Otitis

Question 1

Draw normal ear structure?

Answer 1

Question 2

Label the tympanic membrane?

Answer 2

Question 3

What types of ear disease are there?

Answer 3

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

Question 4

Outline different pinnal diseases?

Answer 4

Question 5

Discuss ear margin seborrhea?

Answer 5

• Relatively uncommon
• Marked breed predilection in Dachshunds (Labradors and golden retrievers)
• Can be a feature of hypothyroidism
• Adherent keratin on both medial and lateral sides of the pinna
• Follicular casts and plugs may trap hair
• Rubbing produces erosions and ulceration
• Pruritus is variable
• Fissuring and secondary infection can be problematic

Question 6

Discuss ear physiology?

Answer 6

• Temp 38.2–38.4 ˚C
• Humidity 88.5%
• pH 6.1/6.2 (lower compared to the skin)
• Otitis associated with rise in temp, humidity and pH
• Sebaceous glands
• Ceruminous glands
• Lipids + sloughed keratinocytes form cerumen
  
  • Cerumen traps small FB
  • Anti-bacterial/yeast
  • Epithelial migration moves wax from TM to the external space (this happens in normal ear)
  • Epithelial migration disturbed by inflammation, wetness, hyperplasia and physical blockage
• REMEMBER BUFFERING
• Ceruminous glands are modified sweat glands

Question 7

What is the Normal flora in the ear canal?

Answer 7

• Gram +ve cocci predominate (but no growth in some dog’s ears)
• Similar species to those found on the skin
• Micrococcus spp.
• Coagulase negative staphylococci, Staphylococcus schleiferi and Staphylococcus pseudintermedius
• Streptococcus species
• Malassezia
• And many others

Question 8

In treating otitis it is useful to consider?

Answer 8

Primary disease

e.g. atopic dermatitis, Otodectes cyanotis

Secondary disease

e.g. Malassezia, Staphylococci & Pseudomonas spp.

Predisposing factors

e.g. Hairy &/or pendulous ears, stenosis

Perpetuating factors

e.g. Ear canal hyperplasia, stenosis and scarring

P.S.P.P. system

Question 9

What are some predisposing factors for otitis?

Answer 9

Conformation

• Excessive hair growth in canals (e.g. poodle)
• Hairy concave pinna (e.g. cocker spaniel)
• Pendulous pinna (e.g. basset hound)
• Stenotic canals (e.g. shar pei)

Excessive moisture

• Environment (heat & high humidity)
• Water (swimmer’s ear, grooming, cleaners)

Obstructive ear disease

• Feline apocrine cystadenomatosis
• Neoplasia
• Polyps
• Primary otitis media
• PSOM (primary secretory otitis media) in CKCS (or brachycephalic breeds), tumour or sepsis

Treatment effects

• Altered normal microflora (e.g. inappropriate cleaner)
• Trauma from cleaning or plucking (don’t rip out hairs in anagen as this will cause folliculitis)

Question 10

What are primary causes of otitis?

Answer 10

Parasites

• Otodectes cynotis
• Demodex spp. (rarely seen only in ear usually systemic as well)
• Scabies

Foreign bodies

• Grass awns

Hypersensitivity

• Atopic dermatitis, food hypersensitivity, medications

Keratinisation disorders

• Primary idiopathic seborrhoea
• Hypothyroidism

Glandular disorders

• Cocker spaniels, English springer spaniels & Labrador retrievers have increased ceruminous glands

Miscellaneous

• e.g. feline proliferative & necrotising otitis externa

Question 11

What is this?

Answer 11

Foreign body otitis

Grass seeds most common

• Classic time late spring to end of summer

Often stimulate violent response in the affected individual – sudden onset

Check the other ear!

Can be hidden in discharge and migrate into middle ear

Painful - chemical restraint is essential in most.

Grass seeds are most common in the summer

Beware the hair that looks like a grass seed and vice versa

Question 12

Describe hypersensitivity otitis?

Answer 12

Hypersensitivity otitis

OE is a common complication of atopic dermatitis and food allergy (CAFR)

Primary otitis is often not recognised and so inadequately treated

Dogs and cats present when there is secondary infection

Prevention of recurrence

• Treat 1˚ disease
• Ensure perpetuating factors are treated
• Ensure owner knows to intervene early!

CAFR = cutaneous adverse food reaction

Question 13

Discuss pathological changes in the external ear canal which perpetuate otitis?

