Disorders of the Inner Ear Flashcards
What is the oval window?
where the stirrup attaches to the cochlea
What are vestibular organs?
organs that sense the position and movement of the head
utricle- lateral
saccule- horizontal
semicircular canals- crista ampullaris- detects rotational acceleration (filled with endolymph)
Acoustic Neuroma:
benign tumor of CN VIII;
symptoms: hearing loss, tinnitus, balance problems
Dx of Acoustic neuroma:
MRI of head/inner ear w/ gadolinium contrast
Tx of Acoustic neuroma:
referral
surgical excision/ gamma knife radiosurgery
What is the most common sudden SNHL?
unilateral loss noticed upon waking up
Idiopathic Sudden SNHL:
develops over seconds to days
may have tinnitus or ear pressure on affected side
ear exam is normal;
MRI to rule out acoustic neuroma
Tx of Sudden SNHL:
35-60% do not need tx;
oral and/or intratympanic injected steroids may improve chances of recovery
Tinnitus:
the perception of ringing in the ears
usually due to hearing loss, most often high frequency HL
can be caused by medications
Dx for tinnitus:
head and neck PE
Audiogram
Impact on quality of life
Screen for depression
Imaging for tinnitus:
if unilateral- MRI;
if pulsatile- MRA or CT of temporal bones (AVM or middle ear tumor)
Vertigo:
sensation of spinning or whirling or a sensation of movement in the absence of movement, disequilibrium
Dizziness is not oftenly a/w ear disorders
fact, suspicion should increase is there is HL too
Dx of vertigo:
most dx of vertigo are based on history;
test gait!
Benign Postural Vertigo:
most common cause of vertigo in the US;
spinning vertigo that lasts SECONDS and is provoked by head movements
delayed onset, down beating nystagmus, that lasts seconds and is fatigueable
No asymmetry of hearing on audiogram
Dx of benign postural vertigo:
dix-hallpike is positive
What causes BPV?
free floating debris in the semicircular canals
Tx for BPV:
canalith repositioning maneuver
Menieres Disease:
SPONTANEOUS EPISODIC attacks of incapacitating, spinning vertigo that lasts 20 min to several hours.
fluctuating SNHL, tinnitus and ear pressure
ear exam is normal
Evaluation of Menieres Disease:
audiogram
What causes Menieres DZ?
endolymphatic hydrops:
in adequate absorption of fluid by the endolymphatic sac
intermittent ruptures of the membranous labyrinth causes vertigo and HL which resolve when the membrane heals
Tx of Menieres DZ:
spontaneous improvement in 60-70%
low salt diet with a diuretic
anti-vetigo meds and anti-emetics
oral and intraympanic steroid injections
Bacterial Labyrinthitis:
severe bacterial infection involving fluid of the cochlea and vestibule;
usually a complication of otitis media
PURULENCE NOTED BEHIND TM, OR COMING THROUGH A PERFORATION;
patient feels extremely ill
Symptoms of Labyrinthitis:
profound usually permanent SNHL;
profound spinning vertigo for days
Tx of Labyrinthitis:
hospitalize with:
tympanostomy tube (if no TM perforation) and IV abx;
anti-emetic and anti-vertigo meds
What meds are the most ototoxic?
aminoglycosides and chemotherapeutic agents
