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Virbac Animal Health (NZ)Presents
“Otitis Externa”
With Fiona BatemanBVSc MACVSc Dipl. ACVD
September 2015
Proudly hosted by Vet Education Pty Ltd
Virbac Animal Health (NZ) FreeWebinar 2015
9/2/2015
Otitis Externa: Dr. Fiona Bateman 1
Otitis ExternaWith
Dr. Fiona BatemanBVSc MACVSc Dipl. ACVD
Otitis externa
Dr. Fiona Bateman BVSc MACVSc DACVDRegistered Specialist in Veterinary Dermatology
Animal Dermatology Solutionswww.animaldermatologysolutions.com.au
Thank you
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9/2/2015
Otitis Externa: Dr. Fiona Bateman 2
Otitis Externa Inflammation of the external
ear canal epithelium
Incidence:
up to 20 % in dogs and 6.6 % in
cats
DOG TM
Pars flacida
Manubriumof theMalleus
Pars tensa
ROSTRALCAUDAL
Photo: Dr. Danielle Hoolahan
Virbac Animal Health (NZ) FreeWebinar 2015
9/2/2015
Otitis Externa: Dr. Fiona Bateman 3
CAT TM
Pars flacida
Manubriumof theMalleus
Pars tensa
ROSTRAL CAUDAL
Photo: Dr. Danielle Hoolahan
Otitis Externa
Any age, sex or breed
Certain breeds: increased risk
Dogs : 5 – 8 years of age
Allergic dermatitis most common
Cats : 1 – 2 years of age
Clinical Signs
Head shaking
Scratching
Pain
Photo: Dr. Danielle Hoolahan
Clinical Signs
Erythema
Excoriations
Alopecia
Exudate
Odour
Photo: Dr. Danielle Hoolahan
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Causes of Otitis Externa
Most cases result from amultifactorial etiology!
Causes can be classified aspredisposing, primary & perpetuatingfactors
These factors make affected ears abetter “incubator”
Predisposing FactorsAlter microenvironment of the ear
canal
Predispose to secondaryopportunistic disease
Examples of predisposing factors Breed ear conformation
High humidity in ear canal
Obstructive ear disease
Treatment errors
Breed Conformation
Pendulous pinnae
Hair within earcanal (hirsutism)
Narrow canalconformation
Increased #of apocrine glands
Photo: Dr. Danielle Hoolahan
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Primary Factors
Initiate & directly produce
inflammation of canal epithelium
turn on “incubator”
If identified & correction is possible
may result in resolution of the ear
disease
Examples of Primary Factors Allergic dermatitis : atopic dermatitis & food
allergy
Contact allergy / irritant reaction
Parasites
Foreign bodies
Cornification disorders
Neoplasia
Immune – mediated diseases
Atopic Dermatitis (AD)
Bilateral pruritic otitis externa occursin 50 – 80 % of AD dogs
Only clinical sign in 10 – 20 %of AD dogs
RecurrentMalassezia iscommon
Food AllergyCutaneous Adverse Food Reaction (CAFR)
Bilateral pruritic otitis externa occursin > 80 % of CAFR dogs
Only clinical signin 20 – 25 %
RecurrentMalassezia iscommon
Photo: Dr. Danielle Hoolahan
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Otitis Externa: Dr. Fiona Bateman 6
Contact ReactionNon – haired pinna
& canal
Often reaction todrugs: neomycin
If inflammationworsens w/ therapy suspect!
Photo: Dr. Danielle Hoolahan
Photo: Dr. Danielle Hoolahan
Cornification Disturbances
Cerumen can be pro-inflammatory
Changes in glandular secretions
“Primary idiopathic seborrhea”
Secondary causes (metabolic,immune-mediated, inflammation),endocrinopathies ( T4 , hyper-adrenocorticism ) Photo: Dr. Danielle Hoolahan
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Perpetuating Factors
Do not initiate disease but perpetuateinflammation
Treatment is important for resolution ofthe otitis externa
Examples of perpetuating factorsBacterial organismsFungal/yeast organismsOtitis mediaChronic pathologic change
Photo: Dr. Danielle Hoolahan
Bacterial Organisms
Often secondary to other factors
Common pathogens :Staph. pseudintermediusStrep sp.Pseudomonas sp.Proteus sp.
CoryneybacteriumpseudoTB, S.schleferi
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Otitis Externa: Dr. Fiona Bateman 8
Yeast / Fungal OrganismsMalassezia : common secondary
infection but also normal ear flora
Candida spp., Aspergillus rare
Dermatophytes &systemic fungalmycoses pinnal dermatitis
Questions?
