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Old 04-26-2011
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Neuro Can you localize this neurologic lesion?

A 50 year old woman undergoes a neurological exam that indicates loss of pain and temperature sensitivity, vibratory sense, and proprioception in both legs. These symptoms indicate?
1. A tumor on medial lemniscal pathway in sacral spinal cord
2. A peripheral neuropathy
3. A large tumor in sacral dorsal horn
4. A large tumor affecting posterior paracentral gyri
5. A large tumor in VPL and PM thalamic nuclei.

Plz give explanations too! Thanks
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  #2  
Old 04-26-2011
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i think its two. because no other option fits the scenario acc. to me. dc-ml syystem would not affect pain and temp, tumor in sacral region would also cause bowel bladder dysfunction and motor weakness., a lesion in the thalamus would not just limit to lower limbs... and am not sure about the function of para central gyrus.....but i think sensations would be afeected by a lesion on somatosensory cortex......
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Old 04-26-2011
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Good question. Yes peripheral neuropathy would be correct. (I read peripheral neuropathy as peripheral nerve injury and dorsal horn as dorsal column) - read the question carefully guys!
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Old 04-26-2011
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bilateral periphral neuropathy only is the cause according to the ques......none other fits ........best ans is 2..........
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2 looks most appropriate by excluding others but how come no motor symptoms
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Old 04-26-2011
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That's a good question.....
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1---this aint correct...if MLP is invovled then contralateral upper limb shud also be involved too...also thr is no MLP in the sacrum......
2---this is correct ....at the level of peripheral nerve we can have loss of both dorsal column and spinothalmic pathway sensations.......bt it shud be bilateral for both legs to be involved......
3--this aint correct ...tumor in dorsl horn only causes loss of sensations carried by dorsal column .....
4---this aint correct .....here also contralateral upper limb is involved...
5--same as 4.........plus contralateral face is also involved due VPM....
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Old 04-26-2011
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thanks guys for your help but the answer given is 4!
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Old 04-27-2011
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Correct Answer ans

ya it can be 4. the posterior part of the paracentral lobule; the medial continuation of the primary somatosensory cortex (postcentral gyrus) in which sensory input from the thigh, leg, and foot are represented.
all other ans previously explained well ..
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