SA - otitis

Question 1

what line the outer ear canal

Answer 1

skin with ceruminous and sebaceos glands

Question 2

what lines the middle ear

Answer 2

simple sq-cub cells
some cilia
goblet cells

Question 3

name 3 parts of the tympanic membrane

Answer 3

pars flaccida (floppy)
stria mallearis (middle)
pars tensa (tense)

Question 4

what is the biggest difference bw dog and cat ears

Answer 4

cat - v large round bullae, small aperture into inner ear

dog - more triangular bulla, wide aperture

Question 5

how does the outer ear self clean

Answer 5

cerumen catches material inc forein mat, microbes and old kcytes
epithelial migration using kcytes (living)

Question 6

how does the middle ear clean

Answer 6

drains fluid via auditory tubes, which also equalises pressure either side of tymp membrane

Question 7

what are the 3 Ps

Answer 7

primry factors (hypersensitivity reactions acronym - PAINFREE)
predisp
perpetuating factors

Question 8

what does PAINFREE stand for (acronym for primary causes of otitis

Answer 8

parasites
allergic skin dz (cAD)
immune mediated (II+III, rare)
neoplasia/ polyps
fx bodies (grass seeds)
rare causes (idiopathic)
epitheliasation defect
endocrinopathy

Question 9

name 2 parasites which cause otitis

Answer 9

otodectes cyanosis

demodex canis/cornei

Question 10

why do neoplasia/polyps cause otitis

Answer 10

block cleaning mech

types = Ceruminus g adeno-/-carcinoma and cystomatosis..

Question 11

what 3 endocrinpathies often lead to otitis

Answer 11

hypothyr
HAC
DM

Question 12

what might cause an epitheliasation defect

Answer 12

1ry seborrhea

vit A dermatosis

Question 13

what are the three predisposing factors

Answer 13

conformation
environ (swimmer, humid)
iatrogenic (over cleaning)

Question 14

perpetuating factors are those which prevent resolution, name 3 broad categories

Answer 14

MO inf
pathological changes
otitis media

Question 15

name 2 g+ cocci and 2 g- bacilli which can cause otitis

Answer 15

g+ = staph pseudointermedius and strep canis
g- = pseudomonas aeruginosa and proteus mirabilis

Question 16

what type of pathological changes would impede healing

Answer 16

chronic inflm - hyperplasia (CG and epi), calcification, osteomyelitis, all –> stenosis

Question 17

how does OM develop

Answer 17

rupture of TM OR asc inf from the resp tract if epithelial transport fails

Question 18

after a full CE, a specialised otic exam takes place, desc

Answer 18

external palp (normal, pruritis = otodectes/malassezia, pain= g-, stiff = hyperlasia etc)
otoscopic ex = ID 1ry and perpetuating factors and integrity of TM

Question 19

what might be used to reduce hyperplasia if its too pronounced to conduct otoscopic ex

Answer 19

gcort (predn) for 2wks

Question 20

what dx tests are there

Answer 20

cytology, parasites, C+S
imaging
otoscopy
otic lavage (if TM intact)

Question 21

why is cytology useful (cotton smear)

Answer 21

quick, in house, easy, cheap
assess ext and middle ear
can assess reaction to tx
diff sterile from MO inflma

Question 22

is C+S a gold std test in otitis investigation

Answer 22

NO. needs to be interpreted with cytology, not to be used for assessing response to tx

Question 23

desc the normal radiological features of the ear

Answer 23

air filled, bulla is smooth and thin walled

Question 24

how should position a dog for a ear xray

Answer 24

D-V as positioning easy, bullar closer to plate. alternative = R-Cd mouth as allows more comparison.
ETT are a problem - often take out for this. other positions superimpose or dont allow comparison of the 2 bullae

Question 25

what is CT best for

Answer 25

bony lesions

Question 26

what is MRI best for

Answer 26

ST images

Question 27

how long does CT and MRI take

Answer 27

CT - 5mins | MRI - 40m

Question 28

why are video-otoscopy useful

Answer 28

can see middle ear cytology + culture + neoplasia samples can be taken polyps can be removed tx can be given

Question 29

in the management of otitis, what is the 1st step to tx

Answer 29

resolve the perpetuationg factors - NSAIDs, sx, lavages, abx..

Question 30

how can pathological changes be resolved

Answer 30

only some can firstly, but give csteroids - reduce itching, dec secretions, and reduce scar and proliferative change

Question 31

if sx required to resolve pathological changes, what might be possible

Answer 31

TECA (total ear canal ablation) bulla osteotomy salvage procedures basically..

Question 32

where should antimicrobial be administered to tx OE and OM

Answer 32

topically (if TM intact). --- OI needs systemic and if any osteomyelitis with TM that does too

Question 33

how can you control predisp factor?

Answer 33

``` wash after swimming remove hair dont let O over wash clip around ears clean droopy ones 1/wk ```

Question 34

what is a good way to control dry waxy ears, that are malassezia prone?

Answer 34

propylene glycol

Question 35

whats a good way to prevent bacterial inf in moist ears

Answer 35

chlorhexadine

Question 36

what are the RF poss from tx

Answer 36

``` canal or TM trauma vestibular syndrom horners deafness irritation, sensitivity or ototoxicity ```