Neuro help!

[laethia]

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Hi guys! I'd really appreciate it if someone can help me with this:
I don't understand how a peripheral nerve problem can lead to loss of all sensory modalities in a "stocking and glove" distribution. I'm ok with the one nerve one area concept... ie. sever the median, knock out sensation over some fingers... but this is really confusing me!
Thanks in advance

 

[osli]

Syringomyelia knocks out the ventral white commissure in the central part of the spinal cord, thus affecting any fibers that might cross there. This explains the characteristic pattern of deficit type and distribution. If you know what tracts run where and cross where, then it makes perfect sense. And it isn't a peripheral nerve problem... it only seems that way.

 

[laethia]

Thanks for your response 🙂 Correct me if I'm wrong... but isn't syringomyelia something that gives you a cape-like distribution in pain & temp only, and usually spares everything else? My question was referring to the "stocking and glove" pattern of peripheral neropathies. I'm pretty lost!

 

[osli]

lol, that's what I get for not thinking. Stocking and glove is a typical buzzword and I completely overlooked it and was thinking about just the glove part. You're right, it isn't syringomyelia but a peripheral polyneuropathy, often from diabetes. I think the key is that axons most distant from their cell body are affected first. All nerve types can be involved.

 

[hj0517]

yeah I have to agree, distal neurons are affected first and as a result you get a glove and stocking distribution.

In terms of lesions and levels, thinking in basic terms has helped me answer questions in the past (anterior or ventral is motor and posterior or dorsal is sensory) then just know levels of cross over are different for each bundle and also decussation for the paresis questions. I realise this is barn door basic - but it helped me 🙂

 

[DragonWell]

Don't quote me on this, but I seem to remember reading something about relative hypoxia combined with length of axons as possible explanations for the stocking and glove pattern seen in early DM neuropathy. Goljan says DM neuropathy is due to osmotic damage to Schwann cells, but I thought there was also microvascular damage involved as well.