Ear disease management Flashcards
What are the key consideration when thinking about perfroming otoscopy for investigation of ear disease?
- Is this possible?
- Assistance from VN or owner for restraint
- Pain
- Do not look?
- Admit for chemical restraint?
- Treat for short period and then reassess?
- Fear
- As for pain, or pretreatment with anxiolytic (e.g. trazadone)
- Need a long-time solution!
- Look at the good ear first
- Head forward and slightly downwards
- Straighten canal and use a small cone
- Cones must be sterilised between use*
What are you looking for during an otoscope exam?
- Canal
- Wall - swelling ulceration, hyperplasia, hair, masses, redness
- Lumen - wax, pus, ear mites, foreign bodies and occlusion
- Drum
- Present or absent, changes in colour, bulging?
- Discharge / cerumen
- What is normal ?
- No wax is unusual
- Heaped up or spread along the canal
- Colour
- Texture
- What is normal ?
- Smell
- Useful as a measure of infection in many cases
Do not guess the nature of the exudate: Use Cytology
How do you tell what is affecting a dogs ear?
Need to do cytology
If you only have one chance to sample - Consider taking bacteriology swab on slide forwith and then submit swab for bacteriology
What processing do you need to do with samples from the ear?
- Parasites (Otodectes & Demodex) - Mix gently in LP and coverslip
-
Wax samples
- Poor stickiness
- Use staining rack
- Apply methylene blue* only and coverslip
-
Purulent samples
- Stain as for cytology (all three stains)
What is the significance of biofilms in ears?
- A common finding in otitis due to bacteria (and yeasts) = extracellular matrix material produced by bacteria, usually when the bacteria are in larger numbers and in close proximity.
- Leading to lack of penetration of antibiotic and disinfectant agents
- Increased difficulty in cleaning
What is seen here?
Biofilm - Lacey/filigree matrix material and zones of none or different staining material around organisms
Why is the issue with bacteriology on its own for diagnostics of ear disease?
Confirms and/or identifies bacteria present in the ear canal - need to do cytology first
* Presence of bacteria ≠ disease – the ear is not sterile!
Commonly affected by:
* Previous antibiotic ear creams
* Previous otic cleaners
Provides susceptibility data
* MIC and disk diffusion techniques
* Flawed when considering topical treatment
When should you do bacteriology of the ear?
Cytological reasons
* Rods are seen. The most suitable antibiotic treatments can only be chosen if the organisms are known
* Marked purulent or pyogranulomatous discharge without organisms being noted. Possibility of finding a pathogen that is relevant, but also may grow organisms that are irrelevant clinically.
Clinical reasons
* In the event of treatment failure.
* If there is a suspicion of meticillin-resistant Staphylococcus species (MRS).
* If considering video otoscopy or ear flush for diagnosis or treatment in a bacterial otitis as in the event of an adverse event following these procedures, systemic antimicrobials may be required.
What are the reasons for flusing the ear?
- diagnosic - to be able to see the ear canal
-
therapeutic
- to Dilutes and removes bacteria, yeasts and inflammatory mediators
- With appropriate cleaners anti-microbial effects
- Removes pus which may inactivate antibiotics
- Removes old treatments
What should you flush the ear with?
- **Normal saline **
- Safe, widely available
- Sterile
-
Squalene
- Oily liquid to dissolve waxy discharges
- Considered safe
-
Chlorhexidine (dilute)
- Known to be problematic at higher concentrations
- Considered safe in dogs – not known in cat. Use commercial products
- e.g. TRIZChlor (Dechra) and Otodine (Nextmune)
-
Others – for use after the drum is known to be intact
- cerumolytics emulsify ear wax for easy removal e.g. 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
What factors do you base the chose of ear cleaner off?
- Cleaning power
- Antimicrobial action
- Potential for ototoxicity
Cleanaural (pH 6.5): What are the properties of this ear cleaner?
What is it used for?
general perpose
Properties
* Good cleaner
* Good antimicrobial properties
* Staph killed at 1/32 Pseudomonas killed at 1/8 and Malassezia killed at 1/32
However quite ‘stingy’ in inflamed ear
Unlikely to be ‘otosafe’ - don’t use unless you know drum is intact
Epiotic (pH 7.0): : What are the properties of this ear cleaner?
What is it used for?
general purpose
Properties
* Fair to good cleaner
* Fair to good antimicrobial properties
* Staph killed at ½, Pseudomonas killed at 1/8 and Malassezia killed at 1/8
* Drying effect on the canal
* Comfortable in the ear
* Probably not otosafe (PCMX and docusate sodium)
Otodine (TRIZChlor) (pH 8.0): What are the properties of this ear cleaner?
What is it used for?
Purulent otitis
Properties
* Watery cleaner
* Doesn’t sting
* Poor ceruminolytic action
* Good to fair antimicrobial properties
* Staph killed at 1/2
* Pseudomonas killed at 1/16
* Malassezia killed at 1/8
* Appears otosafe in the dog – data lacking for the cat
Cerumaural & Otoact (squalene-based cleaners): What are the properties of this ear cleaner?
What is it used for?
What is it used for?
