ABSTRACT
Nerve conduction studies (NCS) are an essential aspect of the assessment of patients with peripheral neuropathies. However, conventional NCS do not reflect activation of small afferent fibers, including Aδ and C fibers. A definitive gold standard for laboratory evaluation of these fibers is still needed and therefore, clinical evaluation remains fundamental in patients with small fiber neuropathies (SFN). Several clinical and research techniques have been developed for the assessment of small fiber function, such as (i) microneurography, (ii) laser evoked potentials, (iii) contact heat evoked potentials, (iv) pain-related electrically evoked potentials, (v) quantitative thermal sensory testing, (vi) skin biopsy-intraepidermal nerve fiber density and (vii) corneal confocal microscopy. The first five are physiological techniques, while the last two are morphological. They all have advantages and limitations, but the combined use of an appropriate selection of each of them would lead to gathering invaluable information for the diagnosis of SFN. In this review, we present an update on techniques available for the study of small afferent fibers and their clinical applicability. A summary of the anatomy and important physiological aspects of these pathways, and the clinical manifestations of their dysfunction is also included, in order to have a minimal common background.
Subject(s)
Peripheral Nervous System Diseases , Small Fiber Neuropathy , Evoked Potentials , Humans , Nerve Fibers, Unmyelinated , Pain , Peripheral Nervous System Diseases/diagnosis , Skin/innervation , Small Fiber Neuropathy/diagnosisABSTRACT
Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of acquired immune-mediated diseases, which typically involve the striated muscle with a variable involvement of the skin and other organs. Clinically, they are characterized by proximal muscle weakness, elevation of muscle enzymes, myopathic changes on electromyography and an abnormal muscle biopsy. The different IIM have been classified according to their distinctive histopathologic features in dermatomyositis (DM), polymyositis (PM), inclusion body myositis (IBM) and immune-mediated necrotizing myopathy (IMNM). Several myositis-specific antibodies are associated with the different phenotypes, as well as with different risk of neoplastic disease and systemic complications. The basis for the treatment of DM, PM, and IMNM is immunosuppression. For IBM there are only symptomatic treatments. Steroids, associated or not with other immunosuppressant drugs, are the first line of treatment. Biologic drugs will allow future individualized therapies. The 10-year survival of DM, PM and IMNM is 62 to 90%. The leading causes of death are neoplastic, lung and cardiac complications. IBM does not impair survival, although it affects the quality of life.
Subject(s)
Myositis/pathology , Antibodies , Dermatomyositis/pathology , Electromyography , Humans , Immunosuppressive Agents/classification , Immunosuppressive Agents/therapeutic use , Muscle, Skeletal/pathology , Myositis/drug therapy , Polymyositis/pathologyABSTRACT
Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of acquired immune-mediated diseases, which typically involve the striated muscle with a variable involvement of the skin and other organs. Clinically, they are characterized by proximal muscle weakness, elevation of muscle enzymes, myopathic changes on electromyography and an abnormal muscle biopsy. The different IIM have been classified according to their distinctive histopathologic features in dermatomyositis (DM), polymyositis (PM), inclusion body myositis (IBM) and immune-mediated necrotizing myopathy (IMNM). Several myositis-specific antibodies are associated with the different phenotypes, as well as with different risk of neoplastic disease and systemic complications. The basis for the treatment of DM, PM, and IMNM is immunosuppression. For IBM there are only symptomatic treatments. Steroids, associated or not with other immunosuppressant drugs, are the first line of treatment. Biologic drugs will allow future individualized therapies. The 10-year survival of DM, PM and IMNM is 62 to 90%. The leading causes of death are neoplastic, lung and cardiac complications. IBM does not impair survival, although it affects the quality of life.
