of the intertubercular bursa in horses. J. Am. Vet. Med. Ass. 214, 221-225.


Archer, D.C., Clegg, P.D. and Edwards, G.B. (2004) Septic tenosynovitis of the tarsal sheath of an Arab gelding and suspected sepsis of the lateral digital flexor tendon subsequent to bacterial peritonitis. Vet. Rec. 155, 485-489.


Davenport, C., Boston, R. and Richardson, D. (2001) Effects of enrofloxacin and magnesium deficiency on matrix metabolism in equine articular cartilage. Am. J. Vet. Res. 62, 160-166.


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