Waxy (ceruminous) otitis
Properties
* Dissolve and mobilise waxy, greasy discharge
* No antimicrobial properties
* Considered to be otosafe
* Cerumaural greasier than Otoact
TRIZ EDTA (pH 7.9): What are the properties of this ear cleaner?
What is it used for?
What is it used for?
Base for additions or as pre-flush
Properties
* Poor ceruminolytic properties
* No antimicrobial activity (by itself)
* Appears otosafe
* Pre-treatment and base for other treatments only
TRIZ EDTA with added N-acetyl cysteine: What are the properties of this ear cleaner?
What is it used for?
What is it used for?
If you not have this avalible how can you make it with other drugs?
Biofilm busting
Properties
* Disrupts biofilm
* Some antimicrobial activity
* Appears otosafe
* May be irritant in the inflamed ear
Homemade with Parvolex 200 mg/ml Concentrate for Solution for Infusion
Why is a endotrachial tube recomended with ear flushing?
Endotracheal tube protects aspiration of flushing solution
What is the plan around treating otitis?
- Remove/reduce microbes
- Reduce swelling, discomfort or pain
- Normalise canal lumen and function
Treat for 7-14 days
Repeat examination
What are the treatment stages of managing otitis?
- Inflammation
- Control inflammation to prevent severe dysbiosis
- Dysbiosis / overgrowths
- change the environment causing the dysbiosis to correct this
- Purulent otitis
- kill the microorganisms first and then change the environment to prevent recurrence
If have to use ototoxic otic products avoid concurrent use of drugs that might increase risk, What are these drugs?
- Frusemide and other loop diuretics
- Cis-platin
- Erythromycin
- NSAIDS
What are the charateristics of Erythroceruminous otitis?
What is the treatment?
Clinically
* Red, waxy itchy ear
* Often a feature of allergic skin disease
Cytology shows cocci ± Malassezia, squames, but no neutrophils
* Microbial overgrowth
Treat
* Cleaner appropriate for the level of discharge
* Corticosteroid alone
What type of ear disease is this?
Erythroceruminous otitis
What are the charateristic of acute purulent otitis?
What is the treatment?
Clinical signs
* Redness, pruritus, pain and discharge
* May be secondary features of lichenification on the pinna
Cytology
* Neutrophils and bacteria (intra and extracellular)
Treatment
* First-line ointment based on cytology and otoscopy
* Once to twice daily therapy for 7-14 days
* Canaural / Surolan / Easotic *
* Sufficient amount (0.7-1.0 mls for a large dog)
* Alternatively, Neptra or Osurnia (once or twice respectively)
* Combined with a suitable cleaner e.g.
* Otodine/TRIZChlor – watery, disinfectant & doesn’t sting
What should you do if you have a sever case of Purulent otitis?
- Consider putting a charcoal swab in the fridge at time of the first appointment
- Send a swab off if rods seen regardless of time course (cost discussion needed)
- If the ear is very swollen
- Steroids for 1-2 days before further otoscopic examination
- If a large volume of discharge / unclear time course
- Admit for flush etc – treat as chronic case
*Re-check - Obligatory
- May need to restore epithelial migration
- Period of cleaning beyond microbiological and anatomical cure
What is the course of action with a chronic allergic otitis?
Long term Malassezia and S. pseudintermedius dysbiosis and overgrowth
Treat the ear prophylactically with steroids ± cleaner to prevent flares
Currently no products with marketing authorization for this use – cascade choice
Commonly used products include, Cortavance† (hydrocortisone aceponate spray), Recicort † (Triamcinolone drops), dexamethasone diluted in sterile water (0.25 mg /ml) or by adding dexamethasone to cleaning products †.
†. not considered safe in the middle ear
What is the plan with a dog with Pseudomonas otitis?
With severe disease
* Always flush if purulent material
* Presume drum ruptured – collagenase produced by bacteria makes this likely
* Therefore, presume OM –possibility of OI
Warn owner that flushing / treatment / disease risks
* Horner’s syndrome / facial paralysis
* Hearing loss
* Cost – expensive if severe to treat medically
* Possibility of need for TECA
* Non-licensed products (get signed release)
* Increased risk in the cat
- Assess skin and ears / cytology / otoscopy / bacteriology
- Flush to clean & examined (normal saline)
- Use biofilm busting cleaner (TRIS-NAC for 5 minutes)
- Use a disinfectant cleaner (TRIZChlor or Otodine – 5-10 minute soak)
- Apply a suitable antibiotic (Aurizon® marbofloxacin, dexamethasone) or TRIZEDTA with 2% marbofloxaxin and 0.2% dexamethasone added)†
- Provide anti-inflammatory and analgesia
- Intraoperative opiate and dexamethasone 0.2mg/kg IV then
- Prednisolone ½ -1 mg /kg SID PO
- Paracetamol 15mg /kg TID PO initially
- Check initially at 7-10 days – treatment is likely needed for 3 – 6 weeks
*
What are the treatment options for the end stage ear?
- Lateral wall resection
- No role in the end stage ear
- Limited role in chronic otitis
- Often worsens the situation
- Total ear canal ablation
- For the chronically painful ear – welfare choice!
- Low risk of complications in hands of a specialist
- Economically justified in many cases
