Análise do jitter com agulha concêntrica em pacientes com miastenia gravis autoimune adquirida / Concentric needle jitter analysis in patients with autoimmune acquired myasthenia gravis

A técnica de eletromiografia de fibra única (EMGFU), mediante análise do jitter, é o método neurofisiológico mais sensível para a confirmação do distúrbio da junção neuromuscular na miastenia gravis (MG). Os registros são tradicionalmente obtidos com agulha de fibra única, de alto custo e reutilizável. Por causa da necessidade atual do uso de material descartável, a agulha concêntrica vem sendo utilizada em substituição à agulha de fibra única. A técnica utilizada é semelhante, porém os potencias de ação para a análise do jitter são obtidos com eletrodo de agulha concêntrica (Eletromiografia de fibra única - jitter com agulha concêntrica, EMGFU-JAC). Contudo, os estudos são escassos e as metodologias utilizadas são heterogêneas com a utilização dessa agulha. OBJETIVOS: Este estudo tem por objetivo mensurar os valores de jitter obtidos com agulha concêntrica, no músculo Orbicularis Oculi, em sujeitos saudáveis e em pacientes com MG autoimune adquirida e avaliar a validade do método nas formas generalizada e ocular da doença. MÉTODOS: Foram estudados 20 sujeitos saudáveis, 20 pacientes com miastenia gravis forma generalizada (grupo MGG) e 13 com a forma ocular da doença (grupo MGO). A EMGFU-JAC foi realizada em todos os participantes, idealmente com 20 medidas de jitter em cada estudo. O jitter foi expresso como a média das diferenças consecutivas (MCD). Em todos os pacientes do estudo foram realizados o teste de estimulação repetitiva e dosagem sérica de anticorpo antirreceptor de acetilcolina (ac-AChR) no momento da análise do jitter. Nos pacientes soronegativos para ac-AChR, foi pesquisado o anticorpo antimúsculo específico tirosina-quinase (ac-MuSK). Foram definidos o limite superior da normalidade (LSN) para a média do MCD de cada estudo e para valores individuais de MCD. Os critérios de anormalidade foram: (1) média do MCD acima do LSN; ou (2) mais de 10% dos valores individuais de MCD acima do LSN. A definição do LSN para valores...

Single fiber electromyography (SFEMG) technique, through jitter analysis, is the most sensitive neurophysiological method for confirmation of neuromuscular junction disorder in myasthenia gravis (MG). Records are traditionally obtained with single fiber needle, which is reusable and has a high-cost. Due to the current need of using disposable material, concentric needle has been used to replace single fiber needle. The technique is similar, but the action potential for jitter analysis is obtained with concentric needle electrode (SFEMG - concentric needle jitter, SFEMG-CNJ). However, studies are scarce and methodologies used are heterogeneous with the use of this needle. OBJECTIVES: This study aims to measure jitter values obtained with concentric needle in the Orbicularis Occuli muscle in healthy subjects and in patients with autoimmune acquired MG and to assess the validity of the method in generalized and ocular forms of the disease. METHODS: 20 healthy subjects, 20 patients with generalized myasthenia gravis (GMG group) and 13 with the ocular form of the disease (OMG group) were studied. SFEMG-CNJ was performed on all participants, ideally with 20 jitter values in each study. Jitter was expressed as the mean consecutive difference (MCD). Repetitive nerve stimulation and serum acetylcholine receptor antibody (AChR-ab) were performed in all patients in the study, by the time of jitter analysis. Tyrosine kinase specific antibody muscle antibodies (MuSK-ab) were performed in AChR-ab negative patients. The upper limit of normality (ULN) for the mean MCD and for individual jitter values were defined. The abnormality criteria were: (1) mean MCD above ULN; or (2) more than 10% of individual jitter values above ULN. The definition of ULN for individual jitter values was based on the concept that two out of 20 jitter values above ULN are acceptable in a healthy muscle for voluntary contraction technique. Therefore, the ULN for the 18th highest...

Combined nerve conduction index in diabetic polyneuropathy.

