scholarly journals Current View of Diagnosing Small Fiber Neuropathy

2020 ◽  
pp. 1-23
Author(s):  
Lisette Raasing ◽  
Oscar Vogels ◽  
Marcel Veltkamp ◽  
Christiaan van Swol ◽  
Jan Grutters
Keyword(s):  
Small Fiber Neuropathy ◽  
Diagnostic Methods ◽  
Work Flow ◽  
Current View ◽  
C Fibers ◽  
Small Fiber ◽  
Sensory Changes ◽  
Diagnostic Work ◽  
Sensory Fibers

Small fiber neuropathy (SFN) is a disorder of the small myelinated Aδ-fibers and unmyelinated C-fibers [5, 6]. SFN might affect small sensory fibers, autonomic fibers or both, resulting in sensory changes, autonomic dysfunction or combined symptoms [7]. As a consequence, the symptoms are potentially numerous and have a large impact on quality of life [8]. Since diagnostic methods for SFN are numerous and its pathophysiology complex, this extensive review focusses on categorizing all aspects of SFN as disease and its diagnosis. In this review, sensitivity in combination with specificity of different diagnostic methods are described using the areas under the curve. In the end, a diagnostic work-flow is suggested based on different phenotypes of SFN.

scholarly journals Long-Time Course of Idiopathic Small Fiber Neuropathy

2018 ◽  
Vol 79 (3-4) ◽  
pp. 161-165 ◽  
Author(s):  
Pia Flossdorf ◽  
Walter F. Haupt ◽  
Anna Brunn ◽  
Martina Deckert ◽  
Gereon R. Fink ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Time Course ◽  
Benign Disease ◽  
Small Fiber Neuropathy ◽  
Disease Course ◽  
Peripheral Neuropathies ◽  
Small Fiber ◽  
Long Time ◽  
Large Fiber

Background: Small fiber neuropathy (SFN) is a challenging subtype of peripheral neuropathies. Once the diagnosis has been established, there is an uncertainty how SFN may progress, whether larger fibers will become involved over time, whether quality of life may be compromised, or whether repeated diagnostic workup in patients with unknown underlying cause may increase the yield of treatable causes of SFN. Methods: We evaluated 16 patients with documented long-time course of idiopathic SFN. Results: Clinical and electrophysiological course remained stable in 75% of the patients, while 25% SFN-patients developed large fiber neuropathies. Conclusions: Our data suggest that SFN represents a benign disease course in the majority of patients without severely limiting the quality of life.

Small Fiber Neuropathy

2019 ◽  
Vol 39 (05) ◽  
pp. 570-577 ◽  
Author(s):  
Lan Zhou
Keyword(s):  
Skin Biopsy ◽  
Lifestyle Modification ◽  
Specific Treatment ◽  
Small Fiber Neuropathy ◽  
Fiber Density ◽  
Small Fiber ◽  
Intraepidermal Nerve Fiber Density ◽  
Associated Conditions ◽  
Density Evaluation

AbstractSmall fiber neuropathy (SFN) is common, and can be associated with many medical conditions. The majority of the patients with SFN suffer from painful paresthesia which can negatively impact their quality of life. Skin biopsy with intraepidermal nerve fiber density evaluation is the gold standard diagnostic test. Autonomic function testing is useful when autonomic symptoms are present. Screening for associated conditions should be done in every patient, even when a known underlying associated condition is present, before the neuropathy evaluation. Etiology-specific treatment, lifestyle modification, and pain control are the key elements of SFN management. This article will review the clinical presentation, skin biopsy procedure, utility of diagnostic tests, associated conditions, management, and prognosis of SFN.

scholarly journals A Systematic Review of the Diagnostic Methods of Small Fiber Neuropathies in Rehabilitation

Diagnostics ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 613
Author(s):  
Rita Chiaramonte ◽  
Marcello Romano ◽  
Michele Vecchio
Keyword(s):  
Systematic Review ◽  
Small Fiber Neuropathy ◽  
Diagnostic Methods ◽  
Cochrane Library ◽  
Diagnostic Tools ◽  
Exclusion Criteria ◽  
Diagnostic Measures ◽  
Small Fiber ◽  
Diagnostic Approaches ◽  
English Articles

