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Hoeijmakers JG, Faber CG, Lauria G, Merkies IS, Waxman SG. Small-fibre neuropathies—advances in diagnosis, pathophysiology and management. Nat Rev Neurol 2012; 8:369-79. [DOI: 10.1038/nrneurol.2012.97] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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102
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Nitoda E, Kallinikos P, Pallikaris A, Moschandrea J, Amoiridis G, Ganotakis ES, Tsilimbaris M. Correlation of diabetic retinopathy and corneal neuropathy using confocal microscopy. Curr Eye Res 2012; 37:898-906. [PMID: 22632054 DOI: 10.3109/02713683.2012.683507] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE/AIM To employ corneal confocal microscopy to assess differences in the extent of corneal nerve fiber alterations between diabetic patients classed according to retinopathy status and nondiabetic patients. MATERIALS AND METHODS Two hundred seventy-eight corneas of 139 patients with type 2 diabetes mellitus and 94 corneas of 47 age-matched control participants were scanned using corneal confocal microscopy. Images of the subbasal nerve plexus were collected and analyzed for nerve fiber density (NFD), nerve branch density (NBD), nerve fiber length (NFL), and nerve fiber tortuosity (NFT). Diabetic patients were categorized into three groups according to the classification of diabetic retinopathy (DR) proposed in the Early Treatment of Diabetic Retinopathy Study, based on indirect fundoscopy, fundus photography, and fluorescein angiography findings. A separate classification into four groups according to the severity of peripheral diabetic neuropathy (DN) was also used, based on the results of clinical and electrodiagnostic examinations. RESULTS Average NFD, NBD, and NFL differed significantly according to DR status and were found to be lower, whereas NFT was found to be higher in diabetic patients than control participants. A positive correlation between diabetic corneal neuropathy and peripheral DN was also found. CONCLUSIONS Nerve fiber alterations of the subbasal nerve plexus of diabetic corneas appear to progress in parallel with DR and peripheral DN. Corneal confocal microscopy could possibly represent a promising adjuvant technique for the early diagnosis and assessment of human DN.
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Affiliation(s)
- E Nitoda
- Department of Ophthalmology, University of Crete, Heraklion, Greece
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103
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Abstract
PURPOSE OF REVIEW This review discusses the literature on Fabry disease mainly in the domain of neurology with special attention to recent advancement. RECENT FINDINGS Fabry neuropathy is known as a length-dependent peripheral neuropathy affecting mainly the small myelinated (Aδ) fibers and unmyelinated (C) fibers. Recently, concerning heterozygotes, it seems that they suffer from peripheral neuropathy at a higher rate than previously shown, significant multisystemic disease, and severely decreased quality of life. The existence of an atypical variant of Fabry disease with late-onset cerebrovascular disease (cerebrovascular variant) is now suggested, like the cardiac and renal variants of Fabry disease. Although enzyme replacement therapy (ERT) has been shown to have some positive effects on reduction of neuropathic pain, the improvement of detection threshold for thermal sensation and sweat function, the effect of ERT on the central nervous system has not been established. Gene replacement therapy, chemical chaperone therapy, and ERT using modified α-N-acetylgalactosaminidase are in progress, and induced pluripotent stem cells were generated from mouse models of Fabry disease. SUMMARY Heterozygotes should be carefully monitored for precise estimation and adequate therapy. Early initiation of ERT before irreversible organ failure is most important, and alternative therapeutic approaches are currently being explored.