Subject(s)
Humans , Myositis/pathology , Polymyositis/pathology , Muscle, Skeletal/pathology , Dermatomyositis/pathology , Electromyography , Immunosuppressive Agents/classification , Immunosuppressive Agents/therapeutic use , Antibodies , Myositis/drug therapyABSTRACT
Fabry's disease is an X-linked multisistemic lisosomal storage disorder caused by deficiency or absence in α-Galatosidase A. Symptoms develop early in childhood with small fiber neuropathy, autonomic disorders and skin lesions (angiokeratomas). More severe in males, patients develop over years heart disease (hypertrophic cardiomyopathy, bradycardia), proteinuria, renal failure, transient ischemic attacks and stroke, associated with decreased life expectancy. We report five patients with Fabry's disease aged between 21 to 56 years and with family history. Neuropathic symptoms are described and neurophysiological testing findings of nerve conduction studies, quantitative sensory testing, autonomic testing and sympathetic skin response are presented.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Young Adult , Fabry Disease/diagnosis , Carbamazepine/therapeutic use , Sensitivity and Specificity , Fabry Disease/drug therapy , Peripheral Nervous System Diseases/diagnosis , Analgesics, Non-Narcotic/therapeutic use , Somatosensory Disorders/diagnosis , Enzyme Replacement TherapyABSTRACT
The occurrence of mutations of TDP-43, FUS, and C9ORF72 in amyotrophic lateral sclerosis (ALS) suggests pathogenic alterations to RNA metabolism and specifically to microRNA (miRNA) biology. Moreover, several ALS-related proteins impact stress granule dynamics affecting miRNA biogenesis and cellular miRNA levels. miRNAs are present in different biological fluids and have been proposed as potential biomarkers. Here we used next-generation sequencing to perform a comparative analysis of the expression profile of circulating miRNAs in the serum of 2 mutant superoxide dismutase 1 transgenic mice. Top hit candidates were then validated using quantitative real-time polymerase chain reaction, confirming significant changes for 6 miRNAs. In addition, one of these miRNAs was also altered in mutant TDP-43 mice. Then, we tested this set of miRNAs in the serum from sporadic ALS patients, observing a significant deregulation of hsa-miR-142-3p and hsa-miR-1249-3p. A negative correlation between the revised ALS functional rating scale and hsa-miR-142-3p levels was found. Bioinformatics analysis of the regulatory network governed by hsa-miR-142-3p identified TDP-43 and C9orf72 as possible targets, suggesting a connection with ALS pathogenesis. This study identifies miRNAs that are altered in ALS that may serve as potentials biomarkers.
Subject(s)
Amyotrophic Lateral Sclerosis/diagnosis , Amyotrophic Lateral Sclerosis/genetics , Circulating MicroRNA/blood , Circulating MicroRNA/genetics , Genome-Wide Association Study , Transcriptome/genetics , Adult , Aged , Animals , Biomarkers/blood , Disease Models, Animal , Female , Humans , Male , Mice, TransgenicABSTRACT
Fabry's disease is an X-linked multisistemic lisosomal storage disorder caused by deficiency or absence in α-Galatosidase A. Symptoms develop early in childhood with small fiber neuropathy, autonomic disorders and skin lesions (angiokeratomas). More severe in males, patients develop over years heart disease (hypertrophic cardiomyopathy, bradycardia), proteinuria, renal failure, transient ischemic attacks and stroke, associated with decreased life expectancy. We report five patients with Fabry's disease aged between 21 to 56 years and with family history. Neuropathic symptoms are described and neurophysiological testing findings of nerve conduction studies, quantitative sensory testing, autonomic testing and sympathetic skin response are presented.
Subject(s)
Fabry Disease/diagnosis , Adult , Analgesics, Non-Narcotic/therapeutic use , Carbamazepine/therapeutic use , Enzyme Replacement Therapy , Fabry Disease/drug therapy , Female , Humans , Male , Middle Aged , Peripheral Nervous System Diseases/diagnosis , Sensitivity and Specificity , Somatosensory Disorders/diagnosis , Young AdultABSTRACT
Background: Carpal tunnel syndrome (CTS) represents 90% of entrapment neuropathies. Severity may be greater in older patients. Aim: To describe the electrophysiological findings in adult patients with CTS and determine if severity is related to age. Material and Methods: Descriptive and retrospective study of electrophysiological findings in patients over 18 years of age with clinical suspicion of CTS, studied between January 2011 and December 2015. Neurophysiological severity was classified in 3 grades, comparing them by age, gender and laterality. Results: Of 1156 patients subjected to electrophysiological studies due to a clinical suspicion of CTS, 690 (60%) had electrophysiological features of the disease. In 274 patients (24%) the compromise was mild, in 162 (14%) it was moderate and in 254 (22%) it was severe. There was a positive association between age and CTS severity (p < 0.01). Severity was significantly greater in males than females (p < 0.01). Bilateral CTS was present in 471 patients (68%), which was associated with increased age and severity (p < 0.01). Conclusions: Electrophysiological severity in CTS increases with age. Other factors associated with higher severity are male gender and bilateral disease.