UNLABELLED: Diabetic polyneuropathy can be confirmed by nerve conduction studies. The data can be analyzed in the form of a combined index instead of individual parameters. METHODS: The combined index included five parameters of nerve conduction studies commonly used for evaluation of polyneuropathies. We evaluated sensitivity in 100 diabetic patients with suspected polyneuropathy, and specificity in 200 non-diabetic patients with suspected lumbosacral radiculopathy. All results were expressed in number of standard deviations (SD). RESULTS: The sensitivity of the combined index was 81 or 74%, and specificity was 97 or 98%, using respectively -2.0 or -2.5 SD as cutoff. The range of sensitivity of the other parameters was 57-65% or 48-56%, and specificity range was 96-98% or 98-100%, using the same criteria. DISCUSSION: The combined index had higher sensitivity and equivalent specificity compared to isolated parameters.

Combined nerve conduction index in diabetic polyneuropathy / Índice combinado de condução nervosa na polineuropatia diabética

Diabetic polyneuropathy can be confirmed by nerve conduction studies. The data can be analyzed in the form of a combined index instead of individual parameters. METHODS: The combined index included five parameters of nerve conduction studies commonly used for evaluation of polyneuropathies. We evaluated sensitivity in 100 diabetic patients with suspected polyneuropathy, and specificity in 200 non-diabetic patients with suspected lumbosacral radiculopathy. All results were expressed in number of standard deviations (SD). RESULTS: The sensitivity of the combined index was 81 or 74%, and specificity was 97 or 98%, using respectively -2.0 or -2.5 SD as cutoff. The range of sensitivity of the other parameters was 57-65% or 48-56%, and specificity range was 96-98% or 98-100%, using the same criteria. DISCUSSION: The combined index had higher sensitivity and equivalent specificity compared to isolated parameters.

A polineuropatia diabética pode ser confirmada por estudos de condução nervosa. Os dados podem ser analisados por um índice combinado ao invés de parâmetros isolados. MÉTODOS: O índice combinado incluiu cinco parâmetros usados rotineiramente na avaliação de polineuropatias. Avaliamos a sensibilidade em 100 pacientes diabéticos com suspeita de polineuropatia e a especificidade em 200 pacientes não diabéticos com suspeita de radiculopatia lombossacral. Todos os resultados foram expressos em número de desvios-padrão (DP). RESULTADOS: A sensibilidade do índice combinado foi 81 ou 74%, e a especificidade foi 97 ou 98%, usando respectivamente -2,0 ou -2,5 DP como ponto de corte. A sensibilidade dos parâmetros isolados oscilou entre 57-65% ou 48-56%, e a especificidade foi 96-98% ou 98-100%, usando os mesmos critérios. DISCUSSÃO: O índice combinado apresentou melhor sensibilidade e especificidade equivalente aos parâmetros isolados.

Acute axonal polyneuropathy with predominant proximal involvement: an uncommon neurological complication of bariatric surgery.

Bariatric surgery is frequently indicated in the treatment of morbid obesity. Previously unreported complications have been associated to this surgery; among them, neurological complications have gained attention. We report the case of a 25-year-old man submitted to gastric surgery for treatment of morbid obesity who developed, two months after surgery, acute proximal weakness in lower limbs. The electroneuromyography revealed axonal peripheral polyneuropathy with predominant proximal involvement. After treatment with immunoglobulin and vitamin supplementation, rapid clinical and neurophysiologic recovery was observed. We describe the clinical and electroneuromyographic features of this case, stressing the difficulty of initial diagnosis, particularly in the differential diagnosis with Guillain-Barré syndrome. We discuss the importance of nutritional follow-up and the eventual indication of routine vitamin supplementation in these patients.

Acute axonal polyneuropathy with predominant proximal involvement: an uncommon neurological complication of bariatric surgery / Polineuropatia axonal aguda com acometimento proximal predominante: manifestação neurológica incomum de cirurgia bariátrica

Bariatric surgery is frequently indicated in the treatment of morbid obesity. Previously unreported complications have been associated to this surgery; among them, neurological complications have gained attention. We report the case of a 25-year-old man submitted to gastric surgery for treatment of morbid obesity who developed, two months after surgery, acute proximal weakness in lower limbs. The electroneuromyography revealed axonal peripheral polyneuropathy with predominant proximal involvement. After treatment with immunoglobulin and vitamin supplementation, rapid clinical and neurophysiologic recovery was observed. We describe the clinical and electroneuromyographic features of this case, stressing the difficulty of initial diagnosis, particularly in the differential diagnosis with Guillain-Barré syndrome. We discuss the importance of nutritional follow-up and the eventual indication of routine vitamin supplementation in these patients.

