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Find video protocols related to scientific articles indexed in Pubmed.
When should MERRF (myoclonus epilepsy associated with ragged-red fibers) be the diagnosis?
Arq Neuropsiquiatr
PUBLISHED: 06-13-2014
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Myoclonic epilepsy associated with ragged red fibers (MERRF) is a rare mitochondrial disorder. Diagnostic criteria for MERRF include typical manifestations of the disease: myoclonus, generalized epilepsy, cerebellar ataxia and ragged red fibers (RRF) on muscle biopsy. Clinical features of MERRF are not necessarily uniform in the early stages of the disease, and correlations between clinical manifestations and physiopathology have not been fully elucidated. It is estimated that point mutations in the tRNALys gene of the DNAmt, mainly A8344G, are responsible for almost 90% of MERRF cases. Morphological changes seen upon muscle biopsy in MERRF include a substantive proportion of RRF, muscle fibers showing a deficient activity of cytochrome c oxidase (COX) and the presence of vessels with a strong reaction for succinate dehydrogenase and COX deficiency. In this review, we discuss mainly clinical and laboratory manifestations, brain images, electrophysiological patterns, histology and molecular findings as well as some differential diagnoses and treatments.
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Muscle biopsy in Pompe disease.
Arq Neuropsiquiatr
PUBLISHED: 05-22-2013
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Pompe disease (PD) can be diagnosed by measuring alpha-glucosidase levels or by identifying mutations in the gene enzyme. Muscle biopsies can aid diagnosis in doubtful cases. Methods: A review of muscle biopsy from 19 cases of PD (infantile, 6 cases; childhood, 4 cases; and juvenile/adult, 9 cases). Results: Vacuoles with or without glycogen storage were found in 18 cases. All cases had increased acid phosphatase activity. The vacuole frequency varied (almost all fibers in the infantile form to only a few in the juvenile/adult form). Atrophy of type 1 and 2 fibers was frequent in all forms. Atrophic angular fibers in the NADH-tetrazolium reductase and nonspecific esterase activity were observed in 4/9 of the juvenile/adult cases. Conclusion: Increased acid phosphatase activity and vacuoles were the primary findings. Most vacuoles were filled with glycogen, and the adult form of the disease had fewer fibers with vacuoles than the infantile or childhood forms.
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Salbutamol therapy in congenital myasthenic syndrome due to DOK7 mutation.
J. Neurol. Sci.
PUBLISHED: 03-27-2013
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Salbutamol is a selective B2-adrenergic agonist, which has previously been described to be associated with partial improvement of myasthenia gravis and congenital myasthenic syndromes (CMS). In this study, we analyzed the effect of salbutamol in five patients with Dok-7 CMS.
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Myasthenia gravis and thymus: long-term follow-up screening of thymectomized and non-thymectomized patients.
Arq Neuropsiquiatr
PUBLISHED: 03-05-2013
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Thymoma screening is recommended at the onset of myasthenia gravis (MG) or when patients with MG present with clinical deterioration or a progressive increase of anti-acetylcholine receptor antibody. However, it is unknown if it is necessary to repeat the screening of thymoma at fixed intervals, even in the absence of MG deterioration, when the initial screening is negative. We analyzed the recurrence rate and incidence of new thymoma in a series of patients with well-controlled MG. The sample consisted of 53 patients, aged 17 to 72 years, and the follow-up varied between 75 and 472 months. The chest computerized tomography detected thymus abnormalities in eight patients at the initial screening and no abnormalities in all patients at a second screening after five years. The findings of this study support the classical opinion that screening for thymoma should be recommended only if there is clinical deterioration due to the disease.
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Identification and functional characterization of a novel mutation in the NKX2-1 gene: comparison with the data in the literature.
Thyroid
PUBLISHED: 02-06-2013
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NKX2-1 mutations have been described in several patients with primary congenital hypothyroidism, respiratory distress, and benign hereditary chorea, which are classical manifestations of the brain-thyroid-lung syndrome (BTLS).
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The clinical value of laryngeal electromyography in laryngeal immobility.
J Clin Neurosci
PUBLISHED: 02-18-2011
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Although laryngeal electromyography (LEMG) is commonly performed, there are no data confirming its efficacy. We evaluated 40 patients with a laryngoscopic diagnosis of unilateral vocal-fold immobility who underwent LEMG of the thyroarytenoid (TA) and cricothyroid (CT) muscle, with the immobile side of each muscle being compared to the normal side. The immobile side compared to the normal side showed more fibrillation potentials and positive sharp waves for the TA (p=0.04), longer MUAP duration for the TA (p=0.04) and CT (p=0.01), more polyphasic potentials for the TA (p=0.002), and more frequent decreased recruitment for the TA (p<0.01) and CT (p=0.008). Specificity and positive predictive value were around 90%. Sensitivity, negative predictive value and accuracy were around 50%. These results suggest that altered LEMG findings are reliable and they can be used to determine the innervation status of an immobile muscle. Conversely, when the LEMG is normal, the results should be reviewed.