Subject(s)
Humans , Male , Female , Adolescent , Adult , Middle Aged , Aged , Aged, 80 and over , Young Adult , Severity of Illness Index , Carpal Tunnel Syndrome/physiopathology , Age Factors , Electromyography , Carpal Tunnel Syndrome/diagnosis , Sex Factors , Retrospective Studies , Median Nerve/physiopathology , Neural ConductionABSTRACT
Human herpes virus 7 (HHV-7) is a cause of encephalitis, meningitis and myeloradiculoneuropathy in adults who are immunocompetent or with immunosuppression. The involvement of the peripheral nervous system is always associated with myelitis. We report a case of acute polyradiculoneuropathy due to HHV-7, without involvement of central nervous system, in an immunocompetent patient. A 35-years-old man complained of lumbar pain radiating to both buttocks. On examination muscle strength and tendon reflexes were normal. He had asymmetric pinprick and light touch saddle hypoesthesia and also in the perineal region, dorsum and lateral aspect of the left foot. Magnetic resonance imaging showed mild thickening and contrast enhancement of cauda equina nerve roots. Polymerase chain reaction performed on cerebrospinal fluid was positive for HVV-7. Other inflammatory, infectious and neoplastic etiologies were ruled out. Lumbar pain and hypoesthesia improved progressively and neurological examination was normal after one month. He did not receive antiviral therapy.
Subject(s)
Humans , Male , Adult , Polyradiculoneuropathy/virology , Herpesvirus 7, Human/isolation & purification , Roseolovirus Infections/complications , Immunocompetence , Magnetic Resonance Imaging , Polymerase Chain Reaction , Acute DiseaseSubject(s)
Age Factors , Carpal Tunnel Syndrome/physiopathology , Electromyography , Severity of Illness Index , Adolescent , Adult , Aged , Aged, 80 and over , Carpal Tunnel Syndrome/diagnosis , Female , Humans , Male , Median Nerve/physiopathology , Middle Aged , Neural Conduction , Retrospective Studies , Sex Factors , Young AdultABSTRACT
Human herpes virus 7 (HHV-7) is a cause of encephalitis, meningitis and myeloradiculoneuropathy in adults who are immunocompetent or with immunosuppression. The involvement of the peripheral nervous system is always associated with myelitis. We report a case of acute polyradiculoneuropathy due to HHV-7, without involvement of central nervous system, in an immunocompetent patient. A 35-years-old man complained of lumbar pain radiating to both buttocks. On examination muscle strength and tendon reflexes were normal. He had asymmetric pinprick and light touch saddle hypoesthesia and also in the perineal region, dorsum and lateral aspect of the left foot. Magnetic resonance imaging showed mild thickening and contrast enhancement of cauda equina nerve roots. Polymerase chain reaction performed on cerebrospinal fluid was positive for HVV-7. Other inflammatory, infectious and neoplastic etiologies were ruled out. Lumbar pain and hypoesthesia improved progressively and neurological examination was normal after one month. He did not receive antiviral therapy.
