Defense & Barriers: Otitis Flashcards
EXTERNAL ear canal…
function?
contains what 3 things?
VERTICAL ear canal?
HORIZONTAL ear canal?
= CONDUCTS AIR VIBRATIONS TO THE TYMPANUM
contains…
1. hair follicles
2. sebaceous glands
3. ceruminous glands (MODIFIED APOCRINE)
VERTICAL ear canal?
= FIRST part of the canal that’s CONTINUOUS WITH THE PINNA
HORIZONTAL ear canal?
= starts after ANNULAR CARTILAGINOUS PROMINENCE
CERUMEN…
secreted by what? (2)
made of what?
2 functions?
what happens if TOO MUCH cerumen (clinical sign & why it happens)?
secreted by…
1. CERUMINOUS glands
2. SEBACEOUS glands
made of SLOUGHED EPITHELIAL CELLS
2 functions?
1. TRAPS debris, parasites & microorganisms (immune)
2. PROTECTS TYMPANUM from DESSICATION
if TOO MUCH CERUMEN = NUTRIENT-RICH MEDIUM FOR MICROORGANISMS, prone to CHRONIC EAR INFECTIONS
label…
white arrow?
blue arrow?
yellow arrow?
WHAT STRUCTURES ARE THESE (1 main, 1 other)?
white arrow = PARS FLACCIDA
blue arrow = PARS TENSA
yellow arrow = STRIA MALLEARIS
TYMPANIC MEMBRANE & STRIA
TYMPANIC MEMBRANE…
what landmark should we look for?
2 portions, their functions, appearance, what happens if one is damaged? (2 for each)
landmark = TUFT OF HAIR?
2 portions…
1. PARS FLACCIDA = DORSAL portion
–> VARIABLY prominent depending on PRESSURE IN MIDDLE EAR CAVITY
–> FLATTER in cats
- PARS TENSA = “EAR DRUM”
–> TRANSLUCENT, GRAY MEMBRANE that TRANSMITS SOUND WAVES
–> if it RUPTURES –> CHRONIC OTITIS –> FIBROSIS –> LOOKS MORE OPAQUE
STRIA MALLEARIS…
= what/where is it?
where is the TIP of the bone pointing?
= C-SHAPED BONE located on the MEDIAL PART of TYMPANIC MEMBRANE that ATTACHES IT TO THE MANUBRIUM/HANDLE OF THE MALLEUS (acoustic ossicles)
TIP points to the NOSE (rostral)
A = ??
B = ?? (pathologic)
A = normal pars TENSA (ear drum)
B = BULGING pars FLACCIDA
what structure is this?
NORMAL TYMPANIC MEMBRANE
MIDDLE EAR CAVITY…
alternative name?
lined by what?
DORSAL portion?
–> contains what 3 things?
MIDDLE portion?
–> location?
–> what main structure is here?
VENTRAL portion?
–> name?
–> function?
–> unique feature in cats?
what TUBE is present/what does it CONNECT?
alternative name = TYMPANIC cavity
lined by RESPIRATORY EPITHELIUM
DORSAL portion?
–> contains ACOUSTIC OSSICLES (malleus, incus, stapes) & TYMPANIC NERVE
MIDDLE portion?
–> located ADJACENT TO TYMPANIC MEMBRANE
–> contains PROMONTORY (bony shelf) = opposite mid dorsal aspect of TYMPANIC MEMBRANE, and its CAUDAL END is called the ROUND WINDOW
VENTRAL portion?
–> called BULLA (largest bone)
–> function = acts as SINK for STERILE EFFUSION/INFECTION in middle ear cavity
–> in CATS = tympanic bulla SEPARATED BY BONY SEPTUM
AUDITORY/EUSTACHIAN TUBE connects the NASOPHARYNX to the MIDDLE EAR CAVITY
what should we AVOID when rupturing tympanic membrane? where is it located?
AVOID the ROUND WINDOW
located at the CAUDAL END of the PROMONTORY in the MIDDLE EAR CAVITY
which part of the middle ear cavity is the LARGEST?
VENTRAL portion, BULLA
INNER ear…
contains what TYPE of structures?
3 main structures present?
relation to middle ear infection (& alternative name)?
adverse effect of a medication?
contains NEUROLOGIC structures
3 main?
