Ambulatory Topic #2: Causes of Hearing Loss
At my present clinic, my attending does the annual physical
exam for the state-employed divers. Many of them have exostoses, which are bony
outgrowth of the external auditory canal related to repetitive exposures to
cold water. They are common in divers and swimmers. This led us into a
conversation about hearing loss and thus my topic of the day.
There are 2 types of hearing loss: Conductive vs
Sensorineural
Conductive = caused by lesion in external or middle ear
Sensorineural = lesions in cochlea or CN VIII
Conductive
1.
External canal
a.
WAX! (Cerumen impaction)
b.
Otitis externa (TIP: Don’t forget to palpate
external ear before introducing otoscope!)
c.
Exostoses
2.
TM performation
a.
Trauma
b.
Secondary to middle ear infection
3.
Middle ear
a.
Middle ear effusion (Otitis media, allergic
rhinitis)
b.
Otosclerosis (bony fusion between stapes and ova
= immobilization)
c.
Neoplasm
d.
Congenital malformation
Sensorineural
1.
Old Age (Presbycusis)
a.
Degeneration of sensory cells
b.
MOST COMMON
2.
Too many concerts (Noise-induced hearing loss)
a.
>85 dB for prolonged time
b.
Damaged hair cells
3.
Infection
a.
Viral or bacterial
4.
Drug-induced hearing loss
a.
Aminoglycosides
b.
Cisplatin
c.
Furosemide
d.
Aspirin can cause tinnitus (usually reversible)
5.
Inner ear injury
a.
Skull fx
6.
Meniere’s Dz
a.
Fluctuating, unilateral hearing loss
b.
Ear feels “full”
c.
Vertigo
7.
CNS cause
a.
Acoustic neuroma
b.
Meningitis
c.
Neuritis of auditory nerve
8.
Congenital
a.
TORCH infections
Tips on Hearing Tests:
RINNE vs WEBER
CONDUCTION LOSS
|
Finding:
|
Rinne Test
(Abnl)
|
Bone conduction (BC) >
Air conduction (AC)
|
Weber Test
|
Sound
lateralizes to AFFECTED side*
|
SENSORINEURAL LOSS
|
|
Rinne Test
(Nl)
|
AC > BC
|
Weber Test
|
Sound
lateralizes to UNAFFECTED side
|
*This means that the tuning fork is heard louder in the ear
with the conductive hearing loss.
I remember it as the Rinne test is Abnormal and sound lateralizes to the Affected side. Both start with “A”.
Source: Step Up to Medicine 2nd Ed.
Source: Step Up to Medicine 2nd Ed.
You are posting some serious knowledge on this blog! Hearing loss is always a great thing to keep in mind. Definitely need to rule it out in older patients before declaring them delirious or demented.
ReplyDelete-Harrison
blog.harrisonreedpa.com
Absolutely. Good point, Harrison!
ReplyDeleteHi,
ReplyDeleteMy name is John and I have a quick question about your blog! Could you please email me?
Thank you,
John
You did not leave your email address. Please email me directly at Bianca.Belcher@gmail.com
ReplyDeleteCheers!