Subject(s)
Herpesvirus 7, Human/isolation & purification , Immunocompetence , Polyradiculoneuropathy/virology , Roseolovirus Infections/complications , Acute Disease , Adult , Humans , Magnetic Resonance Imaging , Male , Polymerase Chain ReactionABSTRACT
BACKGROUND: It is uncertain whether vitamin B-12 supplementation can improve neurophysiologic function in asymptomatic elderly with low vitamin B-12 status or whether folate status affects responses to vitamin B-12 supplementation. OBJECTIVE: We assessed the effects of a single intramuscular injection of 10 mg vitamin B-12 (which also contained 100 mg vitamin B-6 and 100 mg vitamin B-1) on vitamin B-12 status and neurophysiologic function in elderly community-dwelling Chileans with low serum vitamin B-12 concentrations who were consuming bread fortified with folic acid. DESIGN: A pretreatment and posttreatment study was conducted in 51 participants (median ± SD age: 73 ± 3 y; women: 47%) with serum vitamin B-12 concentrations <120 pmol/L at screening. Vitamin B-12 status was defined by combining vitamin B-12, plasma total homocysteine (tHcy), methylmalonic acid (MMA), and holotranscobalamin into one variable [combined indicator of vitamin B-12 status (cB-12)]. The response to treatment was assessed by measuring cB-12 and neurophysiologic variables at baseline and 4 mo after treatment. RESULTS: Treatment increased serum vitamin B-12, holotranscobalamin, and cB-12 (P < 0.001) and reduced plasma tHcy and serum MMA (P < 0.001). Treatment produced consistent improvements in conduction in myelinated peripheral nerves; the sensory latency of both the left and right sural nerves improved on the basis of faster median conduction times of 3.1 and 3.0 ms and 3.3 and 3.4 ms, respectively (P < 0.0001). A total of 10 sensory potentials were newly observed in sural nerves after treatment. Participants with high serum folate at baseline (above the median, ≥33.9 nmol/L) had less improvement in cB-12 (P < 0.001) than did individuals whose serum folate was less than the median concentration (i.e., with a concentration <33.9 nmol/L). CONCLUSION: Asymptomatic Chilean elderly with poor vitamin B-12 status displayed improved conductivity in myelinated peripheral nerves after vitamin B-12 treatment and an interaction with folate status, which was detected only with the use of cB-12. This trial was registered at www.controlled-trials.com as ISRCTN02694183.
Subject(s)
Dietary Supplements , Folic Acid/blood , Nerve Fibers, Myelinated/drug effects , Neural Conduction/drug effects , Peripheral Nerves/drug effects , Vitamin B 12 Deficiency/drug therapy , Vitamin B 12 , Aged , Chile , Female , Food, Fortified , Homocysteine/blood , Humans , Male , Methylmalonic Acid/blood , Nerve Fibers, Myelinated/physiology , Nutritional Status , Peripheral Nerves/physiology , Vitamin B 12/blood , Vitamin B 12/pharmacology , Vitamin B 12/therapeutic use , Vitamin B 12 Deficiency/blood , Vitamin B Complex/blood , Vitamin B Complex/pharmacology , Vitamin B Complex/therapeutic useABSTRACT
Recent genetic and neuropathologic advances support the concept that frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are overlapping multisystem disorders. While 10-15% of ALS patients fulfil criteria for FTD, features of motor neuron disease appear in approximately 15% of FTD patients, during the evolution of the disease. This overlap has been reinforced by the discovery of Transactive Response DNA Binding Protein 43 kDa (TDP43) inclusions as the main neuropathologic finding in the majority of ALS cases and almost a half of FTD cases. Also, an expansion in the intron of C9ORF72 (chromosome 9p21) has been identified in families affected by ALS, ALS-FTD and FTD. This review provides an update on the recent genetic and neuropathologic findings of ALS and FTD and a characterization of their clinical presentation forms, based on the current diagnostic criteria. Finally it underscores the importance of having a national registry of patients with ALS and FTD, to provide an earlier diagnosis and a multidisciplinary care.
Subject(s)
Amyotrophic Lateral Sclerosis , Frontotemporal Dementia , Amyotrophic Lateral Sclerosis/diagnosis , Amyotrophic Lateral Sclerosis/genetics , Amyotrophic Lateral Sclerosis/pathology , Amyotrophic Lateral Sclerosis/psychology , DNA Repeat Expansion , DNA-Binding Proteins/genetics , Frontotemporal Dementia/diagnosis , Frontotemporal Dementia/genetics , Frontotemporal Dementia/pathology , Frontotemporal Dementia/psychology , Genotype , Humans , MutationABSTRACT
Recent genetic and neuropathologic advances support the concept that frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are overlapping multisystem disorders. While 10-15% of ALS patients fulfil criteria for FTD, features of motor neuron disease appear in approximately 15% of FTD patients, during the evolution of the disease. This overlap has been reinforced by the discovery of Transactive Response DNA Binding Protein 43 kDa (TDP43) inclusions as the main neuropathologic finding in the majority of ALS cases and almost a half of FTD cases. Also, an expansion in the intron of C9ORF72 (chromosome 9p21) has been identified in families affected by ALS, ALS-FTD and FTD. This review provides an update on the recent genetic and neuropathologic findings of ALS and FTD and a characterization of their clinical presentation forms, based on the current diagnostic criteria. Finally it underscores the importance of having a national registry of patients with ALS and FTD, to provide an earlier diagnosis and a multidisciplinary care.
