Canine Otitis

Question 1

Predisposing factors for canine otitis?

Answer 1

• conformation
• obstruction
• excessive moisture/cerumen/hair
• cornification disorders
• immunosuppression

Question 2

1* factors initiating canine otitis?

Answer 2

• FBs
• parasites (mites esp)
• hypersensitivity skin disease (atopic dermatitis/cutaneous food hypersensitivity)
• contact dermatitis beware topical ear products
• immune mediated dx
• others (misc)

Question 3

What does granular knobbly external ear/pinna indicate?

Answer 3

Demodex

Question 4

2* factors that cause ear idsease in an aborlam ear only or just contribute to pathoglogy?

Answer 4

• bacteria (s. pseudintermedius, pseudomonas (G- shift) proteus, klebsiella, E. Coli)
• yeasts - malasezzia

Question 5

Perpetuating facotrs that prevent resolution of otitis and cause structural/functional changes?

Answer 5

• ear canal pathology (epidermal/dermal/adnexal)

- > stenosis of lumen

Question 6

How long does otitits externa take to develop to middle ear disease?

Answer 6

• 50% cases extend within 6 months

Question 7

4 main management aims of otitis tx?

Answer 7

• reverse perpetuating factors (skin disease and otitis media)
• resolve 2* infection(==skin disease)
• address 1* factors (skin disease)
• remove predisposing factos

Question 8

which breed are predisposed to middle ear disease?

Answer 8

cocker spaniels

Question 9

Does the tympanic membrane have to be broken for otitis media to occour?

Answer 9

no 70% cases in tact (heals up after rputure)

Question 10

Which signs commonly thought to r/o otitis media actually do not rule out?

Answer 10

• Tympanic membrane intact
• imaging normal
• no neuro signs

Question 11

What happens when acute otitis externa progresses to chronic otitis?

Answer 11

• shift from G+ nd malasezia to G- Pseudomonas
• or malasezia may be seen alone
  (nb. multiple partially effective abx attempts may create resistance)

Question 12

Diagnostics for ear infections?

Answer 12

> cytology
- selection for bacterial culture
- nature inflam response
culture
- does not replace cytology!!!
- NB. 20% repeatabilty of pathogen culture from identical swabs
- AND different pathogens may be grown frrom different sites (extrna v media etc)

Question 13

Indications for surgery?

Answer 13

• tumours
• polyps
• irreversible stenosis
• aggressive medical tx failed/not possible/not wanted
• fulli nvestigation of all factors

Question 14

common causes of tx failure?

Answer 14

• not long enough
• inadequate cleaning
• failure to id/tx otitis media and soft tissue changes
• failure to id/control 1* causes otitis

Question 15

is conventional sensitivity testing of value for topical tx?

Answer 15

no - too many otherfactors affect it?

Question 16

adverse effects of tx on outer ear??

Answer 16

>canal and TM.. 
- occlusion/maceration, epidermal turnover and migration, glandular changes, micro FB formation, atrophic defects 
> allergic/iritant dermatitis
- prolonged exposure (pooling)
- penetration enhancers
- topical sensitisers

Question 17

potential adverse effects of otic medications on middle ear?

Answer 17

> middle ear effects

• facial n (inc ps fibres) dmage
• symp neurons for occular innervation (Horner’s syndrome)
• Otitits media, cholesteatoma

Question 18

potential adverse effects of otic medications on inner ear?

Answer 18

• diffusion into inner ear via round window
• ototoxicity (ear positiions) damaging vestibulo-cochlear nerve or inner ear (enhanced in OM)
• may occour weeks later
• rare

Question 19

Golden rules for treating otic disease?

Answer 19

1. stenosis = tx failure
2. aural lavage under GA
3. sample most proximal site affeted
4. systemic Abx not indicated usually
5. conventional bacterial sensitivity testing little value for topical tx
6. avoid human reserved Abx
7. monitor response with CYTOLOGY
8. do not stop Abx before complete clinical AND MICRBIOLOGICAL cure
9. keep cleaning!!

Question 20

Potential systemic side effects following absorption of topical tx?

Answer 20

• GCs
• basal cortisol, ACTH stim, T4, insulin
  > dont understand what this slide means, look up??