Electrophysiological studies in patients with seropositive/seronegative myasthenia gravis

Background: Myasthenia gravis (MG) affects the neuromuscular transmission, causing fluctuating muscle weakness and fatigue. This study is carried out with the aim to study the electrophysiologic findings of different subtypes of MG referred to our center in Tehran, Iran. Methods: All patients with MG presenting to neurology department of Shariati Hospital, Tehran University of Medical Sciences were enrolled. Clinically, patients with MG were categorized as ocular vs. generalized. The acetylcholine receptor (Ach-R) and muscle-specific receptor tyrosine kinase (anti-MuSK) antibodies were performed. Repetitive Nerve Stimulation (RNS) was performed using the standard method, with supramaximal stimulation of muscles at the 3 Hz frequency by surface electrode at rest. Abductor pollicis brevis (APB) (median nerve), anconeus (radial nerve), trapezius (accessory nerve), and nasalis (facial nerve) muscles were studied in all patients. Single fiber electromyography (SFEMG) was performed by standard method. Results: 196 seropositive patients with MG were included in the study. In electrophysiological studies, RNS was performed for 146 patients of Ach-R-Ab positive MG, with positive results in 110 patients. In addition, SFEMG was conducted for 8 patients with negative RNS, which resulted in 7 positive tests.

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Congenital myasthenic syndromes in adult neurology clinic

Neurology ◽

10.1212/wnl.0000000000006478 ◽

2018 ◽

Vol 91 (19) ◽

pp. e1770-e1777 ◽

Cited By ~ 9

Author(s):

Justin C. Kao ◽

Margherita Milone ◽

Duygu Selcen ◽

Xin-Ming Shen ◽

Andrew G. Engel ◽

...

Keyword(s):

Myasthenia Gravis ◽

Clinical Laboratory ◽

Age At Onset ◽

Diagnostic Delay ◽

Repetitive Nerve Stimulation ◽

Congenital Myasthenic Syndromes ◽

Muscle Diseases ◽

Seronegative Myasthenia Gravis ◽

Neurology Clinic ◽

Myasthenic Syndromes

ObjectiveTo investigate the diagnostic challenges of congenital myasthenic syndromes (CMS) in adult neuromuscular practice.MethodsWe searched the Mayo Clinic database for patients with CMS diagnosed in adulthood in the neuromuscular clinic between 2000 and 2016. Clinical, laboratory, and electrodiagnostic data were reviewed.ResultsWe identified 34 patients with CMS, 30 of whom had a molecular diagnosis (14 DOK7, 6 RAPSN, 2 LRP4, 2 COLQ, 2 slow-channel syndrome, 1 primary acetylcholine receptor deficiency, 1 AGRN, 1 GFPT1, and 1 SCN4A). Ophthalmoparesis was often mild and present in 13 patients. Predominant limb-girdle weakness occurred in 19 patients. Two patients had only ptosis. Age at onset ranged from birth to 39 years (median 5 years). The median time from onset to diagnosis was 26 years (range 4–56 years). Thirteen patients had affected family members. Fatigable weakness was present when examined. Creatine kinase was elevated in 4 of 23 patients (range 1.2–4.2 times the upper limit of normal). Repetitive nerve stimulation revealed a decrement in 30 patients. Thirty-two patients were previously misdiagnosed with seronegative myasthenia gravis (n = 16), muscle diseases (n = 15), weakness of undetermined cause (n = 8), and others (n = 4). Fifteen patients received immunotherapy or thymectomy without benefits. Fourteen of the 25 patients receiving pyridostigmine did not improve or worsen.ConclusionMisdiagnosis occurred in 94% of the adult patients with CMS and causes a median diagnostic delay of nearly 3 decades from symptom onset. Seronegative myasthenia gravis and muscle diseases were the 2 most common misdiagnoses, which led to treatment delay and unnecessary exposure to immunotherapy, thymectomy, or muscle biopsy.

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Muscle-Specific Receptor Tyrosine Kinase Antibody-Positive and Seronegative Myasthenia Gravis

Frontiers of Neurology and Neuroscience - Immune-Mediated Neuromuscular Diseases ◽

10.1159/000212372 ◽

2009 ◽

pp. 109-119 ◽

Cited By ~ 10

Author(s):

Srikanth Muppidi ◽

Gil I. Wolfe

Keyword(s):

Tyrosine Kinase ◽

Myasthenia Gravis ◽

Receptor Tyrosine Kinase ◽

Specific Receptor ◽

Seronegative Myasthenia Gravis

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Comparison of two rapid tests for the detection of legionellaceae in water: a microbiological-immunological method and a commercial gene-probe testkit

Water Science & Technology ◽

10.2166/wst.1995.0648 ◽

1995 ◽

Vol 31 (5-6) ◽

pp. 403-406 ◽

Cited By ~ 1

Author(s):

E. Frahm ◽

U. Obst

Keyword(s):

Monoclonal Antibodies ◽

Conventional Method ◽

Standard Method ◽

False Positive ◽

Gene Probe ◽

Immunological Method ◽

Probe Test ◽

Rapid Tests ◽

Positive Results

Two recently developed Legionella detection tests, a microbiological-immunological method based on monoclonal antibodies (carried out as a colony-blot assay) and a commercial gene-probe testkit (the EnvironAmp Legionella Kit), are compared with the standard method. The colony-blot assay is faster than the conventional method; the gene-probe test is much faster still and is the most sensitive, but in consequence is at greater risk of false-positive results.

