USMLE Forums Logo
USMLE Forums
Your Reliable
USMLE Online Community
44,126 Members
174,179 Posts
Home
USMLE Articles
USMLE News
USMLE Polls
USMLE Books
USMLE Apps
Go Back   USMLE Forums > USMLE Step 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 06-17-2011
bebix's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,379
Threads: 194
Thanked 3,000 Times in 874 Posts
Reputation: 3010
MRI 56 y/o man with vertigo and dysphagia

56-year-old man with history of hypertension woke up one morning with persistent vertigo. When he walked, he swayed to the right with occasional falls. He complained of dysphagia. Examination showed loss of the gag reflex on the right and leftward deviation of the uvula, among other signs and symptoms.

T2-weighted axial image
56 y/o man with vertigo and dysphagia-screen-shot-2011-06-17-10.16.53-pm.png
click image to enlarge

The most commonly affected artery is:

A) Posterior inferior cerebellar artery
B) Anterior Spinal Artery
C) Vertebral artery
D) Superior cerebellar artery
E) Posterior cerebral artery
Reply With Quote
The above post was thanked by:
Claus_CU (06-18-2011), CraCIT (12-09-2011), ntp0015 (06-25-2011), pass7 (06-18-2011), patelMD (06-17-2011), struggle (06-17-2011), usluipek (06-18-2011)



  #2  
Old 06-17-2011
pass7's Avatar
USMLE Forums Guru
 
Steps History: 1+CK+CS+3
Posts: 409
Threads: 30
Thanked 138 Times in 108 Posts
Reputation: 148
Default

is it lateral medullary syndrome??? my answer is post. inferior cerebellar artery (PICA)
Reply With Quote
The above post was thanked by:
bebix (06-18-2011)
  #3  
Old 06-17-2011
USMLE Forums Newbie
 
Steps History: Not yet
Posts: 3
Threads: 0
Thanked 1 Time in 1 Post
Reputation: 11
Default

posterior inferior cerebellar artery
Reply With Quote
The above post was thanked by:
bebix (06-18-2011)
  #4  
Old 06-17-2011
USMLE Forums Guru
 
Steps History: Not yet
Posts: 329
Threads: 70
Thanked 230 Times in 143 Posts
Reputation: 240
Default

Quote:
Originally Posted by bebix View Post
56-year-old man with history of hypertension woke up one morning with persistent vertigo. When he walked, he swayed to the right with occasional falls. He complained of dysphagia. Examination showed loss of the gag reflex on the right and leftward deviation of the uvula, among other signs and symptoms.

T2-weighted axial image
Attachment 1565
click image to enlarge

The most commonly affected artery is:

A) Posterior inferior cerebellar artery
B) Anterior Spinal Artery
C) Vertebral artery
D) Superior cerebellar artery
E) Posterior cerebral artery
My Answer..A
Reply With Quote
The above post was thanked by:
bebix (06-18-2011)
  #5  
Old 06-17-2011
jahn77's Avatar
USMLE Forums Guru
 
Steps History: Step 1 Only
Posts: 329
Threads: 20
Thanked 219 Times in 125 Posts
Reputation: 229
Default

If location is this (attach) - probable artery is posterior cerebral artery...PICA is quite low to be there. My guess is E.
Attached Thumbnails
56 y/o man with vertigo and dysphagia-pastedimage109.jpg  
Reply With Quote
The above post was thanked by:
bebix (06-18-2011)
  #6  
Old 06-18-2011
drciri's Avatar
USMLE Forums Addict
 
Steps History: 1+CK+CS
Posts: 163
Threads: 48
Thanked 217 Times in 64 Posts
Reputation: 227
Send a message via Skype™ to drciri
Default

my answer is A..


do post the answer pls
Reply With Quote
The above post was thanked by:
bebix (06-18-2011)
  #7  
Old 06-18-2011
Claus_CU's Avatar
USMLE Forums Addict
 
Steps History: 1 + CS
Posts: 114
Threads: 8
Thanked 86 Times in 61 Posts
Reputation: 96
Default

I think is A...but Im not sure
Reply With Quote
The above post was thanked by:
bebix (06-18-2011)
  #8  
Old 06-18-2011
bebix's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,379
Threads: 194
Thanked 3,000 Times in 874 Posts
Reputation: 3010
Default

Quote:
Originally Posted by jahn77 View Post
If location is this (attach) - probable artery is posterior cerebral artery...PICA is quite low to be there. My guess is E.
Hi jahn77. I really dont think that's the correct location (upper midbrain) for the patient's symptoms...
Reply With Quote
  #9  
Old 06-18-2011
bebix's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,379
Threads: 194
Thanked 3,000 Times in 874 Posts
Reputation: 3010
Default

somebody else wants to try?
Reply With Quote
  #10  
Old 06-18-2011
bebix's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,379
Threads: 194
Thanked 3,000 Times in 874 Posts
Reputation: 3010
Correct Answer correct answer

correct answer MC artery => Vertebral artery

An infarct of the posterolateral medulla produces the lateral medullary or Wallenberg’s syndrome.

