Today's Veterinary Practice provides comprehensive information to keep every small animal practitioner up to date on companion animal medicine and surgery as well as practice building and management.
Issue link: http://todaysveterinarypractice.epubxp.com/i/815220
65 MAY/JUNE 2017 ■ TVPJOURNAL.COM DERMATOLOGY DETAILS Deep Ear Flushing This procedure is very helpful not only as a diagnostic tool but also as part of the treatment plan. 9 A short course (2 to 3 weeks) of an anti-inflammatory dose of oral and/or topical glucocorticoids may be needed before deep ear flush in order to decrease inflammation and stenosis of the ear canals. This procedure should be performed under general anesthesia so that the ear can be completely cleaned and the ear canal and tympanic membrane examined. Anesthesia also allows the placement of an endotracheal tube, which precludes the aspiration of fluids that may pass through the middle ear into the auditory tube and then into the posterior pharynx. Ideally, computed tomography of the tympanic bulla should be performed before the flush to stage ear disease and help make the decision to perform myringotomy if otitis media is present. Several techniques to clean and flush the ears exist. 9 Follow-up visits after flushing are very important to monitor response to therapy and evaluate the status of the tympanic membrane. If myringotomy is performed, the tympanic membrane usually heals within 30 days after the procedure. Deep ear flush and myringotomy are best performed by experienced practitioners with a video- otoscope; therefore, referral to a dermatologist might be ideal. For a description of one deep ear flush technique, please visit tvpjournal.com . TREATMENT There are 5 general goals of otitis externa treatment: 1. Resolve discomfort and pain. 2. Remove debris and discharge. 3. Eliminate infection from the external and middle ears. 4. Reverse chronic pathologic changes, when possible. 5. Identify and treat the primary cause of the otitis. Topical Therapy In most cases of otitis externa, topical therapy alone is sufficient and is preferred when possible. In contrast, chronic, severe cases of otitis externa and otitis media often require additional systemic therapy. The amount of medication applied is important. Generally, the recommendation is to use about 0.5 to 1 mL (10 to 20 drops) per ear, depending on the size of the dog. Ear Cleaners Ear cleaners should be used at home as part of most treatment protocols initially (once daily to twice weekly depending on the severity of the otitis and amount of discharge present) and as maintenance therapy (usually once to twice weekly) to help prevent future infections once the otitis and infection are resolved. 10–13 Removal of debris and purulent material greatly improves the efficacy of topical antimicrobials, especially aminoglycosides and polymyxin B. However, overcleaning should be avoided because it can contribute to maceration and ear disease. Clients should be educated on the proper technique to clean the ears and to avoid using cotton balls and cotton swabs inside the ears. Available ear cleaners include drying agents, antiseptics, ceruminolytics, and combination products. For a table listing these cleaners, please visit tvpjournal.com . Acaricidals Many different acaricidal products may be used to treat infections caused by Otodectes cynotis (ear mites) and, less commonly, Demodex species. 10–13 Veterinary acaricidal products for label and extralabel use include ivermectin, milbemycin, selamectin, fipronil, monosulfiram, permethrin, piperonyl butoxide, pyrethrins, thiabendazole, and rotenone. 13 Antimicrobials It is important to always use higher volumes or concentrations of topical antibiotics because they may prove efficacious, even when resistance has been suggested on a susceptibility panel. With topical drugs, concentrations 100 to 1000 times superior to the minimum inhibitory concentration may be reached. 13 Antimicrobials should be used until 1 week past negative cytologic results for most bacterial and/or yeast otic infections. 10-13 Twice- daily applications are usually recommended. For Pseudomonas ( Figure 7 ) and multidrug-resistant infections, I recommend treating the patient until 1 week past negative cytologic and culture results.