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-   -   Result of Skin Biopsy is Negative (https://www.neurotalk.org/peripheral-neuropathy/167968-result-skin-biopsy-negative.html)

Idiopathic PN 04-19-2012 04:47 AM

Quote:

Originally Posted by echoes long ago (Post 871448)
there should be a written record of what your nerve density was. it is part of the procedure to calculate that percentage.

http://www.ccjm.org/content/76/5/297.full

This is from the Cleveland Clinic Journal of Medicine

Skin biopsy
Skin biopsy is a minimally invasive procedure in which 3-mm-diameter punch biopsy specimens are taken from the distal leg, distal thigh, and proximal thigh of one lower limb. The procedure takes only 10 to 15 minutes.

Biopsy specimens are immunostained using an antibody against protein gene product 9.5, which is a panaxonal marker. Small nerve fibers in the epidermis are counted under a microscope, and intraepithelial nerve fiber densities are calculated and compared with established normative values. The diagnosis of small fiber neuropathy can be established if the intraepidermal nerve fiber density is lower than normal (FIGURE 1). Nerve fiber density may be normal in the early stage of small fiber neuropathy, but in this setting skin biopsy often shows abnormal morphologic changes in the small fibers, especially large swellings,24 and repeat biopsy in 6 to 12 months may be considered.

The diagnostic efficiency of skin biopsy is about 88%.21,23 For diagnosing small fiber neuropathy, it is more sensitive than quantitative sensory testing21,25 and more sensitive and less invasive than sural nerve biopsy.26 Intraepidermal nerve fiber density also correlates well with a variety of measures of severity of HIV distal sensory neuropathy and thus may be used to measure the severity and treatment response of small fiber neuropathy.27

It could be then that I am in an early stage of small fiber neuropathy? But, they should have included a notation in the report about abnormal morphologic changes, if they saw one.

I should call my doctor's clinic to request for the record of my nerve density. Is this what its called - "record of the nerve density"? I am sorry for this kind of question...I dont know what to ask for...If I say to the clinic staff "skin biopsy result", they will say I have it. I want to say the specific report I need. ( I dont even know myself how the report looks like:confused:)

Thank you and sorry for ranting....:o

glenntaj 04-19-2012 06:29 AM

Yes, you should.
 
The only way the result could have been determined is by comparison with "normal" ranges.

I've written a lot about this before--I think the normal ranges are rather arbitrarily set. There is considerable variation in nerve fiber density among asymptomatic people, which was discovered when they first started doing this at Johns Hopkins a few decades ago. So the range of normal was set at between 5% and 95% density levels of all the subjects they tested. People with density levels below 5% and above 95% are considered to be positive for small fiber neuropathy.

The problem with this is that one seldom has any idea of what level one was at BEFORE symptoms--almost no one goes in for skin biopsy until there are symptoms. Suppose one started at around the 50th percentile (though one would not know this, generally). One has a skin biopsy and the results show the density at around the 20th percentile. This would be listed as "normal", but it might well represent a significant dimunition from that person's "normal" level.

This is part of the reason why they are also supposed to report the condition of nerves--if there are swellings, excessive branchings, evidence of inflammatory infiltration. It's also why often multiple skin biopsies with numbers tracked can be informative--one looks for the trend.

Idiopathic PN 04-19-2012 06:43 AM

Quote:

Originally Posted by glenntaj (Post 871494)
The only way the result could have been determined is by comparison with "normal" ranges.

I've written a lot about this before--I think the normal ranges are rather arbitrarily set. There is considerable variation in nerve fiber density among asymptomatic people, which was discovered when they first started doing this at Johns Hopkins a few decades ago. So the range of normal was set at between 5% and 95% density levels of all the subjects they tested. People with density levels below 5% and above 95% are considered to be positive for small fiber neuropathy.

The problem with this is that one seldom has any idea of what level one was at BEFORE symptoms--almost no one goes in for skin biopsy until there are symptoms. Suppose one started at around the 50th percentile (though one would not know this, generally). One has a skin biopsy and the results show the density at around the 20th percentile. This would be listed as "normal", but it might well represent a significant dimunition from that person's "normal" level.

This is part of the reason why they are also supposed to report the condition of nerves--if there are swellings, excessive branchings, evidence of inflammatory infiltration. It's also why often multiple skin biopsies with numbers tracked can be informative--one looks for the trend.

When you mentioned about : "It's also why often multiple skin biopsies with numbers tracked can be informative....", does that mean that the doctor should have punched from several areas or does it mean that I should have follow up skin biopsies to establish trending?

glenntaj 04-20-2012 06:05 AM

Actually--
 
--it means BOTH.

Typical skin biopsy sites are the lower leg near the ankle, the outside of the thigh, and often right above the elbow int he fleshy part of the arm. This is done to see how "length-dependent" any neurological process may be; many neuropathies show slow progression from the nerves farthest away from the center of the body to those closer over time ("distal to proximal gradient").

Since skin biopsy is a quick, relatively non-invasive procedure, it can be repeated in the same locations over time to track progression and patterns. I've had four in nine years. They have shown my re-enervation--I went from being in the second percentile originally three months into my neuropathic syndrome to the eighteenth percentile on the last one almost two years ago (which technically makes me "normal"--though I doubt I was at the eigtheenth percentile before all this began).

Idiopathic PN 04-20-2012 12:11 PM

Quote:

Originally Posted by glenntaj (Post 871810)
--it means BOTH.

