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Taub DG, Woolf CJ. Age-dependent small fiber neuropathy: Mechanistic insights from animal models. Exp Neurol 2024; 377:114811. [PMID: 38723859 PMCID: PMC11131160 DOI: 10.1016/j.expneurol.2024.114811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/07/2024] [Accepted: 05/05/2024] [Indexed: 05/28/2024]
Abstract
Small fiber neuropathy (SFN) is a common and debilitating disease in which the terminals of small diameter sensory axons degenerate, producing sensory loss, and in many patients neuropathic pain. While a substantial number of cases are attributable to diabetes, almost 50% are idiopathic. An underappreciated aspect of the disease is its late onset in most patients. Animal models of human genetic mutations that produce SFN also display age-dependent phenotypes suggesting that aging is an important contributor to the risk of development of the disease. In this review we define how particular sensory neurons are affected in SFN and discuss how aging may drive the disease. We also evaluate how animal models of SFN can define disease mechanisms that will provide insight into early risk detection and suggest novel therapeutic interventions.
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Affiliation(s)
- Daniel G Taub
- F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Department of Neurobiology, Harvard Medical School, Boston, MA, USA.
| | - Clifford J Woolf
- F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Department of Neurobiology, Harvard Medical School, Boston, MA, USA
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2
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Gad H, Mohammed I, Dauleh H, Pasha M, Al-Barazenji T, Hussain K, Malik RA. Case report: Nerve fiber regeneration in children with melanocortin 4 receptor gene mutation related obesity treated with semaglutide. Front Endocrinol (Lausanne) 2024; 15:1385463. [PMID: 38974580 PMCID: PMC11227249 DOI: 10.3389/fendo.2024.1385463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 06/07/2024] [Indexed: 07/09/2024] Open
Abstract
Melanocortin 4 receptor (MC4R) mutations are the commonest cause of monogenic obesity through dysregulation of neuronal pathways in the hypothalamus and prefrontal cortex that regulate hunger and satiety. MC4R also regulates neuropathic pain pathways via JNK signaling after nerve injury. We show evidence of corneal small fiber degeneration in 2 siblings carrying a heterozygous missense variant c.508A>G, p.Ille170Val in the MC4R gene. Both children were treated with once weekly semaglutide for 6 months with no change in weight, and only a minor improvement in HbA1c and lipid profile. However, there was evidence of nerve regeneration with an increase in corneal nerve fiber density (CNFD) [child A (13.9%), child B (14.7%)], corneal nerve branch density (CNBD) [child A (110.2%), child B (58.7%)] and corneal nerve fiber length (CNFL) [child A (21.5%), child B (44.0%)].
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Affiliation(s)
- Hoda Gad
- Research Department, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Idris Mohammed
- Endocrinology Department, Sidra Medicine, Doha, Qatar
- College of Health & Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Hajar Dauleh
- Endocrinology Department, Sidra Medicine, Doha, Qatar
| | - Maheen Pasha
- Endocrinology Department, Sidra Medicine, Doha, Qatar
| | | | | | - Rayaz A. Malik
- Research Department, Weill Cornell Medicine-Qatar, Doha, Qatar
- Institute of Cardiovascular Medicine, University of Manchester, Manchester, United Kingdom
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Murin PJ, Khasiyev F, Profirovic J, Fedorova M, Kafaie J. Comparing FGFR-3 and TS-HDS Seropositive Small Fiber Neuropathy: Unique Patient Features, Symptoms, Laboratory, and Nerve Conduction Study Findings. J Clin Neuromuscul Dis 2024; 25:171-177. [PMID: 38771226 DOI: 10.1097/cnd.0000000000000478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
OBJECTIVES Small fiber neuropathy presents a significant diagnostic and therapeutic challenge. To solve this challenge, efforts have been made to identify autoantibodies associated with this condition. Previous literature has often considered tri-sulfated heparin disaccharide (TS-HDS) and fibroblast growth factor receptor 3 (FGFR3) as a singular seropositive group and/or focused primarily on symptomatic associations. METHODS One hundred seventy-two small fiber neuropathy patients with a Washington University Sensory Neuropathy panel were selected for TS-HDS seropositivity, FGFR-3 seropositivity, and seronegative controls. Data were collected to on the demographic, symptomatic, and laboratory profiles of each subgroup. RESULTS Percent female (P = 0.0043), frequency of neuropathic pain symptoms (P = 0.0074), and erythrocyte sedimentation rate (P = 0.0293), vitamin D (P < 0.0001), and vitamin B12 (P = 0.0033) differed between the groups. Skin biopsy was more frequently normal within both the FGFR-3 and the TS-HDS cohort (P = 0.0253). CONCLUSIONS TS-HDS and FGFR-3 display a distinct phenotype from both controls and one another. Immunoglobulin M (IgM) against FGFR-3 and IgM against TS-HDS may be individually valuable markers for the development of distinct clinical phenotypes.
