External Ear

Question 1

What is the incidence of congenital aural atresia

Answer 1

1: I 0,000 - 20,000.

Question 2

What is the most likely diagnosis of a fistula 1 em anterior to the tragus associated with a cystic bulge in the anterior ear canal in an 8-month-old infant

Answer 2

1st branchial arch sinus, type 2.

Question 3

What is the incidence of facial nerve displacement in congenital aural atresia

Answer 3

25 - 30%.

Question 4

How is NOE treated

Answer 4

6 weeks of 2 different IV antibiotics directed against the organism cultured; alternatively, ciprofloxacin and rifampin for several months; hyperbaric oxygen is recommended for advanced NOE.

Question 5

Using the rating system developed by Jahrsdoefer, what score is associated with the best outcome after surgical treatment of aural atresia

Answer 5

8 or greater (80% chance of obtaining an SRT 15 - 25 dB).

Question 6

What test should be used to assess auditory function in these patients

Answer 6

ABR.

Question 7

In a patient with aural atresia and no evidence of SNHL, when should a CT scan of the temporal bones be obtained

Answer 7

Age 4 or 5.

Question 8

What medication reduces the absorption of ciprofloxacin

Answer 8

Antacids containing calcium or magnesium salts.

Question 9

What is tympanophonia

Answer 9

Audition of one’s own breath sounds.

Question 10

What are the symptoms of patulous eustachian tube

Answer 10

Aural fullness, autophony, tympanophonia that improve when the head is placed down between the legs; onset often occurs with weight loss or after irradiation to the nasopharynx.

Question 11

On CT imaging, which ear structures are best seen on axial views

Answer 11

Body of the malleus and incus, incudostapedial joint, and the round window.

Question 12

Which has a male predilection

Answer 12

Both.

Question 13

What does stenosis of the external auditory canal predispose to

Answer 13

Canal cholesteatoma.

Question 14

How do patients with EAC cholesteatoma present

Answer 14

Chronic dull pain, usually unilaterally, with otorrhea and normal hearing.

Question 15

How do patients with keratosis obturans usually present

Answer 15

Conductive hearing loss, acute severe otalgia, usually bilaterally; otorrhea is rare.

Question 16

What imaging studies are used to diagnose NOE

Answer 16

CT scan with contrast, technetium-99m bone scan.

Question 17

What are the two types of bony growths in the EAC

Answer 17

Diffuse exostoses and osteomata.

Question 18

Which is more common

Answer 18

Exostoses.

Question 19

Which is more likely to be bilateral

Answer 19

Exostoses.

Question 20

Which is more likely to be seen in surfers

Answer 20

Exostoses.

Question 21

What structure is most at risk during removal of a 1st branchial arch sinus

Answer 21

Facial nerve.

Question 22

T/F: Surgery is contraindicated in children with unilateral atresia

Answer 22

False; many will operate if the patient is likely to achieve a residual conductive deficit of 30 dB or less.

Question 23

What study is used to monitor the response to therapy

Answer 23

Gallium-67 scan.

Question 24

What are the reasons for persistent conductive hearing loss after aural atresia repair

Answer 24

Inadequate mobilization of the ossicular mass from the atretic bone, an unrecognized incudostapedial joint discontinuity, or a fixed stapes.

Question 25

Why is ciprofloxacin contraindicated in children

Answer 25

It has been shown to cause arthropathy of the weight-bearing joints in immature animals.

Question 26

What is the term for a keratin plug occluding the EAC

Answer 26

Keratosis obturans.

Question 27

What are the indications for removal of exostoses

Answer 27

Less than 1 mm aperature, recurrent otitis externa, water trapping.

Question 28

What are the physical findings in a patient with EAC cholesteatoma

Answer 28

Localized erosion and periostitis of the posterior-inferior EAC associated with otorrhea.

Question 29

Why is it particularly difficult to assess the auditory function in patients with bilateral atresia

Answer 29

Masking dilemma.

Question 30

What advantage does hugging the middle fossa dura have on protecting the facial nerve

Answer 30

One will enter the middle ear first in the epitympanum; the facial nerve will always lie medial to the ossicular heads in the epitympanum.

Question 31

Which is usually attached to the tympanosquamous suture line

Answer 31

Osteomata.

Question 32

What is the typical presentation of an auricular endochondral pseudocyst

Answer 32

Painless, fluctuant outpouching on the upper anterior surface of the auricle, often preceded by low-grade chronic trauma.

Question 33

What signs and symptoms are specific for necrotizing otitis externa (NOE)

Answer 33

Persistent otalgia for longer than I month. Persistent, purulent otorrhea with granulation tissue for several weeks. Diabetes mellitus, another immunocompromised state, or advanced age. Cranial nerve involvement.

Question 34

What factors are considered contraindications to correction of unilateral atresia

Answer 34

Poor mastoid pneumatization, anterior displacement of the middle ear, and facial nerve anomalies.

Question 35

What is the most important factor in assessing the possibility of surgery in a patient with congenital aural atresia

Answer 35

Presence of the stapes.

Question 36

When is surgery indicated in the treatment of NOE

Answer 36

Progression of pain despite aggressive medical therapy, persistence of granulations, and development of cranial nerve involvement.

Question 37

What is the most causative organism of NOE

Answer 37

Pseudomonas aeruginosa.

Question 38

What are some treatments for patulous eustachian tube

Answer 38

Reassurance, weight gain, SSKI (1 0 gtt in juice po TID), Premarin nasal spray (25 mg in 30 cc NS, 3 gtt per nose TID), occlusion of the ET, and myringotomy and tympanostomy tube placement.

Question 39

What are the reasons for recurrent conductive hearing loss after aural atresia repair

Answer 39

Refixation of the ossicular chain or tympanic membrane lateralization.

Question 40

How can one differentiate between relapsing polychondritis involving the ear and other causes of external otitis

Answer 40

Relapsing poiychondritis spares the lobule.

Question 41

Which portion of the ossicular chain is least likely to be malformed in patients with congenital aural atresia

Answer 41

Stapes footplate.

Question 42

On CT imaging, which ear structures are best seen on coronal views

Answer 42

Stapes, oval window and the vestibule.

Question 43

Why is it difficult to treat infections involving the perichondrium or cartilage

Answer 43

The metabolic demands of cartilage are low, and its blood supply is hence diminished.

Question 44

What are the 2 most important landmarks of the anterior approach

Answer 44

The middle cranial fossa dura superiorly and the TMJ anteriorly.

Question 45

Why are diabetics more prone to NOE

Answer 45

The pH of their cerumen is higher and more conducive to bacterial growth.

Question 46

What are the physical findings in a patient with keratosis obturans

Answer 46

Thickened TM, widened EAC medially, hyperemic canal skin with granulation tissue.

Question 47

How does the infection spread from the external canal to the skull base

Answer 47

Through the fissures of Santorini.

Question 48

Why should surgery be delayed until age 5

Answer 48

To allow for completion of pneumatization of the temporal bone.

Question 49

What are the 2 basic approaches for repair of aural atresia

Answer 49

Transmastoid and anterior approaches.

Question 50

T/F: A patient with a score of 5 or less is considered a very poor operative candidate

Answer 50

True.

Question 51

Which cranial nerves are most commonly involved in NOE

Answer 51

VII (75%), X (70%), XI (56%).

Question 52

Which wave of the ABR is ear-specific

Answer 52

Wave I.