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Üçeyler N, He L, Schönfeld D, Kahn AK, Reiners K, Hilz MJ, Breunig F, Sommer C. Small fibers in Fabry disease: baseline and follow-up data under enzyme replacement therapy. J Peripher Nerv Syst 2011; 16:304-14. [DOI: 10.1111/j.1529-8027.2011.00365.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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105
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Malik RA, Veves A, Tesfaye S, Smith G, Cameron N, Zochodne D, Lauria G. Small fibre neuropathy: role in the diagnosis of diabetic sensorimotor polyneuropathy. Diabetes Metab Res Rev 2011; 27:678-84. [PMID: 21695760 DOI: 10.1002/dmrr.1222] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 06/06/2011] [Indexed: 12/15/2022]
Abstract
Small fibres constitute 70-90% of peripheral nerve fibres and regulate several key functions such as tissue blood flow, temperature and pain perception as well as sweating, all of which are highly relevant to the clinical presentation and adverse outcomes associated with foot ulcerations in patients with diabetes. Recent studies demonstrated significant abnormalities in the small fibres in subjects with impaired glucose tolerance and diabetes, despite normal electrophysiology, suggesting that the earliest nerve fibre damage is to the small fibres. Unfortunately, guidelines and consensus statements focus on large fibres and continue to advocate electrophysiology as a diagnostic modality and as a primary end point for the assessment of therapeutic benefit. (In part, this reflects the difficulties in quantifying small fibre dysfunction and damage.) We have therefore critically assessed currently available techniques that measure small fibre dysfunction in diabetic neuropathy, using quantitative sensory and sudomotor testing. We have assessed the role of identifying structural damage by quantifying intraepidermal nerve fibre density in skin biopsies and corneal nerve morphology using corneal confocal microscopy. Finally, we propose a definition for diabetic neuropathy that incorporates small fibre damage.
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Affiliation(s)
- R A Malik
- Division of Cardiovascular Medicine, University of Manchester, Manchester, UK.
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106
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Dabbah M, Graham J, Petropoulos I, Tavakoli M, Malik R. Automatic analysis of diabetic peripheral neuropathy using multi-scale quantitative morphology of nerve fibres in corneal confocal microscopy imaging. Med Image Anal 2011; 15:738-47. [DOI: 10.1016/j.media.2011.05.016] [Citation(s) in RCA: 163] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 04/22/2011] [Accepted: 05/25/2011] [Indexed: 01/18/2023]
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Abstract
Diabetic peripheral neuropathy (DPN) is a debilitating condition that affects about 50% of diabetic patients. The symptoms of DPN include numbness, tingling, or pain in the arms and legs. Patients with numbness may be unaware of foot trauma, which could develop into a foot ulcer. If left untreated, this may ultimately require amputation. Currently, the only method of directly examining peripheral nerves is to conduct skin punch or sural/peroneal nerve biopsies, which are uncomfortable and invasive. Indirect methods include quantitative sensory testing (assessing responses to heat, cold, and vibration) and nerve electrophysiology. Here, I describe research undertaken in my laboratory, investigating the possibility of using a range of ophthalmic markers to assess DPN. Corneal nerve structure and function can be assessed using corneal confocal microscopy and non-contact corneal esthesiometry, respectively. Retinal nerve structure and visual function can be evaluated using optical coherence tomography and perimetry, respectively. These techniques have been used to demonstrate that DPN is associated with morphological degradation of corneal nerves, reduced corneal sensitivity, retinal nerve fiber layer thinning, and peripheral visual field loss. With further validation, these ophthalmic markers could become established as rapid, painless, non-invasive, sensitive, reiterative, cost-effective, and clinically accessible means of screening for early detection, diagnosis, staging severity, and monitoring progression of DPN, as well as assessing the effectiveness of possible therapeutic interventions. Looking to the future, this research may pave the way for an expanded role for the ophthalmic professions in diabetes management.
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108
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Repeatability of measuring corneal subbasal nerve fiber length in individuals with type 2 diabetes. Eye Contact Lens 2011; 36:245-8. [PMID: 20724854 DOI: 10.1097/icl.0b013e3181eea915] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To analyze the repeatability of measuring nerve fiber length (NFL) from images of the human corneal subbasal nerve plexus using semiautomated software. METHODS Images were captured from the corneas of 50 subjects with type 2 diabetes mellitus who showed varying severity of neuropathy, using the Heidelberg Retina Tomograph 3 with Rostock Corneal Module. Semiautomated nerve analysis software was independently used by two observers to determine NFL from images of the subbasal nerve plexus. This procedure was undertaken on two occasions, 3 days apart. RESULTS The intraclass correlation coefficient values were 0.95 (95% confidence intervals: 0.92-0.97) for individual subjects and 0.95 (95% confidence intervals: 0.74-1.00) for observer. Bland-Altman plots of the NFL values indicated a reduced spread of data with lower NFL values. The overall spread of data was less for (a) the observer who was more experienced at analyzing nerve fiber images and (b) the second measurement occasion. CONCLUSIONS Semiautomated measurement of NFL in the subbasal nerve fiber layer is highly repeatable. Repeatability can be enhanced by using more experienced observers. It may be possible to markedly improve repeatability when measuring this anatomic structure using fully automated image analysis software.
