Clinical Hearing Disorders Flashcards
What are the 3 possible classifications of hearing loss?
conductive
sensorineural
mixed
What are the 2 types of congenital hearing loss? What percent do each make up of the total?
environmental (50%) & genetic (50%)
What are the “ABCD’s” or congenital hearing loss?
- A- affected family member
- B- bilirubin
- C- congenital intrauterine causes/CMV
- D- synDromes,
- ’s - small (1/50 in NICU)
What is the most common cause of non-syndromic congenital sensorineural hearing loss (SNHL)?
CMV
What is the median age of identification of hearing loss in an infant born with asymptomatic CMV?
18 months - most are not detected on newborn screening
35-50% of patients with cytomegalic inclusion disease will have what condition?
bilateral deafness
What is a newborn screening for hearing loss & how does it work?
most states obligate hospitals to perform hearing screenings at birth
every newborn gets an otoaccousticemission (OAE) - device that pics up the response to clicking sounds
OAE clicks & then detects depolarizations in the inner ear - if this is normal → implies the presence of normal anatomy
What are the symptoms seen in congenital rubella?
- congenital cataract
- cardiovascular anomalies
- intellectual disabilities
- retinitis
-
deafness
- 5-10% of mothers with rubella in first trimester
What is the underlying mechanism of deafness in congenital rubella?
degeneration of the oran of Corti
adhesion between the organ of Corti & Reissner’s membrane, rolled up tectorial membrane, partial or complete stria atrophy
Why do 20% of babies with kernicterus have severe deafness?
damage to the dorsal & ventral cochlear nuclei and superior & inferior collculi nuclei
What type of hearing loss is seen in kernicterus babies?
high frequency hearing loss
What bilirubin level is indicative of exchange transfusion?
serum level > 20mg/dL
What are the two types of hearing loss seen in congenital syphilis? Which is more severe?
early (infantile)- often severe & bilateral - usually fatal
late (tardive)- progressive hearing loss w/ varying severity & onset
75-80% of genetic deafness is due to genes with what type of inheritance pattern?
autosomal recessive
What is term for congenital non-syndromic hearing loss that has an autosomal recessive loci? How many loci & how many genes?
autosomal dominant loci? How many loci & how many genes?
x-linked loci?
- Recessive:
- DFNB (DeaFness Neurologic Autosomal recessive)
- 21 loci & 19 genes
- Dominant:
- DFNA
- 38 loci & 11 genes
- X-inked
- DFN
What is the most common cause of genetic non-syndromic deafness (~49%)? What is the prevalence of carrier state in US?
DFNB1 locus
chromosome 13 Gap Junction B2 gene mutation (GJB2) for connexin 26
1:31 carriers
What is the most common cause of autosomal dominant hearing loss?
DFNA6/14–WS1
What is the gene mutated in X-linked non-syndromic hearing loss? Mechanism & type of hearing loss?
DFN3 locus
POUF4 transcription factor
mixed hearing impairment w/ fixation of stapes (conductive) w/ perilymphatic gusher (sensorineural)
What is the rare X-linked disorder that affects the collagen of the basement membranes of the kidneys & the inner ear?a
Alport Syndrome
What are the symptoms/clinical picture seen in a patient with Alport Syndrome?
- renal failure
- hematuria in infancy
- progressive sensorineural hearing loss
- may not be evident until 2nd decade of life
What autosomal recessive disorder presents with a thyroid goiter & profound sensorineural hearing loss?
Pendred Syndrome
What is the cause of hearing loss in patients with Pendred Syndrome?
abnormal iodine metabolism
Mondini aplasia or enlarged vestibular aqueduct
What test is performed to diagnose Pendred Syndrome?
Perchlorate discharge test
(+) abnormal organification of nonorganic iodine
What is the most common type of autosomal recessive syndromic hearing loss?
Usher syndrome
What syndrome is characteristic of senorineural hearing loss & retinitis pigmentosa? It accounts for what fraction of all deaf & blind persons in the US?