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Affiliation(s)
- Peyton J Murin
- Department of Neurology, Saint Louis University, Saint Louis, MO
| | - Farid Khasiyev
- Department of Neurology, Saint Louis University, Saint Louis, MO
| | - Jasmina Profirovic
- Department of Pharmaceutical and Administrative Sciences, St. Louis College of Pharmacy at UHSP, St. Louis, MO
| | | | - Jafar Kafaie
- Department of Neurology, Saint Louis University, Saint Louis, MO
- Department of Pharmacology and Physiology, Saint Louis University, Saint Louis, MO
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Geerts M, Hoeijmakers JGJ, Essers BAB, Merkies ISJ, Faber CG, Goossens MEJB. Patient satisfaction and patient accessibility in a small fiber neuropathy diagnostic service in the Netherlands: A single-center, prospective, survey-based cohort study. PLoS One 2024; 19:e0298881. [PMID: 38626240 PMCID: PMC11020963 DOI: 10.1371/journal.pone.0298881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 01/27/2024] [Indexed: 04/18/2024] Open
Abstract
INTRODUCTION Small fiber neuropathy (SFN) is a common cause of neuropathic pain in peripheral neuropathies. Good accessibility of diagnostics and treatment is necessary for an accurate diagnosis and treatment of SFN. Evidence is lacking on the quality performance of the diagnostic SFN service in the Netherlands. Our aim was to determine the patient satisfaction and -accessibility of the diagnostic SFN service, and to identify areas for improvement. METHODS In a single-center, prospective, survey-based cohort study, 100 visiting patients were asked to fill in the SFN patient satisfaction questionnaire (SFN-PSQ), with 10 domains and 51 items. Cut-off point for improvement was defined as ≥ 25% dissatisfaction on an item. A chi-square test and linear regression analyses was used for significant differences and associations of patient satisfaction. RESULTS From November 2020 to May 2021, 98 patients with SFN-related complaints filled in the online SFN-PSQ within 20 minutes. In 84% of the patients SFN was confirmed, average age was 55.1 (52.5-57.8) years and 67% was female. High satisfaction was seen in the domains 'Waiting List Period', Chest X-ray', 'Consultation with the Doctor or Nurse Practitioner (NP)', 'Separate Consultation with the Doctor or NP about Psychological Symptoms', and 'General' of the SFN service. Overall average patient satisfaction score was 8.7 (IQR 8-10) on a 1-to-10 rating scale. Main area for improvement was shortening the 8-week period for receiving the results of the diagnostic testing (p < 0.05). General health status was statistically significant associated with patient satisfaction (p < 0.05). CONCLUSION A good reflection of the high patient satisfaction and -accessibility of the SFN-service is shown, with important points for improvement. These results could help hospitals widely to optimize the logistic and diagnostic pathway of SFN analysis, benchmarking patient satisfaction results among the hospitals, and to improve the quality of care of comparable SFN services.
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Affiliation(s)
- Margot Geerts
- Department of Neurology, School of Mental Health and Neuroscience, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Janneke G. J. Hoeijmakers
- Department of Neurology, School of Mental Health and Neuroscience, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Brigitte A. B. Essers
- Department of Clinical Epidemiology and Medical Technology Assessment, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Ingemar S. J. Merkies
- Department of Neurology, School of Mental Health and Neuroscience, Maastricht University Medical Center+, Maastricht, The Netherlands
- Department of Neurology, Curacao Medical Center, Willemstad, Curacao
| | - Catharina G. Faber
- Department of Neurology, School of Mental Health and Neuroscience, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Mariëlle E. J. B. Goossens
- Department of Rehabilitation Research & Department of Clinical Psychological Sciences, Maastricht University, Maastricht, The Netherlands
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Sand T, Grøtting A, Uglem M, Augestad N, Johnsen G, Sandvik J. Neuropathy 10-15 years after Roux-en-Y gastric bypass for severe obesity: A community-controlled nerve conduction study. Clin Neurophysiol Pract 2024; 9:130-137. [PMID: 38618240 PMCID: PMC11015066 DOI: 10.1016/j.cnp.2024.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 02/29/2024] [Accepted: 03/18/2024] [Indexed: 04/16/2024] Open
Abstract
Objective We searched for long-term peripheral nerve complications 10-15 years after Roux-en-Y gastric bypass surgery (RYGB), using a comprehensive nerve conduction study (NCS) protocol. Methods Patients (n = 175, mean age 52.0, BMI 35.2) and 86 community-controls (mean age 56.8, BMI 27.2) had NCS of one upper and lower limb. New abnormality scores from 27 polyneuropathy-relevant (PNP27s) and four carpal tunnel syndrome-relevant NCS-measures (CTS4s) were compared between groups with non-parametric statistics. Estimated prevalences were compared by 95 % confidence limits. The clinical neurophysiologist's diagnosis was retrieved from hospital records (PNP-ncs, CTS-ncs, other). Results Abnormality score did not differ between RYGB and control groups (PNP27s: 1.9 vs 1.7, CTS4s: 0.7 vs 0.6, p > 0.29). BMI correlated weakly with CTS4s in patients (rho = 0.19, p = 0.01), and less with PNP27s (rho = 0.12, p = 0.12). Polyneuropathy (PNP-ncs) prevalence was 12 % in patients and 8 % in controls. CTS-ncs prevalence was 21 % in patients and 10 % in controls (p = 0.04). Conclusions NCS-based abnormality scores did not differ between patients 10-15 years after RYGB and community-recruited controls, neither for PNP nor CTS. Significance Long-term polyneuropathic complications from RYGB have probably been avoided by modern treatment guidelines. NCS-diagnosed CTS is common in overweight RYGB patients. RYGB-patients with significant neuropathic symptoms need clinical evaluation.
