Palatal prolapse during nasal expiration in patients with myasthenia gravis.

INTRODUCTION/AIMS: We have encountered patients with myasthenia gravis (MG) who exhibited palatal prolapse (PP) during nasal expiration in the supine position while awake. This may be an overlooked cause of dyspnea in MG patients. This study aimed to examine and describe the characteristics of MG patients with PP. METHODS: We reviewed the medical records of 183 consecutive patients who were diagnosed with MG in our hospital from 2012 to 2021. Thirty-two patients underwent laryngoscopy because of bulbar symptoms. Eight of these patients (25%) exhibited PP on laryngoscopy. Clinical features of these eight patients were retrospectively characterized. RESULTS: Median age of the eight patients with PP was 70 years. Six were men. Median body mass index was 21.6 kg/m2 . All patients exhibited PP in the supine position but not the sitting position. Although no patient had abnormal findings on spirometry nor chest computed tomography, six reported dyspnea or difficulty with nasal expiration only in the supine position. PP improved in all four patients who underwent edrophonium testing. All eight patients eventually improved after immunotherapy. DISCUSSION: PP during nasal expiration may be a cause of dyspnea in MG patients, along with respiratory muscle impairment, lung disease, and vocal cord paralysis. Laryngoscopy in the supine position is required to confirm.

Two-step nationwide epidemiological survey of myasthenia gravis in Japan 2018.

OBJECTIVE: To study the updated prevalence and clinical features of myasthenia gravis (MG) in Japan during 2017. METHODS: We sent survey sheets to the randomly selected medical departments (number = 7,545). First, we asked the number of MG patients who visited medical departments from January 1, 2017, to December 31, 2017. Then, we sent the second survey sheet to the medical departments that answered the first survey to obtain the clinical information of patients who received MG diagnosis between January 1, 2015, and December 31, 2017. RESULTS: The received answer to the first survey were 2,708 (recovery rate: 35.9%). After all, the prevalence of the 100,000 population was estimated as 23.1 (95%CI: 20.5-25.6). As a result of the second survey, we obtained 1,464 case records. After checking the duplications and lacking data, we utilized 1,195 data for further analysis. The median [interquartile range (IQR)] from the onset age of total patients was 59 (43-70) years old. The male-female ratio was 1: 1.15. The onset age [median (IQR)] for female patients was 58 (40-72) years old, and that for male patients was 60 (49-69) years old (Wilcoxon-Mann-Whitney test, p = 0.0299). We divided patients into four categories: 1) anti-acetylcholine receptor antibody (AChRAb) (+) thymoma (Tm) (-), 2) AChRAb(+)Tm(+), 3) anti-muscle-specific kinase antibody (MuSKAb) (+), and AChRAb(-)MuSKAb(-) (double negative; DN). The onset age [median (IQR)] of AChRAb(+)Tm(-) was 64 (48-73) years old, and AChRb(+)Tm(+) was 55 (45-66), MuSKAb(+) was 49 (36-64), DN was 47 (35-60) year old. The multivariate logistic regression analysis using sex, initial symptoms, repetitive nerve stimulation test (RNST), and edrophonium test revealed that sex, ocular symptoms, bulbar symptoms, and RNST were factors to distinguish each category. The myasthenia gravis activities of daily living profile at the severest state were significantly higher in MuSKAb(+). MuSKAb(+) frequently received prednisolone, tacrolimus plasmapheresis, and intravenous immunoglobulin; however, they received less acetylcholine esterase inhibitor. 99.2% of AChRAb(+)Tm(+) and 15.4% of AChRAb(+)Tm(-) received thymectomy. MuSKAb(+) did not receive thymectomy, and only 5.7% of DN received thymectomy. The prognosis was favorable in all categories. CONCLUSION: Our result revealed that the prevalence of Japanese MG doubled from the previous study using the same survey method in 2006. We also found that the onset age shifted to the elderly, and the male-female ratio reached almost even. Classification in four categories; AChRAb(+)Tm(-), AChRAb(+)Tm(+), MuSKAb(+), and DN, well describe the specific clinical features of each category and differences in therapeutic approaches.

[Immune checkpoint inhibitor-induced anti-striational antibodies in myasthenia gravis and myositis: a case report].

