External and Middle Ear Pathology II

Question 1

Name 5 predisposing factors to ear disease

Answer 1

1. Conformation (Stenotic EAM), Excessive hair
2. Excessive moisture- swimming, humid climate
3. Excessive Cerumen Production
4. Treatments (iatrogenic)
5. Obstructive Ear Disease- disorders of growth, inflammation
6. Systemic diseas- immune supression, debilitation, catabolic states

Question 2

What is the pathogenesis of otitis externa?

Answer 2

• Extension from the external environment
• Hematogenous spread (cancer cells breaking away)
• Extension from the middle ear

Question 3

What are the gross features of acute phase Otitis Externa?

Answer 3

• Erythema, Warmth
• Otorrhea = ear discharge/
  drainage
• Otorrhagia = bleeding from the
  ear
• Otodynia/ otalgia = ear pain

Question 4

What are the gross features of chronic phase otitis externa?

Answer 4

• nodular proliferative phase lesions, bosselation
• severe cases have ear canal stenosis
• chronic cases are pinnal haematomas
• inspissated (thickened) debris

Question 5

What causes an aural haematoma?

Answer 5

• Either head shaking or self-trauma secondary to OE
• haematoma can form intrachondrially or subparachondrially
• often associated with cartilage fractures histologically

Question 6

What are the clinical signs of parasitical otitis externa?

Answer 6

• Head Shaking
• Repeated Ear Twitching
• Excessive ear itching
• trauma of the auricle and base of ear

Question 7

What are three examples of parasites that can cause primary otitis externa?

Answer 7

• Notoedres cati
• Otodectes cyanotis
• Psoroptes cuniculi

Question 8

How does a type I hypersensitivity cause primary otitis externa?

Answer 8

• Reaction to ectoparasites
• Systemic reaction to ingested allergens (food, drugs…)

Question 9

What is ear margin sebborhea?

Answer 9

type of keratinisation disorder
* waxy crusts cover the ear margin and form small fissures

Question 10

Give 4 examples of foreign bodies that can cause primary otitis externa

Answer 10

• Plants
• Hair
• Hardened secretions
• Medication
• Sand/ Dirt

Question 11

Give an example of a glandular disorder that causes primary otitis externa

Answer 11

• Ceruminous gland hyperplasia (masses due to a build-up of ear wax)

Question 12

Give 4 autoimmune diseases that cause primary otitis externa

Answer 12

• Lupus erythematous
• Pemphigus (folaceous, vulgaris, erythematous)
  all cause scaling, crusting (multifocal to coalescing)

Question 13

What is Vasculitis?

Answer 13

Type III sensitivity
due to a vaccine reaction

Question 14

What is Myringitis?

Answer 14

Inflammation of the tympanic membrane

Question 15

What is otitis media?

Answer 15

Inflammation of the tympanic cavity

Question 16

What are the clinical signs of otitis media?

Answer 16

• Head tilt
• Facial paralysis
• Drooping ears

Question 17

What is a type I hypersensitivity?

Answer 17

• igE mediated
• causes the release of histamine and other inflammatory mediators

Question 18

What is type IV hypersensitivity?

Answer 18

Allergic Contact Dermatitis

Question 19

How does frostbite cause primary otitis externa?

Answer 19

• Decrease in teemperature
• This causes blood to be shunted from the extremities
• Damage of tissue may lead to inflammation

Question 20

Give an example of an autoimmune disease that causes otitis externa

Answer 20

lupus erythematous

Question 21

What is the route of infection for otitis media?

Answer 21

• Perforation of the tympanic membrane
• Ascension along the auditory tube
• Extension via degeneration of the temporohyoid joint
• Extension via erosion of the tympanic bulla
• migration along vascular or neural pathways

Question 22

What are microtia?

Answer 22

Small pinna

common in some species of goat

Question 23

What species are most predisposed to nasopharyngeal polyps?

Answer 23

Most common in cats under two years old

Question 24

What is the gross pathology of nasopharyngeal polyps?

Answer 24

pedunculated to polyploid, pale tan mass with smooth surface

Question 25

What are the clinical signs of otits media?

Answer 25

• Head tilt
• Facial Paralysis
• Drooping ears
• Concurrent respiratory signs

Question 26

What is type IV hypersensitivity?

Answer 26

• Allergic contact dermatitis
  *

Question 27

What does chronic otitis externa look like?

Answer 27

• Hyperpigmentation
• Lichenification
• pyoderma secondary to pruritis

Question 28

What dog species is most likely to get primary idiopathic seborrhea?

Answer 28

Dachshunds

Question 29

What two endocrin disorders cause keratinisation disorders?

Answer 29

• Hypothyroidism
• Hyperadrenocorticism

Question 30

What lipid related condition also causes keratinisation disorders

Answer 30

epidermal lipid metabolism

Question 31

What is the effect of frostbite?

Answer 31

• Decrease in ambient temperature
• Blood shunted from extremities

Question 32

Name three things (not frostbite or vasculitis) that cause vascular disease

Answer 32

• Bacterial sepsis
• Juvenile cellulitis
• Auricular/ Aural chondritis (autoimmune reaction against cartilage)

Question 33

What respiratory pathogens are often implicated in otitis media?

Answer 33

• Pasteurella multocida, Trueperella, pyogenes, Mycoplasma, Mycoplasma spp. Histophilus somni

Question 34

What are the clinical signs of otitis media?

Answer 34

• Head tilt
• Facial paralysis
• drooping ears
• concurent respiratory signs

Question 35

What are the predisposing factors for nasal pharyngeal polyps?

Answer 35

• Upper respiratory infection
• otitis media

Question 36

What is the predisposing factor for tympanokeratomas?

Answer 36

• Chronic otitis media

Question 37

What is the gross pathology of a tympanokeratoma?

Answer 37

• Tympanic cavity filled and expanded with pasty yellow to pale-tan material
• loss of normal structures

Question 38

What is a papillomatosis?

Answer 38

• Flattened, verrucous, well-circumscribed, often depigmented, hyperkeratotic plaques
• associated with equine caballus papillomavirus
• can progress to squamous cell carcinoma