new_n_lost
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A previously well 54 year old man develops blurred vision and headache overnight. On examination, he has normal movements of the right eye, but complete opthalmoparesis of the left eye. The left pupil is dilated. There is some sensory loss to light touch and pin prick over the left cheek. The rest of the neurological examination is normal. Pulse is 80/min, blood pressure 130/87.
Which of these is the least likely anatomical site to explain his problem :-
A. Left cavernous sinus
B. Left posterior communicating artery
C. Left superior orbital fissure
D. Left carotid artery
E. Brain stem and pons
Edited by new_n_lost on 06/03/07 - 05:00 PM
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| tompat
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is it b.
cavernous sinus and superior orbital fissure harbour III n ophthalmic division of V nerve so any anatomic prob there like thrombosis n blow out # cud lead to such a problem overnight.
lt. carotid artery atheroscerosis and embolization of brain stem involving upper pons n mid brain cud lead to such prob.
posterior communicating artery anuerisms are second most common in circle of willis, affecting III n but in that case i dont see why V n will be affected
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| forumdoctor
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i am also going with B, i can rule out all except D.
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| Jackofknives
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Id say its E.
A, C, D can result in those deficits no doubt.
Posterior communication artery aneurysm can develop pretty quickly, compressing CN3, results in opthalmoparesis, it could also compressing V1, V2, CN4. Intracranial aneurysm also gives headache. Pulse and blood pressure is useless without knowing his values from the day before.
It cannot just be brain stem and pons b/c CN3 must be affected, and it nucleus lies in mesencephalon.
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| forumdoctor
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Jack, . spinal nucleus of trigeminal which extends from rostral pons to spinal cord. cental process of trigeminal which carry pain and temperature of the ipsilateral of the face synapses in spinal nucleus of trigeminal, any lesion here may result in loss pain and temp in the ipsilateral face.
So i ruled out E, in the option.
NNL, ans plssssssssssssss
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| Jackofknives
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Doc, for option E i was not talking about CN5 but CN3
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| SILVER
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B. Left posterior communicating artery
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| new_n_lost
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THE LEAST LIKELY ANATOMICAL SITE TO EXPLAIN HIS SITUATION WILL BE E
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FORUM RULES-- Those who believe in telekinesis, raise my hand. I get enough exercise just by pushing my luck --P4U World.." The pure and simple truth is rarely pure and never simple."
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| SILVER
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oh!
nnl and his least likely questions! 
i didn't read it carefully
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Expecting the world to treat you fairly because you are a good person, is like expecting the lion not to attack you because you are a vegetarian.
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| tompat
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yah i cud see it afterwards but i had already opted for b, good question nnl, that was a good treat!
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| tompat
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ok lets talk about this 1, i didn't feel its worth a new topic.
a 55 yr old man presents with extraocular muscle paralysisin one eye but no accomodation or pupillary light reflex abnormality in any eye, this wud be due to
1.post communicating artery anuertsm
2.edh
3.diabetes mellitus
4.uncal herniation due to tumor.
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| Jackofknives
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Hmm, it cannot be 1, 2, 4. Supposedly its 3, an explanation would be nice.
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| forumdoctor
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C, diabetic melitus pt experiance extacular muscle weakness sparing pupil. while herination, aneurism and hematoma effects first parasympthathetic causing loss of pupilary light reflex, mydriasis and later extraocular muscle paralysis.
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| drduck
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i think.....E
most importantly.....brainstem or pontine lesions......NEVER cause dialtation of pupils..........always and always MIOSIS.....or pin point pupils..........thats enough for the least possible.......
forget touch pain and temperature.....
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| tompat
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yah forumdoc is right.
it s about the arrangement of fibers of occulomotor nerve. motor fibers supplying extraoccular muscles are in the center and parasympathetic are on outer side.so any lesion affecting from out side wud be compromising parasympathetics first and then motor.
while in case of diabetes mellitus (vascular lesions)motor fibers are affected first and then parasympathetics.
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