A 78-year-old man was treated with ipilimumab and nivolumab for advanced renal cell carcinoma with liver and lymph node metastasis. He developed diplopia, ptosis, dysphagia, and weakness of the limbs and neck, 1 month after treatment. Serum creatine kinase (CK) levels were elevated, and neck MRI revealed inflammation of the deep trunk muscles. Although anti-acetylcholine receptor antibody was negative, the edrophonium test was positive. Anti-striational antibodies such as the anti-titin and the anti-muscular voltage-gated potassium channel (Kv 1.4) antibodies (which serve as biomarkers of immune checkpoint inhibitors associated with myasthenia gravis and myositis) were positive (anti-titin antibody titer 11.51, normal <1 index; anti-Kv 1.4 antibody titer 15.13, normal <1 index). Intravenous methylprednisolone pulse therapy (1,000 mg/day for 3 days), plasmapheresis, and oral prednisolone (PSL) (20 mg/day) administration improved the patient's neurological function and normalized the serum CK levels. The PSL dosage was tapered without any worsening of clinical signs. The antibody titers decreased but remained positive (anti-titin antibody 5.00, anti-Kv 1.4 antibody 3.83) one year after the initial evaluation. Therefore, low-dose PSL (5 mg/day) administration was continued, and the patient was in remission.

The history of acetylcholinesterase inhibitors in the treatment of myasthenia gravis.

The beneficial effects of acetylcholinesterase inhibitors for the treatment of myasthenia gravis (MG) was a major discovery that came about through one young physician putting together a string of previous observations. To understand how this discovery came to light, we must first go back to earlier times when men hunted by bow-and-arrow to capture their prey. The substance used to poison the prey was eventually was identified as curare. Centuries later, a connection was made between the physiological effects of curare and a disease entity with no known pathological mechanism or treatment, myasthenia gravis. In 1935, house officer Dr. Mary Walker was the first physician to try physostigmine in the treatment of MG, which had previously been used to treat curare poisoning. What she saw was a dramatic improvement in the symptoms experienced in patients with MG, and thus became the first documented case of use of physostigmine, an acetylcholinesterase inhibitor, in the treatment of MG. This article is a summary of the history of the use of acetylcholinesterase inhibitors in the treatment of myasthenia gravis. This article is part of the special issue entitled 'Acetylcholinesterase Inhibitors: From Bench to Bedside to Battlefield'.

Idiopathic Orbital Inflammation Appearing on the Affected Side of Preceding Myasthenia Gravis.

The patient was a 70-year-old man with idiopathic orbital inflammation (IOI) that appeared on the severely affected side of preceding myasthenia gravis (MG). The patient was diagnosed with MG 5 years prior to the onset of IOI. When IOI was diagnosed, an edrophonium test was negative. IOI was considered because he complained of left orbital pain, eyelid swelling, and cerebral MRI exhibited the enhanced lesions along the left orbital periosteum. A biopsy specimen revealed pathological findings compatible with IOI. The administration of corticosteroids was effective for improving the ocular symptoms. IOI should be considered when ocular symptoms deteriorated with soft tissue swelling/pain in MG patients.

[A case of Miller Fisher syndrome with a false-positive edrophonium test].

A 69-year-old woman presented with acute bilateral ptosis, ophthalmoplegia, ataxia, and hyporeflexia in the extremities following an antecedent upper respiratory infection. We suspected that she had Miller Fisher syndrome (MFS) and performed an edrophonium test (ET) to rule out myasthenia gravis (MG). Edrophonium chloride improved the patient's bilateral ptosis, but not her ophthalmoplegia. Given the absence of the waning phenomenon on electrophysiological examination, the anti-acetylcholine receptor antibody, and a diurnal variation of symptoms, we concluded that the ET result was a false-positive. A diagnosis of MFS was confirmed by the presence of a positive anti-GQ1b antibody. To our knowledge, this is the first case report of MFS with a false-positive ET.

Reliability and main findings of the flexible endoscopic evaluation of swallowing-Tensilon test in patients with myasthenia gravis and dysphagia.

BACKGROUND AND PURPOSE: Diagnosis of pharyngeal dysphagia caused by myasthenia gravis (MG) based on clinical examination alone is often challenging. Flexible endoscopic evaluation of swallowing (FEES) combined with Tensilon (edrophonium) application, referred to as the FEES-Tensilon test, was developed to improve diagnostic accuracy and to detect the main symptoms of pharyngeal dysphagia in MG. Here we investigated inter- and intra-rater reliability of the FEES-Tensilon test and analyzed the main endoscopic findings. METHODS: Four experienced raters reviewed a total of 20 FEES-Tensilon test videos in randomized order. Residue severity was graded at four different pharyngeal spaces before and after Tensilon administration. All interpretations were performed twice per rater, 4 weeks apart (a total of 160 scorings). Intra-rater test-retest reliability and inter-rater reliability levels were calculated. RESULTS: The most frequent FEES findings in patients with MG before Tensilon application were prominent residues of semi-solids spread all over the hypopharynx in varying locations. The reliability level of the interpretation of the FEES-Tensilon test was excellent regardless of the rater's profession or years of experience with FEES. All four raters showed high inter- and intra-reliability levels in interpreting the FEES-Tensilon test based on residue clearance (kappa = 0.922, 0.981). The degree of residue normalization in the vallecular space after Tensilon application showed the highest inter- and intra-rater reliability level (kappa = 0.863, 0.957) followed by the epiglottis (kappa = 0.813, 0.946) and pyriform sinuses (kappa = 0.836, 0.929). CONCLUSION: Interpretation of the FEES-Tensilon test based on residue severity and degree of Tensilon clearance, especially in the vallecular space, is consistent and reliable.

