Inflammation of the External and Middle Ear Flashcards
Give some examples of primary causes of otitis externa and media (8)
- Infectious (ectoparasites, fungal, viral)
- Foreign bodies
- Hypersensitivity disorders
- Keratinisation disorders (endocrinopathies)
- Obstruction (neoplasia, polyps, cysts)
- Immune-mediated skin diseases (puppy strangles)
- Trauma
- Sunburn
What are the common parasites of the outer and middle ear? (4)
- Otodectes cynotis
- Demodex spp.
- Sarcoptiform mites
- Neotrombicula autumnalis
Otodectes cynotis
Where is otodectes cynotis most common? (5)
- 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
How do mites like otodectes cynotis cause disease? (3)
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
Demodex canis
Demodex canis / cati
What is demodex canis / cati and how does it cause disease? (6)
- 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)
Sarcoptes scabiei var. canis - mites found on deep skin scrapes - burrowing mite
What are the different sarcoptiform mites in different species? (4)
- Sarcoptes scabiei (dog)
- Notoedres cati (cat)
- Psoroptes spp (rabbit, horse, sheep)
- Notoedres spp (rodents)
How do sarcoptiform lead to otitis externa and media? (7)
What are neotrombicula autumnalis? (4)
What do foreign bodies usually involve? (3)
What are the different primary causes of hypersensitivity / allergy of otitis externa/media? (3)
- Atopy
- Cutaneous Adverse Food Reaction (CAFR)
- Contact Hypersensitivity
Where is atopy located and how is it diagnosed?
What is cutaneous adverse food reaction (CAFR)? (3)
What is contact hypersensitivity and what are some examples? (3)
What are keratinisation disorders due to? (3)
What are the disorders of growth that cause otitis externa/media? (6)
- Feline ceruminous gland hyperplasia (ceruminous cystomatosis)
- Feline nasopharyngeal (inflammatory) polyp
- Neoplasia
How does obstructive ear disease lead to otitis and give an example and gross morphological findings? (6)
What is feline nasopharyngeal (inflammatory) polyp, where does it originate from and what are the causes? (4)
How does neoplasia lead to obstructive ear disease? (4)
Give some examples of external and middle ear tumours (6)
What are the different immune-mediated diseases that cause otitis externa/media? (3)
- Pemphigus foliaceus
- Cutaneous vasculitis
- Puppy strangles
What is vesicular and pustular dermatitis and what are the causes? (4)
What is pemphigus foliaceus? (3)
What is cutaneous vasculitis and how does it cause otitis externa/media and what are its causes? (6)
What is canine juvenile sterile granulomatous dermatitis and lymphadenitis (Puppy strangles)? (3)
Canine juvenile sterile granulomatous dermatitis and lymphadenitis (puppy strangles)
What is dermatophytosis, which species is it seen in and what lesions does it produce? (4)
What is canine distemper virus and what lesions does it produce? (3)
Aural haematoma
What is an aural haematoma caused by? (4)
Squamous cell carcinoma - due to actinic dermatitis
What is actinic dermatitis and what does it cause and the lesions produced? (3)
Give examples of secondary causes of otitis externa/media. (3)
- Bacteria (opportunistic)
- Yeast (opportunistic)
- Treatment effects - irritant reaction to topical medication, iatrogenic overcleaning.
Which bacteria colonise 2y to inflammation? (gram positive and negative) (7)
What are biofilms? (3)
Malassezia dermatitis
What is Malassezia dermatitis? (3)
What are the treatment effects that are secondary causes of otitis externa/media? (3)
What are the perpetuating factors of otitis externa/media? (prevent resolution + inc risk of recurrence) (5)
- Progressive pathologic changes - tympanic membrane alterations
- Equine aural plaques
- Microorganisms
- Inappropriate treatment
- Otitis media
What are the different progressive pathologic changes of the outer and middle ear? (Epidermal, ear canal, glandular, peri-cartilaginous connective tissue) (8)
What is otitis media? (7)
- 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
What are the types of guttural pouch disease? (3)
What are equine aural plaques (ear pinna papilloma), what are the lesions and clinical signs? (3)
Give examples of predisposing factors of otitis externa/media. (5)
- Anatomic configuration/conformation
- Excessive moisture
- Excessive cerumen production/accumulation
- Treatment effects
- Systemic disease (immunosuppression, FeLV, FIV, FIP)
Which breed of dog is predisposed to ear disease?
Shar pei
What are the different conformation predisposing factors of otitis? (3)
What activity predisposes to ear infections?
Swimming
How does excessive moisture lead to ear infections? (2)
What is the systemic approach to otitis external? (7 steps to carry out diagnosis)
What is the systemic approach to otitis media? (7)