1. COCHLEA = HEARING apparatus, looks like spiral
2. VESTIBULE & SEMI-CIRCULAR CANALS = BALANCE apparatus
3. VESTIBULOCOCHLEAR NERVE (CN VIII)
if OTITIS MEDIA, then can lead to INNER EAR INFECTION
can have INNER EAR damage from OTOTOXIC MEDICATIONS, causing BALANCE/HEARING issues
PRIMARY causes of otitis…
= definition
overall DDXs? (5, 3 sub)
= occurs when something DIRECTLY INITIATES INFLAMMATION & cause alterations in MICROENVIRONMENT/SECONDARY INFECTIONS
DDxs?
1. ectoparasites
2. obstructions (foreign bodies, polyps, tumors)
3. allergic dermatitis
4. autoimmune disease
5. cornification disorders
4 ECTOPARASITES that can cause OTITIS?
- OTODECTES CYNOTIS = ear mite, MOST COMMON CAUSE OF OTOTITIS EXTERNA in cats, ESPECIALLY YOUNG CATS/CATS IN SHELTERS
- DEMODEX (demodicosis)
- OTOBIUS MEGNINI = SPINOUS EAR TICK, found in WESTERN US
- CHIGGERS = BRIGHT RED & usually found around PINNA
ALLERGIC DERMATITIS in EAR CANAL…
= what is it/what species is it most common in?
what can cause it?
what 3 signs would indicate it (irritant contact dermatitis)?
2 examples of medications that cause this? (one of the medications is found in what?)
= ALLERGIC SKIN DISEASE that’s the MOST COMMON CAUSE OF OTITIS EXTERNA in DOGS
what can cause it?
can be caused by anything that can CONTACT SURFACE or INSIDE of ear
irritant contact dermatitis?
1. starts AFTER starting APPROPRIATE (based on C&S) therapy
2. cytology shows INCREASED INFLAMMATORY cells
3. see SCALING/BURNS on CONCAVE ASPECT OF PINNA
medications?
1. NEOMYCIN
2. PROPYLENE GLYCOL is an INACTIVE INGREDIENT found in OTIC MEDICATIONS
identify
ALLERGIC DERMATITIS
FOREIGN BODIES in the ear…
3 common clinical signs?
signalment?
dangers?
examples? (5)
3 common clinical signs?
1. UNILATERAL
2. ACUTE
3. PAINFUL
signalment?
YOUNG, LARGE BREED CURIOUS DOGS
dangers?
can cause TYMPANUM PERFORATION
examples?
1. PLANTS (plant awns, foxtails, seeds)
2. DIRT/SAND
3. CERUMINOLINTHS (wax balls/plugs)
4. DEAD INSECTS
5. DRIED MEDICATION
identify
TUMOR in EXTERNAL EAR CANAL
identify
TUMOR in EXTERNAL EAR CANAL
TUMORS in ear canal…
clinical sign/signalment?
etiology?
in DOGS…
in CATS…
what issues does this cause?
clinical sign/signalment?
UNILATERAL, OLDER DOGS
etiology?
arises from CERUMINOUS glands
in DOGS…
usually BENIGN CERUMINOUS ADENOMA
in CATS….
>50% MALIGNANT CERUMINOUS ADENOCARCINOMA
what issues does this cause?
OBSTRUCTION in ear
–> INTERRUPTS SELF-CLEANING MECHANISM of the ear
–> buildup of DEBRIS/CERUMEN
–> NUTRITIVE for bacteria & causes SUPPURATIVE INFLAMMATION
–> can cause SECONDARY BACTERIAL INFECTIONS
identify
INFLAMMATORY POLYP
INFLAMMATORY POLYPS that cause OTITIS…
in cats?
arises from…
clinical sign/signalment?
how does it travel? (2)
why is an oral exam indicated?
4 pathologic descriptors?
2 ways to remove?
in cats?
MOST COMMON NON-NEOPLASTIC OBSTRUCTIVE MASSES in CAT EAR CANALS
arises from…
RESPIRATORY EPITHELIUM that LINES MIDDLE EAR or EUSTACHIAN TUBE
clinical sign/signalment?
UNILATERAL, YOUNG ADULT CATS
how does it travel?
1. through TYMPANIC MEMBRANE –> EAR CANAL
2. DOWN EUSTACHIAN TUBE –> NASOPHARYNGEAL REGION
oral exam?
can be indicated because MAY NEED TO MOVE SOFT PALATE TO SEE IT
4 pathologic descriptors?
1. multilobulated
2. smooth
3. pink
4. fleshy
2 ways to remove?