The most commonly affected artery is intracranial vertebral artery occlusion (80%), followed by the posterior inferior cerebellar artery (PICA), superior middle and inferior medullary arteries.

The constellation of signs and symptoms comprising Wallenberg’s syndrome can be deduced from the key structures within the posterolateral medulla, and are as follows:

1– Dyspahgia and hoarseness with ipsilateral loss of the gag reflex and ipsilateral vocal cord paralysis secondary to weakness of the pharyngeal and laryngeal muscles supplied by the nucleus ambiguus.
2– Loss of pain and temperature sensation from the ipsilateral face secondary to involvement of the spinal trigeminal nucleus and tract.
3– Loss of pain and temperature sensation from the contralateral body secondary to involvement of the lateral spinothalamic tract.
4– Ipsilateral cerebellar ataxia, including axial lateropulsion from
involvement of the inferior cerebellar peduncle.
5– Vertigo, with associated nausea and vomiting, from involvement of the vestibular nuclei.
6– Ipsilateral Horner’s syndrome from involvement of the descending sympathetic fibers destined for the intermediolateral cell column. This is a pre ganglionic form of Horner’s.
7– Hiccuping, of uncertain etiology, but usually attributed to involvement of the respiratory center in the medullary reticular formation.
8– Abnormalities of saccades, referred to as ocular lateropulsion, are also characteristic of this syndrome, described as hypometric saccades away from the side of the lesion and hypermetric saccades towards the side of the lesion. This is probably secondary to damage of olivocerebellar fibers related to ocular movement traveling in the lateral medulla.

Lateral medullary or Wallenberg’s syndrome:

56 y/o man with vertigo and dysphagia-brainstem.jpg
click image to enlarge

56 y/o man with vertigo and dysphagia-brain2.jpg
click image to enlarge

56 y/o man with vertigo and dysphagia-brainstem_art.jpg
click image to enlarge
Reply With Quote
The above post was thanked by:
CraCIT (12-09-2011), jahn77 (06-18-2011)
  #11  
Old 06-18-2011
USMLE Forums Guru
 
Steps History: Not yet
Posts: 300
Threads: 45
Thanked 623 Times in 204 Posts
Reputation: 633
Default

Tricky question!

Do you think it is more appropriate to ask "which of the following is the most likely site of occlusion" rather than "most commonly affected?" Even though the most common site of occlusion is indeed the Vertebral artery, the PICA is almost always "affected" because it is the branch that supplies the lateral medulla.

Thoughts?

Good question though, I had no idea that vertebral artery stenosis was the most common cause of wallenberg's!

Keep em coming bebix, got my exam on Wednesday!
Reply With Quote
The above post was thanked by:
bebix (06-18-2011), jahn77 (06-18-2011)
  #12  
Old 06-18-2011
USMLE Forums Guru
 
Steps History: Not yet
Posts: 300
Threads: 45
Thanked 623 Times in 204 Posts
Reputation: 633
Default

I hope they don't give us both of the options of PICA or vertebral artery on the test because I would still be hesitant to choose vertebral artery!
Reply With Quote
  #13  
Old 06-18-2011
bebix's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,379
Threads: 194
Thanked 3,000 Times in 874 Posts
Reputation: 3010
Default

Quote:
Originally Posted by apx85 View Post
I hope they don't give us both of the options of PICA or vertebral artery on the test because I would still be hesitant to choose vertebral artery!
haha...

Actually the vertebral artery is the MC artery affected (occlusion, dissection...)

and remember...this syndrome is almost always due to infarction... a small number of cases are the result of hemorrhage or tumor.

Last edited by bebix; 06-18-2011 at 06:59 AM. Reason: added info
Reply With Quote
  #14  
Old 06-18-2011
bebix's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,379
Threads: 194
Thanked 3,000 Times in 874 Posts
Reputation: 3010
Default

btw, this question is from Clinical Neuroradiology
Reply With Quote
  #15  
Old 06-18-2011
USMLE Forums Guru
 
Steps History: Not yet
Posts: 300
Threads: 45
Thanked 623 Times in 204 Posts
Reputation: 633
Default

So would there not be any collateral flow to the PICA if there is occlusion of the proximal vertebral artery?
Reply With Quote

Kaplan Step 1 Classroom Anywhere

  #16  
Old 06-18-2011
bebix's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,379
Threads: 194
Thanked 3,000 Times in 874 Posts
Reputation: 3010
Default

Quote:
Originally Posted by apx85 View Post
So would there not be any collateral flow to the PICA if there is occlusion of the proximal vertebral artery?
i guess with an acute lesion nop...
Reply With Quote



Reply

Tags
Figures- , MRI-Images , Nervous-System- , Neuroanatomy- , Pathology- , Step-1-Questions

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


RSS Feed
Find Us on Facebook

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2013)