Otitis Flashcards
Describe the follicle type found in ears
In all but Cockers are simple follicles, Cockers hve complex follicles
Name the portions of the tympanic membrane
- Pars flaccida
- Pars tensa
Name and define the types of ear disease that are possible
- Pinnal disease: diseases affecting the ear flap
- Otitis externa: inflammation of the outer ear
- Otitis media: inflammation of the middle ear
- Otitis interna: inflammation of the inner ear
What is pinnal disease typically a reflection of?
Otitis externa
Name the pruritic conditions that may affect the pinnal margins
- Scabies
- Neotrombiculosis
- Rarely atopy
Name the non-pruritic diseases that may affect the pinnal margins
- Vasculitis
- Pinnal margin seborrhoea
- Squamous cell carcinoma
- Actinic dermatosis
Name the pruritic diseases that typically affect the pinnal surface
- Atopic dermatitis
- Food allergy
- pemphigu foliaceous
- Fleas (cats)
- Contact irritant dermatitis
Name the non-pruritic diseases that typically affect the pinnal suface
- Pemphigus foliaceous
- Alopeciea in HAC or hypoT
- Contact irritant dermatitis
Name the pruritic diseases that typically affect the pinnal body
Aural haematoma
Name the non-pruritic diseases that typically affect the pinnal body
Auricular chondritis
Which breed is predisposed to ear amrgin seborrhoea?
Dachshunds
Describe the appearance of ear margin seborrhoea
- Adherent keratin on both sides of pinna lumpy, thickened area of scale felt around the edge, removal leads to ulceration
- Follicular casts and plugs may trap hair
- Rubbing produces ulcerations and erosions
- Fissuring and secondary infection can occur
- Pruritus variable
What condition can ear margin seborrhoea occur secondary to?
Hypothyroidism
What are the differential diagnoses for ear margin seborrhoea?
- Early vasculitis
- Early localised scabies
- Many other seborrhoeic conditions if widespread
Describe the appearance of pinnal margin vasculitis
Notch in the end of the ear
Describe the treatment for ear margin seborrhoea
- Emolient rinses, vaseline, propylene glycol
- Surgery to trim end of ear off, will not be recognisable once hair regrows
Describe the normal physiology of the ear
- Temp: 28.2-28.4degreesC
- 88.5% humidity
- pH 6.1-6.2
- Sebaceous and ceruminous glands present
- Cerumen present
- Normal flora
What is cerumen made up of?
LIpids and sloughed keratinocytes
Describe the function of cerumen
- Traps small foreign bodies
- Anti-bacterial, anti-yeast properties
- Removal of pathogens and foreign bodies via epithelial migration from tympanic membrane to the external space
What factors disturb epithelial migration?
- Inflammation
- Wetness
- Hyperplasia
- Physical blockage
Describe the normal flora of the ear canal
- Gram +ve cocci predominate
- Some dogs have no growth
- Similar to those found on skin e.g.
- Micrococcus spp.
- Coagulase negative staphylococci: Staph. schleiferi, pseudintermedius, aureus
- Streptococcus spp.
- Malassezia
What is the most important factor in otic disease?
Humidity - changes epithelial defences, microbiological proliferation, treatment
Identify the broad groups of causes of otitis externa
- Predisposing causes
- Primary causes
- Secondary disease
- Perpetuating factors
- Disease progression
List the predisposing causes of otitis externa
- Conformation
- excessive moisture
- Obstructive ear disease
- Primary otitis media
- Treatment effects
- General immunosuppression due to catabolic states, debilitation etc.