A cirurgia bariátrica é freqüentemente indicada no tratamento da obesidade mórbida. Complicações previamente não relatadas têm sido associadas a essa cirurgia; dentre estas, as complicações neurológicas têm recebido destaque. Relatamos o caso de um homem de 25 anos de idade submetido a cirurgia gástrica para tratamento de obesidade mórbida que desenvolveu, dois meses após a cirurgia, fraqueza de predomínio proximal nos membros inferiores, de instalação aguda. A eletroneuromiografia demonstrou polineuropatia periférica axonal nos membros inferiores, de predomínio proximal. Após tratamento com imunoglobulina e suplementação vitamínica, apresentou rápida melhora clínica e neurofisiológica. Descrevemos as características clínicas e eletroneuromiográficas desse caso, destacando a dificuldade diagnóstica inicial, particularmente com relação ao diagnóstico diferencial com síndrome de Guillain-Barré. Discutimos a importância de acompanhamento nutricional e a eventual indicação de suplementação vitamínica de rotina nesses pacientes.

A case of primary spinal myoclonus: clinical presentation and possible mechanisms involved.

Spinal myoclonus is a rare movement disorder characterized by myoclonic involvement of a group of muscles supplied by a few contiguous segments of the spinal cord. Structural lesions are usually the cause, but in primary spinal myoclonus the etiology remains unknown. We present the case of a 26-year-old woman with cervical spinal myoclonus in which both clinical and electromyographic findings pointed to the segment C1-C3 as the origin of the myoclonus. Laboratorial examinations were normal and no structural lesion was found in magnetic resonance imaging (MRI). Botulinum toxin type A was injected in infrahyoid muscles and cervical paraspinal musculature. The patient remained free of symptoms for almost five months. The pathophysiology of spinal myoclonus remains speculative, but there is evidence that various possible mechanisms can be involved: loss of inhibitory function of local dorsal horn interneurons, abnormal hyperactivity of local anterior horn neurons, aberrant local axons re-excitations and loss of inhibition from suprasegmentar descending pathways.

[Bilateral hemifacial spasm: case report]. / Espasmo hemifacial bilateral: relato de caso.

Bilateral hemifacial spasm (BHS) is a rare focal movement disorder often associated with vascular compression of both facial nerves. The contractions are usually asymmetric and asynchronous. Typically, one side is affected first and there is a long but variable interval for the symptoms on the other side to occur. BHS must be differentiated from other conditions including blefarospasm, facial myokymia, facial tics, oromandibular dystonia, and hemimasticatory spasm. The most successful and non-invasive symtomatic treatment is botulinum toxin injections but microvascular decompression surgery is another therapeutic option. We report the case of a 70 years old man with bilateral hemifacial spasms and present a brief review of the literature.

A case of primary spinal myoclonus. Clinical presentation and possible mechanisms involved

Spinal myoclonus is a rare movement disorder characterized by myoclonic involvement of a group of muscles supplied by a few contiguous segments of the spinal cord. Structural lesions are usually the cause, but in primary spinal myoclonus the etiology remains unknown. We present the case of a 26-year-old woman with cervical spinal myoclonus in which both clinical and electromyographic findings pointed to the segment C1-C3 as the origin of the myoclonus. Laboratorial examinations were normal and no structural lesion was found in magnetic resonance imaging (MRI). Botulinum toxin type A was injected in infrahyoid muscles and cervical paraspinal musculature. The patient remained free of symptoms for almost five months. The pathophysiology of spinal myoclonus remains speculative, but there is evidence that various possible mechanisms can be involved: loss of inhibitory function of local dorsal horn interneurons, abnormal hyperactivity of local anterior horn neurons, aberrant local axons re-excitations and loss of inhibition from suprasegmentar descending pathways

Espasmo hemifacial bilateral. Relato de caso / Bilateral hemifacial spasm: case report

Espasmo hemifacial bilateral é um distúrbio de movimento raro geralmente associado à compressäo vascular dos nervos faciais. Caracteriza-se clinicamente por contrações assimétricas e assíncronas da musculatura facial e por longa latência entre a instalaçäo dos movimentos em cada hemiface. Deve ser diferenciado de outras condições como blefaroespasmo, miocimia facial, tiques faciais, distonia oromandibular e espasmo hemimastigatório. O tratamento sintomático mais eficaz e menos invasivo consiste em aplicações de toxina botulínica mas abordagem cirúrgica de descompressäo microvascular é outra alternativa terapêutica. Relatamos o caso de homem de 70 anos com espasmo hemifacial bilateral e fazemos uma breve revisäo da literatura