Small Animal Sx - The Ear 2

drraythe's version from 2015-11-24 19:58


Question Answer
what are the 3 main sx dzs of the middle ear?(1) otitis media (2) nasopharangeal polyp (3) neoplasia
why does otitis media usually happen in DOGS?in DOGS usu 2* to otitis externa-- examine the typmanic membrane (is it still intact?)
what does otitis media usually happen in CATS?in CATS can occur as a 1* condition without otitis externa
what characterizes END STAGE otitis?calcification of ear canal and otitis media
what is important to know about the middle ear anatomy?there is the eustachian tube-- communication with the pharanyx! this is esp important with why polyps will migrate into pharynx
clinical signs of otitis media?head tilt, esp. if associated with nystagmus, circling, vestibular dysfunction, facial nerve deficits, nausea, vomiting, horner's syndrome (Can be a sign OR a consequence)
what does a normal tympanic membrane look like? (anatomy?)Manubrium is from the hammer (malleus), dorsal aspect is pars flaccida, and then radiating from malleus is pars tensa (<--the part that vibrates!)
if pars tensa (membrane of tympanum) is enlarged and thickened and inflamed, what might you have to do?might have to pierce through it-- this is called myringotomy which is done to allow for drainage of middle ear to faciliatate healing of problem. Tympanic membrane will tend to heal by itself
how does a cat's tympanum differ from a dogs?pars tensa (the vibrating membrane part) tends to be bigger
healthy tympanic bullae on rads looks like what?full of air, can see compartmentalization sometimes, the wall is THIN (if dzed, can be thickened, connection to ear canal can be gone bc stenosis)
what is the special radiographic positioning to assess the bulla?open mouth- pt in dorsal recumb, mouth open, take shot through open mouth
where do ear polyps originate from? how does the dz happen?originate from epithelium of tympanic bulla, then migrate through external ear canal, piercing through the tympanum. can also migrate through eustacean tube into the pharynx (this can interfere with the respiration!)
first attempt to deal with polyp can be?grab with forceps and pull- usually have a stalk and pull and it will break. Then have to do an osseus bulla expiration/scraping to remove epithelium or there will be recurrance.
indications for bulla osteotomy? (3)(1) otitis media (2) nasopharyngeal polyp (3) neoplasm of epithelium of bulla
landmarks for how to do a bulla osteotomy for scraping in order to tx polyps?Ramus (angle) of mandible, trachea, lingual fascial vessels, and mixillary veins together form the jugular vein. So, between trachea and mandible, medial to the jugular vein, this is the place where we make our opening
Once you have determined where to cut for your bulla osteotomy, what do you do?open skin, SQ, easy bc mostly just CT in this area and can push mm aside. Use gelpi retractor. Then by feeling touch smooth round surface (bulla) and then with periosteal elevator scrape up periosteum so it is peeled off. Then use a Steinmann pin attached to a jacobs handle, and use this to slowly pierce a hole into the osseus bulla. Once hole is made, with rongeurs, inc size of hole. In this case we are approacing the osseus bulla ventrally (ventral drainage! the TECA LBO was a LATERAL approach). then, scrape out bulla and take samples-- always scarpe TOWARDS YOURSELF. Then flush with WARM water (cold will irritate) and then place a drain exiting thorough 2* incison. Then reappose muscles, close SQ with simple continuous, then close skin.
how do nasopharangeal polyps affect the local area?inflamed and hyperplastic epithelium of bulla, can project into pharynx through auditory tube, may cause dysphagia, dyspnea. May also spread out through tear in ear drum and into external ear canal
polyps usually affect who and may be associated with what?affects young cats and may be associated with resp. viral infections
pic of how polyp can appear from pharynx
pic of how polyp can appear from ear canal
most important thing for successful tx of polyp is..going into bullae and removing osseus epithelum (where they originate from)
if there is horner's as a result of your bulla osteotomy, what can you tell owners?will go back to normal in 2-3 weeks usually
if the polyp is still attached, or if you pulled to polyp out but the stalk is still there, what should you do?can pull polyp back into bulla and remove with epithelium. If there is just a stalk, stalk should be pulled into bulla and removed with epithelium
what should you know about doing a bulla osteotomy on a CAT specifically?in the CAT the bulla is divided into CRANIOLATERAL and CAUDOMEDIAL compartments- BOTH must be opened.
what nervous tissue is often damaged with the bulla osteotomy?sympathetic (post ganglionic) fibers on promontory near septum are often traumatized