Otitis 2

Question 1

What are benefits of ear cleaning with otitis?

Answer 1

• Removal of infectious debris & disruption of microbial biofilms
• Visualisation of TM
• Assess epithelium: hyperplasia, ulceration, defects
• Expose and/or sample otic polyps/tumours
• Enhance action of topical therapy

Question 2

What do ear cleaning methods depend on?

Answer 2

• Severity of otitis (stenosis, pain)
• Type and volume of discharge
• Client factors e.g. finances
• Patient factors e.g. Tympanic Membrane rupture

Question 3

What are drugs with Potential to cause deafness and/or
vestibular signs if applied to middle ear?

Answer 3

• Polymixin B
• Ticarcillin
• Imipenem
• Gentamicin (mainly an issue with systemically use)
• Propylene glycol (very low concentrations seem to be tolerated)
• Alcohols e.g. isopropyl
• Acids e.g. salicylic
• Chlorhexidine >0.15% (dogs; never use in cats)
• Injectables that can’t be given IV

Question 4

What are Drugs that may enhance effect of potentially ototoxic treatments?

Answer 4

• Frusemide and other loop diuretics
• Cisplatin
• Erythromycin
• NSAIDs

Question 5

What is a biofilm? How is it treated?

Answer 5

• Microbes stuck together in extracellular matrix
• Protected environment, infection difficult to treat
• N-acetylcysteine, Betaine/polyhexanide
• Disrupt biofilm and reduce viability of Staphylococcus
  spp. and Pseudomonas spp.
  – Sterile water/saline lavage, instill product, massage (< 5 mins)
  – Remove by suction, thoroughly lavage with sterile saline

Question 6

Why would you use anti-inflammatories? What would you use?

Answer 6

• Resolve progressive pathological change - epithelial + glandular hyperplasia + stenosis
• Glucocorticoids = anti-pruritic, decreased glandular secretions, exudation, scar tissue + proliferative changes
  = Systemic / topical prednisolone

Question 7

What is different when doing cytology sampling of external ear canal and middle ear?

Answer 7

• EEC = indirect smear using cotton bud
• Middle ear = otoscopic guidance, urinary catheter + suction using syringe then spray onto slide

Question 8

How do you select topical antimicrobials?

Answer 8

• On cytology - no microbial overgrowth = anti-inflammatories
• yeast = topical antiseptic/antifungals
• bacteria = topical antiseptics/antibiotics

Question 9

What is spectrum of activity of different ear treatments?

Answer 9

• Chlorhexidine = G+ve cocci, G-ve rods, Malassezia
• Fucidic acid, framycetin, florfenicol = G+ve cocci
• Polymixin B, marbofloxacin, gentamicin = G+ve cocci,
  G-ve rods
• Clotrimazole, miconazole, nystatin = Malassezia

Question 10

What is proprietary topical antimicrobials?

Answer 10

• Use of combination of cerumenolytics, antiseptics, antibiotics, antifungals + corticosteroids
  = NOT LICENCED if ruptured eardrum
• Potential for ototoxicity

Question 11

What should be done for treatment if you can’t see the eardrum?

Answer 11

• No treatment licenced for use with ruptured tympanic membrane =
• Treat 1-2 wks with systemic prednisolone & recheck
• Clean ear (ideally GA) & recheck
• Treat with ‘safe’ water-based product & recheck

Question 12

What could you use to treat pseudomonas?

Answer 12

• Active against G-ve rods + safe =
• silver sulfadiazine
• enrofloxacin
• marbofloxacin

Question 13

What would you use to treat hypersensitivity otitis?

Answer 13

• Recicort - triamcinolone (licenced for 7 days)
• Dexadresson (dexamethasone)
• Cortavance (HCA)
• need to treat allergic inflammation to prevent recurrence

Question 14

What is long term treatment of ear problems?

Answer 14

• Ear cleaning - Otoact - weekly
• Anti-inflammatory - HCA - cortavance (on skin lesions + ears twice weekly)
• Skin barrier = EFAs in FOOD - daily
• Allergen specific immunotherapy

Question 15

What can otitis lead to?

Answer 15

• Solid, non-pliable EEC on external palpation
• Severe stenosis and fibrosis on otoscopy
• Marked mineralisation of ear canals and/ or osteomyelitis on diagnostic imaging
• Neoplasia/polyps
• Cholesteatoma
• Para-aural abscessation

Question 16

What is the pathogenesis of otitis media and interna?

Answer 16

• Extension from chronic OE =
  – Most common in dogs
  – Bacterial infection often present
• Primary OM = pathogenesis not always clear =
  – Cats: ET inflammation (URT virus) or obstruction (polyp)
  – Dogs: ET dysfunction (PSOM), abnormal ET/middle ear conformation (brachycephalics)
  – Haematogenous spread from internal disease (rare)

Question 17

What is primary secretory otitis media?

Answer 17

• CKCS & other brachycephalics
• Mucous build up in middle ear (sterile)
• Present for deafness or pain or incidental finding on CT/MRI
• Bulging TM on otoscopy
• Myringotomy to sample for cytology
• Repeated flushing with sterile water eventually liberates large mucous plug

Question 18

What are clinical signs of otitis media + interna?

Answer 18

• +/- clinical signs of OE
• Pain
• Horner’s syndrome
• Loss of hearing
• Vestibular disease =
  – Ataxia +/- falling
  – Head tilt to affected side
  – Spontaneous/rotary nystagmus
  – Anorexia/vomiting