Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SMALL ANIMAL > 23.11.4: Ear disease 1 > Flashcards

23.11.4: Ear disease 1 Flashcards

From lecture on 2/3/2023

1
Q

Otitis externa

A

inflammation of the outer ear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Otitis media

A

inflammation of the middle ear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Otitis interna

A

inflammation of the inner ear (see neurology)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

1

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

2

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

3

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

1

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

2

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

3

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

4

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

5

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

6

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

7

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

8

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

1

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

2

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

3

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

4

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

5

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

6

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What components form cerumen and how does it move out of the ear? How can this be interfered with?

A

Cerumen = lipids + sloughed keratinocytes
* Cerumen also traps small FB, and acts as anti-bacterial, anti-yeast, and buffers changes in pH well
* Epithelial migration moves wax from the typical membrane to the external space
* Epithelial migration is disturbed by inflammation, wetness, hyperplasia, and physical blockage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What factors can cause microbial overgrowth (dysbiosis) in the ear? Which microorganisms commonly overgrow?

A

Factors causing dysbiosis:
* Humidity
* Inflammation and swelling
* Reduced epithelial migration
* Epithelial surface changes

Most commonly these overgrow:
* Staphylococcus pseudintermedius
* Malassezia pachydermatitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is P.S.P.P. and how does it help us in treating otitis?

A
  • If we have a combination of these factors, we will see greater and longer-lasting disease.
  • Considering each of these factors allows targeted assessment (cytology, C&S, underlying cause) and direct targeted treatment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are some predisposing causes to otitis?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

True/false: ear plucking is essential in dogs with a history of otitis.

A

False.
* Ear plucking can cause trauma; steroids are preferable to reduce inflammation but these cannot be dispensed by groomers
* Owners can take the hairs that come away easily, but should not yank hairs out

26
Q

Primary causes of otitis

A

Parasites
* Otodectes cynotis
* Demodex spp.
* Scabies

Foreign bodies e.g. grass awns

Hypersensitivity
* Atopic dermatitis
* Food hypersensitivity
* Medications

Keratinisation disorders
* Primary idiopathic seborrhea
* Hypothyroidism

Glandular disorders: some breeds have increased ceruminous glands

Miscellaneous e.g. feline proliferative and necrotising otitis externa

27
Q

Which breeds have increased ceruminous glands, disorders of which can represent a primary cause of otitis?

A
  • Cocker spaniels
  • English Springer spaniels
  • Labrador retrievers
28
Q

Which parasites might cause ear and tail base disease in cats and why is this?

A

Otodectes cyanotis
This is due to the way cats curl up when they sleep

29
Q

What is this and how would you treat?

A

Otodectes cyanotis
* Common cause of otitis
* May also cause hypersensitivity disease in some patients
* Run away from light and the otoscope

Treatment
* Most ear creams are effective against localised disease
* Moxidectin / selamectin spot on work
* Likely that isoxazolines also effective
* May need a cleaner ± steroids

30
Q

What history and clinical exam findings would you expect from a dog with an otic foreign body?

A
  • Late spring to early summer
  • Sudden onset, violent response
  • Very painful and bothering the dog greatly; however, compared to atopy, there are not many external signs
  • Chemical restraint often essential to examine eat
  • Foreign body may be hidden in discharge or migrate into the middle ear
31
Q

How common is hypersensitivity otitis externa and how should it be prevented?

A

Otitis externa is a very common complication of atopic dermatitis and food allergy. It is often inadequately recognised and not treated until it is severe/ there is secondary infection.

Prevention of recurrence:
* Treat the primary disease
* Ensure perpetuating factors are treated
* Ensure the owner knows to intervene early

32
Q
A

Hypersensitivity otitis externa

33
Q

True/false: gram positive rods are normal in the ear.

A

True but not in large amounts.

34
Q

Clinical signs of otitis externa

A
  • Aural / otic pruritus, headshaking
  • Mild to marked exudate
  • Malodour
  • Head tilt: may be neuro or pain
  • Deafness: may be toxic or neuro

On clinical exam:
* Erythema, swelling, scaling, discharge (otorrhea), malodour, pain
* Secondary: pinnal lesions common, pyotraumatic dermatitis, haematoma

35
Q

Which bacteria can cause acute secondary disease in the ear? (1)

A
36
Q

Which gram +ve bacteria can cause chronic secondary disease in the ear? (2)

A
37
Q

Which gram -ve bacteria can cause chronic secondary disease in the ear? (3)

A
38
Q

Which fungi can cause secondary disease in the ear?

A
39
Q

What are some perpetuating factors that contribute to otitis? (1-4)

A
40
Q

What is present on cytology?

A

Malassezia

41
Q

What is present on cytology?