Usher syndrome
½ of death & blind persons
What is the most common form of autosomal dominant syndromic hearing loss?
Waardenburg syndrome
What syndrome is characterized by unilateal or bilateal SNHL, pigmentary anomalies (white forelock, vitiligo, heterochromia irides) & craniofacial features (broad nasal root, synophrys, dystopia canthorum)
Waardenburg syndrome
What is dystopia canthorum?
wide-set eyes
What is synophrys?
unibrow
At what time point in gestation does the cochlea reach adult size?
9 weeks
Are congenital inner ear malformations more likely to be unilateral or bilateral?
bilateral (65%)
What condition is characterized by complete agenesis of the petrous portion of the temporal bone?
michel aplasia
When does the insult responsible for Michel Aplasia occur? What is the malformation? Why does this lead to hearing loss?
prior to the end of the 3rd gestational week
complete agenesis of petrous portion of the temporal bone - no inner ear structures → anacusis
What is anacusis?
total deafness
Cochlear implants or conventional amplification are not useful in what type of hearing loss?
anacusis
total deafness
What condition is characterized by only the basal coil of the cochlea developing? This is often associated with other physiologic feature?
Mondini Aplasia
endolymphatic duct is usually enlarged
Mondini Aplasia is described in what 5 conditions?
Pendred
Waarenburg
Treacher Collins
Wildervanck
CMV
What is the presentation of a patient with Mondini Aplasia?
presentation ranges from deafness → normal hearing
usually asymmetric, but affects both ears
What condition is characterized by poorly differentiated organ of Corti with deformed tectorial membrane & collapsed Reissner’s membrane - but normal bony labyrinth & superior portion of membranous labrynth?
Scheibe Aplasia
a.k.a.
Cochlearsaccular Dysplasia / Pars Inferior Dysplasia
What is the most common form of inner ear aplasia?
Scheibe Aplasia
Scheibe Aplasia is describe in what 5 conditions?
Jervell Lange-Nielsen
Refsum
Usher
Waardenburg
congenital rubella
Treatment for Scheibe Aplasia?
conventional amplification with rehab intervention is beneficial
Treatment for Michel aplasia?
no treatment
cochlear implants and conventional amplification are not useful
What condition is characterized by cochlear duct differentiation that is limited at the level of the basal coil? This results in what type of hearing loss?
Alexander Aplasia
high-frequency hearing loss w/ adequate residual hearing in low frequencies
Treatment for Alexander Aplasia?
conventional amplification is beneficial
What condition is characterized by vestibular aqueduct 1.5 mm or greater? Cause?
Enlarged Vestibular Aqueduct Syndrome
hydrodynamic changes & labyrinthine membrane disruption
Symptoms seen in Enlarged Vestibular Aqueduct Syndrome? Treatment?
early onset SNHL
usually bilateral & progressive
vertigo or incoordination
Treatment: avoid head trauma/contact sports
Performing a CT/MRI is most beneficial in diagnosing what general type of hearing loss?
unilateral
Performing a Connexin 26/GJB2 assay is most beneficial in diagnosing what general type of hearing loss?
bilateral
looking for DFNB1
What are the common causes of non-congenital conductive hearing loss?
diseases interrupting sound transmission to the inner ear
- cerumen (wax) impaction
- infection (OM, OE)
- external canal pathology
- tympanic membrane pathology
- middle ear pathology
What condition is characterized by vascular, spongy bone to fibrosis & sclerotic bone? Where in the ear is this the most common?
otosclerosis
usually near anterior oval window (antefenestrum)
What are the symptoms seen in otosclerosis?
Treatment?
- Symptoms
- progressive conductive or mixed hearing loss
- 30-50yr
- type A tympanogram
- (+) Schwartze’s sign
- Treatment
- observation
- hearing aid
- stapedectomy
What is Schwartze’s sign?
promontory hyperemia/redness
What condition is suggestive by conductive hearing loss with hypermobile TM & malleus on pneumatic otoscopy? This leads to what type of hearing loss?
Ossicular discontinuity
conductive hearing loss with a deep tympanogram
What are the common causes of ossicular discontinuity? Treament?