This systematic review describes the several methods to diagnose and measure the severity of small fiber neuropathies and aims to guide the physician to define all the diagnostic approaches for adopting the best strategies described in the current literature. The search was conducted in PubMed, EMBASE, Cochrane Library and Web of Science. Two reviewers independently reviewed and came to consensus on which articles met inclusion/exclusion criteria. The authors excluded all the duplicates, animals’ studies, and included the English articles in which the diagnostic measures were finalized to assess the effectiveness of rehabilitation and pharmacologic treatment of patients with small fiber neuropathies. The search identified a total of 975 articles with the keywords “small fiber neuropathy” AND “rehabilitation” OR “therapy” OR “treatment”. Seventy-eight selected full-text were analyzed by the reviewers. Forty-one publications met the inclusion criteria and were included in the systematic review. Despite the range of diagnostic tools for the assessment of small fiber neuropathy, other robust trials are needed. In addition, always different diagnostic approaches are used, a unique protocol could be important for the clinicians. More research is needed to build evidence for the best diagnostic methodologies and to delineate a definitive diagnostic protocol.

Case 77: Painful Small Fiber Neuropathy in Posttreatment Lyme Disease Syndrome

2019 ◽  
pp. 390-393
Author(s):  
Peter Novak
Keyword(s):  
Lyme Disease ◽  
Orthostatic Hypotension ◽  
Autonomic Failure ◽  
Small Fiber Neuropathy ◽  
Cerebral Hypoperfusion ◽  
Supine Hypertension ◽  
Autonomic Testing ◽  
Small Fiber ◽  
Immune Globulins ◽  
Sensory Fibers

This case illustrates autonomic failure in painful post-Lyme disease syndrome. Autonomic testing has shown supine hypertension, orthostatic hypotension, and hypocapnic cerebral hypoperfusion (HYCH). Small fiber neuropathy was painful, affecting sensory fibers. Patient noted improvement in the pain by about 40% after 12 month of intravenous immune globulins.

Case 62: Small Fiber Neuropathy with Symptomatic Improvement on Immune Globulins

2019 ◽  
pp. 328-331
Author(s):  
Peter Novak
Keyword(s):  
Symptomatic Improvement ◽  
Small Fiber Neuropathy ◽  
Fiber Density ◽  
Autonomic Testing ◽  
Small Fiber ◽  
Epidermal Nerve Fiber Density ◽  
Immune Globulins ◽  
Sensory Fibers ◽  
Nerve Fiber Density ◽  
Epidermal Nerve Fiber

Autonomic testing revealed length-dependent small fiber neuropathy affecting sensory fibers. Repeated titer of acetylcholine ganglionic antibody was negative, but repeated epidermal nerve fiber density testing showed progressive deterioration. Symptoms improved with intravenous immune globulin therapy.

scholarly journals Definition and diagnosis of small fiber neuropathy: consensus from the Peripheral Neuropathy Scientific Department of the Brazilian Academy of Neurology

2018 ◽  
Vol 76 (3) ◽  
pp. 200-208 ◽  
Author(s):  
Francisco de Assis Aquino Gondim ◽  
Amilton Antunes Barreira ◽  
Rinaldo Claudino ◽  
Márcia Waddington Cruz ◽  
Francisco Marcos Bezerra da Cunha ◽  
...  
Keyword(s):  
Peripheral Neuropathy ◽  
Neurological Examination ◽  
Normal Values ◽  
Small Fiber Neuropathy ◽  
Manuscript Submission ◽  
Small Fiber ◽  
Sensory Fibers ◽  
The City ◽  
Preliminary Draft

ABSTRACT The aim of this study was to describe the results of a Brazilian Consensus on Small Fiber Neuropathy (SFN). Fifteen neurologists (members of the Brazilian Academy of Neurology) reviewed a preliminary draft. Eleven panelists got together in the city of Fortaleza to discuss and finish the text for the manuscript submission. Small fiber neuropathy can be defined as a subtype of neuropathy characterized by selective involvement of unmyelinated or thinly myelinated sensory fibers. Its clinical picture includes both negative and positive manifestations: sensory (pain/dysesthesias/pruritus) or combined sensory and autonomic complaints, associated with an almost entirely normal neurological examination. Standard electromyography is normal. A growing list of medical conditions is associated with SFN. The classification of SFN may also serve as a useful terminology to uncover minor discrepancies in the normal values from different neurophysiology laboratories. Several techniques may disclose sensory and/or autonomic impairment. Further studies are necessary to refine these techniques and develop specific therapies.

scholarly journals A novel gain-of-function sodium channel β2 subunit mutation in idiopathic small fiber neuropathy