Give examples of how conformation can be a predisposing cause of otitis externa
- Excessive hair growth in canals (e.g. poodle) leads to wax accumulation and secondary infection
- Hair concave pinnae e.g. Cocker, produce occlusive blanket around head
- Pendulous pinnae e.g. Bassett hound, long canal and long pinna covering it increases humidity
- Stenotic canals e.g. Shar Pei
Explain how excessive moisture in the ear may occur
- Environment (head and humidity)
- Water (Swimmer’s ear, grooming, cleaners)
Give examples of how obstructive ear disease may occur as a predisposing cause of otitis externa
- Feline apocrine cystadenomatosis (common old cat problem)
- Neoplasia
- Polyps
- Wax blockage
- Trauma e.g. bite across canal
Give examples of how primary otitis media can be a predisposing cause otitis externa
- Primary secretory otitis media (PSOM) in CKCS
- Tumour
- Sepsis
Give examples of how treatment effects can be predisposing causes for otitis externa
- Altered microflora e.g. inappropriate cleaner
- Trauma from cleaning or plucking
List primary causes of otitis externa
- Parasites
- Foreign bodies
- Hypersensitivity
- Keratinisation disorders
- Glandular disorders
- Miscellaneous
Identify parasites that may act as a primary cause for otitis externa
- Otodectes cynotis common cause
- Demodex
- Scabies
Describe the treatment of Otodectes cynotis
- Most ear creams are effective with localised disease: Selamectin or moxidectin spot on enough for single cat
- May also need cleaner +/- steroids
Give an example of a very common foreign body that can act as a primary cause of otitis externa
Grass seeds
Give examples of hypersensitivities that may act as primary causes of otitis externa
- Atopic dermatitis
- Food hypersensitivity
- Medications
Discuss the importance of otitis externa as a complication of hypersensitivity
- Common complication of AD and CAFR
- Primary otitis often not recognised and inadequately treated
- Presented when there is secondary infection
- Recurrence common before hypersensitivity is recognised
Give examples of keratinisation disorders that may act as primary causes of otitis externa
- Primary idiopathic seborrhoea
- Hypothyroidism
Explain how glandular disorders can act as primary causes of otitis externa
Cockers, English Springers and Labrador retrievers have increased ceruminous glands so produce lots of wax, can be difficult to remove and lead to accumulation of debris/pathogens adn cause inflammation
Give an example of a primary cause of otitis externa in kittens
Feline proliferative and nectrotising otitis externa
Identify the secondary diseases that can cause otitis externa
- Bacteria
- Yeast
- Fungi
Compare acute and chronic bacterial disease as secondary disease causing otitis external
- Acute: Gram +ve bacteria e.g. Staph spp. Strep spp. Corynebacerium spp.
- Chronic disease: iterventions contribute to changes in ear flora. Gram +ve e.g. Enterococcus, and Gram -ve e.g. Pseudomonas spp, Proteus spp, Eschericia coli spp.
Describe yeast infections as a secondary disease that can cause otitis externa
- Malassezia common
- Hypersensitivity component, can mean some yeasts are very inflammatory in the ear
- Lipid dependent Malassezia also
- Candida spp. also (uncommon)
Give an example of a fungal infection that can act as a secondary disease leading to otitis externa
Aspergillus spp, very uncommon
List perpetuating factors in otitis externa
- Pathological changes in external ear canal
- e.g. changes in canal wall
- Changes in glandular tissue
- Changes in tympanum
- Otitis media
Describe pathological changes (acute and chronic) in the canal wall as a perpetuating factor in otitis externa
- Inflammation causing failure of epithelial migration
- Acute change: oedema, hyperplasia
- Chronic change: proliferative change, canal stenosis, calcification of pericartiaginous fibrous tissue
Explain how pathological changes of the glandular tissue in the external ear can act as perpetuating factors for otitis externa
- Hyperplasia of ceruminous and sebaceous glands, hidradenitis
- Produce more watery substance in ear, will not reduce bacterial numbers
- Then will become more cellular and diverted emulsion - sticky, wet wax with neutrophils = pus
What is hidradenitis?