A

Rods, possibly also some Malassezia

42
Q

Describe how as disease progresses, microorganisms within the ear change

A
  • Initially, may see Malassezia overgrowth
  • After this, may see staphylococci, and then gram -ve rods
  • In many cases, Pseudomonas aeruginosa is the endpoint
43
Q

Progressive pathological changes that occur with time in the untreated / unsuccessfully treated ear

A
  • Epidermal hyperkeratosis and hyperplasia
  • Dermal oedema
  • Fibrosis
  • Ceruminal gland hyperplasia and dilation
  • Abnormal epithelial cell migration
  • Tympanic membrane alterations
  • Otitis media (happens in 16% of acute and 50-80% of chronic otitis externa)
44
Q

Clinical signs of otitis media

A

Variable clinical signs - often vague
* Non specific signs may be due to pain
* Often, concurrent otitis externa is the most obvious sign
* Deafness
* Yawning
* Pain on eating
* Signs of otitis interna if progression
* Damage to nerves running through middle ear (e.g. facial nerve) leads to more obvious signs
* Pictured: Horner’s syndrome - can occur with otitis media or interna

45
Q

Consequences of otitis media

A

Conductive deafness
* Loss of drum (animals have normal hearing with single hole in tympanic membrane)
* High pressure fluid / mucus in the iddle ear
* Chronic otitis externa / otitis media ± cholesteatoma

Horner’s syndrome / facial paralysis
* Ear and lip droop, asymmetrical lips, dribbling
* Keratoconjunctivitis sicca, neurogenic dry nose
* Anisocoria with ipsilateral miosis, ptosis of upper eyelid

Vestibular syndrome (otitis interna)

46
Q

Investigation of otitis media

A
  • Appearance of drum on otoscopy
  • Sampling of middle ear for bacteriology, fungal culture, cytology via myringotomy or ruptured tympanic membrane
  • Palpation of granulation tissue in the middle ear
  • BAER (hearing testing)
  • Imaging e.g. CT
47
Q

Treatment of otitis media

A

Intact drum:
* Perform myringotomy and flush until clean

Using C&S and culture data:
* Use aqueous antibiotics 2-3 times per day following cleaning with saline or an appropriate cleaner e.g. TRIZEDTA with 0.15 w/w chlorhex in dogs
* Pain relief
* Systemic antimicrobials not typically used

Severe cases
* Consider total ear canal ablation (TECA) ± OR bulla osteotomy
* Seek advice from experienced or referral vets

48
Q

What would constitute a severe case of ear disease where you might consider TECA ± BO?

A
  • Poor response to therapy
  • Intractable otitis externa
  • Evidence of marked new bone on radiographs / CT
49
Q

What is Primary secretory otitis media and which breeds is it seen in? What are the clinical exam findings and treatment options?

A

Seen in CKCS and other brachys
* Present for deafness or neck pain; can be mistaken for syringomyelia
* There is marked mucoid build-up in middle ear
* Bulging middle ear noted on otoscopy
* Repeated flushing and myringotomy (3-5 times) will help for 18 months
* Sputolysin (a mucolytic) and N-acetyl-cysteine have been used by some; steroids are used to reduce mucus proliferaton but these do have adverse effects

50
Q

Indications for myringotomy

A
51
Q

Imaging modality used and 1 & 2

A

CT

52
Q

Imaging modality, species, findings

A

MRI
Dog
Normal - air in the bulla

53
Q

Imaging modality, species, findings

A
54
Q

Compare the use of MRI and CT for imaging the ear

A

CT = £1200-1800
MRI = £3000-4000

  • MRI offers far better appreciation of soft tissue structures and should be considered when there may be wider neurological diagnoses
  • CT is often as useful and a much cheaper alternative in many cases
55
Q

Causes of otitis interna

A
  • Extension of otitis media (majority of cases)
  • Haematogenous and ascending infection via the auditory tube
  • Adverse drug reaction
56
Q

Clinical signs of otitis interna

A
  • Head tilt to the affected side
  • Spontaneous or rotatory nystagmus
  • Asymmetric limb ataxia with preservation of strength
  • Falling
  • Vomiting ± anorexia
57
Q

Differential diagnoses for otitis interna

A
  • Other peripheral vestibular diseases
  • Idiopathic vestibular syndrome
  • Neoplasia (e.g. of vestibulocochlear nerve)
  • Hypothyroidism
58
Q

Diagnosis of otitis interna

A

Seek advice from experienced / referral vets
* Establish the presence of systemic and/or localised disease (OE / OM)
* Pruritus, headshaking, pain around the TMJ may be useful indicators of local disease
* Perform complete neurological examination
* Otic examination ± myringotomy
* MRI (possibly CT)

59
Q

Treatment of otitis interna

A

Seek advice from experienced / referral vets
* In the absence of another cause, long-term use of systemic antibiotics has been advocated
* This may be based on culture of the middle ear
* Ability to cross the BBB
* Consider possible side effects e.g. toxicity

60
Q

Which antibiotic can cause acute deafness and vestibular syndrome?

A

Gentamycin

61
Q

Neurological signs consistent with ototoxicity (e.g. in drug reaction)

A
  • Profound hearing loss and vestibular signs

Remember:
* No in-ear reatment is considered otosafe - there is always a risk
* Clinical signs are complicated by competing signs from bacterial toxins / invasion and inflammation

62
Q

What should you do if you suspect an adverse event (e.g. ototoxicity following antimicrobial administration)?

A

SMALL ANIMAL (90 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions