External, Middle, And Inner Ear

Question 1

Auricular infections?

Answer 1

• Perichondritis
• Ramsay-Hunt syndrome

Question 2

What is Perichondritis?

Answer 2

• Infection of the auricular cartilage
• Pathogens: Pseudomonas aeruginosa, S. aureus, Streptococcus
• Risk of cauliflower ear

Question 3

What is ramsey hunt syndrome?

Answer 3

• Herpes zoster with a facial nerve palsy
• Pathophysiology: primary infection or reactivation of HSV

Question 4

What things can cause an obstruction of the external auditory ear canal?

Answer 4

• Cerumen • Foreign body • Keratosis obliterans • Polyps

Question 5

What is the image showing?

Answer 5

Cerumen blocking the ear canal

Question 6

Explain forgein bodies in the external ear canal?

Answer 6

• If you do not know what the object is, DO NOT IRRIGATE. Also, you do not always know the status of the tympanic membrane.
• Plant materials or insects will swell.
• Use an operating otoscope or a microscope to remove the foreign body in conjunction with a Hartman forceps or an alligator forceps.

Question 7

keratosis obliterans?

Answer 7

External auditory canal cholesteatoma caused by blockage of the EAC permitting accumulation of epithelial debris

Question 8

Otitis externa can happen from what?

Answer 8

• Allergic • Excematoid • Bacterial • Fungal • Viral

Question 9

History and PE of bacterial acute otitis externa?

Answer 9

• History – Pain – Tenderness – Itching – Hearing loss
• Physical examination – Swollen external auditory canal – Erythema (variable) – Watery, scant exudate – Pronounced tenderness

Question 10

Common type of bacterial acute otitis externa?

Answer 10

• Diffuse (“swimmer’s ear”)

–Most common form of bacterial AOE

–Optimally managed with ototopical agents

Question 11

Principles of treating bacterial acute otitis externa?

Answer 11

• Clean the canal
• Topical therapy
• Suitable pain management

Question 12

What is an issue using aminoglycosides (neomycin)?

Answer 12

Neomycin Sensitization

• Incidence increasing due to widespread, long-standing use
• Cross-reactivity with other aminoglycosides
• Routine use not recommended because of high risk for sensitization

Question 13

What is otitis media?

Answer 13

• Otitis media (OM): A term for any inflammatory middle ear condition.
• Acute suppurative otitis media: – Early TM appearance: still transparent, bulging – Middle phase: suppurative (purulent fluid behind TM) – Late phase: weeping and possible rupture
• Otitis media with effusion(OME): After the acute phase passes, sterile fluid remains which will either clear in about 90 days of may become re-infected.

Question 14

Adults with middle ear effusion?

Answer 14

Concern for malignancy.

Thorough exam of head and neck to include the larynx and nasopharynx.

Question 15

Acute otitis media can manifest with what?

Answer 15

• Acute otitis media (AOM)

– Without perforation

– With perforation

– With tympanostomy tubes (AOMT)

Question 16

Overview of chronic otitis media?

Answer 16

• Chronic middle ear effusion
• Chronic nonsuppurative otitis media – Cholesteatoma – Dry perforation
• Chronic suppurative otitis media – Without cholesteatoma – With cholesteatoma

Question 17

treating acute otitis media ?

Answer 17

• Systemic antibiotics are the mainstay of therapy for AOM in ears with intact tympanic membranes

Question 18

Explain tympanostomy tubes?

Answer 18

• Myringotomy with insertion of tympanostomy tubes is the most common type of surgery that children in North America and Europe undergo
• Estimated 1 million operations are performed in Canada and the U.S.annually Usually as an ambulatory procedure
• Primary indications for tympanostomy tube insertion are recurrent episodes of acute otitis media and otitis media with persistent effusion.

Risks of leaving middle ear disorders untreated: hearing loss, which raises concerns about possible negative consequences for speech development, language acquisition and learning.
Questions have been raised, however, about the effectiveness of this surgery, the appropriate management of children with recurrent episodes of acute otitis media and otitis media with persistent effusion, the economic cost and the numbers of procedures performed.

Question 19

Indications for Tympanostomy tubes?

Answer 19

• AAOHNS Referral Guidelines and Indications for Tympanostomy Tube (Child meets at least 1 criterion below)
• Severe AOM
• Hearing loss of > 30 dB threshold concurrent with a persistent effusion > 3 months
• Poor response to antibiotic for OM. Second-line antibiotic fails. Breakthrough AOM while on antibiotic prophylaxis.
• Treatment failure due to multiple drug allergies or intolerances
• Impending or actual complication of OM, such as mastoiditis, facial nerve paralysis, lateral sinus thrombosis, meningitis, brain abscess, or labyrinthitis
• OME > 3months (Consider adenoidectomy if over age 4 or second set of tympanostomy tubes)
• 6 or more months of effusions in the previous 12 months
• Recurrent episodes of otalgia or AOM (> 3 episodes/6 months or > 4 episodes/12 months)
• Persisting or recurrent ear discharge
• Retraction of the TM or pars flaccida, negative middle ear pressure, or TM perforation > 3months
• AOM with imminent air travel or barotrauma (injury following pressure changes) following air travel
• Craniofacial anomalies that predispose to middle ear dysfunction (eg, cleft palate, Down’s syndrome)

Question 20

Acute otitis media with tubes bacteriaology?

Answer 20

• Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis), Pseudomonas aeruginosa and Staphylococcus aureus, are commonly recovered as primary and secondary pathogens in Acute OM with tubes

Question 21

Explain acute otitis media with tubes treatment?

Answer 21

• Ototopical antibiotics alone are appropriate therapy in uncomplicated cases – Fluoroquinolones
• Adjunctive systemic antibiotics may be used – When ototopical treatment fails (after 7-10 days) – In children with associated streptococcal pharyngitis – When infection has spread beyond middle ear or external ear canal – With lack of adherence to ototopical therapy
• Special populations (eg, immunocompromised patients) require additional consideration

Question 22

Tympanic membrane perforations?

Answer 22

• Infection is the most common reason to develop a perforation.
• Traumatic perforations may result from penetrating trauma or blows to the ear (eg, being struck with the flat of the hand; falling from water skis with the head hitting the water surface, ear down).
• Inexpertly performed irrigation of the ear canal for wax can lead to perforation. In some settings, when irrigation for cerumen is relegated to medical assistants, otolaryngologists may see 10-20 patients per year with this injury.
• Failure of surgically created openings to heal when the tube extrudes results in chronic TMP.

Question 23

Repair of tmypanic membrane perforations?

Answer 23

• 80-90% will heal without needing surgical intervention.
• Observe water precautions with an open TM.
• May eventually need a tympanoplasty or a tympanomastoidectomy.

Question 24

What is Otosclerosis?

Answer 24

• Otosclerosis can result in conductive and/or sensorineural hearing loss. The primary form of hearing loss in otosclerosis is conductive hearing loss (CHL) whereby sounds reach the ear drum but are incompletely transferred via the ossicular chain in the middle ear, and thus partly fail to reach the inner ear(cochlea). This usually will begin in one ear but will eventually affect both ears with a variable course.

Question 25

Treatment of otosclerosis?

Answer 25

• Treatment for the hearing loss caused by otosclerosis is through hearing aid application or through laser stapedotomy with placement of a piston prosthesis.

Question 26

Components of the bony labyrinth?

Answer 26

Bony Labyrinth

Embryology

Components: Vestibule Semicircular canals Cochlea

Question 27

Other components of the inner ear?

Answer 27

• Cochlear Aqueduct
• Vestibular Aqueduct

Question 28

explain the Membranous labyrinth?

Answer 28

– Embryology

– The membranous labyrinth is enclosed within the bony labyrinth.

– Endolymphatic duct: connects the endolymphatic compartment to the endolymphatic sac.

– Periotic duct: within the cochlear aqueduct, connects the scala tympani to the posterior cranial fossa.

Question 29

Explain the semicircular canals?

Answer 29

• The three semicircular canals open into the vestibule,

– Horizontal canal

– Superior canal

– Posterior canal

Question 30

What is the shape of the cochlea?

Answer 30

The shape of the cochlea resembles that of a snail shell with two and onehalf turns

Question 31

What is the Modiolus?

Answer 31

Modiolus: the central conical core of the cochlea.

Question 32

what are two inner ear diseases and related to cochlear fluid?

Answer 32

Meniere’s disease

Perilymphatic fistula

Question 33

Features of meniere’s Disease?

Answer 33

• Fluctuating hearing • Tinnitus • Aural fullness • Vertigo

Question 34

Meniere’s Disease tiggers?

Answer 34

• Caffeine • Alcohol, Aspirin products • Tobacco • Sodium • The NO CATS approach.

Question 35

Hair cells are held how? Stimulus?

Answer 35

• Hair cells • The hair cells are held in position by a system of supporting cells. • stimulus for activating the hair cell. • Each hair cell is innervated at its base

Question 36

What are the receptors on the hair cells?

Answer 36

• Stereocillia • Kinocillium

Question 37

What are stereocilla?

Answer 37

Actin filaments within a tubular membrane

Question 38

Mechano-electrical transduction by hair cells?

Answer 38

Movement of the hair bundle in the depolarizing direction leads to increases in membrane conductance, meaning that the membrane becomes more permeable to positively charged ions

Question 39

Mechanical events that take place in the cochlea when a sound wave enters the inner ear?

Answer 39

Sound waves normally enter the inner ear via the oval window and are transmitted rapidly through the cochlear fluid. Movement of the oval window by the stapes footplate is met with equal and opposite action of the round window

Question 40

The basilar membrane is a what?

Answer 40

Basilar membrane is a resonant structure • The basilar membrane is deflected in response to sound waves in the inner ear.

The deformation of the basilar membrane is a traveling wave.

Question 41

How does the basilar membrane work?

Answer 41

Different regions of the basilar membrane respond maximally to different sound frequencies based on the local physical properties. ie The topotonical basilar membrane

Variation in the width of the basilar membrane

Question 42

Excitation of the auditory nerve fibers?

Answer 42

• Shearing motion of the stereocillia
• Shearing results in depolarization or hyperpolarization

Question 43

Afferent and efferent innervation to the organ of corti?

Answer 43

Question 44

Explain begnin positional vertigo?

Answer 44

Typical complaint: spells of vertigo when turning over in bed, “top shelf vertigo”

Examine the patient for nystagmus and vertigo in the Dix-Hallpike position : head-hanging R and L

Vertigo lasts shorter than 1 minute

Geotropic, torsional nystagmus with upbeat component

Brought on only by positional changes

Latency of few seconds up to 45 sec

Fatigues with repeated testing

Question 45

What is the pathophys of BPPV?

Answer 45

In BPPV, the otoliths become dislodged from the hair cells and membrane to which they were attached, migrate out of the utricle, and enter the semicircular canals. The posterior semicircular canal is almost always the involved canal since it is the most dependent of the 3 canals. Now when the patient turns his head, both the otoliths and endolymph start to move. Once the patient stops turning his head, the endolymph should stop moving as well. However, the otoliths continue to move and drag the endolymph with them. Angular acceleration receptors in the semicircular canal continue to fire and tell the brain that the head is still turning. The eyes, however, tell the brain that the head has stopped moving. Receiving conflicting information, the brain resolves this dilemma by rationalizing that the room must be spinning in the opposite direction.

Question 46

What is the dix-hallpike manuver?

Answer 46

The Dix–Hallpike test is performed with the patient sitting[3] upright on the examination table with the legs extended. The patient’s head is then rotated to one side by approximately 45 degrees. The clinician helps the patient to lie down backwards quickly with the head held in approximately 20 degrees of extension.

Question 47

The epley manuver is what?

Answer 47

• The patient begins in an upright sitting posture, with the legs fully extended and the head rotated 45 degrees towards the affected side.
• The patient is then quickly and passively forced down backwards by the clinician performing the treatment into a supine position with the head held approximately in a 30 degree neck extension (Dix-Hallpikeposition) where the affected ear faces the ground.
• The clinician observes the patient’s eyes for “primary stage” nystagmus.
• The patient remains in this position for approximately 1–2 minutes.
• The patient’s head is then turned 90 degrees to the opposite direction so that the unaffected ear faces the ground, all while maintaining the 30 degree neck extension.
• The patient remains in this position for approximately 1–2 minutes.
• Keeping the head and neck in a fixed position relative to the body, the individual rolls onto their shoulder, rotating the head another 90 degrees in the direction that they are facing. The patient is now looking downwards at a 45 degree angle.
• The eyes should be immediately observed by the clinician for “secondary stage” nystagmus and this secondary stage nystagmus should beat in the same direction as the primary stage nystagmus. The patient remains in this position for approximately 1–2 minutes.
• Finally, the patient is slowly brought up to an upright sitting posture, while maintaining the 45 degree rotation of the head.
• The patient holds sitting position for up to 30 seconds.