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109
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Tavakoli M, Malik RA. Corneal confocal microscopy: a novel non-invasive technique to quantify small fibre pathology in peripheral neuropathies. J Vis Exp 2011:2194. [PMID: 21248693 DOI: 10.3791/2194] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The accurate quantification of peripheral neuropathy is important to define at risk patients, anticipate deterioration, and assess new therapies. Conventional methods assess neurological deficits and electrophysiology and quantitative sensory testing quantifies functional alterations to detect neuropathy. However, the earliest damage appears to be to the small fibres and yet these tests primarily assess large fibre dysfunction and have a limited ability to demonstrate regeneration and repair. The only techniques which allow a direct examination of unmyelinated nerve fibre damage and repair are sural nerve biopsy with electron microscopy and skin-punch biopsy. However, both are invasive procedures and require lengthy laboratory procedures and considerable expertise. Corneal Confocal microscopy is a non-invasive clinical technique which provides in-vivo imaging of corneal nerve fibres. We have demonstrated early nerve damage, which precedes loss of intraepidermal nerve fibres in skin biopsies together with stratification of neuropathic severity and repair following pancreas transplantation in diabetic patients. We have also demonstrated nerve damage in idiopathic small fibre neuropathy and Fabry's disease.
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Affiliation(s)
- Mitra Tavakoli
- Division of Cardiovascular Medicine, University of Manchester.
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110
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Abstract
PURPOSE OF REVIEW The present review focuses on recent developments in diagnosis and treatment of sensory neuropathies. It does not seek to establish a comprehensive classification of sensory neuropathies, nor treatment guidelines per se. RECENT FINDINGS Diagnostic criteria and guidelines have been developed for distal symmetric polyneuropathies, small fiber sensory neuropathies and sensory neuronopathies. Novel diagnostic tools such as skin biopsies now allow diagnosis of small fiber sensory neuropathies. Genetic testing has defined new subtypes of mitochondrial neuropathies and inherited neuropathies with sensory involvement. Intravenous immunoglobulin and tumor necrosis factor-alpha inhibitors show promise for some dysimmune sensory neuropathies or neuronopathies. Additional options for management of neuropathic pain are emerging. SUMMARY Diagnostic methods for both acquired and hereditary sensory neuropathies have progressed in recent years, leading to earlier and more specific diagnoses and a better understanding of disease mechanisms. Much progress remains to be made regarding symptomatic and disease-modifying therapy for a range of sensory neuropathies, including those due to diabetes, HIV infection and from dysimmune or hereditary causes.
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111
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Tavakoli M, Boulton AJM, Efron N, Malik RA. Increased Langerhan cell density and corneal nerve damage in diabetic patients: role of immune mechanisms in human diabetic neuropathy. Cont Lens Anterior Eye 2010; 34:7-11. [PMID: 20851037 DOI: 10.1016/j.clae.2010.08.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 08/13/2010] [Accepted: 08/17/2010] [Indexed: 12/23/2022]
Abstract
AIM/HYPOTHESIS Immune mechanisms have been proposed to play a role in the development of diabetic neuropathy. We employed in vivo corneal confocal microscopy (CCM) to quantify the presence and density of Langerhans cells (LCs) in relation to the extent of corneal nerve damage in Bowman's layer of the cornea in diabetic patients. METHODS 128 diabetic patients aged 58 ± 1 yrs with a differing severity of neuropathy based on Neuropathy Deficit Score (NDS-4.7 ± 0.28) and 26 control subjects aged 53 ± 3 yrs were examined. Subjects underwent a full neurological evaluation, evaluation of corneal sensation with non-contact corneal aesthesiometry (NCCA) and corneal nerve morphology using corneal confocal microscopy (CCM). RESULTS The proportion of individuals with LCs was significantly increased in diabetic patients (73.8%) compared to control subjects (46.1%), P = 0.001. Furthermore, LC density (no/mm(2)) was significantly increased in diabetic patients (17.73 ± 1.45) compared to control subjects (6.94 ± 1.58), P = 0.001 and there was a significant correlation with age (r = 0.162, P = 0.047) and severity of neuropathy (r = -0.202, P = 0.02). There was a progressive decrease in corneal sensation with increasing severity of neuropathy assessed using NDS in the diabetic patients (r = 0.414, P = 0.000). Corneal nerve fibre density (P < 0.001), branch density (P < 0.001) and length (P < 0.001) were significantly decreased whilst tortuosity (P < 0.01) was increased in diabetic patients with increasing severity of diabetic neuropathy. CONCLUSION Utilising in vivo corneal confocal microscopy we have demonstrated increased LCs in diabetic patients particularly in the earlier phases of corneal nerve damage suggestive of an immune mediated contribution to corneal nerve damage in diabetes.
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Affiliation(s)
- M Tavakoli
- Division of Cardiovascular Medicine, University of Manchester and Manchester Royal Infirmary, Manchester, M13 9NT, UK
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112
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Tavakoli M, Quattrini C, Abbott C, Kallinikos P, Marshall A, Finnigan J, Morgan P, Efron N, Boulton AJM, Malik RA. Corneal confocal microscopy: a novel noninvasive test to diagnose and stratify the severity of human diabetic neuropathy. Diabetes Care 2010; 33:1792-7. [PMID: 20435796 PMCID: PMC2909064 DOI: 10.2337/dc10-0253] [Citation(s) in RCA: 247] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The accurate quantification of human diabetic neuropathy is important to define at-risk patients, anticipate deterioration, and assess new therapies. RESEARCH DESIGN AND METHODS A total of 101 diabetic patients and 17 age-matched control subjects underwent neurological evaluation, neurophysiology tests, quantitative sensory testing, and evaluation of corneal sensation and corneal nerve morphology using corneal confocal microscopy (CCM). RESULTS Corneal sensation decreased significantly (P = 0.0001) with increasing neuropathic severity and correlated with the neuropathy disability score (NDS) (r = 0.441, P < 0.0001). Corneal nerve fiber density (NFD) (P < 0.0001), nerve fiber length (NFL), (P < 0.0001), and nerve branch density (NBD) (P < 0.0001) decreased significantly with increasing neuropathic severity and correlated with NDS (NFD r = -0.475, P < 0.0001; NBD r = -0.511, P < 0.0001; and NFL r = -0.581, P < 0.0001). NBD and NFL demonstrated a significant and progressive reduction with worsening heat pain thresholds (P = 0.01). Receiver operating characteristic curve analysis for the diagnosis of neuropathy (NDS >3) defined an NFD of <27.8/mm(2) with a sensitivity of 0.82 (95% CI 0.68-0.92) and specificity of 0.52 (0.40-0.64) and for detecting patients at risk of foot ulceration (NDS >6) defined a NFD cutoff of <20.8/mm(2) with a sensitivity of 0.71 (0.42-0.92) and specificity of 0.64 (0.54-0.74). CONCLUSIONS CCM is a noninvasive clinical technique that may be used to detect early nerve damage and stratify diabetic patients with increasing neuropathic severity.
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Affiliation(s)
- Mitra Tavakoli
- Division of Cardiovascular Medicine, University of Manchester and Central Manchester Foundation Trust, Manchester, U.K
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Tavakoli M, Asghar O, Alam U, Petropoulos IN, Fadavi H, Malik RA. Novel insights on diagnosis, cause and treatment of diabetic neuropathy: focus on painful diabetic neuropathy. Ther Adv Endocrinol Metab 2010; 1:69-88. [PMID: 23148152 PMCID: PMC3475285 DOI: 10.1177/2042018810370954] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Diabetic neuropathy is common, under or misdiagnosed, and causes substantial morbidity with increased mortality. Defining and developing sensitive diagnostic tests for diabetic neuropathy is not only key to implementing earlier interventions but also to ensure that the most appropriate endpoints are employed in clinical intervention trials. This is critical as many potentially effective therapies may never progress to the clinic, not due to a lack of therapeutic effect, but because the endpoints were not sufficiently sensitive or robust to identify benefit. Apart from improving glycaemic control, there is no licensed treatment for diabetic neuropathy, however, a number of pathogenetic pathways remain under active study. Painful diabetic neuropathy is a cause of considerable morbidity and whilst many pharmacological and nonpharmacological interventions are currently used, only two are approved by the US Food and Drug Administration. We address the important issue of the 'placebo effect' and also consider potential new pharmacological therapies as well as nonpharmacological interventions in the treatment of painful diabetic neuropathy.
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Affiliation(s)
- Mitra Tavakoli
- Mitra Tavakoli, PhD Omar Asghar, MRCP Uazman Alam, MRCP Ioannis N. Petropoulos, MSc Hassan Fadavi, MD Division of Cardiovascular Medicine, University of Manchester, Manchester, M13 9NT, UK
| | - Omar Asghar
- Mitra Tavakoli, PhD Omar Asghar, MRCP Uazman Alam, MRCP Ioannis N. Petropoulos, MSc Hassan Fadavi, MD Division of Cardiovascular Medicine, University of Manchester, Manchester, M13 9NT, UK
| | - Uazman Alam
- Mitra Tavakoli, PhD Omar Asghar, MRCP Uazman Alam, MRCP Ioannis N. Petropoulos, MSc Hassan Fadavi, MD Division of Cardiovascular Medicine, University of Manchester, Manchester, M13 9NT, UK
| | - Ioannis N. Petropoulos
- Mitra Tavakoli, PhD Omar Asghar, MRCP Uazman Alam, MRCP Ioannis N. Petropoulos, MSc Hassan Fadavi, MD Division of Cardiovascular Medicine, University of Manchester, Manchester, M13 9NT, UK
| | - Hassan Fadavi
- Mitra Tavakoli, PhD Omar Asghar, MRCP Uazman Alam, MRCP Ioannis N. Petropoulos, MSc Hassan Fadavi, MD Division of Cardiovascular Medicine, University of Manchester, Manchester, M13 9NT, UK
| | - Rayaz A. Malik
- Mitra Tavakoli, PhD Omar Asghar, MRCP Uazman Alam, MRCP Ioannis N. Petropoulos, MSc Hassan Fadavi, MD Division of Cardiovascular Medicine, University of Manchester, Manchester, M13 9NT, UK
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Tavakoli M, Marshall A, Pitceathly R, Fadavi H, Gow D, Roberts ME, Efron N, Boulton AJ, Malik RA. Corneal confocal microscopy: a novel means to detect nerve fibre damage in idiopathic small fibre neuropathy. Exp Neurol 2009; 223:245-50. [PMID: 19748505 DOI: 10.1016/j.expneurol.2009.08.033] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 08/28/2009] [Accepted: 08/28/2009] [Indexed: 01/30/2023]
Abstract
Patients with idiopathic small fibre neuropathy (ISFN) have been shown to have significant intraepidermal nerve fibre loss and an increased prevalence of impaired glucose tolerance (IGT). It has been suggested that the dysglycemia of IGT and additional metabolic risk factors may contribute to small nerve fibre damage in these patients. Twenty-five patients with ISFN and 12 aged-matched control subjects underwent a detailed evaluation of neuropathic symptoms, neurological deficits (Neuropathy deficit score (NDS); Nerve Conduction Studies (NCS); Quantitative Sensory Testing (QST) and Corneal Confocal Microscopy (CCM)) to quantify small nerve fibre pathology. Eight (32%) patients had IGT. Whilst all patients with ISFN had significant neuropathic symptoms, NDS, NCS and QST except for warm thresholds were normal. Corneal sensitivity was reduced and CCM demonstrated a significant reduction in corneal nerve fibre density (NFD) (P<0.0001), nerve branch density (NBD) (P<0.0001), nerve fibre length (NFL) (P<0.0001) and an increase in nerve fibre tortuosity (NFT) (P<0.0001). However these parameters did not differ between ISFN patients with and without IGT, nor did they correlate with BMI, lipids and blood pressure. Corneal confocal microscopy provides a sensitive non-invasive means to detect small nerve fibre damage in patients with ISFN and metabolic abnormalities do not relate to nerve damage.
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Affiliation(s)
- Mitra Tavakoli
- Division of Cardiovascular Medicine, Central Manchester Foundation Trust and University of Manchester, Manchester, M13 9NT, UK
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