1. TRACTION EVULSION = yank out through EAR CANAL or NASOPHARYNX
2. SURGICAL INTERVENTION = only if traction evulsion doesn’t work, has LOWER chance of recurrence though
identify
INFLAMMATORY POLYP
identify
CORNIFICATION DISORDER
CORNIFICATION DISORDERS that are PRIMARY CAUSES OF OTITIS…
= definition
causes WHAT?
3 examples?
= diseases of SKIN TURNOVER
causes ICHTHYOSIS!
3 examples?
1. HYPERADRENOCORTICISM (CUSHING’S)
2. HYPOTHYROIDISM
3. SEBACEOUS ADENITIS = no more sebaceous glands, so HYPERKERATOTIC/SCALY skin compensates
5 AUTOIMMUNE diseases that are PRIMARY CAUSES OF OTITIS?
- PEMPHIGUS FOLIACEUS = this is the MOST COMMON autoimmune disease in CATS/DOGS/HORSES
- VASCULITIS = tends to affect TIPS or MARGINS of ears where VESSELS are most FRAGILE/PRONE TO ISCHEMIC DAMAGE
- SUBEPIDERMAL BLISTERING DISEASES = separation of DERMIS from EPIDERMIS due to GENETIC/AUTOIMMUNE issue with HEMIDESMOSOMES
- ERYTHEMA MULTIFORME = causes ULCERATED ear canals
- JUVENILE CELLULITIS = STERILE PYOGRANULOMATOUS INFLAMMATION
identify & category of what it is
PEMPHIGUS FOLIACEUS
AUTOIMMUNE disease that causes PRIMARY OTITIS
identify & category of what it is
ERYTHEMA MULTIFORME
AUTOIMMUNE DISEASE that causes PRIMARY OTITIS
use a term to describe this hair canal
what is this term in regards to otitis?
HYPERTRICHOTIC (hairy)
PREDISPOSING FACTOR for otitis
PREDISPOSING FACTORS for otitis…
= definition
why does it need to be treated?
examples? (7)
= factors that ALTER THE MICROENVIRONMENT of the EAR CANAL & INCREASE RISK OF OTITIS especially once INFLAMMATION IS PRESENT
why does it need to be treated?
need to be TREATED to RESOLVE OTITIS
examples?
1. PENDULOUS PINNA = contributes to WARM, HUMID, DARK environment
- STENOTIC ear canals = common in BRACHYCEPHALIC BREEDS & SHAR PEIS
- HYPERTRICHOSIS = HAIRY ear canals
–> poodles
–> yorkshire terriers
–> schnauzers - TREATMENT effects
–> IRRITATING cleanser
–> TRAUMA from COTTON-TIPPED APPLICATOR
–> PLUCKING hair - IMMUNOSUPPRESSION
–> FIV/FeLV
–> HYPOthyroidism
–> HYPERadrenocorticism - EXCESSIVE CERUMEN PRODUCTION
–> common in COCKER spaniels and SPRINGER spaniels
–> once there’s INFLAMMATION, CERUMINOUS GLANDS become HYPERPLASTIC and HYPERSECRETORY - EXCESSIVE MOISTURE IN EAR CANAL
–> MALASSEZIA YEAST is common in dogs that SWIM OFTEN
when should you PLUCK HAIR FROM EAR CANAL? what can it accidentally cause?
ONLY if you CANNOT TOPICALLY TREAT THE EAR!!
if done too much, can cause SECONDARY BACTERIAL INFECTIONS
what are PERPETUATING FACTORS of otitis?
2 main things? (4 for first one, second is dogs/cats)
= things that make it HARDER for OTITIS TO RESOLVE once it’s present
(1) PROGRESSIVE PATHOLOGIC CHANGES
1. GLANDULAR HYPERPLASIA
2. STENOSIS OF EAR CANAL
3. FIBROSIS
4. MINERALIZATION of EAR CANAL
(2) OTITIS MEDIA
in DOGS…
–> EXTENSION of OTITIS EXTERNA INFECTION through RUPTURED TYMPANIC MEMBRANE
in CATS…
–> EXTENSION of INFECTION into NASOPHARYNX via AUDITORY TUBE
does an INTACT tympanic membrane rule out OTITIS MEDIA? why or why not?
what diagnostic tool do we use to examine it?
it does NOT because TYMPANIC MEMBRANE CAN HEAL QUICKLY
OTOSCOPE
