Peripheral Neuropathy; Is my case the norm??

[johnnypro]

Hi,
I started having tingling in both feet last Oct (2010) right after knee replacement surgery. Of course the doctors poo-pooed it as being a temporary result of the surgery. AND of course it wasn't and even if it was, it was in BOTH feet. D'oh!!! It has gotten worse since then, and now the buzzing / numbness / pain is in the bottoms and tops of both feet all the time, and occasionally in my scalp, face, arms and hands. My neurologist did tests to confirm the neuropathy, send me for a Neck Cat Scan, then prescribed Gabapentin and referred me back to my GP with the idea that I probably had Diabetis.

My GP has done multiple Fasting Blood Sugars and I've never gotten to 126. I am usually between 110 and 125 so I realize I'm pre-diabetic. But my GP says there is no way this is caused by diabetis.

They've tested me for B12 and that was good also. I'm going back in to the doctor in a few weeks and he's gonna test me for Lyme Disease and a few other things. Any suggestions from anyone out there?? I've also had a problem with my hands cramping, but have no idea if that's at all releated.

I'm just worried that there is something more to this than an Idiopathic neuropathy. Thanx!!! JP

[Christopher R Newey, DO]

Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.

Without the ability to examine and obtain a history, I can not tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.

There are two types of sensory neuropathies in the body – large and small fibers. With small fiber neuropathies, symptoms including burning or buzzing or other vague symptoms starting in the feet and hands then in some cases spreading to other parts of the body; much like you describe. A test called EMG/NCS is sometimes useful; however, it may not show an abnormality in small fiber neuropathy, and a definitive diagnosis can only be made with a skin biopsy so that the number of nerve endings can literally be counted. There are other tests of the function of small nerves that can be ordered, such as QSART testing which looks at how much sweat the skin makes, since sweating is in a sense of function of these small nerves. There are several causes of small fiber neuropathy, including diabetes, vitamin deficiencies, and autoimmune problems.

The other type of sensory neuropathy is called a large fiber neuropathy. There are several categories of this type of neuropathy, and there are many many causes, and symptoms can be similar to that of small fiber neuropathy. Sensory neuropathies can involve just one nerve or several nerves in the body. Some types of sensory neuropathies occur and progress very slowly, others sort of wax and wane (with flare-ups) and some are progressive. One of the most common causes of neuropathy is diabetes, and sometimes only glucose intolerances, or abnormal rises in blood sugar after a glucose load can be the only indication (this is called a oral glucose tolerance test. Other causes include but are not limited to hereditary/genetic causes (such as in a disease called Charcot-Marie-Tooth, in which there is a family history of sensory neuropathy usually from an early age associated with other clinical features such as high-arched feet), autoimmune problems (such as lupus (SLE), Sjogren's, Churg-Strauss (in which asthma also occurs), polyarteritis nodosa, which affects blood vessels), and demyelinating diseases (such as CIDP). Vitamin B12 and B6 deficiency, as well as excess vitamin B6, can also cause neuropathy. Some toxins, such as lead, arsenic, and thalium can cause large fiber sensory neuropathy. Other causes include abnormalities of protein metabolism, as in a type called amyloidosis or monoclonal proteinemia. In many neuropathies, both the sensory and motor nerves (the nerves that supply the muscles) are involved, leading to sensory symptoms as well as weakness.

The diagnosis of large fiber neuropathy can be made by findings on an EMG/NCS. Rarely, in some cases a lumbar puncture provides useful in formation, and very rarely a nerve biopsy is required.

Pre-diabetes can cause neuropathy. But as you can see, there are many causes. If you have not done so, I would suggest you follow up with a neurologist who specializes in neuromuscular medicine.

Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.

[johnnypro]

Thank you for your reply, Dr. Newey!!!

Just to add a few things, I have been to a Neurologist, who did a bunch of tests (torture??) with needles and electricity to determine that I had Peripheral Neuropathy. His initial thought was to get a Cat Scan of my neck thinking that maybe a past injury from Whiplash might be causing this. The results of the scan were negative (arthritus, but nothing else) and he just referred me back to my GP saying it must be Diabetis. He also put me on 100mg of Gabapentin 2x a day.

My GP sent me for Bloodwork and ruled out B12 deficiency and a few other things. I'm supposed to go back to him for more testing in 2 weeks. I'm on 300mg of Gabapentin 3x a day now and tolerating it fine. I don't think it stops the buzzing and numbing as much as making me not care.

Any other directions you can think of to point my GP in? He is going to give me a Lyme Disease test and I'm going to ask him to check for Glucose Intolerance.

BTW, I am a 58 year old male who has had 2 Cataracts, an aeortic Aneurism w/ Valve replacement, 2 knee replacements, kidney stones which clogged the kidney and caused a MRSA blood infection, and shoulder surgery all in the last 5 years. Fun, huh???

Thanx again!!!  JP