Detectable voice change with the edrophonium test in laryngeal myasthenia gravis.

A case of laryngeal myasthenia gravis in a 65-year-old woman presenting with hoarseness as the sole symptom is reported. Voice spectrography was performed before and after injection of intravenous edrophonium. There was a marked improvement in the patient's voice after the administration of edrophonium, which was confirmed by the changes seen on the sound spectrogram. This was the only objective indication of a diagnosis of myasthenia gravis. No thymoma was seen on chest X-ray and the patient was negative for anti-acetylcholine receptor antibodies. Treatment for laryngeal myasthenia gravis was initiated and the patient's vocal problems resolved. This case emphasizes the need to consider systemic diseases in the differential diagnosis of hoarseness and demonstrates the need for careful follow-up in such patients.

Hopeahainol A binds reversibly at the acetylcholinesterase (AChE) peripheral site and inhibits enzyme activity with a novel higher order concentration dependence.

Natural product inhibitors of AChE are of interest both because they offer promise as inexpensive drugs for symptomatic relief in Alzheimer's disease and because they may provide insights into the structural features of the AChE catalytic site. Hopeahainol A is an uncharged polyphenol AChE inhibitor from the stem bark of Hopea hainanensis with a constrained, partially dearomatized bicyclic core. Molecular modeling indicates that hopeahainol A binds at the entrance of the long but narrow AChE active site gorge because it is too bulky to be accommodated within the gorge without severe distortion of the gorge as depicted in AChE crystal structures. We conducted inhibitor competition experiments in which AChE inhibition was measured with hopeahainol A together with either edrophonium (which binds at the base of the gorge) or thioflavin T (which binds to the peripheral or P-site near the gorge mouth). The results agreed with the molecular modeling and indicated that hopeahainol A at lower concentrations (<200 µM) bound only to the P-site, as hopeahainol A and thioflavin T were unable to form a ternary complex with AChE while hopeahainol A and edrophonium did form a ternary complex with essentially no competition between them. Inhibition increased to a striking extent at higher concentrations of hopeahainol A, with plots analogous to classic Dixon plots showing a dependence on hopeahainol A concentrations to the third- or fourth order. The inhibition at higher hopeahainol A concentrations was completely reversed on dilution and blocked by bound edrophonium. We hypothesize that bound hopeahainol A induces conformational changes in the AChE active site that allow binding of additional hopeahainol A molecules, a phenomenon that would be unprecedented for a reversible inhibitor that apparently forms no covalent bonds with AChE.

Análisis de impacto presupuestal del uso de anticuerpos bloqueadores de acetilcolina receptores, comparado con la prueba de Tensilon, de estímulo repetitivo, electromiografía con electrodo de fibra única e I CE test para pacientes con miastenia gravis / Budget impact analysis of the use of acetylcholine receptor blocking antibodies, compared to the Tensilon test, repetitive stimulus, electromyography with single fiber electrode and IEC test for patients with myasthenia gravis

Tecnologías evaluadas: -Tecnologías actuales: electromiografía con electrodo de fibra única e ICE test;\r\n-Tecnología nueva: anticuerpos bloqueadores de acetilcolina receptores, prueba de Tensilon, prueba de estímulo repetitivo. Población: Esta prueba se puede aplicar a todas las edades y a todos los sexos, ya que la aparición de la enfermedad puede presentarse en toda la población. Perspectiva: Tercer pagador - Sistema General de Seguridad en Salud (SGSSS) colombiano. Horizonte temporal: El horizonte temporal de este AIP en el caso base corresponde a un año. Adicionalmente se reportan las estimaciones del impacto presupuestal para los años 2 y 3, bajo el supuesto de la inclusión en el POS en el año 1. Costos incluidos: Solo se tuvieron en cuenta los costos de las pruebas: -Electromiografía con electrodo de fibra única: $71.262,1; -Ice test: $26.223,3; Prueba completa de Tensilon: $24.000; -Prueba de estímulo repetitivo: $46.219,1; -Test de anticuerpos contra receptor de acetilcolina por RIA (ACRA): $45.416. Fuente de costos: Para todas las pruebas diagnósticas se utilizó el promedio ponderado estimado desde los registros de uso de servicios de 2014 SISPRO (módulo de prestación de servicios, mediante conexión OBDS), teniendo como corte de búsqueda la fecha del desarrollo de este impacto (20/10/2015). Todos los costos de las pruebas son ponderados por el número de unidades utilizadas que reporta la misma base de datos. Además, todas\r\nlas tecnologías son costeadas desde bases de aseguradores, para confirmación de precios. Resultados: Actualmente, el mercado se encuentra dominado por la electromiografía con electrodo de fibra única, la cual se encuentra dentro del plan de beneficios, pero por opinión de los realizadores, una vez que la prueba de acetilcolina receptores y de Lambert entre al plan de beneficios, se aumentará su participación, lo cual repercutirá en un ahorro al sistema, dado que dichas pruebas son menos costosas.(AU)