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Affiliation(s)
- Trond Sand
- Department of Neurology and Clinical Neurophysiology, St. Olavs Hospital, Trondheim University Hospital, Norway
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health, Norwegian University of Science and Technology, Trondheim, Norway
| | - Arnstein Grøtting
- Department of Neurology and Clinical Neurophysiology, St. Olavs Hospital, Trondheim University Hospital, Norway
| | - Martin Uglem
- Department of Neurology and Clinical Neurophysiology, St. Olavs Hospital, Trondheim University Hospital, Norway
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health, Norwegian University of Science and Technology, Trondheim, Norway
| | - Nils Augestad
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health, Norwegian University of Science and Technology, Trondheim, Norway
| | - Gjermund Johnsen
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
- Norwegian National Advisory Unit on Advanced Laparoscopic Surgery, Clinic of Surgery, St. Olavs Hospital, Trondheim University Hospital, Norway
| | - Jorunn Sandvik
- Department of Surgery, Møre and Romsdal Hospital Trust, Ålesund, Norway
- Centre for Obesity Research, Clinic of Surgery, St. Olavs Hospital, Trondheim University Hospital, Norway
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
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Nabar S, Fernandez J, Prakash V, Safder S. Gastrointestinal manifestations seen in pediatric patients diagnosed with small fiber neuropathy. J Pediatr Gastroenterol Nutr 2024; 78:583-591. [PMID: 38504414 DOI: 10.1002/jpn3.12099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/22/2023] [Accepted: 09/23/2023] [Indexed: 03/21/2024]
Abstract
OBJECTIVES Small fiber neuropathy (SFN) affects the fibers involved in cutaneous and visceral pain and temperature sensation and are a crucial part of the autonomic nervous system. Autonomic dysfunction secondary to SFN and autoimmune receptor antibodies is being increasingly recognized, and gastrointestinal (GI) manifestations include constipation, early satiety, nausea, vomiting, and diarrhea. Enteric nervous system involvement may be a possible explanation of abnormal GI motility patterns seen in these patients. METHODS Children suspected to have SFN based on symptoms underwent skin biopsy at the Child Neurology clinic at Arnold Palmer Hospital for Children, which was processed at Therapath™ Neuropathology. SFN was diagnosed using epidermal nerve fiber density values that were below 5th percentile from the left distal leg (calf) as reported per Therapath™ laboratory. RESULTS Twenty-six patients were diagnosed with SFN. Retrospective chart review was performed, including demographic data, clinical characteristics, and evaluation. A majority of patients were white adolescent females. Autonomic dysfunction, including orthostasis and temperature dysregulation were seen in 61.5% of patients (p = 0.124). Somatosensory symptoms, including pain or numbness were seen in 85% of patients (p < 0.001). GI symptoms were present in 85% of patients (p < 0.001) with constipation being the most common symptom seen in 50% of patients. This correlated with the motility testing results. CONCLUSIONS Pediatric patients with SFN commonly have GI symptoms, which may be the main presenting symptom. It is important to recognize and look for symptoms of small fiber neuropathy in children with refractory GI symptoms that may explain multisystemic complaints often seen in these patients.
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Affiliation(s)
- Shruti Nabar
- Center for Digestive Health and Nutrition, Orlando Health Arnold Palmer Hospital for Children, Orlando, Florida, USA
| | - Jenelle Fernandez
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Vikram Prakash
- Orlando Health Arnold Palmer Hospital for Children Neurology, Orlando, Florida, USA
| | - Shaista Safder
- Center for Digestive Health and Nutrition, Orlando Health Arnold Palmer Hospital for Children, Orlando, Florida, USA
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Zirpoli GR, Farhad K, Klein MC, Downs S, Klein MM, Oaklander AL. Initial validation of the Mass. General Neuropathy Exam Tool (MAGNET) for evaluation of distal small-fiber neuropathy. Muscle Nerve 2024; 69:185-198. [PMID: 38112169 PMCID: PMC10842781 DOI: 10.1002/mus.28013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 11/14/2023] [Accepted: 11/19/2023] [Indexed: 12/20/2023]
Abstract
INTRODUCTION/AIMS Diagnosis of small-fiber neuropathy (SFN) is hampered by its subjective symptoms and signs. Confirmatory testing is insufficiently available and expensive, so predictive examinations have value. However, few support the 2020 SFN consensus-case-definition requirements or were validated for non-diabetes neuropathies. Thus we developed the Massachusetts General Hospital Neuropathy Exam Tool (MAGNET) and measured diagnostic performance in 160 symptomatic patients evaluated for length-dependent SFN from any cause and 37 healthy volunteers. METHODS We compared prevalences of abnormalities (vital signs, pupil responses, lower-limb appearance, pin, light touch, vibration and position sensitivity, great-toe strength, muscle stretch reflexes), and validated diagnostic performance against objective SFN tests: lower-leg skin-biopsy epidermal neurite densities and autonomic function testing (AFT). Sensitivity/specificity, feasibility, test-retest and inter-rater reliability, and convergence with the Utah Early Neuropathy Scale were calculated. RESULTS Patients' ages averaged 48.5 ± 14.7 years and 70.6% were female. Causes of neuropathy varied, remaining unknown in 59.5%. Among the 46 with abnormal skin biopsies, the most prevalent abnormality was reduced pin sharpness at the toes (71.7%). Inter-rater reliability, test-retest reliability, and convergent validity excelled (range = 91.3-95.6%). Receiver operating characteristics comparing all symptomatic patients versus healthy controls indicated that a MAGNET threshold score of 14 maximized predictive accuracy for skin biopsies (0.74) and a 30 cut-off maximized accuracy for predicting AFT (0.60). Analyzing patients with any abnormal neuropathy-test results identified areas-under-the-curves of 0.87-0.89 for predicting a diagnostic result, accuracy = 0.80-0.89, and Youden's index = 0.62. Overall, MAGNET was 80%-85% accurate for stratifying patients with abnormal versus normal neuropathy test results. DISCUSSION MAGNET quickly generates research-quality metrics during clinical examinations.
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Affiliation(s)
- Gary R. Zirpoli
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Khosro Farhad
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Madeleine C. Klein
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Sean Downs
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Max M. Klein
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Anne Louise Oaklander
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Pathology (Neuropathology), Massachusetts General Hospital, Boston, MA, USA
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Geerts M, Hoeijmakers JG, van Eijk-Hustings Y, Brandts L, Gorissen-Brouwers CM, Merkies IS, Joore MA, Faber CG. Cost of illness of patients with small fiber neuropathy in the Netherlands. Pain 2024; 165:153-163. [PMID: 37556388 PMCID: PMC10723644 DOI: 10.1097/j.pain.0000000000003008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 08/11/2023]
Abstract
ABSTRACT Neuropathic pain is associated with substantial healthcare costs. However, cost-of-illness studies of small fiber neuropathy (SFN) are scarce. Our aim was to estimate the healthcare, patient and family, and productivity costs of patients with SFN in the Netherlands from a healthcare and societal perspective. In addition, the association of costs with age, pain impact on daily life, anxiety, depression, and quality of life (Qol) were examined. Cost questionnaires were completed by 156 patients with confirmed SFN. The average annual total health care and societal cost (€, 2020) was calculated at patient, SFN adult population, and societal level. The average annual healthcare, patient and family, and productivity costs per patient with a Pain Impact Numerical Rating Scale of 0 to 3 (mild), 4 to 6 (moderate), and 7 to 10 (severe) were calculated by using the cost questionnaire data. Quality of life was determined by the EuroQol 5D utility scores. Anxiety and depression were assessed using the Hospital Anxiety and Depression Scale. Associations of all costs were analyzed using linear regression analyses. At the patient level, the average annual SFN healthcare and societal cost of SFN was €3614 (95% confidence interval [CI] €3171-€4072) and €17,871 (95% CI €14,395-€21,480). At the SFN population level, the average healthcare costs were €29.8 (CI €26.4-€34.2) million, and on a societal level, these were €147.7 (CI 120.5-176.3) million. Severe pain was associated with significant lower Qol and higher depression scores, higher healthcare, patient and family, and productivity costs ( P < 0.001).
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Affiliation(s)
- Margot Geerts
- Department of Neurology, Maastricht University Medical Center+, School of Mental Health and Neuroscience, Maastricht, the Netherlands
| | - Janneke G.J. Hoeijmakers
- Department of Neurology, Maastricht University Medical Center+, School of Mental Health and Neuroscience, Maastricht, the Netherlands
| | - Yvonne van Eijk-Hustings
- Department of Clinical Epidemiology and Medical Technology Assessment, Maastricht University Medical Center+, CAPHRI Care and Public Health Research Institute, Maastricht, the Netherlands
| | - Lloyd Brandts
- Department of Clinical Epidemiology and Medical Technology Assessment, Maastricht University Medical Center+, CAPHRI Care and Public Health Research Institute, Maastricht, the Netherlands
| | - Carla M.L. Gorissen-Brouwers
- Department of Neurology, Maastricht University Medical Center+, School of Mental Health and Neuroscience, Maastricht, the Netherlands
| | - Ingemar S.J. Merkies
- Department of Neurology, Maastricht University Medical Center+, School of Mental Health and Neuroscience, Maastricht, the Netherlands
- Department of Neurology, Curacao Medical Center, J. H. J. Hamelbergweg, Willemstad, Curacao
| | - Manuela A. Joore
- Department of Clinical Epidemiology and Medical Technology Assessment, Maastricht University Medical Center+, CAPHRI Care and Public Health Research Institute, Maastricht, the Netherlands
| | - Catharina G. Faber
- Department of Neurology, Maastricht University Medical Center+, School of Mental Health and Neuroscience, Maastricht, the Netherlands
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Løseth S, Nebuchennykh M, Brokstad RT, Lindal S, Mellgren SI. Cutaneous nerve biopsy in patients with symptoms of small fiber neuropathy: a retrospective study. Scand J Pain 2024; 24:sjpain-2023-0071. [PMID: 38381703 DOI: 10.1515/sjpain-2023-0071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 11/20/2023] [Indexed: 02/23/2024]
Abstract
OBJECTIVES We aimed to investigate to what extent small fiber tests were abnormal in an unselected retrospective patient material with symptoms suggesting that small fiber neuropathy (SFN) could be present, and to evaluate possible gender differences. METHODS Nerve conduction studies (NCS), skin biopsy for determination of intraepidermal nerve fiber density (IENFD) and quantitative sensory testing (QST) were performed. Z-scores were calculated from reference materials to adjust for the effects of age and gender/height. RESULTS Two hundred and three patients, 148 females and 55 males had normal NCS and were considered to have possible SFN. 45.3 % had reduced IENFD, 43.2 % of the females and 50.9 % of the males. Mean IENFD was 7.3 ± 2.6 fibers/mm in females and 6.1 ± 2.3 in males (p<0.001), but the difference was not significant when adopting Z-scores. Comparison of gender differences between those with normal and abnormal IENFD were not significant when Z-scores were applied. QST was abnormal in 50 % of the patients (48.9 % in females and 52.9 % in males). In the low IENFD group 45 cases out of 90 (50 %) were recorded with abnormal QST. In those with normal IENFD 51 of 102 (50 %) showed abnormal QST. CONCLUSIONS Less than half of these patients had reduced IENFD, and 50 % had abnormal QST. There were no gender differences. A more strict selection of patients might have increased the sensitivity, but functional changes in unmyelinated nerve fibers are also known to occur with normal IENFD. Approval to collect data was given by the Norwegian data protection authority at University Hospital of North Norway (Project no. 02028).
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Affiliation(s)
- Sissel Løseth
- Department of Neurology and Clinical Neurophysiology, University Hospital of North Norway, Tromsø, Norway
- Department of Clinical Medicine, UiT the Artic University of Norway, Tromsø, Norway
| | - Maria Nebuchennykh
- Department of Neurology and Clinical Neurophysiology, University Hospital of North Norway, Tromsø, Norway
| | - Ruth Therese Brokstad
- Department of Neurology and Clinical Neurophysiology, University Hospital of North Norway, Tromsø, Norway
| | - Sigurd Lindal
- Department of Pathology, University Hospital of North Norway, Tromsø, Norway
- Department of Clinical Medicine, UiT the Artic University of Norway, Tromsø, Norway
| | - Svein Ivar Mellgren
- Department of Neurology and Clinical Neurophysiology, University Hospital of North Norway, Tromsø, Norway
- Department of Clinical Medicine, UiT the Artic University of Norway, Tromsø, Norway
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Marwaha B. Role of Tau protein in long COVID and potential therapeutic targets. Front Cell Infect Microbiol 2023; 13:1280600. [PMID: 37953801 PMCID: PMC10634420 DOI: 10.3389/fcimb.2023.1280600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 10/06/2023] [Indexed: 11/14/2023] Open
Abstract
Introduction Long COVID is an emerging public health burden and has been defined as a syndrome with common symptoms of fatigue, shortness of breath, cognitive dysfunction, and others impacting day-to-day life, fluctuating or relapsing over, occurring for at least two months in patients with a history of probable or confirmed SARS CoV-2 infection; usually three months from the onset of illness and cannot be explained by an alternate diagnosis. The actual prevalence of long-term COVID-19 is unknown, but it is believed that more than 17 million patients in Europe may have suffered from it during pandemic. Pathophysiology Currently, there is limited understanding of the pathophysiology of this syndrome, and multiple hypotheses have been proposed. Our literature review has shown studies reporting tau deposits in tissue samples of the brain from autopsies of COVID-19 patients compared to the control group, and the in-vitro human brain organoid model has shown aberrant phosphorylation of tau protein in response to SARS-CoV-2 infection. Tauopathies, a group of neurodegenerative disorders with the salient features of tau deposits, can manifest different symptoms based on the anatomical region of brain involvement and have been shown to affect the peripheral nervous system as well and explained even in rat model studies. Long COVID has more than 203 symptoms, with predominant symptoms of fatigue, dyspnea, and cognitive dysfunction, which tauopathy-induced CNS and peripheral nervous system dysfunction can explain. There have been no studies up till now to reveal the pathophysiology of long COVID. Based on our literature review, aberrant tau phosphorylation is a promising hypothesis that can be explored in future studies. Therapeutic approaches for tauopathies have multidimensional aspects, including targeting post-translational modifications, tau aggregation, and tau clearance through the autophagy process with the help of lysosomes, which can be potential targets for developing therapeutic interventions for the long COVID. In addition, future studies can attempt to find the tau proteins in CSF and use those as biomarkers for the long COVID.
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Affiliation(s)
- Bharat Marwaha
- Department of Cardiology, Adena Health System, Chillicothe, OH, United States
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Ludwig B, Deckert M, Krajnc N, Keritam O, Macher S, Bsteh G, Zulehner G, Thurnher M, Berger T, Seidel S, Willinger U, Rommer P. Reported neurological symptoms after severe acute respiratory syndrome coronavirus type 2 infection: A systematic diagnostic approach. Eur J Neurol 2023; 30:2713-2725. [PMID: 37306533 DOI: 10.1111/ene.15923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 06/08/2023] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND PURPOSE Following increasing demands of patients with suspected neurological symptoms after infection with severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), the Department of Neurology at the Medical University of Vienna established a new outpatient clinic to systematically assess, diagnose, and document neurological complaints potentially associated with a prior SARS-CoV-2 infection. METHODS The data presented here include prospectively collected 156 outpatients from May 2021 to April 2022. Patients underwent semistandardized interviewing about symptoms with reported onset after SARS-CoV-2 infection, neurological examination, and comprehensive diagnostic workup. RESULTS Reported new onset symptoms after infection included fatigue (77.6%), subjective cognitive impairment (72.4%), headache (47.7%), loss of smell and/or taste (43.2%), and sleep disturbances (42.2%). Most patients had a mild coronavirus disease (COVID-19) disease course (84%) and reported comorbidities (71%), of which the most frequent were psychiatric disorders (34%). Frequency of symptoms was not associated with age, sex, or severity of COVID-19 course. A comprehensive diagnostic workup revealed no neurological abnormalities in the clinical examination, or electrophysiological or imaging assessments in the majority of patients (n = 143, 91.7%). Neuropsychological assessment of a subgroup of patients (n = 28, 17.9%) showed that cognitive impairments in executive functions and attention, anxiety, depression, and somatization symptoms were highly common. CONCLUSIONS In this systematic registry, we identified fatigue, cognitive impairment, and headache as the most frequently reported persisting complaints after SARS-CoV-2 infection. Structural neurological findings were rare. We also suspect a link between the growing burden of the COVID-19 pandemic on personal lives and the increase in reported neurological and psychiatric complaints.
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Affiliation(s)
- Birgit Ludwig
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences & Mental Health, Medical University of Vienna, Vienna, Austria
| | - Matthias Deckert
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences & Mental Health, Medical University of Vienna, Vienna, Austria
| | - Nik Krajnc
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences & Mental Health, Medical University of Vienna, Vienna, Austria
| | - Omar Keritam
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences & Mental Health, Medical University of Vienna, Vienna, Austria
| | - Stefan Macher
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences & Mental Health, Medical University of Vienna, Vienna, Austria
| | - Gabriel Bsteh
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences & Mental Health, Medical University of Vienna, Vienna, Austria
| | - Gudrun Zulehner
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences & Mental Health, Medical University of Vienna, Vienna, Austria
| | - Majda Thurnher
- Section of Neuroradiology and Musculoskeletal Radiology, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Thomas Berger
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences & Mental Health, Medical University of Vienna, Vienna, Austria
| | - Stefan Seidel
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences & Mental Health, Medical University of Vienna, Vienna, Austria
- Rehabilitation Clinic Pirawarth, Bad Pirawarth, Austria
| | - Ulrike Willinger
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences & Mental Health, Medical University of Vienna, Vienna, Austria
| | - Paulus Rommer
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences & Mental Health, Medical University of Vienna, Vienna, Austria
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12
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Gomez F, Mehra A, Ensrud E, Diedrich D, Laudanski K. COVID-19: a modern trigger for Guillain-Barre syndrome, myasthenia gravis, and small fiber neuropathy. Front Neurosci 2023; 17:1198327. [PMID: 37712090 PMCID: PMC10498773 DOI: 10.3389/fnins.2023.1198327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 07/31/2023] [Indexed: 09/16/2023] Open
Abstract
COVID-19 infection has had a profound impact on society. During the initial phase of the pandemic, there were several suggestions that COVID-19 may lead to acute and protracted neurologic sequelae. For example, peripheral neuropathies exhibited distinctive features as compared to those observed in critical care illness. The peripheral nervous system, lacking the protection afforded by the blood-brain barrier, has been a particular site of sequelae and complications subsequent to COVID-19 infection, including Guillain-Barre syndrome, myasthenia gravis, and small fiber neuropathy. We will discuss these disorders in terms of their clinical manifestations, diagnosis, and treatment as well as the pathophysiology in relation to COVID-19.
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Affiliation(s)
- Francisco Gomez
- Department of Neurology, University of Missouri, Columbia, MO, United States
| | - Ashir Mehra
- Department of Neurology, University of Missouri, Columbia, MO, United States
| | - Erik Ensrud
- Department of Neurology, University of Missouri, Columbia, MO, United States
| | - Daniel Diedrich
- Department of Anesthesiology and Perioperative Care, Mayo Clinic, Rochester, MN, United States
| | - Krzysztof Laudanski
- Department of Anesthesiology and Perioperative Care, Mayo Clinic, Rochester, MN, United States
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13
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Comparison of cutaneous silent period parameters in patients with primary Sjögren's syndrome with the healthy population and determination of ıts relationship with clinical parameters. Rheumatol Int 2023; 43:355-362. [PMID: 36048188 DOI: 10.1007/s00296-022-05198-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 08/23/2022] [Indexed: 02/07/2023]
Abstract
Small fiber neuropathy (SFN) is one of the main neurological manifestations in primary Sjögren's Syndrome (pSS). For the detection of SFN, cutaneous silent period (CSP) measurement is gaining popularity recently due to its non-invasiveness and practical application. Evaluating SFN involvement in patients with pSS using CSP and evaluating its relationship with clinical parameters. Patients with a diagnosis of pSS and healthy volunteers demographically homogeneous with the patient group were included in the study. The CSP responses were recorded over the abductor pollicis brevis muscle. The latency and duration values of the responses were obtained. In patient group, EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI), Hospital Anxiety and Depression Scale (HADS), Short Form-36 (SF-36) questionnaire, Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) and Central Sensitization Inventory (CSI) were applied for the evaluation of symptom severity, mood, quality of life, presence of neuropathic pain and central sensitization, respectively. The mean CSP latency was significantly longer in patient group compared to control group (p < 0.001). Mean CSP duration was also significantly shorter in patient group (p < 0.001). There were no significant differences in CSP parameters according to patients' neuropathic pain or central sensitization profile. There were significant correlations of CSP parameters (latency and duration, respectively) with ESSPRI dryness (ρ = 0.469, p = 0.004; ρ = -0.553, p < 0.001), fatigue (ρ = 0.42, p = 0.011; ρ = -0.505, p = 0.002), pain (ρ = 0.428, p = 0.009; ρ = -0.57, p < 0.001) subscores and mean ESSPRI score (ρ = 0.631, p < 0.001; ρ = -0.749, p < 0.001). When SF-36 subscores and CSP parameters were investigated, a significant correlation was found only between "bodily pain" subscore and CSP duration (ρ = -0.395, p = 0.017). In HADS, LANSS and CSI evaluations, a significant correlation was found only between HADS anxiety score and the CSP duration (ρ = 0.364, p = 0.02). As indicated by CSP measurement, SFN is more prominent in patients with pSS than in the healthy population. It is important to investigate the presence of SFN because of its correlation with the leading symptoms in the clinical spectrum of pSS.
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14
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Shelly S, Ramon-Gonen R, Paul P, Klein CJ, Klang E, Rahman N, Nikitin V, Ben David M, Dori A. Nerve Conduction Differences in a Large Clinical Population: The Role of Age and Sex. J Neuromuscul Dis 2023; 10:925-935. [PMID: 37545257 PMCID: PMC10578272 DOI: 10.3233/jnd-230052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2023] [Indexed: 08/08/2023]
Abstract
BACKGROUND The normal limits of nerve conduction studies are commonly determined by testing healthy subjects. However, in comprehensive real-life nerve conduction electrodiagnostic (EDX) evaluations, multiple nerves are tested, including normal nerves, for purposes of comparison with abnormal ones. OBJECTIVE This study aims to evaluate the average values of normal nerve conduction studies in a large population and examined the influence of age and sex. METHODS EDX parameters were extracted from an electronic database of studies performed from May 2016 to February 2022. Established normal values were used to determine the classification of a nerve study as normal. RESULTS We identified 10,648 EDX reports with 5077 normally interpreted nerve conduction studies (47.6%) of which 57% (n = 2890) were for females. The median age of studies with no abnormalities was 45.1 years (range < 1 to 92) overall and 42.5 years (range: 0.16 -89.5 years) for males and 47.5 years (range:<1 -91.7) for females. Correlations between age and amplitude, latency, and velocity (p < 0.001) were observed in most nerves. Amplitude correlated negatively with age in adults in all nerves with a mean of -0.44 (range: -0.24 to -0.62). However, in the pediatric population (age < 18 years), amplitude as well as velocity increased significantly with age. In the adult cohort, sex differences were noted, where females had higher mean sensory nerve action potentials in ulnar, median, and radial evaluations (p < 0.001). In older patients (aged > 70 years) with normally interpreted EDX studies (845 records of 528 patients), sural responses were present in 97%. CONCLUSIONS This real-life study confirms that advanced aging is associated with decreased nerve conduction amplitudes, increased latency, and the slowing of conduction velocity. The findings also indicate higher sensory amplitudes and conduction velocities in females. Sural nerve responses were identified in most adults over age 70.
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Affiliation(s)
- Shahar Shelly
- Department of Neurology, Rambam Medical Center, Haifa, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Roni Ramon-Gonen
- The Graduate School of Business Administration, Bar-Ilan University, Ramat-Gan, Israel
| | - Pritikanta Paul
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, IL, USA
| | | | - Eyal Klang
- Department of diagnostic imaging, Sheba Medical Center, Sackler Faculty Institute, Tel Aviv, Israel
- The Sami Sagol AI Hub, ARC Innovation Center, Sheba Medical Center, Tel Hashomer, Israel
| | - Nisim Rahman
- The Sami Sagol AI Hub, ARC Innovation Center, Sheba Medical Center, Tel Hashomer, Israel
| | - Vera Nikitin
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Neurology, Sheba Medical Center, Ramat Gan, Israel
| | - Merav Ben David
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Neurology, Sheba Medical Center, Ramat Gan, Israel
| | - Amir Dori
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Neurology, Sheba Medical Center, Ramat Gan, Israel
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15
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Chao CC, Hsieh PC, Janice Lin CH, Huang SL, Hsieh ST, Chiang MC. Limbic Connectivity Underlies Pain Treatment Response in Small-Fiber Neuropathy. Ann Neurol 2022; 93:655-667. [PMID: 36511844 DOI: 10.1002/ana.26577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/16/2022] [Accepted: 11/28/2022] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Small-fiber neuropathy (SFN) is characterized by neuropathic pain due to degeneration of small-diameter nerves in the skin. Given that brain reorganization occurs following chronic neuropathic pain, this study investigated the structural and functional basis of pain-related brain changes after skin nerve degeneration. METHODS Diffusion-weighted and resting-state functional MRI data were acquired from 53 pathologically confirmed SFN patients, and the structural and functional connectivity of the pain-related network was assessed using network-based statistic (NBS) analysis. RESULTS Compared with age- and sex-matched controls, the SFN patients exhibited a robust and global reduction of functional connectivity, mainly across the limbic and somatosensory systems. Furthermore, lower functional connectivity was associated with skin nerve degeneration measured by reduced intraepidermal nerve fiber density and better therapeutic response to anti-neuralgia medications, particularly for the connectivity between the insula and the limbic areas including the anterior and middle cingulate cortices. Similar to the patterns of functional connectivity changes, the structural connectivity was robustly reduced among the limbic and somatosensory areas, and the cognition-integration areas including the inferior parietal lobule. There was shared reduction of structural and functional connectivity among the limbic, somatosensory, striatal, and cognition-integration systems: (1) between the middle cingulate cortex and inferior parietal lobule and (2) between the thalamus and putamen. These observations indicate the structural basis underlying altered functional connectivity in SFN. INTERPRETATION Our findings provide imaging evidence linking structural and functional brain dysconnectivity to sensory deafferentation caused by peripheral nerve degeneration and therapeutic responses for neuropathic pain in SFN. ANN NEUROL 2022.
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Affiliation(s)
- Chi-Chao Chao
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Paul-Chen Hsieh
- Department of Dermatology, National Taiwan University Hospital, Taipei, Taiwan.,Department of Dermatology, NTU BioMedical Park Hospital, Hsinchu, Taiwan
| | - Chien-Ho Janice Lin
- Department of Physical Therapy and Assistive Technology, National Yang Ming Chiao Tung University, Taipei, Taiwan.,Yeong-An Orthopedic and Physical Therapy Clinic, Taipei, Taiwan
| | - Shin-Leh Huang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan.,Department of Neurology, Fu Jen Catholic University Hospital, New Taipei City, Taiwan
| | - Sung-Tsang Hsieh
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan.,Department of Anatomy and Cell Biology, National Taiwan University College of Medicine, Taipei, Taiwan.,Center of Precision Medicine, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Ming-Chang Chiang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
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16
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McCoy SS, Hetzel S, VanWormer JJ, Bartels CM. Sex hormones, body mass index, and related comorbidities associated with developing Sjögren's disease: a nested case-control study. Clin Rheumatol 2022; 41:3065-3074. [PMID: 35701626 PMCID: PMC9610811 DOI: 10.1007/s10067-022-06226-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/20/2022] [Accepted: 05/24/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Sjögren's disease (SjD), a highly female predominant systemic autoimmune disease, peaks in perimenopause. Prior studies lack details on timing or type of sex hormone exposure. We examined SjD risk using endogenous and exogenous hormone exposure and related comorbidities. METHODS We performed a retrospective case-control study of adult women, nested within a population cohort. Cases had SjD diagnosed by a rheumatology provider or two SjD diagnoses from a non-rheumatology provider with a positive anti-SSA antibody or salivary gland biopsy. Cases were age-matched to three SjD-free controls. We calculated modified composite estrogen scores (mCES) and collected demographics, comorbidities, and endogenous and exogenous hormone exposures. Risk ratios were adjusted for demographics. RESULTS Of 546 SjD cases and 1637 age-matched controls, mCES was not significantly associated with SjD in adjusted models. The top individual hormone exposures associated with SjD included estrogen replacement therapy (ERT; RR 1.78 [95% CI 1.47-2.14]), polycystic ovarian syndrome (1.65 [1.28-2.12]), and hysterectomy without bilateral oophorectomy (1.51 [1.13-2.03]). We identified comorbidities preceding SjD including fibromyalgia, pulmonary disease, diabetes, lymphoma, osteoporosis, peripheral vascular disease, and renal disease. Taking comorbidities into account, we developed a predictive model for SjD that included fibromyalgia (2.50 [1.93-3.25]), osteoporosis (1.84 [1.27-2.66]), hormone replacement therapy (HRT) (1.61 [1.22-2.12]), diabetes (0.27 [0.13-0.50]), and body mass index (BMI) (0.97 [0.95-0.99]). CONCLUSIONS We report a novel algorithm to improve identifying patients at risk for SjD and describe sex hormone association with SjD. Finally, we report new comorbidities associated with SjD decrease, BMI and diabetes, and increase, lymphoma and osteoporosis.. Key Points •Given female predominance and typical perimenopausal onset, sex hormones should be considered when studying comorbidities in Sjögren's disease. •The top exposures associated with developing Sjögren's disease included fibromyalgia, osteoporosis, and use of hormone replacement therapy. Possible protective factors included prior diabetes and higher body mass index. •We used our newly identified exposures to generate a predictive algorithm, which has potential to improve diagnosis and pathogenic insights into Sjögren's disease.
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Affiliation(s)
- Sara S McCoy
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin, 1685 Highland Avenue, Madison, WI, 53705-2281, USA.
| | - Scott Hetzel
- Department of Biostatistics and Medical Informatics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
- Department of Population Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Jeffrey J VanWormer
- Center for Clinical Epidemiology and Population Health, Marshfield Clinic Research Institute, Marshfield, WI, USA
| | - Christie M Bartels
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin, 1685 Highland Avenue, Madison, WI, 53705-2281, USA
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17
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Corneal Confocal Microscopy in the Diagnosis of Small Fiber Neuropathy: Faster, Easier, and More Efficient Than Skin Biopsy? PATHOPHYSIOLOGY 2021; 29:1-8. [PMID: 35366285 PMCID: PMC8954271 DOI: 10.3390/pathophysiology29010001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 02/06/2023] Open
Abstract
Chronic pain may affect 30–50% of the world’s population and an important cause is small fiber neuropathy (SFN). Recent research suggests that autoimmune diseases may be one of the most common causes of small nerve fiber damage. There is low awareness of SFN among patients and clinicians and it is difficult to diagnose as routine electrophysiological methods only detect large fiber abnormalities, and specialized small fiber tests, like skin biopsy and quantitative sensory testing, are not routinely available. Corneal confocal microscopy (CCM) is a rapid, non-invasive, reproducible method for quantifying small nerve fiber degeneration and regeneration, and could be an important tool for diagnosing SFN. This review considers the advantages and disadvantages of CCM and highlights the evolution of this technique from a research tool to a diagnostic test for small fiber damage, which can be a valuable contribution to the study and management of autoimmune disease.
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18
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Callaghan BC, Singleton JR. Causes and Implications of Isolated Small Fiber Neuropathy. Neurology 2021; 97:1015-1016. [PMID: 34706973 DOI: 10.1212/wnl.0000000000012895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Brian C Callaghan
- From the Department of Neurology (B.C.C.), University of Michigan, Ann Arbor; and Department of Neurology (J.R.S.), University of Utah, Salt Lake City.
| | - J Robinson Singleton
- From the Department of Neurology (B.C.C.), University of Michigan, Ann Arbor; and Department of Neurology (J.R.S.), University of Utah, Salt Lake City
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