Answer 13

Changes in canal wall

• Inflammation causing failure of epithelial migration
• Acute change: oedema, hyperplasia
• Chronic change: proliferative change, canal stenosis, calcification of pericartilaginous fibrous tissue

Changes in glandular tissue

• Hyperplasia of ceruminous and sebaceous glands, hidradenitis
  n. b. hidradenititis – inflammation around ceruminous glands (more generally around sweat glands)

Question 14

What the clincal features of Otitis externa?

Answer 14

Clinical signs of OE

• Aural pruritus or headshaking
• Mild to marked exudate
• Malodour
• Head tilt
• Deafness

Physical findings

• Erythema, swelling, scaling, discharge (otorrhea), malodour and pain
• Secondary
• pinnal lesions are common
• pyotraumatic dermatitis
• haematoma

Question 15

What is this?

Answer 15

Scarring caused by pseudomas infection

Question 16

What are the clinical signs of otitis media?

Answer 16

Variable clinical signs

• Often non-specific – pain?
• Most often signs of concurrent OE are the most obvious clinical signs
• Deafness
• Pain on eating
• Signs of OI if progression
• Consequences of OM

Question 17

What are the clinical signs of horner’s syndrome?

Answer 17

• Damage to sympathetic nerves to the face
• Drooping of the eyelid on the affected side (ptosis)
• The pupil of the affected eye will be constricted (miosis), or smaller than usual
• The affected eye often appears sunken (enophthalmos)
• The third eyelid of the affected eye may appear red and raised or protruded (conjunctival hyperemia)
• Facial paralysis – CN VII
• Adult age Cocker Spaniels, Pembroke Welsh corgis, boxers, and English setters are most likely to experience this condition.

Question 18

What is Primary Secretory Otitis Media (PSOM) in the CKCS?

Answer 18

It consists of a highly viscous mucus plug which fills the dog’s middle ear and may cause the tympanic membrane to bulge. PSOM has been reported almost exclusively in cavaliers.

Because the pain and other sensations in the head and neck areas, resulting from PSOM, are similar to some symptoms caused by syringomyelia (SM), some examining veterinarians may have mis-diagnosed SM in cavaliers which actually have PSOM and not SM.

• Presented for deafness or neck pain!
• Marked mucoid build-up in the middle ear
• Bulging middle ear noted on otoscopy
• Repeated flushing and myringotomy (3-5 times)
• Sputolysin (mucolytic) has been used by some
• Steroids are used to reduce mucous production

Question 19

How is otitis media investigated?

Answer 19

• Appearance of the drum on video otoscopy
• Sampling of the middle ear for
  
  • Bacteriology
  • Fungal culture
  • Cytology via myringotomy or ruptured TM
• Palpation of granulation tissue in the middle ear
• BAER (hearing testing)
• Imaging

Question 20

When is a Myringotomy indicated?

Answer 20

• Bulging TM with pain or neurological signs (Horner’s, vestibular signs, facial paresis)
• Tympanosclerosis (an “exploratory myringotomy”)
• Radiographic/MRI bulla changes and intact TM
• Evidence of tissue or fluid behind the TM
• Medically unresponsive vestibular disease with an intact TM
• Chronic otitis cases longer than 6 months that have not responded to treatment for otitis externa (requires judgement)

Question 21

How is a Myringotomy performed?

Answer 21

1. Clean and dry the external ear canal as much as you can with saline
2. Incision may be made using
   
   • a 5-French polypropylene catheter (cut end to make sharper) or an open-ended tomcat catheter or a small wire (clitoral) swab
3. Passed through either hand held or video otoscope
4. Position:
   
   • caudoventral aspect of the pars tensa to avoid damaging the tympanic germinal epithelium and the structures of the middle ear.
5. Sampling:
6. Pass swab(s) for cytology and bacteriology
7. instilling and then withdrawing a small amount of sterile saline solution
8. Flush with saline (± other agents depending on the cytology results)

Question 22

What is

BAER

Brainstem auditory evoked response?

Answer 22

Click applied to tested ear (white noise to other)

Peaks of response respond to transition through differing structures (e.g. peak I = vestibulocochlear nerve)

Normal dog – threshold <10dB

Question 23

How can radiography help diagnose otitis media?

Answer 23

• Insensitive way of assessing OM
• See thickening of the wall of the bulla in chronic disease
• Changes absent in many cases of OM
• Lateral oblique and open mouth views.

Question 24

What can be seen here?

