Otitis Externa/Media in Cats & Dogs (Santoro) Flashcards
Otitis externa
Inflammation of the ear canal
Otitis media
Inflammation of the bulla
Otitis interna
Inflammation canaliculi and/or cochlea
Predisposing factors of otitis externa
- Conformational defect (hair, stenosis)
- Swimming/humidity
- Obstructive ear disease (neoplasia, polyps, foreign body)
- Trauma
- improper ear cleaning
- topical irritants
- Excessive cerumen production
- Systemic dz (catabolic states, immune suppression, debilitation)
Primary factors of otitis externa
- Disease, enough for inflammation
- Foreign bodies
- Allergies
- Autoimmune diseases
- Endocrinopathies
- Parasitic diseases
- Masses
Otodectes cynotis (ear mite)
- Non-burrowing psoroptid mite
- On skin surface
- Protected by thick, brown (coffee ground) crust
- Feed on lymph & blood
Primary factor of OE
Otobius megnini (spinous ear tick)
- Larvae & nymphs induce inflammation
- Drops to ground as adult
Primary factor of OE
Eutrombicula alfreddugesi (chigger)
- Bite causes irritation & variable pruritis
- Seasonal - late summer/fall
Primary factor of OE
Otodemodicosis
- More common in cats
- Ceruminous otitis externa
- Suspect immynosuppression
- FeLV, FIV, diabetes, neoplasia
- Ear swab, no need to scrape
Primary factor of OE
Sacroptes scabiei canis (canine scabies)
- Usually ear tips, but can be otitis externa
- Severe pruritis
- Female burrows in epidermis and layws eggs
- Thick, yellow crusts
Primary factor of OE
Notoedres cati (feline scabies)
- Medial, proximal pinnae
- Face, eyelids, neck, feet, perineum
- Female mites burrow
- Intense pruritis
- Highly contagious
- Abundant mites
Primary factor of OE
Intraluminal tumors
- Relatively uncommon
- Obstructive lesions
- Ulceration & necrosis
- Malignant (cats > dogs)
- Ceruminous gland adenocarcinoma
- Squamous cell carcinoma
- mast cell tumors
Primary factor of OE
Nasopharyngeal polyp
- Congenital, bacterial, calicivirus
- Chronic uni/bilateral otitis, mass in ear canal, head tilt
- Treat surgically
Primary factor of OE
Apocrine cystomatosis
- Cysts of apocrine glands
- Adult animals
- Solitary, well-circumscribed, smooth, bluish tense swelling
- Located on concave surface of pinna, vertical ear canal
- Uni or bilateral
- Treat: benign neglect, surgery
Primary factor of OE
Atopic dermatitis
- Erythema & inflammation
- Initially pinnae, vertical canal
- Entire ear canal when chronic
Primary factor of OE
Causes of contact allergy in the ear
- Neomycin/gentamycin
- Miconazole 1%
- Propylene glycol
Primary factor of OE
Primary idiopathic seborrhea
- Incr. cerumen production
- Altered cerumen composition
- Delayed desquamation and stenosis
- Often progress to calcifying otitis externa/media in cocker spaniel
Primary factors of OE
Endocrinopathies as a primary factor of otitis externa
- Hypothyroidism, sex hormone imbalance
- Incr. mucin deposition in dermis
- Hyperplasia/hyperkeratosis of epidermis
- Altered fatty acid production
Primary factor of OE
Autoimmune diseases as primary factors of otitis externa
- Pemphigus foliaceus
- Pemphigus erythematosus
- Systemic lupus erythematosus
Juvenile cellulitis
- Puppies
- Vesiculopustular dz
- Dachshunds, golden retrievers, pointers
- Purulent otitis w/ head & facial lesions
- Blepharitis
- Lymphadenopathy
Primary factor of OE
Secondary factors of otitis externa
- Infection secondary to the inflammatory process
- Bacteria
- Yeast
Bacteria as secondary factors of otitis externa
- Staph pseudointermedius
- Proteus mirabilis
- Pseudomonas
- E. coli
- Klebsiella
- Corynebacterium
Yeast as secondary factors of otitis externa
-
Malassezia pachydermatis
- in some normal dog/cat ears
- Candida albicans
Perpetuating factors of otitis externa
- NOT responsible for the otitis, but cause the otitis to presist
- Otitis media
- Mineralization of the ear canal
- Hyperplasia of the ear canal