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Idiopathic inflammatory myopathies in childhood: a brief review of 27 cases.
Pediatr. Neurol.
PUBLISHED: 01-24-2011
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The most common idiopathic inflammatory myopathies in children include juvenile dermatomyositis, juvenile polymyositis, and myositis associated with another autoimmune disease (overlap myositis). Idiopathic inflammatory myopathies manifest different characteristics affecting children. Only a few investigations of childhood idiopathic inflammatory myopathies were reported, involving 27 patients. In addition, clinical findings, serum muscular enzyme levels, results of electromyography studies, muscle biopsy features, and treatment responses were studied. Seventeen female and 10 male were classified as exhibiting juvenile dermatomyositis (n = 19), juvenile polymyositis (n = 6), or overlap myositis (n = 2). Overlap myositis was associated with systemic sclerosis and systemic erythematous lupus. The mean age at onset was 6.1 years for juvenile dermatomyositis, 4.9 years for juvenile polymyositis, and 8.5 years for overlap myositis. The most common signs included proximal weakness and myalgia. The serum creatine kinase level was increased in 48.2% of patients. An electromyography study revealed myopathic features in 85% of patients. Muscle biopsies led to observations of inflammatory infiltrates with preferential perivascular involvement in the juvenile dermatomyositis group, and endomysial involvement in the juvenile polymyositis group. Fiber atrophy was predominantly perifascicular in the juvenile dermatomyositis group. Treatment with prednisone improved the findings in 81.5% of children.
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MERRF: Clinical features, muscle biopsy and molecular genetics in Brazilian patients.
Mitochondrion
PUBLISHED: 01-11-2011
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Myoclonic epilepsy with ragged red fibers (MERRF) is a mitochondrial disease that is characterized by myoclonic epilepsy with ragged red fibers (RRF) in muscle biopsies. The aim of this study was to analyze Brazilian patients with MERRF. Six patients with MERRF were studied and correlations between clinical findings, laboratory data, electrophysiology, histology and molecular features were examined. We found that blood lactate was increased in four patients. Electroencephalogram studies revealed generalized epileptiform discharges in five patients and generalized photoparoxysmal responses during intermittent photic stimulation in two patients. Muscle biopsies showed RRF in all patients using modified Gomori-trichrome and succinate dehydrogenase stains. Cytochrome c oxidase (COX) stain analysis indicated deficient activity in five patients and subsarcolemmal accumulation in one patient. Molecular analysis of the tRNA(Lys) gene with PCR/RFLP and direct sequencing showed the A8344G mutation of mtDNA in five patients. The presence of RRFs and COX deficiencies in muscle biopsies often confirmed the MERRF diagnosis. We conclude that molecular analysis of the tRNA(Lys) gene is an important criterion to help confirm the MERRF diagnosis. Furthermore, based on the findings of this study, we suggest a revision of the main characteristics of this disease.
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Non-paraneoplastic Lambert-Eaton myasthenic syndrome: a brief review of 10 cases.
Arq Neuropsiquiatr
PUBLISHED: 05-24-2010
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Lambert-Eaton myasthenic syndrome (LEMS) is an immune-mediated disorder of the presynaptic neuromuscular transmission, which more frequently occurs as the remote effect of a neoplasm, in the paraneoplastic form (P-LEMS), or in a non-paraneoplastic form (NP-LEMS); but few studies describe the clinical features of NP-LEMS. We analyzed the clinical manifestations, laboratory findings, electrophysiological studies, and treatment responses in ten Brazilian patients suffering from NP-LEMS. The mean age was 41.5 years. More often neurological findings were hyporeflexia or areflexia with a post-exercise improvement. Treatment response occurred with pyridostigmine, guanidine, prednisone, azathioprine, and cyclosporine; but not response was observed after intravenous immunoglobulin and plasma exchange. Age at onset, clinical manifestations, and electrophysiological abnormalities can help more in the diagnosis than serum antibodies; the symptomatic treatment with pyridostigmine was effective; and the immunosuppressive treatment with prednisone, azathioprine, or cyclosporine was more beneficial than plasma exchange or intravenous immunoglobulin treatment.
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An electrophysiological study of the intermediate syndrome of organophosphate poisoning.
