Dermatology: Otitis Flashcards

1
Q

How does tympanic bulla vary between cats and dogs?

A
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2
Q

How does the epithelium of ear canal and middle ear vary?

A

Ear canal
* Small hairs
* Ceruminous glands
* Sebaceous glands

Middle ear
* Simple squamous to cuboidal
* Few ciliated cells
* Mucous-secreting goblet cells

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3
Q

How does the external ear canal self clean?

A

Cerumen
* Sebaceous and ceruminous gland secretions
* Catches foreign material, desquamates keratinocytes and microbes
* Contains antimicrobial peptides and Igs

Epithelial migration
* Living keratinocytes carry cerumen and contents out of canal

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4
Q

How does the middle ear self clean?

A
  • Mucous from goblet cells traps microbes and cellular debris
  • Eustachian tube- drains mucous from middle ear cavity inot nasopharnx, equalises pressure either side of tympanic membrane
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5
Q

What is the normal flora in the EEC?

A

Gram +ve predominate
* Staph pseudintermeidus, schleferi

Coagulase -ve staphylococci
Streptococcus
Micrococcus
Malassezia

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6
Q

What is otitis externa, media and interna?

A

Inflammation of the
externa: EEC
media- middle ear
interna- inner ear

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7
Q

What can cause pruritic and non pruritic disease of the pinnal margin, skin surface and body of the pinna?

A

Pinnal margin
* Pruritic- sarcoptic mange, harvest mites
* Vascilitis, seborrhoea, SCC

Skin surface
* Pruritic- allergic skin disease, pemiphiguc foliaceus, contact irritant dermatitis, fleas
* Non-pruritic- hyperadrenocorticism, hypothyroidism, pemiphiguc foliaceous, contact irritant dermatitis

Body
* pruritic- aural haematoma
* non-pruritic- auricular chondiritis

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8
Q

What is the acronym for primary causes of otitis?

A

VIP MEGA FAME

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9
Q

What are the most common primary causes of otitis in dogs?

A

Foreign bodies
Allergic skin disease
Bugs- parasites/virus

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10
Q

What are the most common primary causes of otitis in cats?

A

FAB
Flu
Allergic skin disease
Bugs

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11
Q

What parasite is the most common cause of otitis?

A

Otodectes cynotis

  • Dark coffee ground wax, small white mites
  • Most patients have HSR to mites
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12
Q

How is otodected cynotis treated?

A
  • Most oily topical ear products effective
  • Selamectin or moxidectin spot on
  • May need steroids for prutritis and inflammation
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13
Q

What are secondary causes of otitis?

A

Microbial infection-
* gram +ve cocci
* gram -ve rods- pseudomonas

Topical medication reaction
Inappropriate cleaning- physical trauma, excessive moisture

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14
Q

What predisposes of otitis?

A
  • Obstructive ear disease- neoplasia and polyps
  • Conformation- hairy canals, narrow cannals, waxy canals, pendulous pinnae
  • Environment- water, high temp
  • Systemic disease- immune suppression, debilitation
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15
Q

What are prepetuating factors for otitis?

A

Progressive pathological change
* chronic inflammation of soft and bony tissues due to primary and secondary causes

Otitis media

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16
Q

Describe progressive pathological change from otitis?

A
  • Failure of epithelial migration
  • Progressive epithelial hyperplasia, oedema, fibrosis and folding
  • Glandular dilation and hyperplasia
  • Canal stenosis
  • Rupture of tympanum
  • Calcification of pericartilgenous tissue
  • Osteomyeltitis
  • Para-aural abscessation
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17
Q

What are the clinical signs of OE?

A
  • Otic pruritus- scratching, rubbing, headshaking
  • Pain
  • Discharge
  • Loss of hearing
  • Secondary- erythema, lichenification, scaling
  • Otoscopy- epithelial erythema, hyperplasia, erosion/ulceration, fibrosis, stenosis of EEC
18
Q

How does otitis externa progress?

A

Secondary causes and perpetuating factors follow
* Malassezia overgrowth
* Changes in EEC environment- inflammatory change
* Gram -ve rod infection
* Chronic pseudomonas progress to OM in dogs

19
Q

What are the clinical signs of OM and OI?

A
  • OE signs
  • Pain
  • Horners
  • Loss of hearing
  • Vestibular disease- ataxia ± falling, head tilt, spontaneous/rotary nystagmus, anorexia/vomiting
20
Q

What causes primary otitis media?

A

Dogs
* haematogenous spread
* breed related conformation abnormality

Cats
* nasopharyngeal polyps

21
Q

What is primary secretory otitis media?

A
  • CKCS and other brachycepahlics
  • Mucus build up
  • Present for deafness or pain
  • Bulging TM on otosopy
  • Repeated flushing with sterile water eventually liberates large mucus plug
22
Q

What is brain auditory evoked response?