Typical skin biopsy sites are the lower leg near the ankle, the outside of the thigh, and often right above the elbow int he fleshy part of the arm. This is done to see how "length-dependent" any neurological process may be; many neuropathies show slow progression from the nerves farthest away from the center of the body to those closer over time ("distal to proximal gradient").

Since skin biopsy is a quick, relatively non-invasive procedure, it can be repeated in the same locations over time to track progression and patterns. I've had four in nine years. They have shown my re-enervation--I went from being in the second percentile originally three months into my neuropathic syndrome to the eighteenth percentile on the last one almost two years ago (which technically makes me "normal"--though I doubt I was at the eigtheenth percentile before all this began).

The neurologist who did the skin biopsy kept on citing a new paper indicating that the new sites for punching are two: one from the thigh and one from just above the ankle. He said that one site used to be above the knee. I relied on his words because he co-wrote a paper himself (which I think you posted as one of the links).

I really want to have a copy of my report in "percentage format". I want to have a reference point for my next biopsy. Unfortunately, when I talked with the nurse, she informed me that they receive only a one-page report and she does not know about the percentile report. Would you be kind to give me a copy of your report (delete the personal information, of course!) just to have an idea of how it looks like and so I can confidently discuss with her. If I could not get this through her, I will talk to my doctor when I see him next month.

Until now, I am still very confused how come that I registered "normal" when I am feeling all these pain. Sometimes I doubt if the skin punch was from the correct leg but I am convinced that it is - because my symptoms are are symmetrical in my feet/legs and arms/hands. I have the same level of pain in both. May be I am not so familiar yet how complicated nerves are and how it can "trick" test results.

Also, this normal result gives me a little hint of pressure when asked about it. My family can understand but those who are "not-so-close' might think that it could just be in my mind. ;)

echoes long ago 04-20-2012 08:08 PM

contact the lab that did the tests. for what they get paid to do it, it should be a complete report.

glenntaj 04-21-2012 06:44 AM

Basically--
 
here's what my first skin biopsy report said (without the extraneous stuff about how the sample was collected):

Epidermal nerve fibers per millimeter:

Thigh Mean 4.7
Range 3.0-7.7
Reference Values: 21.1 +/- 10.4; range 2.9--57.5
Fifth percentile value 5.2

Leg Mean 3.2
Range 1.3-4.3
Reference Values: 13.8 +/- 5.6; range 0.6--32.2
Fifth percentile value 3.8

The reference values indicate the mean in the tested reference group, which presumably included normals and people suffering from small-fiber syndromes normals (first number), then the standard deviation in that group (the +/- number), then the total range across everyone. These are known as the McArthur protocols. The fifth percentile values are then given, and as you can see, my means are both below that value, so by protocol definition, I have "abnormal intraepidermal nerve fiber density, consistent with a small fiber neuropathy". The report also states "the nerve fibers within the thigh suggest excessive branching, also consistent with a small-fiber neuropathy".

In my most recent skin biopsy, my thigh mean comes back at 9.5, and my leg mean comes back 5.8, which they tell me averages out at about the 18th percentile. This was almost two years ago--it's possible I would show even more re-enervation now, but who knows at what figures I "began".

Dr. Smith 04-21-2012 01:29 PM

Feeling Stigmatized?
 
Quote:

Originally Posted by Idiopathic PN (Post 871902)
Also, this normal result gives me a little hint of pressure when asked about it. My family can understand but those who are "not-so-close' might think that it could just be in my mind. ;)

This "pressure" is stigmatization. I recently came across this article from 2005 on Stigma, Liminality, and Chronic Pain,* which I believe can apply equally to PN and/or other chronic medical conditions. It may help to explain and understand this common experience/phenomenon. It looks to be interesting reading at any rate. :Clever: Disclaimer: I haven't fully digested the article yet. :Hum: :picknose:

More views and experiences - from professionals to fellow painees - can be found googling: stigma chronic pain and stigma peripheral neuropathy

Personally, I try not to care :Dunno: what "those who are 'not-so-close' might think". I have learned enough (from experience) not to share details of my own medical situation with those inclined to think such things, but that's a personal choice/decision.

* FWIW, I had to look up liminality too... :o

Doc

Susanne C. 04-21-2012 05:23 PM

This problem of having an "invisible" disease is one that drives me crazy. My mom was a hypochondriac, imagining serious diseases, going for unnecessary tests and complaining constantly for her 87 years, only the last few of which were compromised at all by her health. As a result having quantifiable test results is disproportionately important to me. I did not mention the progressive loss of sensation until it had passed my ankles and I had developed a serious staph infection. I need a demonstrable problem, preferably blood and pus or at least a better than even certainty of something showing up on an MRI or other test to get me into a doctor's office. When I developed Sciatica years go from a ruptured disc I kept going until I couldn't walk.
But I am insane, and this is a bad way to think. Dr. Smith is right. Remember, we wouldn't care so much about what other people think of us if we realized how seldom they do....
But I can sincerely empathize with your desire to have lab certified proof of your disease, beyond your very real suffering and symptoms. I have been known to carry my results with me, although no one, not TSA agents when I need to bring my hiking pole, or attendants at Disney World when I need to take it with in line, have asked to see them! My husband makes fun of me for this need for documentation. He says watching me walk is more than enough proof.
The problem is almost everyone knows someone like my mother, but not everyone knows someone like us.

Susanne C. 04-21-2012 05:37 PM

The article is interesting, the topic important and valid, but the writer really obscures his point with an almost bizarre quantity of jargon and pedantic words most of which have readily comprehended synonyms. Makes me want a red pencil. Heavy sledding indeed!


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