Answer 24

CT (X-ray computed tomography)

Can see bony changes after chronic pseudomonas otitis

Question 25

How does a dog with bilateral fluid in the bullae look on MRI compared to a normal dog?

Answer 25

Question 26

Discuss otitis interna?

Answer 26

* Incidence is unknown * Cases may develop through * extension of OM (majority) * Haematogenous and ascending infection via the auditory tube **Clinical signs** * Head tilt to the affected side * Spontaneous or rotatory nystagmus * Asymmetric limb ataxia with preservation of strength * Falling * Vomiting and/or anorexia **Differential diagnoses** * Other peripheral vestibular diseases * Idiopathic vestibular syndrome * Neoplasia (vestibulocochlear nerve) * Hypothyroidism **OI diagnosis & treatment** * Establish the presence of systemic disease and/or localised disease (OE/OM) * Pruritus, headshaking and pain around the TMJ may be useful indicators of local disease * Complete neurological examination * Otic examination ± myringotomy * MRI (possibly CT) * In the absence of another cause, long term use of systemic antibiotics has been advocated.

Question 27

Should otoscopy always be attempted and if so how should it be done?

Answer 27

* Assistance from VN or owner for restraint * Pain * Do not look? * Admit for chemical restraint? * Treat for short period with a corticosteroid and then reassess? * Look at the good ear first * Head forward and slightly downwards * Straighten canal and use a small cone * Cones must be sterilised between use\* (29% were contaminated in a study)

Question 28

What should be observed during and otoscope exam?

Answer 28

* Is the surface of the epithelium smooth? (e.g ceruminous gland inflammation) * Is the surface of the canal red? * Is the lumen open and consistently so? * What is the nature of the discharge? * Epithelial migration?

Question 29

What are the examination points of otoscopy?

Answer 29

Smell * Useful as a measure of infection in many cases Canal * Wall - swelling ulceration, hyperplasia, hair, masses * Lumen - wax, pus, ear mites, foreign bodies and occlusion Drum * Present or absent, changes in colour, bulging? (is it green because pus behind it) Wax * What is normal ? * No wax is unusual * Heaped up or spread along the canal * a crude measure of epithelial migration * Colour * Smell * Texture

Question 30

What does the nature of the exudate from the ear tell us about type of pathology?

Answer 30

Question 31

How should ear exudate be sampled and prepared to view?

Answer 31

**Parasites** * Mix gently in LP and coverslip **Wax samples** * Poor stickiness * Use staining rack * Apply methylene blue (Stain 3 of Dif-Quik or equivalent) * only and coverslip **Purulent samples** * Stain as for cytology

Question 32

What flushing solutions are appropriate for ear?

Answer 32

Normal saline * Safe, widely available * Sterile Dilute povodine iodine * This has been recommended by some authors, whilst others state ototoxicity Chlorhexidine * Known to be problematic at higher concentrations * 0.15 % safe in dogs – NOT cat Others – for use after the **drum is known to be intact** * cerumolytics emulsify ear wax for easy removal e.g. squalene, alcohols * aqueous solutions aid in removing pus, mucus and serum from the ears * drying agents decrease moisture in the ears and desiccate the surface keratinocytes e.g boric acid

Question 33

What are the rules of treating otitis?

Answer 33

* Remove/reduce microbes * Reduce swelling, discomfort or pain * Normalise canal lumen and function * Polypharmacy is the rule – medications contain * Antibiotic * Antifungal * Anti-inflammatory agent * Except for Recicort (triancimalone)

Question 34

If ear is swollen what should you do before otoscopic exam?

Answer 34

If the ear is very swollen Steroids for 1-2 days before further otoscopic examination

Question 35

In chronic allergic otitis what is a sensible treatment?

Answer 35

* Long term Malassezia and S. pseudintermedius * Avoid use of antibiotics * Control microflora through * Cleaning * Use local topical steroids to * Control inflammation * This usually results in better overall control, but no licensed products.

Question 36

Discuss Pseudomonas otitis?

Answer 36

* A common problem (35% of OE &/or OM) * Gram negative rod * Highly drug resistant capsule and bacterial wall * Constitutive resistance to many antibiotics * Rapid development of resistance * Many features shared with infections by enterobacteriaciae (e.g. E. coli (esp Extended-Spectrum Beta-Lactamases [ESBLs]), Proteus and Klebsiella spp.) * Often follow a poorly managed or untreated Malassezia or Staphylococcal otitis * Swelling, pain and malodour common * Green to browny black discharge * May be associated with * immunosuppression * Swimming * prior use of antibacterials

Question 37

What is the process of the otic exam?

