Inflammation of the External and Middle Ear

Question 1

Give some examples of primary causes of otitis externa and media (8)

Answer 1

• Infectious (ectoparasites, fungal, viral)
• Foreign bodies
• Hypersensitivity disorders
• Keratinisation disorders (endocrinopathies)
• Obstruction (neoplasia, polyps, cysts)
• Immune-mediated skin diseases (puppy strangles)
• Trauma
• Sunburn

Question 2

What are the common parasites of the outer and middle ear? (4)

Answer 2

• Otodectes cynotis
• Demodex spp.
• Sarcoptiform mites
• Neotrombicula autumnalis

Question 3

Answer 3

Otodectes cynotis

Question 4

Where is otodectes cynotis most common? (5)

Answer 4

• More common in cats - causes 50% of otitis cases
• Less common in dogs
• Mites not always found - can have them in small no. and can be destroyed by secondary infection / inflammation
• Common in ferrets
• Contagion in multi-pet households

Question 5

How do mites like otodectes cynotis cause disease? (3)

Answer 5

Cause hypersensitivity reaction:

• Type I = cytokine-mediated inflammation (eosinophils, neutrophils)
• Type III = complement and Fc receptor-mediated recruitment and activation of leucocytes
• Leads to dark brown coffee-ground to moist exudate

Question 6

Answer 6

Demodex canis

Question 7

Answer 7

Demodex canis / cati

Question 8

What is demodex canis / cati and how does it cause disease? (6)

Answer 8

• Obligate parasites that complete their life cycle on the host
• Localised demodicosis
• Mites may be found in cerumen in generalised demodicosis cases
• Causes lymphocytic mural folliculitis - affects follicle
• Inflammation around hair follicle
• Spectrum - inflammation within hair follicle -> furunculosis (hair follicle ruptures)

Question 9

Answer 9

Sarcoptes scabiei var. canis - mites found on deep skin scrapes - burrowing mite

Question 10

What are the different sarcoptiform mites in different species? (4)

Answer 10

• Sarcoptes scabiei (dog)
• Notoedres cati (cat)
• Psoroptes spp (rabbit, horse, sheep)
• Notoedres spp (rodents)

Question 11

How do sarcoptiform lead to otitis externa and media? (7)

Answer 11

Question 12

What are neotrombicula autumnalis? (4)

Answer 12

Question 13

What do foreign bodies usually involve? (3)

Answer 13

Question 14

What are the different primary causes of hypersensitivity / allergy of otitis externa/media? (3)

Answer 14

• Atopy
• Cutaneous Adverse Food Reaction (CAFR)
• Contact Hypersensitivity

Question 15

Where is atopy located and how is it diagnosed?

Answer 15

Question 16

What is cutaneous adverse food reaction (CAFR)? (3)

Answer 16

Question 17

What is contact hypersensitivity and what are some examples? (3)

Answer 17

Question 18

What are keratinisation disorders due to? (3)

Answer 18

Question 19

Answer 19

Question 20

What are the disorders of growth that cause otitis externa/media? (6)

Answer 20

• Feline ceruminous gland hyperplasia (ceruminous cystomatosis)
• Feline nasopharyngeal (inflammatory) polyp
• Neoplasia

Question 21

How does obstructive ear disease lead to otitis and give an example and gross morphological findings? (6)

Answer 21

Question 22

Answer 22

Question 23

Answer 23

Question 24

What is feline nasopharyngeal (inflammatory) polyp, where does it originate from and what are the causes? (4)

Answer 24

Question 25

How does neoplasia lead to obstructive ear disease? (4)

Answer 25

Question 26

Answer 26

Question 27

Answer 27

Question 28

Give some examples of external and middle ear tumours (6)

Answer 28

Question 29

What are the different immune-mediated diseases that cause otitis externa/media? (3)

Answer 29

* Pemphigus foliaceus * Cutaneous vasculitis * Puppy strangles

Question 30

What is vesicular and pustular dermatitis and what are the causes? (4)

Answer 30

Question 31

What is pemphigus foliaceus? (3)

Answer 31

Question 32

What is cutaneous vasculitis and how does it cause otitis externa/media and what are its causes? (6)

Answer 32

Question 33

What is canine juvenile sterile granulomatous dermatitis and lymphadenitis (Puppy strangles)? (3)

Answer 33

Question 34

Answer 34

Canine juvenile sterile granulomatous dermatitis and lymphadenitis (puppy strangles)

Question 35

Answer 35

Question 36

What is dermatophytosis, which species is it seen in and what lesions does it produce? (4)

Answer 36

Question 37

What is canine distemper virus and what lesions does it produce? (3)

Answer 37

Question 38

Answer 38

Aural haematoma

Question 39

What is an aural haematoma caused by? (4)

Answer 39

Question 40

Answer 40

Squamous cell carcinoma - due to actinic dermatitis

Question 41

What is actinic dermatitis and what does it cause and the lesions produced? (3)

Answer 41

Question 42

Give examples of secondary causes of otitis externa/media. (3)

Answer 42

* Bacteria (opportunistic) * Yeast (opportunistic) * Treatment effects - irritant reaction to topical medication, iatrogenic overcleaning.

Question 43

Answer 43

Question 44

Which bacteria colonise 2y to inflammation? (gram positive and negative) (7)

Answer 44

Question 45

What are biofilms? (3)

Answer 45

Question 46

Answer 46

Malassezia dermatitis

Question 47

What is Malassezia dermatitis? (3)

Answer 47

Question 48

What are the treatment effects that are secondary causes of otitis externa/media? (3)

Answer 48

Question 49

What are the perpetuating factors of otitis externa/media? (prevent resolution + inc risk of recurrence) (5)

Answer 49

* Progressive pathologic changes - tympanic membrane alterations * Equine aural plaques * Microorganisms * Inappropriate treatment * Otitis media

Question 50

Answer 50

Question 51

What are the different progressive pathologic changes of the outer and middle ear? (Epidermal, ear canal, glandular, peri-cartilaginous connective tissue) (8)

Answer 51

Question 52

Answer 52

Question 53

What is otitis media? (7)

Answer 53

* Often extension of otitis externa * 1^y otitis media e.g. in CKCS - primary secretory otitis (similar in humans) * Otitis media 2^y to respiratory infections - infects middle ear via eustachian tube * Most common in cats, rabbits + guinea pigs * Common cause = Pasturella multocida * V. difficult to treat as usually have intact tympanic mem * Inflammation/foreign material within middle ear can have metaplasia of epithelium lining middle ear canal -\> inc mucus production = recurring problem

Question 54

What are the types of guttural pouch disease? (3)

Answer 54

Question 55

Answer 55

Question 56

What are equine aural plaques (ear pinna papilloma), what are the lesions and clinical signs? (3)

Answer 56

Question 57

Give examples of predisposing factors of otitis externa/media. (5)

Answer 57

* Anatomic configuration/conformation * Excessive moisture * Excessive cerumen production/accumulation * Treatment effects * Systemic disease (immunosuppression, FeLV, FIV, FIP)

Question 58

Which breed of dog is predisposed to ear disease?

Answer 58

Shar pei

Question 59

What are the different conformation predisposing factors of otitis? (3)

Answer 59

Question 60

What activity predisposes to ear infections?

Answer 60

Swimming

Question 61

How does excessive moisture lead to ear infections? (2)

Answer 61

Question 62

What is the systemic approach to otitis external? (7 steps to carry out diagnosis)

Answer 62

Question 63

What is the systemic approach to otitis media? (7)

Answer 63