Diagnosis
History & PE findings
Otoscopic examination
Cytology: critical information
Culture & sensitivity ?
Imaging studies
Myringotomy
Biopsy.
Cytology
Critical diagnostic information
Collect discharge & roll on slide
Stain with Diff-Quik®
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Otitis Externa: Dr. Fiona Bateman 9
Ears – what is normal?
Keratinocytes
Wax
Occasional cocci?
Occasional Malassezia?
Wax, keratinocytesCocci
Courtesy: Dr. M Shipstone
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Otitis Externa: Dr. Fiona Bateman 10
Rods
Photo: Dr. Danielle Hoolahan
Malassezia
Otitis MediaMay be cause of recurrence
Not ruled out by intact TM
Photo: Dr. Danielle Hoolahan
Middle ears - imaging
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Courtesy: Dr. M Shipstone
Purulent debris – middle ear
Video 1
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Questions?
Treatment of otitisexterna
Glucocorticoids
Antipruritic, anti-inflammatory , sebaceous & apocrine glandsecretion
Often in combination productstopically
Used as sole topical agent inallergic or ceruminous otitis
Ear Cleaners
Modified cleaning / dryingsolutions : antimicrobialproperties & mildceruminolytic agents
Epi-Otic® , Malacetic Otic®,Kleo’s® ear cleaner, Milo’s®
ear cleaner
Usually not middle ear safe (or no data)
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Otitis externa - treatment
Topical treatment
ALL bacterial otitis
Almost all Malassezia otitis
Systemic treatment
When epithelial lining is compromised
Rods are present
In difficult to medicate animals when ONLYMalassezia are present
If ear drum is ruptured
Topical treatmentConsider MOA of actives
Bacteriostatic vs bacteriocidal
Fungistatic vs fungicidal
Potency of steroid
Determined on basis of
Cytology
Culture and sensitivity?
Antimicrobial selection Cocci
Staphylococcus, Streptococcus
Canaural – framycetin, fusidic acid
Otomax/Mometamax/Easotic – gentamicin
Surolan – polymixin B
TM ruptured
Enrofloxacin
Systemics
If TM ruptured, extensive pinna involvement,methicillin resistant staph on C&S
Antimicrobial selection Rods
Pseudomonas, Proteus, E. coli
Triz-EDTA/Otoflush, pretreat for 15 minutes
Enrofloxacin, Polymixin B, Gentamicin
SECOND LINE
Timentin, ciprofloxacin (failure of response,C&S)
Systemics
OM, Pinnal involvement
NB: UNRELIABLE SOLE THERAPY
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Otitis Externa: Dr. Fiona Bateman 14
Antimicrobial selection Yeast
Malassezia
Disinfectants – if low numbers: Epiotic,Malacetic otic
Miconazole, Clotrimazole
Nystatin (if resistance to previous)
Systemics
OM, severe proliferative change present,impossible to medicate topically
Easotic Hydrocortisone aceponate comparable to betamethasone and mometasone
Gentamicin sulfate
effective against gram-positive and gram-negative aerobic bacteria
Miconazole nitrate
broad-spectrum antifungal
Gentamicin and Miconazole levels persistfor 10 days post treatment period
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Otitis Externa: Dr. Fiona Bateman 15
Treatment volume
Cat 0.15 – 0.2 ml
Dog
5 kg 0.25 – 0.5
10 0.5
20 0.75 – 1.0 ml
> 40 2.0 ml
Otitis Media andruptured ear drums –
help!
