Small Fibre Neuropathy Sfn

[Foggy01]

Hey,

I was wondering if we could collect all the info we have about this condition itself and also its connection to POTS/CFS/fibro/dysautonomia. Just to make an easy resource for those trying to convince doctors about the link between their symptoms and this, or just for their own education. Summaries are fine since I guess we can't get access to the full articles but maybe a summary is enough.

[Guest Alex]

Hey Foggy,

here are "a few" articles that you may be interested in. they are only about SFN, I'll keep looking for more specific articles on POTS/CFS and SFN

Also, the first articles I listed are available in full text.

Enjoy,

Alex

http://brain.oxfordjournals.org/content/131/7/1912.abstract?ijkey=84f5b1d9a62f24c3aab43da4ee4eb5c7be3eeb9b&keytype2=tf_ipsecsha

The diagnostic criteria for small fibre neuropathy: from symptoms to neuropathology

http://www.bmctoday.net/practicalneurology/2009/10/article.asp?f=PN1009_06.php#

Diagnosing Small Fiber Neuropathy Through the Use of Skin Biopsy

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

Small fiber neuropathy: A burning problem

http://www.neuro.org.tw/magz/doc/N201072314349_19-2%20ra.pdf

Pathology and Functional Diagnosis of Small-fiber Painful Neuropathy

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3086960/

Diagnosis and Treatment of Pain in Small Fiber Neuropathy

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3543903/?report=classic

Autonomic Function Tests: Some Clinical Applications

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054760 A Human Model of Small Fiber Neuropathy to Study Wound Healing

http://www.ncbi.nlm.nih.gov/pubmed/23649502

Contribution of QSART to the diagnosis of small fiber neuropathy.

Abstract

Introduction We evaluated incorporation of quantitative sudomotor axon reflex test (QSART) into diagnostic criteria for small fiber neuropathy (SFN) as an addition to quantitative sensory testing (QST) and intraepidermal nerve fiber density (IENFD). Methods 101 patients with clinically suspected SFN underwent QSART, QST, and skin biopsy. The diagnostic yield of existing SFN criteria in these patients was compared to criteria incorporating QSART. The new combined diagnostic criteria were evaluated. Results SFN was diagnosed in 38/101 patients (38%) using current criteria. Addition of QSART to existing SFN criteria resulted in an increased diagnostic yield of 67/101(66%). Applying new SFN criteria requiring abnormality in at least 2 assessments among QSART, QST, and IENFD resulted in a diagnosis of SFN in 57/101 (56%). Discussion Assessment of both somatic and peripheral autonomic small nerve fibers enhances diagnostic criteria for SFN.

http://www.ncbi.nlm.nih.gov/pubmed/23553795

The utility of skin biopsy in management of small fiber neuropathy.

Abstract

Introduction: We examined the role of skin biopsy in the evaluation and management of patients with suspected small fiber neuropathy (SFN). Methods: A retrospective chart review was performed among all patients who underwent skin biopsy for evaluation of SFN at our institution between March, 2008 and March, 2011. Change in management was defined as a new diagnosis or change in treatment in response to both positive and negative skin biopsies. Results: Among 69 patients who underwent skin biopsy, 25 had pathological evidence of an SFN, and 9 had evidence of a borderline SFN. Change in management or diagnosis occurred in 14 of 25 patients with definite SFN, 6 of 9 patients with borderline SFN, and 16 of 35 biopsy negative patients. Conclusions: Skin biopsy changed management or diagnosis in 52% of patients evaluated for a possible SFN and appears to play a valuable role in the workup of these patients.

http://www.ncbi.nlm.nih.gov/pubmed/23551367

Neuropathic itch: diagnosis and management.

Abstract

Chronic pruritus (CP) is a frequent symptom in the general population; in 8% of all patients, it has a neuropathic origin. CP is of neuropathic origin when nerve fiber damage is responsible for the symptom. The damage can be caused by compression or degeneration of the nerve fibers in the skin or extracutaneous in peripheral nerves or the central nervous system. There are significant differences in the pathogenesis and in the clinical presentation of neuropathic CP. Localized neuropathic CP such as brachioradial pruritus or notalgia paresthetica are due to a circumscribed nerve compression and are often limited on the corresponding dermatome. In contrast, generalized neuropathic CP, as in small fiber neuropathies, may be associated with a systemic or metabolic underlying disease. It is not always easy to establish the diagnosis because a variety of diseases can be responsible for this type of CP. The present study shows an overview of possible diseases, diagnostic tools, and the relevant therapy strategies

http://www.ncbi.nlm.nih.gov/pubmed/23279431

Skin biopsy in painful and immune-mediated neuropathies.

Abstract

Starting from the original studies of the 19th century, this review covers some of the advances achieved over the last 15 years since skin biopsy has become a diagnostic tool for neurologists. In a relatively short period of time, focused works demonstrated the correlation between the loss of intraepidermal nerve fibers (IENF) and symptoms and signs of small fiber neuropathy (SFN), and provided standardized protocols for nerve morphometry as well as normative reference values to be used in clinical practice. This contributed to the definition of the diagnostic criteria for SFN that is now recognized as a distinct nosologic entity. The relationship between IENF degeneration and neuropathic pain led to the recent discovery that SFN can be caused by mutations in sodium channels, providing evidence for a new diagnostic approach to the etiology of the disease in patients. The presence of myelinated nerve fibers in the dermis prompted studies focused on demyelinating neuropathies of genetic and immune-mediated origin. Specific changes in dermal myelinated nerves have been described suggesting a potential role for skin biopsy also in these fields. Finally, studies on the sequence of events occurring after nerve degeneration in experimental models and patients with chronic neuropathies allowed to understand better the ability of skin nerves to regenerate and the reasons for its failure, providing important hints for the use of skin biopsy as an outcome measure in clinical practice and neuroprotective trials.

http://www.ncbi.nlm.nih.gov/pubmed/17565534

Evaluation of cutaneous autonomic innervation in idiopathic sensory small-fiber neuropathy.

