Lecture Series Cover Pges - VetEducation · PDF filePars flacida Manubrium of the Malleus Pars...

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


9/2/2015


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


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CAT TM

Pars flacida

Manubriumof theMalleus

Pars tensa

ROSTRAL CAUDAL


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


Clinical Signs

Erythema

Excoriations

Alopecia

Exudate

Odour



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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



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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



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Contact ReactionNon – haired pinna

& canal

Often reaction todrugs: neomycin

If inflammationworsens w/ therapy suspect!



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


Bacterial Organisms

Often secondary to other factors

Common pathogens :Staph. pseudintermediusStrep sp.Pseudomonas sp.Proteus sp.

CoryneybacteriumpseudoTB, S.schleferi


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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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Ears – what is normal?

Keratinocytes

Wax

Occasional cocci?

Occasional Malassezia?

Wax, keratinocytesCocci

Courtesy: Dr. M Shipstone


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Rods


Malassezia

Otitis MediaMay be cause of recurrence

Not ruled out by intact TM


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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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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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 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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Special cases – the hard tomedicate pet

Not all animals can be topicallymedicated easily

Solutions:

Medicate atclinic

Ear wicks

Ear wicks


Before placement In situ

Pre and post hydration



Not all animals can be topically medicated easily

Solutions:

Medicate at clinic

Ear wicks

Indwelling catheters


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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


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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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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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


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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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


9/2/2015


Otitis ExternaWith

Dr. Fiona BatemanBVSc MACVSc Dipl. ACVD

Lecture Series Cover Pges - VetEducation · PDF filePars flacida Manubrium of the Malleus Pars...

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