[atltom]

I have been living with what I thought was idiopathic small fiber sensory neuropathy for the past 12 years.

Decided to go to Johns Hopkins for an evaulation. Results came back as follows:

Normal or negative results for Lyme, TTG, SSa, SSb, endomysial antibody, SPEP, lg quants, TSH (0.57) and SIFE.

Skin biopsy - 25029 distal thigh - right, epidermal nerve fiber density at low
range of normal at approx. 8 fibers/mm
25030 prox thigh - right, epidermal nerve fiber density and
appearance are within a normal range
25028 distal leg - right, epidermal nerve fiber density is reduced
at 2-3 fibers/mm

The three biopsies demonstrate a length-dependent neuropathic process affecting small caliber sensory nerve fibers.

My B6 is elevated at 117 ng/mL where normal is 2.1 - 21.7

Based on the above results the doctor said I had mild small fiber neuropathy. And the tests suggest the cause is the elevated B6. I also had a glucose tolerance test back in 2005 that showed impaired fasting glucose at 108. However, my yearly glucose since then has always been < 100.

The mylegram of my spine that I took with me to JH also shows evidence of lumbar polyradiculopathy. I knew this because I have been seeing a neurosurgeon who is fairly certain that the stenosis is so bad in my lumbar that it is contributing to the PN! In fact, I have scheduled surgery later this month.

My suggestion from JH is to stop my daily B6 supplement of 25 mg sublingual,
treat the lumbar problem conservatively for now, diet and exercise.

Has anyone heard of other cases where the SFN is caused solely by elevated B6? I have been taking the supplement for the past 5-6 yrs along with a multi-vit which also has 18 mg of B6 (as pyridoxine hydrochloride).

I sure would like to hear any feedback you could provide as now I am somewhat torn about the upcoming back surgery. Thanks so much.

[nide44]

Originally Posted by atltom

...............My suggestion from JH is to stop my daily B6 supplement of 25 mg sublingual,
treat the lumbar problem conservatively for now, diet and exercise.

Has anyone heard of other cases where the SFN is caused solely by elevated B6? I have been taking the supplement for the past 5-6 yrs along with a multi-vit which also has 18 mg of B6 .............

Absolutely!!
Get off the B6 .....now!
Too much B6 is proven to cause PN.
Hopkins is one of the best. (I go there, as well.)
Do what they say.... ASAP!

[mrsD]

One should not get PN from 25 mg a day. However, there are some people who have elevated B6 with NO daily supplements at all.

I ran into that when I found a study on autistic children that showed that they had elevated B6 naturally with no supplements.

What may happen is that some people cannot convert B6 to pyridoxal form. This requires Vit B2 riboflavin, the pyridoxal kinase enzyme to be active. Some drugs and toxins inactivate this enzyme so B6 will build up in the serum since the body cannot use it.

The PNs from B6 almost all were found with extremely high doses like 500mg a day. This was a common intervention for female PMS...and that is when some PN toxicity neuropathies were reported. And even then it is a very small number of people. It is just not common. They don't use that high dose anymore, and the only people who take it that way are those with a rare condition called B6 dependency.
Most doctors recommend B6 intake of less than 100mg a day.

If I were you, I'd stop all B6 and wait 6mons and get retested to see what level you are at. If you are normal then, you will know it was from the supplement reading high in the serum. If you are still elevated that will tell you that you have something metabolically wrong and you are not utilizing B6 properly.
If you don't convert properly, you would actually be deficient in the tissues. This would suggest using P5P, the activated form.
What form is in your supplement? Can you check? If your levels do return to a more common number, but you still have PN, I'd say the B6 is not the culprit. If you took your dose just before the blood draw, it might be a fluke, a temp reading until the vitamin moved into the tissues. Timing might be a factor as well.

Tomorrow I will look for some studies for you. You can then print them out and share with your doctor.

[atltom]

Originally Posted by mrsD

One should not get PN from 25 mg a day. However, there are some people who have elevated B6 with NO daily supplements at all.

I ran into that when I found a study on autistic children that showed that they had elevated B6 naturally with no supplements.

What may happen is that some people cannot convert B6 to pyridoxal form. This requires Vit B2 riboflavin, the pyridoxal kinase enzyme to be active. Some drugs and toxins inactivate this enzyme so B6 will build up in the serum since the body cannot use it.

The PNs from B6 almost all were found with extremely high doses like 500mg a day. This was a common intervention for female PMS...and that is when some PN toxicity neuropathies were reported. And even then it is a very small number of people. It is just not common. They don't use that high dose anymore, and the only people who take it that way are those with a rare condition called B6 dependency.
Most doctors recommend B6 intake of less than 100mg a day.

If I were you, I'd stop all B6 and wait 6mons and get retested to see what level you are at. If you are normal then, you will know it was from the supplement reading high in the serum. If you are still elevated that will tell you that you have something metabolically wrong and you are not utilizing B6 properly.
If you don't convert properly, you would actually be deficient in the tissues. This would suggest using P5P, the activated form.
What form is in your supplement? Can you check? If your levels do return to a more common number, but you still have PN, I'd say the B6 is not the culprit. If you took your dose just before the blood draw, it might be a fluke, a temp reading until the vitamin moved into the tissues. Timing might be a factor as well.

