wk 12, lec 3

Question 1

15% of people 20-69 have some degree of

Answer 1

high frequency hearing loss due to noise

Outer and inner hair cells are damaged by noise, but the outer are more vulnerable

Question 2

presbycusis

Answer 2

Presbycusis (age-induced) hearing loss is likely due to a combination of neuronal loss and hair cell loss

Question 3

what substances are ototoxic (toxic to hearing) and what do they damage

Answer 3

Antibiotics, chemotherapeutic agents, diuretics are often implicated

• Many of these substances damage either the outer hair cells or the stria vascularis

Question 4

conductive hearing loss vs sensorineural hearing loss

Answer 4

Conductive hearing loss is typically caused by physical blockages or abnormalities in the outer or middle ear, and is often treatable with medical or surgical interventions.

Sensorineural hearing loss is usually permanent, caused by damage to the cochlea or auditory nerve, and may require assistive devices like hearing aids or cochlear implants for management.

Question 5

conductive hearing loss vs sensorineural hearing loss which frequencies are effected

Answer 5

conductive= all frequencies

sensorineural= higher frequencies

Question 6

conductive hearing loss

Answer 6

impaired sound transmission in the external or middle ear, impacts all frequencies

Question 7

conductive hearing loss causes

Answer 7

Trauma to the tympanic membrane, infection, plugging of the external auditory meatus/canal, otosclerosis, cholesteatoma

Question 8

sensorineural hearing loss causes

Answer 8

▪ Presbycusis (age-induced), ototoxic agents, noise (most common)
▪ Problems with endolymph (Meniere’s), infections of the labyrinth or 8th CN, tumours (acoustic neuroma, brainstem tumours)

Question 9

weber and rinne tests in sensorineural hearing loss

Answer 9

Rinne: AC > BC,
Weber: lateralizes to unaffected ear

Question 10

weber and rinne tests in conductive hearing loss

Answer 10

Rinne: BC > AC,
Weber: lateralizes to affected ear

Question 11

what frequency can humans hear? what is speech range?

Answer 11

• Human ear can hear from 20 – 20000 Hz
  ▪ We’re best at hearing 1000 – 4000, human speech ranges
  from 500 – 2000 Hz

Question 12

what does audiometry assess

Answer 12

• Audiometry assesses hearing at particular tones and is much better at characterizing hearing loss than tuning fork tests

Question 13

what is the main cause of otitis externa

Answer 13

90% of otitis externa is bacterial
▪ Usually staphylococcal, pseudomonas
aeruginosa, or E. coli

Question 14

risk factors for otitis externa

Answer 14

Humidity, loss of cerumen (trauma, excessive Q-tip use), heat, increased pH (the ear should be acidic for barrier immunity), obstruction of the ear canal, exposure, water with bugs

Question 15

clinical features of otitis externa

Answer 15

otalgia
ottorhhea
itchy
▪ Edema → occlusion of the ear canal →
conductive hearing loss
▪ Severe infection can lead to cellulitis (deeper layers, skin involvement)

Question 16

hearing loss in otitis externa

Answer 16

conductive

Question 17

treatment for otitis externa

Answer 17

topical antibiotics
▪ Make sure not to use ototoxic antibiotics with a perforated TM

Question 18

4 types of otitis externa

Answer 18

1. furunculosis
2. chronic otitis externa
3. malignant/necrotizing otitis externa
4. otomycosis

Question 19

what is the worst form of otitis externa (medical emergency )

Answer 19

malignant/necrotizing otitis externa

Question 20

furunculosis (type of otitis externa)? cause?

Answer 20

otitis externa of the outer 1/3 of the ear canal, usually staphylococcal

Question 21

chronic otitis externa cause

Answer 21

less painful, more itchy
▪ Usually caused by repetitive trauma, chronic drainage from a
middle ear infection

Question 22

malignant/necrotizing otitis externa

Answer 22

▪ Progressive, slowly developing infection, severe otalgia, lots of otorrhea, granulation/necrotic tissue in the auditory canal
* Can be life-threatening if the infection colonizes temporal bone, intracranial structures
* Cranial nerve palsies and systemic infection also possible

Question 23

who is malignant/ necrotizing Otitis externa more common in

Answer 23

More common in the elderly, diabetics, immunocompromised
– usually P. aeruginosa

Question 24

otomycosis (type of otitis externa)? cause?

