External and Middle Ear Pathology Flashcards
What is Otitis Externa?
- Inflammation of the external ear pinna- extends to ear canal above the tympanic membrane
What is Otitis Media?
Inflammation of the middle ear
What are the clinical signs of otitis externa?
- Reddening of the pinna
- Swelling or thickening
- Heat
- Extreme pain
- Ear scratching
- Head shaking
- Hair loss
- black waxy/ pus
What bacteria are important?
- Rods but they are not normally expected as commensals
- have significant AMR properties
culture and sensitivity is always warranted with rods
When are cocci interpreted?
- Numbers
- Clinical signs
- Inflammation can be variable
Where would you expect to see dog fleas?
- Expect to see on the tailbase, possibly thighs, flank and other areas
Where would you expect to see cat fleas?
- Cats can develop military dermatitis on the back, neck and face
What is a demodex mite?
‘cigar-shaped’ mite
* clinical presentation is often alopecia around eyes and ears but may be more extensive
What is the most common otodectes?
otodectes cyanotis
What is Neotrombicula autumnalis
»“Harvest mites”
»May cause otic pruritus
»Orange mites
»Generally present in
Henry’s pocket
What are the clinical signs of otitis media?
- Possible facial nerve paralysis
- constriction of pupil
- drooping of eyelid
- sinking of eyeball into the orbital cavity
- Head tilt
- Coordination issues
What is guttural pouch tympany?
Pouch filled with air
What is a guttural pouch empyema?
Pus in a cavity
What are the five cardinal signs of inflamation?
- Pain
- Heat
- Reddening
- Loss of fuction
- Swelling
How could you take an ear swab?
- Moisten the swab with sterile water
- Gently rotate within the ear canal
- leave the slide unstained in order to check for ectoparasites
- Stain/ Examine for bacteria and Yeast
- Swab both ears individually
What may a swab from an ear without active infection contain?
squames and keratin debris
What are the two main points surrounding sarcoptes scabei?
- Pruritic
- Zoonotic
What mite is more common in cats than sarcoptes scabei?
Notoedres cati
In what species is otodectes cyanotis most commonly noted?
dogs and cats
What is otodectes typically accompanied by?
brown waxy discharge similiar to coffee grounds
Where is otodectes prominantly found?
within the ear canal, uncommon to be anywhere else
What psoroptes is usually associated with rabbits?
psoroptes cuniculi
What psoroptes causes widespread lesions noted in other species?
psoroptes ovis
What are the signs of potential facial nerve paralysis?
- Constriction of pupils
- Drooping of eyelids
- Sinking of eyeball into orbital cavity
- Protrusion of third eyelid
What is guttural pouch mycosis?
- Fungi sitting along a carotid artery
- Carotid artery erosion
- Haemorrhage
What does PSPP stand for?
- Primary
- Secondary
- Perpetuating
- Predisposing
Give soem examples of primary causes of otitis
- Allergies
- Parasites
- foreign bodies
- Immune-mediated
- Pyoderma
Give some examples of secondary causes of otitis
- Bacteria
- Yeast
Give some examples of perpetuating causes of otitis
- Ear canal stenosis
- Ulceration
- Otitis media
- Ear cartilage
- Mineralisation
Give some examples of predisposing causes of otitis
- Conformation
- Humidity
- Inaproppriate cleaning
- Irritant treatments
- Systemic disease
How would you take an ear swab?
- Moisten a cotton bud with sterile water
- Gently rotate within the ear canal
- Roll the swab along the slide to make ‘streaks’
- Stain and examine for bacteria
- Swab both ears individually
What is considered to be abnormal on an ear swab?
- Inflammatory cells are abnormal
- however not all otitis cytology may yield inflammatory cells
- inflammatory cells indicate a pathological disease
What is the most common fungus seen in the ear?
Malassezia- broad-based budding
What is a lesser common yeast seen in the ear?
Candida= narrow based budding
What may you need to collect in order to see mites?
deep skin scrapes with ‘capillary ooze’
then suspend these scrapes in mineral oil
What are neotrombicula autumnalis and where are they generally present?
- Harvest mites (orange)
- cause otic puritis
- generally present in henrys pocket
What else can we test for?
- Haematology/ Biochemistry to identify underlying disorders
- Endocrine testing
- Mineral levels (zinc)
- Allergy levels
What is canine leishmaniasis?
- Causes lesions focused around the ears
- May be due to a more generalised lesion however
