scholarly journals Small Fiber Neuropathy in Pulmonary Sarcoidosis and Tuberculosis: Clinical and Histological Correlates

2020 ◽  
Author(s):  
Anna Starshinova ◽  
Natalia Basantsova ◽  
Yulia Zinchenko ◽  
Valeria Shapkina ◽  
Anna Malkova ◽  
...  

Abstract Sarcoidosis (SC) is the granulomatous disease of an unknown origin, where the differential diagnosis with tuberculosis (TB) is challenging and vital for patients’ prognosis. The common neurological complication in SC is a small fiber neuropathy (SFN), that is considered to be the result of the chronic inflammation, and remains significantly understudied. There is no reliable data, whether such complication is observed in TB patients, where the systemic inflammation is also described. Aim: To identify the clinical and histological correlates of the small fiber neuropathy in sarcoidosis and tuberculosis patients.Materials and methods. A study was performed in 2018 – 2019 years and included 71 patients with pulmonary sarcoidosis (n=25), pulmonary tuberculosis (n=21), and healthy subjects (n=25). For the clinical verification of the SFN, the “Small fiber neuropathy screening list” (SFN-SL) was used. A punch biopsy of the skin was performed followed by the enzyme immunoassay analysis with PGP 9.5 antibodies.Results of the study: Up to 60% of sarcoidosis patients and 19% tuberculosis patients report the presence of at least one complaint, which may be associated with SFN. The most frequent complaints included dysfunctions of the cardiovascular, musculoskeletal system and gastrointestinal tract. A negative, statistically significant correlation between the intraepidermal nerve fiber density (IEND) and SFN-SL score was revealed in both groups (Spearman coefficient, r = -0.3508, p = 0.0102, and r = -0.7382, p = 0.0064, respectively). Wherein, the density of small nerve fibers in the patients with pulmonary sarcoidosis was lower, compared to the patients with tuberculosis (Mann-Whitney test, p = 0.0047). Conclusion: In patients with pulmonary sarcoidosis, small fiber neuropathy may develop as a result of systemic immune-mediated inflammation. The most common symptoms of this complication were dysautonomia and mild sensory dysfunction. Wherein, in tuberculosis patients clinical and histological symptoms of the small fiber neuropathy were subsequently less prominent, which may represent the difference between the autoimmune and bacterial inflammation. The validated questionnaires and histologic verification of the diagnosis help to establish the severity of neuropathy of small fibers, to determine the prognosis, to plan the treatment strategн, and also may allude the possibility for the additional criteria of differential diagnosis between two diseases.

2021 ◽  
Vol 28 (4) ◽  
pp. 544-550
Author(s):  
Natalia Gavrilova ◽  
Anna Starshinova ◽  
Yulia Zinchenko ◽  
Dmitry Kudlay ◽  
Valeria Shapkina ◽  
...  

Sarcoidosis (SC) is a granulomatous disease of an unknown origin. The most common SC-related neurological complication is a small fiber neuropathy (SFN) that is often considered to be the result of chronic inflammation and remains significantly understudied. This study aimed to identify the clinical and histological correlates of small fiber neuropathy in sarcoidosis patients. The study was performed in 2018–2019 yy and included 50 patients with pulmonary sarcoidosis (n = 25) and healthy subjects (n = 25). For the clinical verification of the SFN, the “Small Fiber Neuropathy Screening List” (SFN-SL) was used. A punch biopsy of the skin was performed followed by enzyme immunoassay analysis with PGP 9.5 antibodies. Up to 60% of the sarcoidosis patients reported the presence of at least one complaint, and it was possible that these complaints were associated with SFN. The most frequent complaints included dysfunctions of the cardiovascular and musculoskeletal systems and the gastrointestinal tract. A negative, statistically significant correlation between the intraepidermal nerve fiber density (IEND) and SFN-SL score was revealed. In patients with pulmonary sarcoidosis, small fiber neuropathy might develop as a result of systemic immune-mediated inflammation. The most common symptoms of this complication were dysautonomia and mild sensory dysfunction.


Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 536
Author(s):  
Mary A. Kelley ◽  
Kevin V. Hackshaw

Small fiber neuropathy (SFN) is a type of peripheral neuropathy that occurs from damage to the small A-delta and C nerve fibers that results in the clinical condition known as SFN. This pathology may be the result of metabolic, toxic, immune-mediated, and/or genetic factors. Small fiber symptoms can be variable and inconsistent and therefore require an objective biomarker confirmation. Small fiber dysfunction is not typically captured by diagnostic tests for large-fiber neuropathy (nerve conduction and electromyographic study). Therefore, skin biopsies stained with PGP 9.5 are the universally recommended objective test for SFN, with quantitative sensory tests, autonomic function testing, and corneal confocal imaging as secondary or adjunctive choices. Fibromyalgia (FM) is a heterogenous syndrome that has many symptoms that overlap with those found in SFN. A growing body of research has shown approximately 40–60% of patients carrying a diagnosis of FM have evidence of SFN on skin punch biopsy. There is currently no clearly defined phenotype in FM at this time to suggest whom may or may not have SFN, though research suggests it may correlate with severe cases. The skin punch biopsy provides an objective tool for use in quantifying small fiber pathology in FM. Skin punch biopsy may also be repeated for surveillance of the disease as well as measuring response to treatments. Evaluation of SFN in FM allows for better classification of FM and guidance for patient care as well as validation for their symptoms, leading to better use of resources and outcomes.