Otitis Media: treatment Flush clean +/- myringotomy
Systemic anti-microbials – based offMC&S often for 6-8 weeks +
enrofloxacin, cephalexin, clindamycin
itraconazole
Instillation into tympanic cavity
enrofloxacin
Ruptured ear drum Yes enrofloxacin
Saline
Triz EDTA
Maybe? 2% acetic acid / 2%
boric acid
Ticarcillin
No Polymixin B Gentamicin Framycetin Just about
everything else
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Otitis Externa: Dr. Fiona Bateman 16
Otitis Media: Palmeiro et al,2003
86 ears with otitis media
95% ruptured tympanic membranes
Lavage and medical management
82% dogs resolved
7% dogs lost to follow up
Others needed surgery
7 resolved dogs later relapsed
Systemic Therapy
Antibiotics : cases of otitis media orsevere inflammation
Anti-fungals : refractory otitisexterna or otitis media due to yeast
Systemic AntibioticsCocci Cephalexin Amoxycillin/clavulanic acid Clindamycin
Rods EnrofloxacinMarbofloxacin Ciprofloxacin
Systemic Anti-fungals
Malassezia Fluconazole
Itraconazole
Terbinafine
For at least 1 month
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Otitis Externa: Dr. Fiona Bateman 17
Special cases – the hard tomedicate pet
Not all animals can be topicallymedicated easily
Solutions:
Medicate atclinic
Ear wicks
Ear wicks
Photo: Dr. Danielle Hoolahan
Before placement In situ
Pre and post hydration
Photo: Dr. Danielle Hoolahan
Special cases – the hard tomedicate pet
Not all animals can be topically medicated easily
Solutions:
Medicate at clinic
Ear wicks
Indwelling catheters
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Otitis Externa: Dr. Fiona Bateman 18
Special cases – the hard tomedicate pet
Not all animals can be topically medicatedeasily
Solutions: Medicate at clinic Ear wicks Indwelling catheters Poloxamer gel Liquid when refrigerated Soft gel at body temp Impregnated with active
ingredient/s of choice
Special cases – the hard tomedicate pet
Not all animals can be topically medicated easily
Solutions:
Medicate at clinic
Ear wicks
Indwelling catheters
Lanolin based compounds (BNT), Poloxamer gel
CARE WITH RUPTURED EAR DRUMS
Total ear canal ablation
No more ear canal = no more infections = no moretreatment!
Client Education Critical for compliance and
prevention/reduction of infections
Recheck every 1 week initially then reduce
Cytology, cytology, cytology!! May find need to change medication due to
overgrowth of yeast etc.
Medication application – use syringe
Frequency
Technique / volume
Causes of Treatment Failure
Owner’s non-compliance
Dog’s non-compliance
Veterinarian not showing ownershow to treat
Severe fibrosis of ear canal
Not addressing underlying causes
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Otitis Externa: Dr. Fiona Bateman 19
Take Home Messages for Vets
Visualise everything - dump the surgery cases
A clean ear is 50% cured already
Cytology, cytology, cytology, revisits
Demonstrate otic drug administration
No rod otitis should go home without TrisEDTA/Otoflush
Don’t neglect underlying disease unless you wantfrustrated clients
Acknowledgements Dr. Danielle Hoolahan
Dr. Mike Shipstone
Questions? TreatmentTopical Therapy
Consider vehicle
Consider frequency of application
Maceration (‘wetting’) of the ear canal is aconcern
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Otitis Externa: Dr. Fiona Bateman 20
Maceration – steriledebris consisting of
immature(parakeratotoic)epithelial cells
TreatmentTopical Antibiotics
Determined on the basis of Cytology
Culture and Sensitivity ?
Culture and sensitivity: thepitfalls
Schick et. al. (2006)
Triplicate samples sent to three different labs
75% ears differed in isolates in all 3 labs
2/3 labs agreeing in 7.5% of ears
3/3 labs agreeing in 17.5% of ears
Sensitivity testing (8 antibiotics) of Pseudomonasisolates
17.6% agreed on all antibiotics
35.3% differed with 1 antibiotic
47% differed with 2 or more antibiotics
Culture and sensitivity: thepitfalls
Graham-Mize & Rosser (2004)
Paired samples same ear, submitted to samelab
20% grew different cultures entirely
20% grew same organisms but differentsensitivity pattern
Only 60% grew same organisms with samesusceptibility pattern
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Otitis Externa: Dr. Fiona Bateman 21
Culture and sensitivity: thepitfalls
Graham-Mize & Rosser (2004)
Looked at difference between in-housecytology and lab submission
16/50 paired ear swabs grew differentorganisms that did not match cytology
Did not survive transport? Inappropriatetransport medium? Failed to be isolated atlab?
When MC&S performed, should always beinterpreted in the light of in house cytology
Culture and sensitivity: thegood news
Sensitivity results based on serum levels ofantibiotics may not be relevant to topical therapy
Can achieve 100-1000x the MIC at the site ofinfection
Concentration dependent antibiotics(aminoglycosides, fluoroquinolones) have higherbactericidal activity at higher concentrations
Makes emergence of bacterial resistanceextremely improbable
When to culture? When cytology shows uniform pattern of bacteria
AND
Appropriate empirical therapy has failed
AND
All other causes of failure of therapy have been ruledout
OR
Otitis media