Otitis Externa And Media Flashcards
What are the parts of the tympanic membrane ?
Pars flaccida-> often mistaken for a cyst structure just in from of ear drum
Pars tensa
What nerve passes through the middle ear and can be affected in otitis media?
Facial nerve
Inflammation of the ear canal is called?
Otitis externa
What are predisposing causes to otitis externa?
Stenosis Hair in canals Pendulous pinnae Swimmers ear Overactive glands Polyps Neoplasms
What are primary causes of otitis externa?
Parasites, microbes, atopy, food hypersensitivity, drug reactions, contact hypersensitivity, keratinization, glandular disorders, autoimmune disease, solar dermatitis
What are perpetuating factors to otitis externa?
Bacteria, yeast, topical rxn, foreign bodies
Epidermal hyperplasia, hyperkeratosis, dermal edema or fibrosis, lumen stenosis, cartilage mineralization, tympanic membrane changes, middle ear disease
A dog comes into the clinic with erythema, swelling, scaling, crusting, alopecia, otic discharge, and pain on palpation.. you try to do an otic exam but the ear canal is swollen
What do you do?
Anti-inflammatory for 4-7days then redo the exam
What is the most common cause of otitis externa in dogs?
Allergies
What is the main cause of otitis externa in cats?
Parasite- otodectes
Clinical signs of acute otitis externa?
Head shaking - hematoma
Scratching ears Rubbing ears Otic discharge Malodor Red pinna Swollen ear
You do a ear exam and there is a coffee ground like discharge in the ear.. what is you top dx?
Ear mites
You do a ear exam and there is a moist brown discharge.. what is your top dx?
Staph or yeast
You do a ear exam and there is a creamy yellow discharge.. what is you top dx?
Gram neg bacteria
Ear exam done and there is a oil, yellow, tan discharge .. what is your top dx?
Glandular disorder or hypersensitive
You are going to do cytology in an otitis externa case.. where should you collect your sample..
Horizontal ear canal — 2-3 swales
Mites - swab debris on slide with a drop of mineral oil
Yeast / inflammatory cells/ bacteria - roll swab onto slide and heat fix
T/F: if you have a unilateral problem with the ears, you should examine the good ear first
True
- decreases spread of infection
T/F: you should always culture ears
False
Not usually needed for acute cases, Do for chronic rucurrent cases or unresponsive cases
Why should we clean out ear canals with otitis externa?
Remove large amount of debris
Allow drugs to penetrate Ernie canal
Treatment of otitis externa?
Predisposing cause
Cleaning
-ceruminolytic (docusate sodium, emulsify wax and lipids)
Removal of pus - saline or water -bulb syringe or 3 way stop cock system -automatic systemic —ear current -suction system
Drying agent
-acetic acid/ salicylic acid/ benzoic acid
What can you used to clean the ears when you have an intact pars tensa?
Ceruminolytic emulsify wax/lipids - use 10mins priori to cleaning
Cleaning solutions remove debris - chlorhexidine/chlorhexiderm
Drying products -chlorhexiderm, oticlens, and malacetic acid
What can you use to clean the ear canal if you cant see an intact pars tensa?
Avoid ceruminolytic, cleaning solutions, or drying agents
USE normal saline
Treatment of otitis externa?
Topicals
- glucocorticoids, antibiotics, antifungals, parasiticides
Antibiotics
—> aminoglycosides —> must have intact tympanic membrane
—> chloramphenicol
First line - neomycin-polymixin (doesnt work in pus)
Fluoroquinolones
What is the MOA of poloxamer otic gels?
Liquid state at refrigerated temperature; change to gel at body temp
Can be compounded with drugs
Reaches horizontal ear without puncturing the tympanic membrane
Ear canal should be cleaned prior
81% of gram negative otitis externa are resistant to aminoglycosides and flourorquinolones. What are they often susceptible to?
Polymixin-B
—> ticarcillin
—> amikacin