Inflammation around ceruminous glands/sweat glands
Describe pathological change in the tympanum that can act as perpetuating factors for otitis externa
- Dilation, rupture, diverticulum formation
- Diverticulum is false middle ear, cholesteatoma can form inside which balls up and becomes destructive to the containing part of the ear, grows gradually and can cause erosions, Can push M back so far that it appears to be missing
Explain how otitis media (acute and chronic) can act as a perpetuating factor for otitis externa
- Acute: foreign material, mucopurulent exudate
- Chronic: biofilm formation, granulation material, bony change in the bulla
Outline the disease progression of otitis externa
- Secondary disease follows primary cause
- In many dogs and cats, Malassezia -> Staph. -> gram -ve rods
- In many cases, Pseudomonas aeruginosa is endpoint if treatment inadequate
List the progressive pathological changes that occur as a consequence of otitis externa over time
- Epidermal hyperkeratosis and hyperplasia
- Dermal oedema
- Fibrosis
- Ceruminal gland hyperplasia and dilation (sebaceous glands neither proliferate nor produce secretions)
- Abnormal epithelial cell migration
- Tympanic membrane alterations
- Otitis media
Give a rough idea of the proportion of acute and chronic otitis externa that progress to otitis media
- 16% of acute
- 50-80% of chronic
List the potential consequences of otitis media
- Conductive deafness
- Horner’s syndrome
- Vestibular syndrome
Describe the development of conductive deafness from otitis externa ormedia
- Loss of drug
- High pressure fluid/mucous in ear
- Chronic OE or OM +/- cholesteatoma
Describe the clinical signs of Horner’s syndrome
- Ear and lip droop
- Keratoconjunctivitis sicca, neurogenic dry nose
- Anisocoria with ipsilateral muosis, ptosis of upper eyelid
- Enophthalmos of affect side
- Conjunctival hyperaemia on affected side
Describe the classical presentation for Primary Secretory Otitis Media in the CKCS
- Presented for deafness or neck pain
- Marked mucoid build up in middle ear
- Bulging middle ear noted on otoscopy, very obvious
- May see neurological signs: ataxia, facial paralysis, nystagmus, head tilt, seizures
- May see pruritus around th ears without OE
- OE of varying degrees
- Fatigue
How is Primary Secretory Otitis Media treated?
- Make hole in drum followed by repeated flushing and myringotomy (3-5 times)
- Sputolysin (mucolytic) used by some
- Steroids used to reduce mucous production
How may otitis interna develop?
- Extension of OM (majority)
- Haematogenous and ascending infection via the auditory tube
- Systemic infection
Describe the clinical signs of otitis interna
- Head tilt to affected side
- Spontaneous or rotary nystagmus
- Asymmetrical limb ataxia with preservation of strength
- Falling
- Vomiting and anorexia
Describe the 2 main presentations of otitis externa
1: Lichenified, pruritic ear, common for alopecia and erythema to come onto cranial side of ear flap
2: Ceruminous otitis, may show less on pinna and meatus
Describe the clinical signs of otitis externa
- Aural pruritus or head shaking
- Mild to marked exudate
- Malodour
- Head tilt
- Deafness
Describe the common physical findings in otitis externa
- Erythema, swelling, scaling, discharge (otorrhoea), malodour, pain
- Secondary changes: pinnal lesions due to pruritus, pyotraumatic dermatitis elsewhere on head/face (miss ear when scratch), haematoma ue to head shaking/trauma from scratching
Describe the clinical signs of otitis media
- Variable, often non-specific e.g. pain, inappetance
- MOst often signs of concurrent OE are most obvious
- Deafness
- Pain on eating
- Signs of otitis interna if progressing
Outline the investigation of otitis media
- Examine appearance of drum on otoscopy (may require flushing)
- Sampling of middle ear for bacteriology, fungal culture and cytology (myringotomy or ruptured TM)
- Palpation of granulation tissue in middle ear
- BAER hearing test
- Imaging (radiography, CT, MRI)
Compare the normal findings on palpation of granulation tissue in the middle ear, with that of an ear with otitis media
Use probe with slight bend (and only in larger dogs) - should normally hear a tap, rather than a spongy sound
Why is the BAER hearing test used in the investigation of otitis media? Give the full name
- Brainstem auditory evoked response
- Can assess delay in conduction and differentiate conductive from central deafness
Evaluate the role of radiography in the investigation of otitis media
- Insensitive assessment of OM
- Obvious changes only with severe disease
- May see thickening of wall of bulla in chronic disease
- Changes absent in many cases of OM
When using radiography in the investigation of otitis media, which views are taken?