Answer 24

fungal infection of the external auditory canal, up to 10% of otitis externa

▪ Usual agent is Aspergillus (80%), next most common is Candida species
▪ More likely in:
* Diabetes, elderly, past history of HEENT surger in the
mastoid
▪ Often seen in those with poor response to antibacterial antibiotics

Question 25

acute otitis media symptoms

Answer 25

rapid onset of signs and symptoms, including fever and otalgia

Question 26

recurrent acute otitis media

Answer 26

3 or more episodes within a 6-month period or four or more episodes within a 12-month period - complete resolution of symptoms between episodes

Question 27

cause of acute Otitis media

Answer 27

Usually due to auditory tube dysfunction * Up to age 7, eustachian tube is shorter, wider, and more horizontal than in adults – predisposes to upper airway/oral bacteria colonization * Blockage of the tube – swelling of adenoid lymphatic tissue, swelling due to URTI or allergic rhinitis, inadequate tensor palatini function * Lack of breastfeeding (breast milk has antimicrobial sustances in it)

Question 28

pathogenesis of acute otitis media

Answer 28

▪ Obstruction of the auditory tube → air absorbed in middle ear→negative pressure→edema of mucosa with exudate and fluid accumulation→infection from nasopharyngeal secretions

Question 29

bacteria and viruses causing acute otitis media

Answer 29

Major bacteria implicated: H. influenzae, S. pneumoniae, M. catarrhalis ▪ Major viruses implicated: RSV, influenza, parainfluenza, adenovirus

Question 30

clinical features of acute otitis media - what is the triad

Answer 30

▪ Triad of otalgia, fever, and conductive hearing loss * Rare to have tinnitus, vertigo, or facial nerve paralysis ▪ Otorrhea can occur if the TM is perforated ▪ Bulging, red TM (middle ear inflammation) ▪ Often the TM is opaque, bony landmarks are lost ▪ effusion can often be seen behind it, and mobility is limited (pneumatoscopy)

Question 31

type of hearing loss in acute otitis media

Answer 31

conductive

Question 32

otitis media with effusion (serous otitis media) cause

Answer 32

▪ Often due to untreated or unresolved AOM * Persistent effusion in up to 40% of children 30 days after initial AOM, continued for 3 months in 10% * Main concern in pediatric population is impact on hearing at early ages (prior to a year) ▪ Delay in language development

Question 33

otitis media with effusion type of hearing loss

Answer 33

conductice

Question 34

otitis media with effusion clinical feautres

Answer 34

▪ Conductive hearing loss with or without tinnitus ▪ Feeling of fullness in the ear, low-grade fever ▪ May or may not involve otalgia

Question 35

otitis media with effusion on otoscope

Answer 35

▪ TM is translucent/gray (limited inflammation) * Fluid behind the ear, can often see air-fluid levels or bubbles ▪ Loss of light reflex, reduced mobility on pneumatoscopy

Question 36

treat otitis media?

Answer 36

* Most cases resolve on their own ▪ Tympanostomy tubes can improve hearing ▪ Case-by-case treatment depending on presentation

Question 37

most common causes of tympanic membrane perforations

Answer 37

▪ Middle ear infections ▪ Trauma – can be barotrauma or physical injury to the ear

Question 38

clinical features of tympanic membrane perforation

Answer 38

▪ Sudden onset of pain, hearing loss ▪ Can include bloody otorrhea ▪ Vertigo or tinnitus * Usually transient

Question 39

how to fix a tympanic membrane perforation

Answer 39

* Perforations usually heal spontaneously – advisable to wear earplugs while swimming, bathing ▪ Postero-superior damage to the TM is more likely to damage the function of ossicles – more urgent referral to the HEENT

Question 40

what parts of the ear does chronic otitis media affect

Answer 40

both the middle ear and the mastoid cavity

Question 41

tympanic membrane perforation from

Answer 41

recurrent or chronic ear infections

Question 42

where is there a disfunction that causes chronic otitis media

Answer 42

Dysfunction of the Eustachian tube is a significant factor in this disease, observed in approximately 70% of patients undergoing middle ear surgery

Question 43

types of chronic otitis media

Answer 43

1. suppurative or serous chronic otitis media 2. benign chronic otitis media

Question 44

suppurative or serous chronic otitis media

Answer 44

describes character of the drainage through the perforated TM

Question 45

benign chronic otitis media

Answer 45

“dry” – no active infection

Question 46

what is the most common cause of chronic otitis media

Answer 46

viral Viruses usual cause, though bacteria are more likely to contribute in children ▪ Pathogens invade via the external canal → edema, fibrosis, perforation and persistent infection ▪ Can also be a complication of tympanostomy tubes