2021 ◽  
Author(s):  
Matthew Alsaloum ◽  
Julie I. R. Labau ◽  
Daniel Sosniak ◽  
Peng Zhao ◽  
Rowida Almomani ◽  
...  
Keyword(s):  
Action Potential ◽  
Sodium Channel ◽  
Small Fiber Neuropathy ◽  
Dorsal Root Ganglion Neurons ◽  
Action Potential Firing ◽  
Gain Of Function ◽  
C Fibers ◽  
Small Fiber ◽  
Potential Firing ◽  
Ganglion Neurons

Small fiber neuropathy (SFN) is a common condition affecting thinly myelinated Aδ and unmyelinated C fibers, often resulting in excruciating pain and dysautonomia. SFN has been associated with several conditions, but a significant number of cases have no discernible cause. Recent genetic studies have identified potentially pathogenic gain-of-function mutations in several the pore-forming voltage-gated sodium channel α subunits (NaVs) in a subset of patients with SFN, but the auxiliary sodium channel β subunits have been less implicated in the development of the disease. β subunits modulate NaV trafficking and gating, and several mutations have been linked to epilepsy and cardiac dysfunction. Recently, we provided the first evidence for the contribution of a mutation in the β2-subunit to pain in human painful diabetic neuropathy. Here, we provide the first evidence for the involvement of a sodium channel β subunit mutation in the pathogenesis of SFN with no other known causes. We show, through current-clamp analysis, that the newly-identified Y69H variant of the β2 subunit induces neuronal hyperexcitability in dorsal root ganglion neurons, lowering the threshold for action potential firing and allowing for increased repetitive action potential spiking. Underlying the hyperexcitability induced by the β2-Y69H variant, we demonstrate an upregulation in tetrodotoxin-sensitive, but not tetrodotoxin-resistant sodium currents. This provides the first evidence for the involvement of β2 subunits in SFN and strengthens the link between sodium channel β subunits and the development of neuropathic pain in humans.

scholarly journals C-Fiber Loss as a Possible Cause of Neuropathic Pain in Schwannomatosis

2020 ◽  
Vol 21 (10) ◽  
pp. 3569
Author(s):  
Said Farschtschi ◽  
Tina Mainka ◽  
Markus Glatzel ◽  
Anna-Lena Hannekum ◽  
Michael Hauck ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Magnetic Resonance ◽  
Pain Perception ◽  
Small Fiber Neuropathy ◽  
Neurological Deficits ◽  
Whole Body ◽  
Magnetic Resonance Neurography ◽  
Nerve Lesions ◽  
C Fibers ◽  
Small Fiber

Schwannomatosis is the third form of neurofibromatosis and characterized by the occurrence of multiple schwannomas. The most prominent symptom is chronic pain. We aimed to test whether pain in schwannomatosis might be caused by small-fiber neuropathy. Twenty patients with schwannomatosis underwent neurological examination and nerve conduction studies. Levels of pain perception as well as anxiety and depression were assessed by established questionnaires. Quantitative sensory testing (QST) and laser-evoked potentials (LEP) were performed on patients and controls. Whole-body magnetic resonance imaging (wbMRI) and magnetic resonance neurography (MRN) were performed to quantify tumors and fascicular nerve lesions; skin biopsies were performed to determine intra-epidermal nerve fiber density (IENFD). All patients suffered from chronic pain without further neurological deficits. The questionnaires indicated neuropathic symptoms with significant impact on quality of life. Peripheral nerve tumors were detected in all patients by wbMRI. MRN showed additional multiple fascicular nerve lesions in 16/18 patients. LEP showed significant faster latencies compared to normal controls. Finally, IENFD was significantly reduced in 13/14 patients. Our study therefore indicates the presence of small-fiber neuropathy, predominantly of unmyelinated C-fibers. Fascicular nerve lesions are characteristic disease features that are associated with faster LEP latencies and decreased IENFD. Together these methods may facilitate differential diagnosis of schwannomatosis.

Small fibers, large impact: Quality of life in small-fiber neuropathy

2013 ◽  
Vol 49 (3) ◽  
pp. 329-336 ◽  
Author(s):  
Mayienne Bakkers ◽  
Catharina G. Faber ◽  
Janneke G.J. Hoeijmakers ◽  
Giuseppe Lauria ◽  
Ingemar S.J. Merkies
Keyword(s):  
Quality Of Life ◽  
Small Fiber Neuropathy ◽  
Large Impact ◽  
Small Fiber
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