- Cause
- trauma
- chronic otitis media
- eustachian tube dysfunction
- previous surgery
- Treatment
- tympanoplasty with ossicular chain reconstruction
What are the different exam findings you would expect to see in patients with congenital cholesteatoma in age ranges 2-6yr, 4-12yr, and 12-30yr?
- 2-6: tympanic membrane white mass only
- 4-12: middle ear white mass, white TM
- 12-30: mastoid white mass, hearing loss, vertigo
What types of cells are responsible for the development of a congenital cholesteatoma?
epithelial cells in the middle ear adjacent to the malleus & posterior mesotympanum
Treatment for congenital cholesteatoma?
surgical
What is the cause of acquired cholesteatoma? Frequently associated conditions?
middle ear epithelium & keratoma formation with secondary enzymatic erosion - usually through TM perforation / epitympanic (attic) retraction pocket
frequently has chronic otitis media/otorrhea
Treatment for acquired cholesteatoma?
surgical
What is the most common cause of non-congenital sensorineural hearing loss?
noise induced
What is the term for age-related non-congenital sensorineural hearing loss? How is this hearing loss described?
prebycusis
progressive high frequency hearing loss with discrimination loss
What condition is characterized by aural fullness, roaring tinnitus, fluctuating hearing loss, severe episodic whirling vertigo?
Meniere Disease
a.k.a. endolymphatic hydrops
What is Lermoyez Syndrome?
variant of Meniere Disease with increasing fullness & hearing loss relieved with vertigo attack
What is Crisis of Tumarkin?
variant of Meniere Disease that has otolithic crisis w/ drop attacks
What are the systemic autoimmune diseases that can lead to non-congenital hearing loss?
polyarteritis nodosa
wegener granulomatosis
SLE
RA
ulcerative colitis
Whta is Cogan Syndrome?
nonsyphilitic interstitial keratitis & vertigo → bilateral progressive SNHL & bilateral Meniere’s Diseaer *15-20%)
What is the treatment for autoimmune SNHL?
high dose steroids
cytotoxic medications
transtympanic steroids
What is the clinical picture of a patient with idiopathic sudden SNHL?
abrupt or rapidly progressing hearing loss over minutes/days
40-54yr
Most common causes of idiopathic sudden SNHL?
-
Causes
- viral
- immune complex mediated
- vascular
-
Treatment
- High dose steroids
- antivirals
- antibiotics
- diuretics
- histamine
- anticoagulants
What are the symptoms of a perilymphatic fistula?
sudden or progressive SNHL associated with roaring tinnitus, dysacusis, dysequilibrium
What symptoms are seen with a Superior Semicircular canal fistula? Cause?
vertigo induced by lifting, valsalva or sound
dehiscence of superior semicircular canal – middle fossa (body labyrinth has eroded)
Why do aminoglycosides lead to ototoxicity & therefore SNHL?
loss of outer hair cell
Why do macrolides lead to ototixicity & therefore SNHL?
affects stria vascularis
Which diuretics lead to ototixicity & therefore SNHL? Mechanism?
loop diuretics, ethacrynic acid, furosemide
stria vascularis
Why do salicylates lead to ototixicity & therefore SNHL?
affect outer hair cells & spiral ganglion
Why do antidepressants lead to ototixicity & therefore SNHL?
increase serotonin with disinhibition of dorsal cochlear nucleus
Antineoplastic drugs & radiation lead to what type of hearing loss?
ototoxicity - SNHL
What are the tumors of the middle ear?
- multiple myeloma
- leukemia
- neorofibroma
- fibrous dysplasia
- eosinophilic granuloma
- metastatic carcinoma
- glomus tumors/paraganglioma
What is the most common type of cerebellopontine angle tumors?
other type?
acoustic neuroma/vestibular schwannoma (78%)
meningioma (3%)
What test should you do if you suspect a cerebellopontine angle tumor (CPA)?
Treatment?
MRI with & without gadolinium
Treatment: observation vs. surgery vs. radiation