Ear Nightmares: Management of Otic Disease in Veterinary Medicine Holly Roberts, DVM, MS, DACVD

Transcription

1 Ear Nightmares: Management of Otic Disease in Veterinary Medicine Holly Roberts, DVM, MS, DACVD 1. Anatomy of the Ear Canal a. Pinna b. External i. Ear canal 1. Vertical canal 2. Horizontal canal c. Tympanic membrane i. Stria malearis ii. Pars tensa iii. Pars flaccida d. Middle ear i. Tympanic bulla 1. Septum a. Complete in cats b. Incomplete in dogs ii. Nerve iii. Eustachian tube e. Inner ear i. Cochlea 2. Hearing Loss a. Sensorineural i. Disorder of the inner ear ii. Cochlea iii. Congenital iv. Aging related v. True ototoxicity b. Conductive i. Ear plug effective ii. Medications iii. Stenosis iv. Hyperplasia v. Debris 3. Three Ps of Ear Disease a. Predisposing i. Conformation ii. Excessive moisture iii. Obstructive ear disease iv. Primary otitis media v. Systemic disease vi. Treatment effects b. Primary

2 i. Allergy ii. Autoimmune/Immune mediated iii. Endocrine iv. Epithelialization disorders v. Foreign Bodies vi. Glandular disorders vii. Parasites viii. Neoplasia c. Perpetuating Factors of Otitis Externa i. Epithelium 1. Altered migration 2. Failure of migration 3. Excessive debris ii. Canal 1. Stenosis 2. Proliferative changes iii. Middle ear 1. Otitis media 2. Osteomyelitis iv. Cartilage 1. Calcification 4. Diagnostic Approach to Otitis Externa a. Exam i. Ear canal open? ii. Any masses or foreign bodies? iii. Tympanic membrane intact? iv. Exudate? b. Cytology i. Bacteria 1. Cocci vs. rods ii. Yeast iii. Sterile 1. Keratinocytes 2. Neutrophils c. Treatment i. First time infection 1. Open canal 2. Debris a. Ear cleaner 3. Topical therapy a. Targeted antimicrobials vs. triple products i. Ointments vs. liquids vs. packs b. Steroids c. Treat for a week past clinical resolution

3 ii. First line 1. Neomycin- Tresaderm 2. Gentamicin- Otomax, Mometamax 3. Polymyxin B- Surolan iii. Second line* 1. Tobramycin- ophthalmic solution 2. Amikacin:saline 1:10 or 25mg/mL 3. Increased risk of ototoxicity iv. Third line 1. Fluoroquinolones 2. Baytril Otic, Posatex 3. Baytril:dexamethasone:saline 1:1:3 4. Mupirocin:saline 1:5 or 1 tube:30 ml 5. Ticarcillin injectable d. Recurrent Otitis i. Exam 1. Palpate ear canals 2. Otoscopic examination a. Stenosis b. Mass 3. Pain ii. Cytology 1. Monitoring of microorganisms iii. Culture 1. Identifies pathogens 2. Treatment options a. MICs b. Topical therapy iv. Is ear canal open? 1. Yes -> topical therapy 2. No -> oral steroids a. 1 mg/kg PO daily for 30+ days b. <50% improvement, then TECA-BO v. Inflammation present? 1. Topical steroids vi. Painful?? 1. Tramadol 2. Gabapentin 3. Ulcerations: a. Silver sulfadiazine cream: saline 1:5 vii. What organisms are present? 1. Cytology 2. Culture 3. Topical therapy

4 a. Commercially available i. Liquids vs. ointments ii. Packings b. Compounded i. Miconazole:dexamethasone 1:1 ii. Baytril:dexamethasone:saline 1:1:3 iii. Mupirocin:sterile water 1:4 c. TrizEDTA 4. +/- Oral antibiotics a. Treating outside the external ear canal 5. Otitis media a. Historical/clinical signs i. Recurrent otitis ii. Infection never fully resolves iii. Vestibular signs b. How to diagnose? i. History ii. Exam 1. Ruptured tympanum 2. Bulging tympanum iii. Advanced imaging 1. Radiographs 2. CT scan c. Imaging of the Middle Ear i. Skull radiographs 1. Difficult to perform and interpret ii. CT scan 1. Preferred iii. What to evaluate with imaging? 1. Lysis of bulla? a. If present, don t flush! b. Surgery or medial management 2. Mass in or near canal? a. If present, TECA-BO 3. Material within tympanic bulla? a. If no mass or lysis, then myringotomy, culture and deep ear flush iv. Otitis Media in Cats vs Dogs 1. Cats a. Complete septum b. Can only sample dorsal compartment through externa ear canal i. Culture c. Ventral bulla osteotomy

5 2. Dogs a. Incomplete septum b. Can sample both compartments c. Myringotomy & flush v. Myringotomy & Deep Ear Flush 1. If otitis media present, then a. 1. make sure canal is open b. 2. general anesthesia c. 3. copious flush of external canal d. 4. myringotomy e. 5. sample middle ear exudate for culture f. 6. continue to flush 2. Post-flush treatment a. 28+ days for tympanic membrane to heal b. Ear cleaner c. Topical antimicrobial therapy i. +/- Systemic antimicrobial therapy ii. +/- Pain control iii. +/- Steroids iv. Identify primary cause!!! 6. End-stage ear disease a. Clinical signs of end-stage ear disease i. Stenosis in the presence of calcification ii. Cannot medically reverse severe calcification iii. Mass present iv. Lysis of bulla b. Surgical treatment i. Total ear canal ablation and bulla osteotomy c. Palliative care (not ideal) i. Pain medication ii. Ear cleaner to outside of ear iii. Antimicrobials to manage, not resolve