Lateral oblique and open mouth views
Evaluate the use of MRI or CT in the investigation of otitis media
- MRI much better appreciation of soft tissue structures
- CT can be useful cheaper alternative in many cases
What is myringotomy?
Surgical incision into the ear drum, often to relieve presure
List the infication for myringotomy
- Bulging TM with pain or neurological signs
- Tympanosclerosis (as an exploratory mryingotomy)
- Radiographic MRI shows bulla changes and intact TM
- Evidence of tissue or fluid behind the TM
- Medially unresponsive vestibular disease with an intact TM
- Chronic otitis cases longer than 6 months that have not responded to treatment for OE
Briefly outline the method for myringotomy
- Clean and dry external ear canal
- Incision using 5-Frensh polypropylene catheter, Tomcat catheter or small wire swab
- Pass through otoscope
- Position on caudoventral aspect of pars tensa to avoid damaging tympanic germinal epithelium and the structure of the middle ear
- Pass swabs, instill then withdraw small amount of sterile saline solution
- Flush with saline +/- other agents depending on cytology
List the differential diagnoses for otitis interna
- Other peripheral vestibular disease
- Idiopathic vestibular syndrome
- Neoplasia (vestibulocochlear nerve)
- Hypothyroidism
Outline the method of diagnosis of otitis interna
- Establish presence of systemic disease and/or localised disease (OE/OM)
- Pruritus, headshaking and pain around TMJ are useful indicators of local disease
- Complete neuro exaM
- Otic examination +/- myringotomy
- MRI, possibly CT
Outline the key points in the treatment of otitis externa
- Need to treat primary and secondary disease, predisposing factors and perpetuating factors
- Ensure owner knows how to intervene early
- Ensure no debris preventing penetration of treatment
Outline the treatment of otitis interna
- In absence of another cause, long term use of systemic antibiotics advocated
- Based on culture of middle ear
Describe the antibiotic, antifungal and steroid properties of Osurnia (florifenicol) ear treatment
- Bacteriostatic antibiotic, inhibits protein synthesis, active vs Gram +ve and -ve
- Active vs Staph. pseudintermedius
- Terbinafine: active against Malassezia
- Beta-methaasone acetate: GC absorbed systemically in first 2-4 days
Describe the antibiotic, antigfungal and steroid properties of Aurizon ear treatment
- Marbofloxacin, clotrimazole, dexamethasone
- Marbo: active vs G+ve bacteria, G-ve bacteria
- Clotrimazole broad spec
- Dex: absorption over 14 days
Describe the antibiotic, antifungal and steroid properties of Posatex ear treatment
- Orbifloxacin: broad spec, active G+ve and G-ve
- Mometasone furoate glucocorticoid, minial absorption
- Posaconazole, active against Malassezia
Describe the antibiotic, antifungal, anti-ectoparasitic and steroid properties of Surolan ear treatment
- Polymyxin B: bactericidal, active against G-ve incl. Pseudomonas aeruginosa and E. coli
- Miconazole nitrate: active against trichophyton, Microsporum, Malassezia, Candida
- Active against Otodectes cynotis
- Systemic absorptoin of prednisolone
Describe the antibiotic, antifungal and steroid properties of Easotic/Otomax ear treatment, plus additional information
- Gentamicin: mostly G-ve incl Pseudomonas, E coli, and G+ve Staph pseudintermedius
- Hydrocortisone aceponate: short acting, low potency
- Gentamicin is ototoxic so not for performated ear drums
- Easotic contains miconazole nitrate, otomax contains clotrimazole
Describe the antibiotic, antifungal and steroid properties of Canaural ear treatment
- Fusidic acid (diethanolamine fusidate salt): high activity vs Staph
- Framycetin sulphate broad spec. antibiotic, active against G-ve
- Prednisolone glucocorticoid, systemic absorption
- Contains nysatin antifungal
What specific ear history points are important in the investigation o otitis externa or media?
