1/2/2014

1/2/2014

Answers:

Rank the following complaints on presentation of vestibular schwannoma from most common to least common.
A) V2 Dysfunction > Hearing Loss > Tinnitus > Diplopia 
B) Tinnitus > Hearing Loss > Diplopia > V2 Dysfunction 
C) Hearing Loss > Tinnitus > Diplopia > V2 Dysfunction 
D) Tinnitus > Hearing Loss > V2 Dysfunction > Diplopia 
E) Hearing Loss > Tinnitus > V2 dysfunction > Diplopia

95% of VS present w/ unilateral hearing loss. 65% will present with tinnitus. Facial/Trigeminal dysfunction is another common presentation for VS. Diplopia is an unusual in early VS and is not a common presenting symptom.

The IAC is divided into 4 quadrants by what two structures?

The "transverse crest" and the "vertical crest" (aka Bill's bar)

MC Questions:
What is the best study to diagnose a vestibular schwannoma.
A) MRI w/o contrast 
B) MRI w/ contrast 
C) CT w/ contrast 
D) CT w/o contrast 
E) Angiogram

Free Response Question:
What is the definition of "rollover"?

Quick Facts:
-Natural hx of VS includes a slow growth in the IAC and then into the cisterna of the
CPA.
-Average growth rate is 1.8 mm/yr.
-Symptom onset is often slow/insidious but predictable.
-Occasional rapid progression can occur due to cystic degeneration or bleeding.
-Initial growth often affects vestibulocochlear nerve in rigid IAC causing unilateral
hearing loss, tinnitus and vertigo.
-Tumor then progresses to CPA cistern and grows freely w/o symptoms until it reaches 3 cm.
-At this point corneal/mid face numbness, further hearing loss, vertigo and facial
weakness/spasms can occur.
-Further growth causes cerebellar signs including ocular changes, headache, AMS, n/v and eventually death.