NBME 23 Otosclerosis (NBME Answers)

NBME 23 Answers

nbme23/Block 3/Question#33 (reveal difficulty score)
A 78-year-old man has had progressive loss of ...
Otosclerosis 🔍 / 📺 / 🌳 / 📖
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+12 upvote downvote
submitted by ∗mousie(272)

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My understanding if BC>AC this is abnormal = conductive hearing loss = otosclerosis VS Sensoryneural hearing loss will have normal AC>BC = loss of hair cells

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dentist VS: progressive unilateral hearing loss, doesn't affect Rinne Test, associated with NF2 and actor Mark Ruffalo Otoslcerosis is (usually....) progressive bilateral hearing loss, BC > AC. source +

tallerthanmymom If BC > AC in BOTH ears, why does he have hearing loss in only one ear? My logic was that he probably had otosclerosis in both ears and then something extra going on in his right ear that would make it worse than the left. I still don't understand why otosclerosis is the best answer here. +5

dul071 Finally!!!! Someone who ACTUALLY explains what the fuck bone conduction even is and teaches the whole topic. Here's the link for anyone else who struggled to find someone who takes time to explain this concept https://www.youtube.com/watch?v=cZYJL9Jg-3k +4

sonofarathorn ^ Halle-freakin-lujah +

chaosawaits I also was very confused as to why BC > AC in both ears but he only has hearing loss in one ear. Regardless, none of the other choices explained conductive hearing loss so I chose E, but I hate questions like this because I'm right, I know what I'm talking about but I cannot have confidence in my answer which affects me in later questions. +

+9 upvote downvote
submitted by ∗usmile1(154)

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A) acoustic neuroma = sensorineural
B) lesion of cochlear nuclei
C) Loss of hair cells = Presbycusis (age-related progressive bilateral SENSORINEURAL hearing loss)
D) Meniere dz: triad of SENSORINEURAL hearing loss, vertigo, tinnitus

E. Otosclerosis: Slowly progressive conductive hearing loss that most commonly affects ONE ear, with the 2nd ear affected in ∼ 70% of patients as the disease progresses... [this explains the patient's complaint of worse hearing on the right]

pathophys: Abnormal bone growth of the bony labyrinth. Stapedial otosclerosis (most common site) → fixation of stapes to oval window → conductive hearing loss
leads to progressive CONDUCTIVE hearing loss because the ossicle's ability to vibrate becomes increasingly limited.
A unique feature that I have seen come up often on question is that the patients are able to hear better in noisy rather than quiet surroundings.

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+1 upvote downvote
submitted by ∗hello(429)

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can someone please explain this?

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thomasburton My reasoning was BC>AC so this must be a conductive problem (which to me means something middle ear or out) so usually I think something blocking air flow or impeding the ossicles. You can rule out all other answers as they are all causes of sensorineural (AC>BC). +3

madojo Meniere's disease is sensorineural hearing loss with peripheral vertigo due to increased endolymph within the ear. +

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submitted by ∗ergogenic22(401)

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1) know that BC>AC = conductive hearing loss 2) conductive hearing loss means issue with structure before the inner ear 3) everything else occurs in the inner ear or in the brain

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submitted by ∗leaf_house(27)

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In case anyone was wondering, Meniere disease is excessive endolymph buildup in the in the inner ear. It causes vertigo and sensorineural hearing loss--so not this patient's issue. (FA 2020 534)

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-6 upvote downvote
submitted by ∗niboonsh(409)

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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1069039/

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