- Unilateral or bilateral?
- Pruritus/head shaking/scratching
- Smell
- Head tilt
- Signs of facial paralysis
What should you look out for in particular during the clinical examination of an animal presented for ear disease?
- Other skin disease
- Neurological problems
- Ear carriage
- Pinna and outer meatus and upper vertical canal
- Smell
What might be required prior to otoscopy of a diseased ear?
- Treat for short period with corticosteroids, then reassess
- Or chemical restraint if emergency e.g. grass seed suspected
What should be considered during examination of the ear canal?
- Surface of the epithelium: smooth? Papillarae? Cystic bumps?
- Surface of canal: red? Inflamed? Pus?
- Lumen: open and consistently so? Size of lumen?
- Nature of discharge
- Eptihelial migration demonstrated by wax spread up and coming towards opening in a discrete way
Describe changes that may be observed on the tympanic membrane with otic disease
- Present or absent?
- Ruptured or pushed back
- Changes in colour
- Bulging
What pathogen is often associated with otic discharge similar to dry coffee grounds?
Otodectes cynotis
What pathogens are often associated with moist brown exudate otic discharge?
Staphylococcus spp. , Malassezia
Describe the type of otic discharge commonly associated with Gram-ve bacteria, especially Pseudomonas spp.
Purulent yellow/green exudates (malodorous), can also be tarry black. Biofilm produced, feels like snot
What underlying cause is ceruminous discharge with little smell often indicative of?
- Allergy
- Endocrine (esp, hypoT)
- Keratinisation defects
- Bacteroides spp.
Outline the importanve of wax and cytology examination in the investigation of otic disease
- Usually possible even when otoscopy is not
- Best to perform in all cases
- Affected by treatments which are often oily
- Good to have baseline
- Swabs kept in charcoal for reference
- Consider taking bacteriology swab with cytology then submit, store or dispose
Describe the staining of otic wax samples
- Poor stickiness so use staining rack
- Apply methylene blue only and a coverslip (stain 3 of DiffQuik)
Describe the staining of purulent otic wax samples
- Stain as for cytology
- For eosinophilic staining use last 2 stains of DiffQuik alone, squeeze out excess using coverslip
Give examples of factors that may prevent sampling of a representative population from an ear
- Wax or cream blockage can prevent swab getting deeper into the ear to sample the true population of pathogens causing disease
- If ear drum heals over, cannot sample middle ear for the true population causing disease
Discuss the advantages and disadvantages of bacteriology in the investigation of otic disease
- Confirms and/or identifies bacteria present in ear canal
- Presence of bacteria does not equal disease
- Common affected by previous antibiotic ear creams and previous cleaners
- Provides susceptibility data, but flawed when considering topical treatment
Explain why MIC data is not reliable when considering ear treatments
- MIC data relates to oral or parenteral antibiotics
- Much higher doses reach ear when used topically, so MIC achieved more easily in area where it is needed
- Bacteria likely to be susceptible to higher doses so cannot reply on MIC
Explain the diagnostic value of flushing the ears
- See epithelium of ear canal more clearly and assess for hyperplasia, ulceration, masses and defects
- Check integrity of the drum, very difficult to assess correct level of drum in many dogs
Explain the therapeutic value of flushing the ears
- Dilutes and removes bacteria, yeasts and inflamm. mediators
- If add appropriate cleaners has anti-microbial effects
- Removes pus which may inactivate antibiotics
- Removes old treatments
- Removal of debris which can act as a nidus for infection
List the otic flushing solutions that are available
- Normal saline
- Dilute povidone iodine
- Chlorhexidine
- Others: cerumolytics, aqueous solutions, drying agents
Which of the flushing solutions are safest?
Saline and TRIZChlor
