Peripheral neuropathy

Here's the way the nervous system was explained to me, a long time ago:

Think about electricity to your house.

There are wires from your house to a "feeder line" that connects to the other houses on your street.

The "feeder line" connects to a "main line".

You're sitting in your living room, reading a book, and the lights go out!  You look around, thinking the bulb has burned out in the lamp -- and indeed -- all the other lights in the house are working. So it's a very small electrical problem,-- in the body, a pinched nerve, that will recover when you "screw in a new bulb" -- shake it, move around, get the blood flowing.

OR: you look around, and realize the lights are out all throughout the house, but your neighbors have lights! The problem is with the line from your house to the "feeder line" -- in the body, that would be "peripheral neuropathy" -- the nerves from your extremities to your spinal cord are impaired in some way -- but the central nervous system -- the "main line" is functioning fine (no lesions appearing on repeated MRI's of either the brain or spinal cord"

OR: you look around, and realize the lights are out through the entire neighborhood -- a "central nervous system problem".

So a peripheral nerve problem means that somewhere in the nervous system pathways from your extremities (arms, legs) or other more outer areas of the body there is a problem, but the central nervous system is working properly.  The nerves that create sensations like touch (your hands, and yes, your sex organs) are impaired -- signals aren't being transmitted properly to the central nervous system -- but the central nervous system is not impaired.

The next step will be to try to figure out what the peripheral nerve problem is. If it's in the extremities, maybe there's a pinched nerve, or series of pinched or injured nerves somewhere. Or maybe in your spine (which could lead to problems with your extremities and sex organs) there's some mechanical malfunction.

Anyway. Maybe this makes sense?

Denda said...
Hi Uppity!

Sorry to jump in on your post NJgal! I was wondering if what I always thought about the diffference in Peripheral vs CN is the peripheral is dx'd by an emg, where with issues with CN the emg shows normal? I know that's not the end all be all for a dx for either, but can you tell me if that is right or not?

Denda, that's what I always understood, too -- that an emg is done as part of the MS diagnosis process. If the results of the emg come back "positive" -- that means there is a problem with the peripheral nervous system, that is causing the numbness or tingling that the patient is experiencing.

But if the emg comes back "negative" , or normal -- that means the problem isn't with the extremity itself, but further along the "nerve line" -- the central nervous system.

That COULD be a CNS issue. But not necessarily. And presumably you've been tested for all the OTHER things that might cause numbness, and dulled orgasms? Like thyroid issues (both over-active and under-active thyroid problems can cause numbness and tingling), diabetes, menopause, other metabolic disorders? And sometimes there are sensory problems with no known cause....and you just have to live with it. Doctors can't find a reason, nothing more dramatic develops, just a numb leg, or foot, or whatever.

And remember -- none of us here are doctors. We're just guessing, from afar.

Well, let me jump in here and ask a question too. Would a thyroid problem, menopause, or diabetes cause hyperactive knee reflexes and a present Babinski reflex? My MRIs, LP, and EMG were normal too.

Also, what's the difference between an SSER (somatosensory evoked potential response) and an EMG? My SSER on my left leg was abnormal (that's the leg with the abnormal reflexes.)

Thanks! (By the way, Uppity, that's an excellent anaology of the nervous system. I'll have to remember that to use in my anatomy and physiology classes. I think my students would understand that better.)

Lisa, the SSER tests how fast signals are going from the nerves in the body to the brain.  It can detect problems with nerves in the spinal cord and brain.  The EMG tests the peripheral nerves outside of the central nervous system.  Hope this helps.