J Clin Neurosci
PUBLISHED: 05-18-2010
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Acute organophosphate (OP) poisoning is commonly seen in emergency medicine. Neurologists must be alert to detect neuromuscular transmission failure and other neurological complications that follow OP poisoning. We report a 37-year-old male with acute OP poisoning to emphasize the electrophysiological abnormalities during the intermediate syndrome (IMS). Motor nerve conduction studies revealed that a single nerve stimulation evoked a repetitive compound muscle action potential, whereas repetitive nerve stimulation resulted in a combination of a decrement-increment pattern and a repetitive fade response. Thus, electrophysiological studies can be used to monitor patients with IMS, and these test results correlate well with clinical findings in acute OP poisoning.
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Influence of treatment in multiple sclerosis disability: an open, retrospective, non-randomized long-term analysis.
Arq Neuropsiquiatr
PUBLISHED: 03-02-2010
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The efficacies of immunosuppressive (IMS) and immunomodulatory (IMM) drugs for multiple sclerosis (MS) have been reported in several studies. These agents can reduce relapse rates and lesions observed by magnetic resonance imaging studies. However, the effect of these medications in disability progression over 4 years is rarely examined.
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MELAS: clinical features, muscle biopsy and molecular genetics.
Arq Neuropsiquiatr
PUBLISHED: 05-28-2009
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The aim of the study was to analyze a series of Brazilian patients suffering from MELAS.
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Muscle biopsy features in critical ill patients with 2009 influenza A (H1N1) virus infection.
Arq Neuropsiquiatr
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Higher serum creatine kinase (CK) levels in critically ill patients with a confirmed 2009 influenza A (H1N1) infection suggests a possible relationship between the H1N1 virus and muscle tissue. However, there have been no reports with an emphasis on muscle biopsies for patients infected with the H1N1 virus. The objective of this study was to investigate the histological characteristics of the muscle biopsies from critically ill patients with confirmed 2009 H1N1 infections. A series of ten patients with confirmed 2009 H1N1 infection, who presented increased serum CK levels, was analyzed. Histological study found small histochemical alterations in muscles fibers (mainly in NADH, SDH, COX, myophosphorylase, adenylate deaminase and PAS stains), and no histological changes were compatible with inflammatory myopathy. Although our critically ill patients had elevated CK levels, they exhibited few histological/histochemical abnormalities in their muscle biopsy samples; however, those alterations could be consistent with metabolic dysfunction associated with influenza H1N1 infection.
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Electrophysiological characteristics in four patients from Brazil with stiff person syndrome.
J Clin Neurosci
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Stiff person syndrome (SPS) is a rare immune-mediated disorder of the central nervous system characterized by muscle rigidity and episodic muscle spasms. The diagnosis of SPS is based on electrophysiological studies. We analyzed the electrophysiological features in four patients from Brazil who fulfilled the clinical criteria for SPS. The most common electrophysiological abnormalities were continuous motor unit activity, co-contracting, and the presence of the cutaneomuscular reflex. Despite all patients having clinical characteristics of SPS during the disease, no patient met all the electrophysiological criteria for SPS even after repeat electrophysiological studies. This shows that a diagnosis of SPS should not be restricted to patients with all the classic electrophysiological changes but should be considered in the presence of one or some of those changes.
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Congenital myasthenic syndrome: a brief review.
Pediatr. Neurol.
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Congenital myasthenic syndromes comprise heterogeneous genetic diseases characterized by compromised neuromuscular transmission. Congenital myasthenic syndromes are classified as presynaptic, synaptic, or postsynaptic, depending on the primary defects location within the neuromuscular junction. Presynaptic forms are the rarest, affecting an estimated 7-8% of patients; synaptic forms account for approximately 14-15% of patients; and the remaining 75-80% are attributable to postsynaptic defects. Clinical manifestations vary by congenital myasthenic syndrome subtype. Electrophysiologic, morphologic, and molecular descriptions of various forms of congenital myasthenic syndromes have led to an enhanced understanding of clinical manifestations and disease pathophysiology. Although congenital myasthenic syndromes are indicated by clinical manifestations, family history, electrophysiologic studies, and responses to acetylcholinesterase inhibitors, overlap in some presentations occurs. Therefore, genetic testing may be necessary to identify specific mutations in CHAT, COLQ, LAMB2, CHRNA, CHRNB, CHRND, CHRNE, CHRNG, RAPSN, DOK7, MUSK, AGRN, SCN4A, GFPT1, or PLEC1 genes. The identification of congenital myasthenic syndromes subtypes will prove important in the treatment of these patients. Different drugs may be beneficial, or should be avoided because they are ineffective or worsen some forms of congenital myasthenic syndromes. We explore the classification, clinical manifestations, electrophysiologic features, genetics, and treatment responses of each congenital myasthenic syndrome subtype.
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