Question 47

clinical features of chronic otitis media

Answer 47

▪ Otorrhea ▪ May or may not involve conductive hearing loss, tinnitus, or aural fullness ▪ Can have occasional severe intracranial complications in children

Question 48

cholesteatomas

Answer 48

non-neoplastic, cystic lesions lined by keratinizing squamous epithelium or metaplastic mucus- secreting epithelium, and filled with debris

Question 49

where do cholestetomas occur

Answer 49

middle ear -cysts+ keratin * Occur in the middle ear, mostly in the posterior-superior region (sometimes called the attic) * Debris contains mostly keratin, other cellular debris * Cyst is usually between 1 and 4 cm

Question 50

three types of cholesteatomas

Answer 50

1. primary congenital 2. secondary acquired 3. primary acquired

Question 51

primary congenital cholesteatomas

Answer 51

keratined epithelium is “misplaced” into area that should only have bone or simple cuboidal mucosa

Question 52

what type of hearing loss does cholesteatomas lead to

Answer 52

conductive hearing loss

Question 53

secondary acquired cholesteatomas

Answer 53

– Traumatic “implantation” of keratined epithelial cells from the “external-ear” side of the tympanic membrane or auditory canal * Traumatic causes include blast damage, iatrogenic (surgical, insertion of ear tubes) – not as common as primary acquired

Question 53

series impacts of cholesteatomas

Answer 53

Can cause serious bony destruction of the temporal bone→ infected cyst gains access to the dura and intracranial structures→meningitis and death * Cholesteatoma should almost always be removed to avoid this * Can also migrate and rupture into deep neck structures →another source of potentially life-threatening infection

Question 54

primary acquired cholesteatomas

Answer 54

– Recent investigations implicate a combination of chronic inflammation and abnormal TM cell migration

Question 55

most common cause of cholesteatomas

Answer 55

primary acquired mostly in adults

Question 56

pathogenesis of primary acquired cholesteatoma

Answer 56

– Inner surface of the TM consists of respiratory epithelium (simple cuboidal ciliated epithelium with goblet cells) that migrates over its surface in postero- superior direction – As it migrates more rapidly in response to chronic inflammation, it becomes “stuck” to the incus * Next stage – mucous accumulates in the pouch→chronic inflammation (often pseudomonas implicated) if it gets infected * This is followed by implantation/conversion of some of the cells in this cyst to keratinized epithelial cells – Note that the “outer” surface of the TM is pulled into the cystic structure * Outer surface formed from keratinized epithelium, not respiratory epithelium * The “stuck” keratinized cells keep dividing, and continued inflammation is likely linked to: – Growth of the cystic structure – Activation of osteoclasts and invasion of the temporal bone – Conductive hearing loss as the mobility of the ossicles is impaired (remember, the inner surface of the TM got stuck to the incus)

Question 57

type of hearing loss in primary acquired cholesteatoma

Answer 57

– Conductive hearing loss as the mobility of the ossicles is impaired (remember, the inner surface of the TM got stuck to the incus)

Question 58

where do primary acquired cholesteatomas develop in

Answer 58

Tend to see them develop in the pars flaccida (postero-superior to handle of malleus) because: * This is the direction the inner surface of the TM “likes” to migrate * This part of the TM has a lot of resident inflammatory cells * This area is close to the incus

Question 59

clinical features of cholesteatomas

Answer 59

-painless otorrhea - conductive hearing loss * Rarely vertigo or dysequilibrium may arise due to the inflammatory process within the middle ear or due to invasion of the labyrinth * Facial nerve palsy, can also result from the inflammatory process or mechanical compression of the nerve

Question 60

prognosis of choelsteatomas

Answer 60

surgery will usually have hearing loss post-op

Question 61

2 types of dizziness

Answer 61

vertiginous (vertigo) [peripheral and central] non-vertiginous [ organic and functional]

Question 62

vertigo

Answer 62

The environment seems to be moving

Question 63

what 2 problems could cause vertigo

Answer 63

* Caused by inner ear or brainstem-cerebellar disorders – Inner ear = peripheral – Brainstem-cerebellar = central

Question 64

organic non-vertiginous dizziness

Answer 64

a pathology that usually involves visual compromise or low blood pressure

Question 65

functional non-vertiginous dizziness

Answer 65

common in a wide range of mood disorders

Question 66

benign paroxysmal positional vertigo

Answer 66

Acute attacks of transient rotatory vertigo lasting seconds to minutes initiated by certain head positions – Accompanied by rotatory nystagmus