Answer 37

* Assess skin and ears * Cytology * Bacteriology * consider further bacteriology from deep in canal/middle ear later * Flush to clean & observe (? granulation tissue) * Use a disinfectant cleaner (trisclor on for 7-10mins to reduce bacteria rapidly) * Apply a suitable antibiotic * Provide anti-inflammatory and analgesia

Question 38

What is an example treatment for otitis?

Answer 38

* Cleaning – saline * Disinfectant – TRIZChlor 10 minute soak * Antibiotic – e.g. Aurizon * Analgesia – intraoperative opioid e.g. morphine * Anti-inflammatory – dexamethasone 0.2mg/kg IV at end of the procedure\* * \* If allergic aetiology consider IDAT/ELISA during flush as steroids may be used for some time * Home on * Aurizon ear cream 0.4–0.7mls twice daily in the affected ear for 7 days\* * TRIZChlor once daily starting on day 4\* * Prednisolone 0.5mg /kg SID PO * Re-assess at 7 days. If doing well and marked chronic changes increase dose of steroids, consider reducing frequency of drops and cleaner * \*Alternatives include TRIZ EDTA with added enrofloxacin, marbofloxacin or gentamicin, may need increased oral steroid with these

Question 39

Whats the example treatment for multi-resistant organism?

Answer 39

* Cleaning – saline * Disinfectant – TRIZ Chlor 10 minute soak * Antibiotic – silver sulfadiazine * Analgesia – Intraoperative opioid e.g. morphine * Anti-inflammatory – dexamethasone 0.2mg/kg IV at end of the procedure\* * \* If allergic aetiology consider IDAT/ELISA during flush as steroids may be used for some time * Home on * TRIZChlor twice daily * Silver sulfadiazine 1:9 aqueous solution twice daily to fill the ear\* * Prednisolone 0.5 mg /kg SID PO * Pain relief * Re-assess at 5 days to allow complete cleaning and further disinfection. Further otoscopy/flushing as needed. * \*Alternatively gentamicin, ticarcillin if suitable susceptibility data

Question 40

What is stenosis a consequence of?

Answer 40

Chronic low grade trauma Severe acute disease – untreated Trauma Mucinosis ± conformation in the Shar pei

Question 41

List common presenting signs in dogs with otitis externa in dogs?

Answer 41

* Altered ear carriage * Ear pruritus * Head-shaking, scratching, face rubbing * Aural haematoma * Pinnal excoriations * Aural discharge (otorrhea) * Aural odour * Ear pain * Behavioural changes (e.g. depression & inappetance)

Question 42

What is cortavance?

Answer 42

Hydrocortisone aceponate

Question 43

Describe the cytology shown in picture A taken from a dog with otitis externa. Pictures are taken using the x 100 oil immersion lens what are the significance of your findings?

Answer 43

**Description** The slide shows Malassezia and cocci with a small amount of nuclear streaming Neutrophils and other inflammatory cells are not seen **Significance** The presence of yeasts and cocci in cerumen is normal in small numbers. The number of organisms in this field is indicative of overgrowth and disease. Malassezia and Staphylococci are often the first organisms involved in otitis

Question 44

Describe the cytology shown in picture B taken from a dog with otitis externa. Pictures are taken using the x 100 oil immersion lens what are the significance of your findings?

Answer 44

**Description** The slide shows rods and marked nuclear streaming with a large nucleated epithelial cell **Significance** The presence of rods and nuclear streaming is indicative of a bacterial (rod) otitis. Pseudomonas sp., E.coli or Proteus are commonly isolated Bacteriology should be performed in this case

Question 45

Circle the products that would be most appropriate for use in a staphylococcal otitis?

Answer 45

Aurizon - marbofloxacin (fluroquinolone) Posatex - orbifloxacin (fluroquinolone) Easotic - gentamicin Otomax - gentamicin See pic for answers above is just to inform the pictures

Question 46

Circle the products that would be most appropriate for pseudomonas otitis before culture results are available?

Answer 46

Question 48

What is this and what is it resistant to?

Answer 48

**Bacteriology results** Pseudomonas aeruginosa +++ **Susceptible to** * Gentamicin * Ticarcillin **Resistant to** * Enrofloxacin * Marbofloxacin * Neomycin * Polymixin B * Trimethoprim/sulphamethoxazole * Amoxycillin/clavulanate * Cephalexin * Doxycycline