2021 ◽  
Vol 14 ◽  
pp. 175628642110043
Author(s):  
Nadine Egenolf ◽  
Caren Meyer zu Altenschildesche ◽  
Luisa Kreß ◽  
Katja Eggermann ◽  
Barbara Namer ◽  
...  

Background and aims: Small fiber neuropathy (SFN) is increasingly suspected in patients with pain of uncertain origin, and making the diagnosis remains a challenge lacking a diagnostic gold standard. Methods: In this case–control study, we prospectively recruited 86 patients with a medical history and clinical phenotype suggestive of SFN. Patients underwent neurological examination, quantitative sensory testing (QST), and distal and proximal skin punch biopsy, and were tested for pain-associated gene loci. Fifty-five of these patients additionally underwent pain-related evoked potentials (PREP), corneal confocal microscopy (CCM), and a quantitative sudomotor axon reflex test (QSART). Results: Abnormal distal intraepidermal nerve fiber density (IENFD) (60/86, 70%) and neurological examination (53/86, 62%) most frequently reflected small fiber disease. Adding CCM and/or PREP further increased the number of patients with small fiber impairment to 47/55 (85%). Genetic testing revealed potentially pathogenic gene variants in 14/86 (16%) index patients. QST, QSART, and proximal IENFD were of lower impact. Conclusion: We propose to diagnose SFN primarily based on the results of neurological examination and distal IENFD, with more detailed phenotyping in specialized centers.


2019 ◽  
Vol 39 (05) ◽  
pp. 570-577 ◽  
Author(s):  
Lan Zhou

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.


Pain Medicine ◽  
2016 ◽  
Vol 17 (8) ◽  
pp. 1569-1571 ◽  
Author(s):  
Yefim Cavalier ◽  
Phillip J. Albrecht ◽  
Colum Amory ◽  
Gary L. Bernardini ◽  
Charles E. Argoff

Diabetes Care ◽  
2004 ◽  
Vol 27 (8) ◽  
pp. 1974-1979 ◽  
Author(s):  
G. L. Pittenger ◽  
M. Ray ◽  
N. I. Burcus ◽  
P. McNulty ◽  
B. Basta ◽  
...  

2015 ◽  
Vol 114 (3) ◽  
pp. 1554-1564 ◽  
Author(s):  
M. Estacion ◽  
B. P. S Vohra ◽  
S. Liu ◽  
J. Hoeijmakers ◽  
C. G. Faber ◽  
...  

Gain-of-function missense mutations in voltage-gated sodium channel Nav1.7 have been linked to small-fiber neuropathy, which is characterized by burning pain, dysautonomia and a loss of intraepidermal nerve fibers. However, the mechanistic cascades linking Nav1.7 mutations to axonal degeneration are incompletely understood. The G856D mutation in Nav1.7 produces robust changes in channel biophysical properties, including hyperpolarized activation, depolarized inactivation, and enhanced ramp and persistent currents, which contribute to the hyperexcitability exhibited by neurons containing Nav1.8. We report here that cell bodies and neurites of dorsal root ganglion (DRG) neurons transfected with G856D display increased levels of intracellular Na+ concentration ([Na+]) and intracellular [Ca2+] following stimulation with high [K+] compared with wild-type (WT) Nav1.7-expressing neurons. Blockade of reverse mode of the sodium/calcium exchanger (NCX) or of sodium channels attenuates [Ca2+] transients evoked by high [K+] in G856D-expressing DRG cell bodies and neurites. We also show that treatment of WT or G856D-expressing neurites with high [K+] or 2-deoxyglucose (2-DG) does not elicit degeneration of these neurites, but that high [K+] and 2-DG in combination evokes degeneration of G856D neurites but not WT neurites. Our results also demonstrate that 0 Ca2+ or blockade of reverse mode of NCX protects G856D-expressing neurites from degeneration when exposed to high [K+] and 2-DG. These results point to [Na+] overload in DRG neurons expressing mutant G856D Nav1.7, which triggers reverse mode of NCX and contributes to Ca2+ toxicity, and suggest subtype-specific blockade of Nav1.7 or inhibition of reverse NCX as strategies that might slow or prevent axon degeneration in small-fiber neuropathy.


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