Question 67

what is the most common form of positional vertigo

Answer 67

benign paroxysmal positional vertigo

Question 68

symptoms in benign paroxysmal positional vertigo

Answer 68

– Symptoms are usually brief, caused by changing head position – Typical history = worsening when getting out of bed, extending the neck

Question 69

cause of benign paroxysmal positional vertigo

Answer 69

Usually caused by migration of a free-floating otolith [crystals in the ear] (should not be free-floating, should be attached)

Question 70

diagnosis of benign paroxysmal positional vertigo

Answer 70

– Dix-Hallpike Positional Testing * Patient rapidly moved from a sitting position to a supine position with the head hanging over the end of the table, turned to one side at 45° and neck extended 20° holding the position for 20 s – Onset of vertigo and rotatory nystagmus indicate a positive test for the dependent side

Question 71

Meniere's disease vs benign paroxysmal positional vertigo timeline vs vestibular neuronitis

Answer 71

menieres= min to hours bppv= secs to mins vn= days to weeks

Question 72

meniere's disease

Answer 72

Episodic attacks of tinnitus, hearing loss, and vertigo lasting minutes to hours

Question 73

cause of meniere's disease

Answer 73

excess endolymph – Inadequate absorption of endolymph leads to endolymphatic over-accumulation that distorts the membranous labyrinth – Usually begins in middle age

Question 74

triggers of meniere's disease

Answer 74

Triggered by high salt intake, caffeine, stress, nicotine, and alcohol

Question 75

* Diagnostic Criteria for Menière’s Disease (must have all three)

Answer 75

– Two spontaneous episodes of * Rotational vertigo ≥20 min * Audiometric confirmation of Sensorineural Hearing Loss * Tinnitus and/or aural fullness

Question 76

vestibular neuronitis

Answer 76

* Acute onset of disabling vertigo often accompanied by nausea, vomiting, and imbalance without hearing loss that resolves over days leaving a residual imbalance that lasts days to weeks

Question 77

causes of vestibular neuronitis

Answer 77

– Could be viral, often associated with URTI

Question 78

acute and convalescent phase of vestibular neuronitis

Answer 78

* Acute phase – Severe vertigo with nausea, vomiting, and imbalance lasting 1-5 days – Nystagmus – Patient tends to veer towards affected side * Convalescent phase – Imbalance and motion sickness lasting days to weeks – Spontaneous nystagmus away from affected side – Gradual vestibular adaptation requires weeks to months

Question 79

what is labyrinthitis

Answer 79

* Acute infection of the inner ear resulting in vertigo and hearing loss

Question 80

labyrinthitis causes

Answer 80

* May be serous (viral) or purulent (bacterial) – Occurs as a complication of acute and chronic otitis media, bacterial meningitis * Bacterial: S. pneumoniae, H, influenzae, M. catarrhalis, P. aeruginosa, P. mirabilis * Viral: rubella, CMV, measles, mumps, varicella zoster

Question 81

symptoms of labyrinthitis

Answer 81

* Sudden onset of vertigo, N/V, tinnitus, and unilateral hearing loss with no associated fever or pain – Meningitis is a serious complication

Question 82

acoutsic neuromas effects what cell

Answer 82

Schwann cells that myelinate vestibular and/or cochlear nerve

Question 83

acoustic neuroma

Answer 83

* Intracranial tumours that develop from Schwann cells that myelinate the vestibular and/or cochlear nerve – Can take up much of the space of the cerebellopontine angle (80% of tumours in this area are acoustic neuromas) – Most are from the vestibular component of the nerve

Question 84

acoustic neuroma can impact brain and nerves?

Answer 84

alway vestibular and/or cochlear nerve – There’s quite a bit of room in that area of the brain, so often do not elevate intracranial pressure until they are quite large – Can also impinge on the nearby facial nerve and trigeminal nerve

Question 85

risk factors for acoustic neuromas

Answer 85

– Neurofibromatosis type II (defective merlin gene) – Ionizing radiation to the area

Question 86

clinical features of acoustic neuroma

Answer 86

* Hearing loss by far the most common – Can be sudden or gradual, constant or fluctuating – Assume that all unilateral neurosensory hearing loss is due to an acoustic neuroma until proven otherwise * Vertigo is fairly uncommon, but balance difficulties are common * Facial weakness or numbness due to CN VII or V impingement * Headache due to elevated intracranial pressure

Question 87

treatment/prognosis of acoustic neuroma

Answer 87

*Microsurgery or radiation used to treat, generally survival is quite good * 30 – 80% maintain hearing