Pathologic changes caused by perpetuating factors of otitis externa
- Hyperkeratosis
- Epidermal hyperplasia
- Epithelial folds
- Dermal edema & fibrosis
- Cerumial gland hyperplasia/hypertrophy
- Lumen stenosis
- Calcification
Tympanic membrane changes perpetuating otitis exerna
- Opacity
- Dilation
- Diverticulum
Otitis media perpetuating factors for otitis externa
- Epithelial changes
- Purulent accumulation
- Caseation
- Cholesteatoma (skin growth in middle ear)
- Proliferation
- Destructive osteomyelitis
Clinical signs of otitis externa
- Odor
- Head shaking
- Discharge
- Pruritis
- Aural hematoma
- Head tilt
- Pain
- Erythema
- Edema
- Lichenification
- Hyperpigmentation
- Excoriations
- Mineralization
Causes of otitis media
- Extension of otitis externa (most common)
- Ascending infection via eustacial tube
- Hematogenous spread
Neurological signs of otitis media
- Facial nerve paralysis
- KCS
- Horner’s syndrome
- Peripheral vestibular disease
Diagnostic tools for otitis media
- Ear cytology (collect before flush)
- Otoscopy
- Diagnostic imaging
- Biopsy
- Culture & sensitivity
Video-otoscopy
- Under general anesthesia
- Visualize tympanic membrane
- Useful for
- Deep ear flush
- Myringotomy
- Biopsy
Why deep ear flush for otitis media
- Removes exudate
- visualization of tympanic membrane
- un-mask foreign body, tumor
- purulent discharge will inactivate medications
- Perform myringotomy
- Collect curlture/cytology of middle ear
- Flush out middle ear
Myringotomy
- Surgical rupture of the tympanic membrane
- Diagnostic - collection of material
- Therapeutic
- flush the bulla
- permanent opening
Post-flush drugs
- Abx
- Steroids
- Oral pred or triamcinolone
- Topical dexamethasone
Post-myringotomy care
Send patient home w/ topical flush, topical medicatoin, and oral abx based on best guess. Change therapy once you receive culture and sensitivity results.
Medical management of otitis externa
- Topical cleansers and antimicrobials
- Systemic antimicrobials and anti-inflammatories
Surgical management of otitis externa
- TECA-BO
- Vertical canal ablation and lateral wall resection
Medical management of otitis media
- Topicals
- Systemic drugs
Surgical management of otitis media
- TECA-BO
- VBO
Cerumynolytics
- Used to soften impacted material prior to deep flushing
- Some are irritating and potentially ototoxic
- Propylene glycol, lanolin, glycerine, squalene, urea peroxide, DSS, mineral oil
Acidifying agents
- Dry the ear canal
- Less habitable for microbes
- Not for use w/ AG
- Acetic acid, lactic acid, malic acid, boric acid, benzoic acid, salicylic acid
Astringent agents
Burrow’s, domoboro, isopropy alcohol
Anesthetic agents
Proparacaine, lidocaine, pramoxine
Antimicrobial agents
Chlorhexidine, ketoconazole, hypochlorous acid
Tris-EDTA
- Alkalyzing agent
- works well w/ AG, fluoroquinolones
- Chelating agent
- disrupts cell membrane of bacteria & enhances abx therapy
Antibiotics
- Aminoglycosides
- inactivated by low pH or debris
- Gentamycin, tobramycin, amikacin
- Fluoroquinolones
- Enrofloxacin - always associated w/ topical antifungal
- Orbiflaxacin
- Cationic peptides (polymyxin B)
- Florfenicol
Antifungals
- Miconazole
- Clotrimazole
- Nystatin
- Thiabendazole
- Posaconazole
- Terbinafine
Topical glucocorticoids
- Topical formulations less effective
- Syn-otic
- Betamethasone
- Dexamethasone
- Mometasone
- Hydrocortisone
- Triamcinolone
- Prednisolone
Systemic anti-inflammatories
- Useful to decr. pruritis/pain and inflammation
- Decr. stenosis due to fibrotic changes
- no mineralization
Systemic antibiotics
- Only in cases of otitis media
- Extremely severe & chronic otitis externa
- Always w/ topical treatments
Systemic glucocorticoids
- Prednisone/prednisolone
- Methylprednisolone
- Triamcinolone
Treatment duration for otitis media
Minimum of 6-8 wks of topical and systemic antimicrobials
