If you have found your way here, chances are you have recently been diagnosed with Small Fiber Neuropathy (SFN). And chances are you feel alone, hopeless, scared and overwhelmed. Your family and friends want to understand your pain, but how can they? You can’t even describe it, because you have never felt pain like this before.

What makes it even worse is that your own doctor doesn’t seem to understand your level of pain. I sometimes wish there was a magic pill they could take so they would experience the same pain for just one day. But lacking the magic pill, we are dependent on them to believe the description of our pain, and hope they are compassionate enough to help us explore the causes and treatments necessary. And the more you understand, the better equipped you are to help them help you.

There can be many underlying causes of SFN that your doctor should test for. Some of the more common are:

Diabetes/Pre-Diabetes.........................Lyme Disease
Impaired Glucose Tolerance..................Connective Tissue Disease
Alcohol Abuse....................................Sjogrens Syndrome
Vitamin Deficiencies............................Sarcoidosis
Celiac Disease....................................Toxins (includes Chemotherapy)
Gluten Intolerance...............................HIV

Identifying and treating the underlying cause can be important to slowing the progression of SFN. However, it is estimated that 40-50% of SFN is idiopathic – of unknown cause. It is the idiopathic form of SFN that is addressed here. Other threads will cover SFN as it relates to specific underlying causes.


Helpful Reading:

Small Fiber Neuropathy: A burning problem: Published in the Cleveland Clinic Journal of Medicine. It is written for doctors with the Educational Objective to aid in the recognition of SFN symptoms.

Small-Fiber Neuropathy: Answering the Burning Questions: Written by 2 members of the Nerve Injury Unit at Massachusetts General Hospital, it provides information on the symptoms, evaluation, causes and treatment of SFN.

Painful Feet: The Small Fiber Neuropathies: Describes evaluation, diagnostic testing and treatment.

The diagnostic criteria for small fibre neuropathy: from symptoms to neuropathology: This study is one of the best I have seen for comparing the diagnosis of Small Fiber Neuropathy to Large Fiber and Mixed Fiber. Even if you find the technical discussion hard to follow, you will find the results presented in the tables very enlightening.

http://www.smallfiberneuropathy.net/: An informative website devoted exclusively to SFN.


Diagnostic Testing:

An Algorithm for the Evaluation of Peripheral Neuropathy: This article details evaluation and diagnosis of the different types of neuropathy, including Small Fiber Neuropathy.

Electromyography (EMG) and Nerve Conduction Studies (NCS) are not effective in the diagnosis of Small Fiber Neuropathy. They can be used, however, to eliminate involvement of motor and large sensory nerve fibers.

Evaluation of distal symmetric polyneuropathy: Role of autonomic testing, nerve biopsy, and skin biopsy: As you have read in the previous articles, the two most recommended diagnostic tests for SFN are the Skin Punch Biopsy and the Quantitative Sudomotor Axon Reflex Test (QSART). Both are described in this American Academy of Neurology Practice Parameter, published December 2008, that states: "Such testing should be considered especially for the evaluation of ... distal small fiber sensory polyneuropathy"

QSART and other Autonomic Testing is also described by the University of Pittsburg Autonomic Testing

A discussion of Skin Biopsy can be found at the NT Thread: Skyn Biopsy


Pain Management:

For the 40-50% with idiopathic SFN, pain management may be the only treatment. Medications used to treat SFN pain include anticonvulsants, antidepressants, topical analgesics and/or opioids. Each person responds to medications differently. Sometimes it may be necessary to change medications several times before you find one your pain responds to. Sometimes it requires a combination of medications.

A table that includes typical dosage and side effects can be found at page 302 of: Small Fiber Neuropathy: A burning problem.


Supplements:

Supplements for Peripheral Neuropathy: Another aspect of managing your SFN is to understand the role of nutritional supplements. You will find no better information than here at mrsD’s thread.


You are not alone:

There are many members here with a vast array of knowledge about SFN. The links below are just a sampling of the support and advice given to new members. Many of the links above are borrowed from those posts.

small fibre peripheral neuropathy

Pre-diabetes, small fiber neuropathy

This Small Fiber Neuropathy is unbearable

Is this the end of the road? any final suggestions?

My 9 yo son's Small Fibre Neuropathy Story

Newly Diagnosed - Small Fiber/Large Fiber Neuropathy! Please Help!

I have been Dx with idiopathic small sensory nerve fiber neuropathy and nothing helps

Pre-diabetes and neuropathy

If you haven’t found your answers here, chances are others have the same question. So, please start your own thread at the main Peripheral Neuropathy forum. There will be many members ready to answer your burning questions.
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--that complicates the picture in predominantly small-fiber syndromes.

While the majority of people with small-fiber conditions show a length-dependent type of die-back neuropathy, slowly progressive over time and chronic, a small minority present with an all-over body, or at least a beyond stocking/glove, distribution of symptoms. Often, these people have a more acute, or sub-acute, onset than people with length-dependent situations.

There's not a lot of research info out there on this, as it is not anwhere near as common as the small-fiber neuropathies associated with diabetes and vascular autoimmunities. Papers like this are perhaps representative:

http://jnnp.bmj.com/content/72/4/540.abstract

Such syndromes have been likened to a sort of small-fiber sensory Guillain Barre, though distinctions can be made in that other sensory variants of Guillain Barre show evidence of demyelination of larger sensory nerves:

http://www.neurology.org/cgi/content/full/56/1/82

--and the small-fiber variation, by definition, does not involve demyelination. It is thought, though, that both may occur through a molecular-mimicry autoimmune mechanism, are monophasic, and may allow for some degree of recovery, though recovery is often patchy and incomplete.

Dr. Abhey Moghekar of Johns Hopkins has speculated that in at least some of the cases of small-fiber neuropathy that present beyond the extremities the immune attack may be at the level of the dorsal root ganglia. Such situations may provide for less recovery as the damage is to cell bodies rather than to axons, and whiile the latter may regenerate if the rest of the nerve is intact, damage to the cell body (the soma) generally cannot be healed--the cell tends to disintegrate. However, as he once joked to me, evidence to distinguish this is hard to come by with current imaging technology and awaits my autopsy (that's neuroloigst humor for you).

It is known that this type of wider body presentation is relatively common in patients in which symptoms can be traced to gluten-sensitivity/celiac.

See:

http://jnnp.bmj.com/content/79/2/163.abstract

http://www3.interscience.wiley.com/c...6297/HTMLSTART