Tomorrow I will look for some studies for you. You can then print them out and share with your doctor.

mrsD,

The 25 mg I have been taking daily is the P5P form. The 18mg from the daily multi-vit is not. I took my daily dosage about 4 hours before my blood was drawn.

[mrsD]

There have always been reports of B6 as a cause of neuropathy, but some reports don't even include the doses people might have been using.

This report does give doses and is from 2005:

Ned Tijdschr Geneeskd. 2005 Nov 12;149(46):2545-6.
[How much vitamin B6 is toxic?]

[Article in Dutch]

Katan MB.

Wageningen Centre for Food Sciences en Wageningen Universiteit, afd. Humane Voeding, Bomenweg 2, 6703 HD Wageningen. martijn.katan@wur.nl

Comment in:

* Ned Tijdschr Geneeskd. 2005 Nov 12;149(46):2541-4.
* Ned Tijdschr Geneeskd. 2006 Feb 4;150(5):277; author reply 277.
* Ned Tijdschr Geneeskd. 2006 Feb 4;150(5):278; author reply 278.

Vitamin B6 (pyridoxine) causes neuropathy at intakes of 1000 mg per day or more, which is about 800 times the daily intake from foods. There have also been occasional reports of toxicity at intakes of 100-300 mg per day. The US authorities set the no-observed-adverse-effect-level at 200 mg per day and the safe upper limit at 100 mg per day. A report of neurotoxicity in 2 patients who had taken 24 mg and 40 mg of vitamin B6 per day respectively, may be coincidence rather than a true toxic effect of such relatively low doses. However, physicians need to remain alert to high intakes of vitamin B6 as a cause of unexplained neuropathy.

PMID: 16320662 [PubMed - indexed for MEDLINE]

from http://www.ncbi.nlm.nih.gov/pubmed/1...&ordinalpos=18

Many studies echo this:

Ann N Y Acad Sci. 1990;585:250-60.
Vitamin B6 in clinical neurology.

Bernstein AL.

Department of Neurology, Kaiser Permanente Medical Center, Hayward, California 94545.

Many conditions in clinical neurology may be responsive to pyridoxine as a therapeutic agent. The current difficulty is in trying to isolate the conditions that are most likely to respond. Treating seizures is a major part of a neurologic practice. Our current therapeutic agents are only partially successful and limited by multiple side effects. One problem is that patients often have to take these agents for an entire lifetime, further raising the risk of toxicity. If pyridoxine supplementation can improve the efficacy of currently used medications, it will be gladly accepted into our therapeutic arsenal. Headache, chronic pain, and depression all appear to run together in many of our patients. The observations that serotonin deficiency is a common thread between them and that pyridoxine can raise serotonin levels open a wide range of therapeutic options. Small studies have been carried out with mixed success. Comparison with amitriptyline in the treatment of headache appears to show about equal efficacy, although side effects would be expected to be more of a problem with the amitriptyline. Behavioral disorders are relatively common and continue to be a major problem, disrupting the lives of the patients and their families. Current treatments are not acceptable to most people because of the risk of side effects with long-term usage. If, as Dr. Feingold suggests, many of these problems are caused by "toxic" exposures to chemicals that are pyridoxine antagonists, supplementation at early ages may reduce the incidence of hyperactivity and aggressive behavior. This raises the question of safety. Is pyridoxine safe for long-term use in large segments of the population, including children? The studies on children with Down's syndrome and autism, utilizing much higher doses than are used for other therapeutic purposes, seem to indicate relative safety if carefully monitored. Studies involving large population groups with carpal tunnel syndrome, all adults, using 100-150 mg/day have shown minimal or no toxicity in five- to 10-year studies. Women self-medicating for PMS taking 500 to 5000 mg/day have shown peripheral neuropathy within one to three years. It would appear from this retrospective analysis that pyridoxine is safe at doses of 100 mg/day or less in adults. In children there is not enough data to make any sort of suggestion. Because the major neurologic complication is a peripheral neuropathy and the causes of this condition are myriad, pyridoxine may cause neuropathy only in patients with a pre-existing susceptibility to this condition.

PMID: 2162644 [PubMed - indexed for MEDLINE]

Everyone is different. The only way you will find answers to your particular situation is to stop all B6 intake for several months, and see if your PN improves (studies say it does for toxicity). If not, the other factors may be present for you.
I have used P5P 50mg for almost a decade and never had any problem but instead have had nice improvement in my carpal tunnel issues.

[atltom]

Originally Posted by mrsD

There have always been reports of B6 as a cause of neuropathy, but some reports don't even include the doses people might have been using.

This report does give doses and is from 2005:

from http://www.ncbi.nlm.nih.gov/pubmed/1...&ordinalpos=18

Many studies echo this:


Everyone is different. The only way you will find answers to your particular situation is to stop all B6 intake for several months, and see if your PN improves (studies say it does for toxicity). If not, the other factors may be present for you.
I have used P5P 50mg for almost a decade and never had any problem but instead have had nice improvement in my carpal tunnel issues.

mrsD,

Thanks for all of your input. I am going to stop all B6 intake (both the 25 mg P5P and the 18 mg embedded in the multi-vit) for a number of months and see if the PN improves.

I may also move forward with the lumbar stenosis surgery as it is becoming harder and harder to live with and who knows, perhaps it is contributing to the PN as my neurosurgeon believes and not totally ruled out by Johns Hopkins.