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Flashcards in otology Deck (28)
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Middle ear is connected to the nasopharynx by what?

eustachian tube - provides ventilation and mucociliary clearance to the middle ear


where is the pars tensa, malleus, and pars flaccid

When looking at the ear drum, pars tensa is inferior to the umbo and malleus, malleus forms an oblique line, and pars flaccid is superior to the malleus


What does an audiogram measure

It measures hearing level (in dB) as a function of frequency (Hz). These pure tone thresholds measure the sensory (cochlear) aspect of hearing function


What is the minimum dB humans can detect

Humans can detect a one dB difference. On the audiogram, 0 dB is the normal hearing threshold, not zero sound intensity


What is a word recognition score

Represents the ability to discrimination words presentenced at normal conversational loudness levels (0-100%). This is a critical part of the hearing assessment and represents the “neural” aspect of hearing ability (inner hair cell, 8th nerve and central auditory pathways)


Four types of hearing loss and what structures are affected

conductive (external ear, tympanic membrane or middle ear), sensory (cochlear), neural (8th nerve, inner hair cell, central pathways), or sensorineural (combo of sensory and neural structures)


causes of conductive hearing loss

otitis media, TM perforation, Cholesteatoma, Otosclerosis (bones become fixed), Congenital aural atresia


signs and symptoms of acute otitis media

Rapid onset of signs (inflammation of TM, drainage, perforation) and symptoms (pain, fullness/pressure, hearing loss) of an ear infection in the presence of a middle ear effusion.


treatment of acute otitis media

1) Consider Watchful Waiting when uncertain in low-risk patients 2) Systemic Abx 3) Tympanocentesis for culture or acute pain control 4) Myringotomy and Mastoid Surgery in complicated cases


otitis media with effusion- signs/symptoms and treatment

Middle ear fluid in the absence of inflammation/infection. Pain/fullness/popping /hearing loss (can delayed speech and language development), recurrent episodes of AOM. Antihistamines, decongestants, antibiotics, steroids not effective. Treat with time (watchful waiting) or PE tubes


causes of sensory hearing loss

hair cell loss due to presbycusis, noise trauma, ototoxicity, genetic factors. Outer hair cells more susceptible than inner hair cells.


what is presbycusis

Gradual, progressive bilateral hearing loss caused by degenerative physiologic changes associated with aging. Decreased hearing threshold sensitivity. Decreased ability to understand supra-threshold speech. Central auditory process impairment. Associated with greater risk of alzheimers and other cognitive declines


What are the OSA regulations for chronic noise exposure

80 dB for 8 hrs or 90 dB for 4 hours


What is a noise notch

A form of sensory hearing loss where the audiogram shows normal hearing at low frequencies, then an abrupt decrease in hearing level in dB at a high frequency (ie. 4000Hz) but then hearin level in dB goes back up to near normal at higher frequencies (ie. 8000Hz). This occurs around 2000-4000Hz becuase the resonant frequency in the middle ear is around this frequency


What is ototoxicity

Ototoxicity is the tendency of certain therapeutic agents and other chemicals substances to cause functional impairment and cellular degeneration of the tissues of the inner ear, especially the inner ear hair cells and stria vascularis


common ototoxic agents

aminoglycosodes (gentamicin), cancer agents (cis-platinum), macrolides (erthromycin), ASA, quinine, loop diuretics, hydrocodone, viagra


treatment of ototoxicity

stop agent, use corticosteroids, antioxidants (vitamin E), avoid noise exposure


Two types of genetic causes of hearing loss

non-syndromic (70%) and syndromic (30%)


most common causes of non syndromic hearing loss

Connexin 26 (autosomal recessive)


most common causes of syndromic hearing loss

include Waardenburg’s (2%), Usher’s (4-5%), Pendred’s (5%), Brachio-oto-renal (7%), Alport’s (1%), and Jervell, Lange Nielson (0.25%).


What is endolymphatic hydrops

A pathologic condition characterized by expansion of the endolymphatic compartment of the inner ear. Is associated with recurrent episodes of vertigo, sensorineural hearing loss, tinnitus and aural fullness that is refered to as Meneire’s disease


stria vascularis function

maintains proper endolymph fluid homeostasis and the endonuclear potential by pumping K ions into the scala media


How does loss of endonuclear potential affect hearing

it causes sensory hearing loss


Causes of disordered inner ear fluid homestasis and treatment

Impaired blood flow due to: Vascular dysfunction/ vasculitis, systemic metabolic disorders (DM, hypothyroid, renal failure, arteriosclerosis), immune mediated (lupus, sarcoidosis, wegeners). Treated with corticosteroids


hallmarks of neural hearing loss

asymmetry of hearing between the two ear and reduced speech perception scores.


Causes of neural hearing loss

8th nerve tumors, auditory neuropathy, multiple sclerosis


management of vestibular schwannoma

observation, resection, stereotactic radiosurgery


treatment of sensorineural hearing loss

Air Conduction Hearing Aids, Implantable Hearing Aids, Cochlear Implants, Assistive Listening Devices, Speech and Language Training