Abstract

To evaluate the loss of autonomic nerve fibers in patients with clinical pure small-fiber sensory neuropathy, we performed skin punch biopsies in 17 and 15 age- and sex-matched controls. Biopsies were taken 10 cm above the lateral malleolus, and 5-mum sections were stained with hematoxylin and eosin and the panaxonal marker protein gene product (PGP) 9.5. Positively stained fibers, represented as dots, innervating the erector pili muscles, arterioles, and sweat glands (SG) were counted. The ratios between the number of nerve fibers and nuclei of each structure were calculated. The autonomic innervation was significantly reduced in the patients' group compared with controls in all the examined autonomic-innervated structures: SG (0.27 +/- 0.15 vs. 0.66 +/- 0.37, p = 0.001), arterioles (0.38 +/- 0.32 vs. 0.86 +/- 0.45, p=0.002), and the erector pili muscle (0.58 +/- 0.27 vs. 1.23 +/- 0.87, p = 0.036). Our results suggest that autonomic involvement occurs in patients with sensory small-fiber neuropathy and that punch skin biopsy using thin sections is a simple and convenient method to detect these dermal autonomic small-fiber abnormalities.

http://www.ncbi.nlm.nih.gov/pubmed/16434668

The utility of skin biopsy for prediction of progression in suspected small fiber neuropathy.

Abstract

Twenty-eight patients with sensory complaints of unknown etiology had repeated skin biopsies. Patients with large nerve fiber swellings on initial biopsy showed a decline in epidermal nerve fiber density on repeated biopsies (p < 0.05 within group; p < 0.05 vs those without swellings). Patients without nerve fiber swellings did not have changes in nerve fiber density between biopsies. Patients with large nerve fiber swellings were most likely to present clinically with paresthesias (p < 0.05).

http://www.ncbi.nlm.nih.gov/pubmed/6316835

Quantitative sudomotor axon reflex test in normal and neuropathic subjects.

Abstract

We have quantified postganglionic sweat output in human subjects resulting from axon reflex stimulation using acetylcholine electrophoresis. Dehumidified nitrogen of controlled temperature and flow rate was passed through an acrylic plastic chamber placed over a defined area of skin. Sweat droplets were evaporated; humidity change was sensed by a narrow-range humidity sensor housed in a temperature-controlled compartment and was plotted on a chart recorder. The time integral (area under the curve) was continuously integrated and converted to absolute units using a derived equation. Because stimulation and recording were simultaneous, an accurate determination of the latency of the sweat response was also possible. Quantitative sudomotor axon reflex tests were performed on the left forearm and foot of 33 female and 29 male normal subjects aged 11 to 69 years. Acetylcholine, 10%, was electrophoresed for 5 mA-minutes in the forearm and 10 mA-minutes in the foot, and recording was continued for an additional 5 minutes. The mean sweat output in males was 2.7 and 3.0 times that in females in forearm and foot, respectively (p less than 0.0001). Studies in selected autonomic neuropathies confirm that quantitative sudomotor axon reflex tests will detect postganglionic sudomotor abnormalities sensitively and reproducibly.

http://www.ncbi.nlm.nih.gov/pubmed/12210380

Small-fiber neuropathy.

Abstract

Small-fiber neuropathy is a common disorder. It is often "idiopathic" and typically presents with painful feet in patients over the age of 60. Autoimmune mechanisms are often suspected, but rarely identified. Known causes of small-fiber neuropathy include diabetes mellitus, amyloidosis, toxins, and inherited sensory and autonomic neuropathies. Occasionally, small-fiber neuropathy is diffuse or multifocal. Depending on the type of small-fiber neuropathy, autonomic dysfunction can be significant or subclinical. Diagnosis is made on the basis of the clinical features, normal nerve conduction studies, and abnormal specialized tests of small-fiber function. These specialized studies include assessment of epidermal nerve fiber density as well as sudomotor, quantitative sensory, and cardiovagal testing. The sensitivities of these tests range from 59-88%. Each has certain advantages and disadvantages, and the tests may be complementary. Unless an underlying disease is identified, treatment is usually directed toward alleviation ofneuropathic pain.

http://www.ncbi.nlm.nih.gov/pubmed/15546602?dopt=Abstract

Small fiber neuropathy: a common and important clinical disorder.

Abstract

Small fiber neuropathy (SFN) is a neuropathy selectively involving small diameter myelinated and unmyelinated nerve fibers. Interest in this disorder has considerably increased during the past few years. It is often idiopathic and typically presents with peripheral pain and/or symptoms of autonomic dysfunction. Diagnosis is made on the basis of the clinical features, normal nerve conduction studies (NCS) and abnormal specialized tests of small nerve fibers. Among others, these tests include assessment of epidermal nerve fiber density, temperature sensation tests for sensory fibers andsudomotor and cardiovagal testing (QSART) for autonomic fibers. Unless an underlying disease is identified, treatment is usually symptomatic and directed towards alleviation of neuropathic pain.

[davecom]

Alex, you are a saint and a such a valuable resource.

[Guest Alex]

Thanks Dave, you're too kind.

Alex

[Foggy01]

Thanks Alex so much!

[Guest Alex]

bump