A

Used to ID hearing loss
* Noise applied to test ear generates neuronal activity
* Can ID site of pathology at different peaks

23
Q

What is the dignostic plan for otitis of canines?

A

Primary causes
* elimination diet and rechallenge when otitis resolved

Secondary causes
* cytology

Predisposing factors
* Drying anf cleaning of ears post swiming

Perpetuating factors
* Otoscopy under sedation/GA to assess EEC and TM
* DI to investigate OM

24
Q

What is the diagnostic plan of feline otitis?

A

Primary causes
* viral testing?

Secondary causes
* cytology

Predisposing factors
* Diagnotics imaging to investigate poly, biopsy

Perpetuating factors- investivated OM

25
Q

How can otitis be diagnosed with radiography?

A
  • Mineralisation of EEC cartilages
  • Fluid lines,
  • osteolysis and bony proliferation in bullae

Lateral oblique and rostro-caudal

Many OM have normal radiographs- cannot rule out OM

26
Q

What does CT allow asseament of for chronic otitis?

A

EEC- thickening and stenosis, mineralisation
Bony structures- bony change affecting bulla
Middle ear- sensisitive diagnosis
Inner ear- OI may be ID but less info on soft tissue involvment

27
Q

What is myringotomy?
When is it indicated?

A

Create a hole in the ear drum to allow fluid out
* Bulging eardrum with pain or neurological signs
* Radiography/MRI bulla changes and intact eardrum
* Evidence of fluid/tissue behind eardrum
* Medically unresponsive vestibular disease with an intact eardrum
* Chronic OE cases >6m

28
Q

How can otitis be treated?

A
  • Ear cleaning
  • Anti-inflammatories
  • ABs
  • Long term managment
29
Q

Why do otitis cases benefit from ear cleaning?

A
  • Removal of infectious debris and disruption of microbial biofilms
  • Visualisation of TM
  • Assess epithelium
  • Exposure and/or sample otic polyps/tumours
  • Enhance topical therapy
30
Q

What drugs are potentially ototoxic?

A
  • Polymixin B
  • Ticarcillin
  • Gentamycin
  • Propylene glycol- high conc
  • Alcohols
  • Acids
  • Chlorohexidine
  • Non IV injectables
31
Q

Why are ears cleaned differently?

A

Acute- no pain mimimal debris
* conscious

Chronic, copious discharge
* GA, intubation
* Handheld vs video
* Lavage with sterile water/saline
* Post cleaning analgesia

32
Q

What is a biofilm?
What can be used to help treatment?

A

Microbes stuck together in ECM
N-acetly cystine, Betaine/polyhexanide

33
Q

What anti-inflammatory treatments can be used for otitis?

A

Glucocorticoids
* Anti-pruritic, decrease glandular secretions, exudation, scar tissue and proliferative changes
* Systemic pred
* Topical- pred, dexameth, betameth

34
Q

How is EEC sampled?

How is middle ear sampled?

A

EEC- Indirect smear using cotton bud

Middle ear- otoscopic, insert urinary catheter, gentle suction

35
Q

How can topical antimicrobials be selected of cytology?

A
  • No microorganisms- anti-inflam
  • Yeast- topical antiseptics/fungals
  • Bacteria- topical antiseptics/antibiotics
36
Q

What is the spectrum of activity like for?
1. Chlorohex
2. Fucidic acid, framycetin, florfenicol
3. Polymixin B, marbofloaxin, gentamycin
4. Clotrimazole, miconazole, nystatin

A
  1. Gram +ve cocci, -ve rods, malassezia
  2. +ve cocci
  3. +ve cocci, -ve rods
  4. Malassezia
37
Q

Wher are topical antimicrobials not licensed for otitis?

A

Ruptured ear drum

If cannot see use safe water based product and recheck- TrizChlor

38
Q

What should be included in long term managment?

A
  • Therapeutic plan
  • Address predisposing factors
  • Regular 1-2x week ear cleaning
39
Q

How is hypersensitivity of otitis treated?

A

Nothing licensed (long term)
* Recicort 7 days
* Cotracance
* Dexadresson- dexameth

40
Q

When does otitis have a guarded prognosis?

A
  • Solid, non-pliable EEC on external palpation
  • Severe stenosis and fibrosis on otoscopy
  • Marked mineralisation of ear canals
  • Neoplasia/polyps
  • Cholesteatoma
  • Para-aural abscessation
41
Q
  1. What can be used to open canals prior to cleaning?
A

Systemic prednisolone

42
Q

What are examples of ear cleaners?

A

Otodine- antiseptic, mild cerumenolytic
Otoact- cerumenolytic
Otoprof- powerful cerumenolytic
Trizchlor- EDTA, chlorohexidine- antiseptic, flushing
TrizAural- antiseptic, flushing
Cleanaural- cerumenolytic