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Short-Term Ultramicronized Palmitoylethanolamide Therapy in Patients with Myasthenia Gravis: a Pilot Study to Possible Future Implications of Treatment

CNS & Neurological Disorders - Drug Targets ◽

10.2174/1871527318666190131121827 ◽

2019 ◽

Vol 18 (3) ◽

pp. 232-238 ◽

Cited By ~ 5

Author(s):

Emanuela Onesti ◽

Vittorio Frasca ◽

Marco Ceccanti ◽

Giorgio Tartaglia ◽

Maria Cristina Gori ◽

...

Keyword(s):

Pilot Study ◽

Myasthenia Gravis ◽

Repetitive Nerve Stimulation ◽

Beneficial Effects ◽

Antibody Titers ◽

The Stability ◽

Ultramicronized Palmitoylethanolamide ◽

Open Pilot

Background: The cannabinoid system may be involved in the humoral mechanisms at the neuromuscular junction. Ultramicronized-palmitoylethanolamide (μm-PEA) has recently been shown to reduce the desensitization of Acetylcholine (ACh)-evoked currents in denervated patients modifying the stability of ACh receptor (AChR) function. <p> Objective: To analyze the possible beneficial effects of μm-PEA in patients with myasthenia gravis (MG) on muscular fatigue and neurophysiological changes. <p> Method: The duration of this open pilot study, which included an intra-individual control, was three weeks. Each patient was assigned to a 1-week treatment period with μm-PEA 600 mg twice a day. A neurophysiological examination based on repetitive nerve stimulation (RNS) of the masseteric and the axillary nerves was performed, and the quantitative MG (QMG) score was calculated in 22 MG patients every week in a three-week follow-up period. AChR antibody titer was investigated to analyze a possible immunomodulatory effect of PEA in MG patients. <p> Results: PEA had a significant effect on the QMG score (p=0.03418) and on RNS of the masseteric nerve (p=0.01763), thus indicating that PEA reduces the level of disability and decremental muscle response. Antibody titers did not change significantly after treatment. <p> Conclusion: According to our observations, μm-PEA as an add-on therapy could improve muscular response to fatigue in MG. The possible modulation of AChR currents as a means of eliciting a direct effect from PEA on the conformation of ACh receptors should be investigated. The co-role of cytokines also warrants an analysis. Given the rapidity and reversibility of the response, we suppose that PEA acts directly on AChR, though further studies are needed to confirm this hypothesis.

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Myasthenia gravis in children: analysis of 18 patients

Arquivos de Neuro-Psiquiatria ◽

10.1590/s0004-282x2001000500005 ◽

2001 ◽

Vol 59 (3B) ◽

pp. 681-685 ◽

Cited By ~ 13

Author(s):

Maria da Penha A. Morita ◽

Alberto A. Gabbai ◽

Acary S.B. Oliveira ◽

Audrey S. Penn

Keyword(s):

Myasthenia Gravis ◽

Intravenous Immunoglobulin ◽

Acetylcholine Receptor ◽

Nerve Stimulation ◽

Chest Ct ◽

Clinical Severity ◽

Myasthenic Crisis ◽

Repetitive Nerve Stimulation ◽

Follicular Hyperplasia ◽

Receptor Antibodies

Myasthenia gravis (MG) in childhood is rare comprising 10 to 20 % of all myasthenic patients. We studied 18 patients with MG whose first symptoms started from 1 to 12 years of age, followed at the Department of Neurology of the UNIFESP-EPM, from January 1983 to August 1997. There were 10 girls and 8 boys (1.2:1). Eleven patients (61%) presented moderate or severe generalized disease and 4 (22%) had at least one myasthenic crisis. EMG with supramaximal repetitive nerve stimulation was diagnostic in 8 (47%) out of 17 patients, and chest CT was normal in 14 patients. Seropositivity to acetylcholine receptor antibodies was found in 81.6% (9 out of 11 tested) and the levels had no relation to clinical severity. Nine out of 16 patients (56%) worsened with pyridostigmine alone and were treated with prednisone. Four out of those nine continued worsening despite steroids and were subjected to thymectomy (all showed thymic lymphoid follicular hyperplasia). Three patients (75%) improved markedly after thymectomy and one (25%) worsened, eventually getting better with intravenous immunoglobulin and oral azathioprine. MG treatment, using all resources available, has to be individualized for each child.

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