Wednesday, December 25, 2013

12/25/2013

12/25/2013

Answers:
A patient presents saying they stuck a bobby pin deep in their left ear to "clean it out" when they felt a pop and suddenly had hearing loss on that side. On exam the patient lateralizes weber to the right and demonstrates some nystagmus. What is the most likely diagnosis?
A) Ossicular Discontinuity 
B) Stapes subluxation 
C) Tympanic Membrane Perforation 
D) EAC laceration 
E) None of the above

Although this patient also has a TM perf her weber lateralizes to the wrong side as it should lateralize to the side of a CHL. Additionally, her nystagmus is concerning for stapes subluxation and perilymphatic fistula which should be urgently treated.

What is the maximum hearing loss caused solely by ossicular chain dislocation?

60 dB is the maximum hearing loss from OCD (or any CHL)

MC Questions:
Blows to the lateral side of the skull often result in --- fx of t-bone whereas blunt trauma to the occipital skull result in --- fx of t-bone.
A) Longitudinal, Transverse 
B) Longitudinal, Vertical 
C) Transverse, Vertical 
D) Transverse, Longitudinal 
E) Vertical, Longitudinal

Free Response Question:
What is the most common type of temporal bone fracture?

Quick Facts:
Special Tests for Tbone fxs
-Audiometry should be done on all pts as an outpatient usually after hemotympanum has resolved (several weeks).
-If otic capsule fx then very likely there will be complete SNHL.
-Consider urgent audiometry if stapes subluxation into vestibule has occured.
-Facial nerve testing should be done if delayed, complete facial palsy occurs.
-Pts w/ >90% degeneration of facial nerve have poorer recovery and benefit
from surgical decompression.
-Nerve excitability test = place two probes of Hilger nerve stimulators across
the stylomastoid foramen and turn up until facial twitch barely visible...a
3.5mA difference between the injured and uninjured sides correlates with a
>90% loss of neural integrity.
-Electroneuronography can by done by a neurophysiologist = stimulating both
facial nerves with equal current and measuring myogenic potential.
-Neither test is accurate within 3 days of injury as it takes 72 hrs for nerve
fibers distal to site of injury to degenerate.

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