Resection of a ceruminous adenocarcinoma in a horse by a modified vertical ear canal ablation

En-bloc Auriculectomy for Removal of a Large Pinna-Based Ear Mass in a Horse

A 15-year-old Pony of America (POA) gelding presented for evaluation of a large mass present on the right external pinna. Based on gross appearance, the right ear mass was suspected to be neoplastic. The most likely differential diagnosis was that of a fibroblastic sarcoid. Complete auriculectomy via use of a constricting latex-tourniquet performed under multimodal analgesia was proposed as an option to achieve complete resolution of mass growth and improve patient comfort. Benefits of latex tourniquet constriction included immediate lack of bleeding associated with amputation, gradual ischemic necrosis and sloughing of tissue distant to the site of constriction, and cost-effective application. The external pinna sloughed 3 weeks following application of the constricting latex tourniquet. Complete healing was achieved within 3 months from the time of tourniquet application. The middle ear canal sealed closed as a result of auriculectomy, with no observed long-term discomfort or morbidity aside from reduction in hearing. This is the first report of total external ear amputation in the horse. Complete auriculectomy via use of a constricting latex tourniquet is a feasible method for en-bloc removal of large, complicated ear masses.

Antimicrobial dosing for common equine drugs: a content review and practical advice for veterinarians in Australia

BACKGROUND

Appropriate dosing with antimicrobial agents is critical for effective treatment and to prevent the development of antimicrobial resistance.

METHODS

A review was undertaken of equine journal articles (Equine Veterinary Journal, Equine Veterinary Education, Australian Veterinary Journal, Australian Equine Veterinarian, Journal of Veterinary Internal Medicine and Journal of Equine Veterinary Science) between January 2015 and August 2018. Those with dosing regimens for procaine penicillin G, gentamicin or trimethoprim-sulfonamide in adult horses were examined and evaluated. Pharmacokinetics and -dynamics of these drugs were also reviewed.

RESULTS & CONCLUSION

The most frequently reported doses for penicillin, gentamicin and trimethoprim-sulfonamide were 20-25,000 IU/kg, 6.6 mg/kg and 30 mg/kg, respectively. Veterinarians treating equine patients in Australia should be aware of the current recommended doses and inter-dosing intervals to ensure efficacy in therapy and to preserve the usefulness of these antimicrobials for the future.