Some current challenges in research on air pollution and health / Desafíos actuales de la investigación sobre contaminación del aire y salud

This commentary addresses some of the diverse questions of current interest with regard to the health effects of air pollution, including exposure-response relationships, toxicity of inhaled particles and risks to health, multipollutant mixtures, traffic-related pollution, accountability research, and issues with susceptibility and vulnerability. It considers the challenges posed to researchers as they attempt to provide useful evidence for policy-makers relevant to these issues. This commentary accompanies papers giving the results from the ESCALA project, a multi-city study in Latin America that has an overall goal of providing policy-relevant results. While progress has been made in improving air quality, driven by epidemiological evidence that air pollution is adversely affecting public health, the research questions have become more subtle and challenging as levels of air pollution dropped. More research is still needed, but also novel methods and approaches to address these new questions.

Este comentario aborda algunos de los temas de interés actual en relación con los efectos de la contaminación del aire sobre la salud, tales como las relaciones exposición-respuesta, la toxicidad y riesgos para la salud de las partículas inhaladas, las mezclas de contaminantes múltiples, la contaminación relacionada con el tráfico, la investigación sobre responsabilidad, y los problemas de susceptibilidad y vulnerabilidad. Considera los retos que se presentan a los investigadores que intentan proporcionar evidencia para los responsables políticos en estas cuestiones. Este texto acompaña otros trabajos con resultados del proyecto ESCALA, un estudio en varias ciudades de América Latina que tiene como objetivo general proporcionar resultados relevantes para la política pública. Aunque ha habido avances para mejorar la calidad del aire, gracias a la evidencia epidemiológica de que la contaminación aérea está afectando negativamente a la salud pública, las preguntas de investigación se han vuelto más sutiles y difíciles a medida que los niveles de contaminación se reducen. Se necesita más investigación, pero también nuevos métodos y enfoques capaces de enfrentar estas preguntas.

Dropped head with positive intravenous edrophonium, progressing to myasthenia gravis.

'Dropped head syndrome' (DHS) may be associated with a variety of neurological diseases. The absence of neurological clues to the underlying cause of DHS can make management particularly challenging. We review six patients who presented with only DHS, responded to intravenous edrophonium and turned out to have myasthenia gravis (MG) including similar patients who were previously documented. Six patients presented with neck weakness and three had bulbar symptoms. Acetylcholine receptor (AchR) was positive in four patients. One patient had thymoma. The interval from the onset of DH to the presentation of typical MG features was shorter in patients who tested positive for anti-Ach antibody (1-2 months) than in patients who tested negative for anti-AchR antibody (13 months, 4 years). Our results suggest that patients with DHS responding to intravenous edrophonium might turn out to have MG and such patients might respond to a combination of anticholinesterase agents and steroids.

Congenital myasthenic syndromes: current diagnostic and therapeutic approaches.

Congenital myasthenic syndromes (CMS) are rare genetically and clinically heterogeneous disorders characterized by an impaired neuromuscular transmission. Exact prevalence data are not available, approximately 2000 to 3000 patients worldwide have been diagnosed on a molecular level; mutations in 14 different genes are known to date leading to causal defects in presynaptic nerve terminal, synaptic cleft, and postsynaptic apparatus. At last, all known mutations are estimated to cause approximately 50% of all clinically diagnosed CMS. However, phenotypes may vary widely and symptoms can be unspecific, therefore CMS are often missed and their prevalence may be underestimated. But, the exact diagnosis is extremely important to start early appropriate therapy to prevent life-threatening events and to improve the clinical course. Most patients are eligible for drug therapy with esterase inhibitors, 3, 4-diaminopyridine, ephedrine, fluoxetine or quinidine, but the effect of these drugs differs depending on the underlying genetic defect. Moreover, very little is known about the best treatment and care in these patients over a longer period of time.This article provides an overview of specific clinical symptoms, diagnostic work-up, and care including possible pharmacotherapy in case of CMS.

Discordant thymectomy in identical twins concordant for myasthenia gravis.

BACKGROUND: Thymectomy is standard therapy fornonthymomatousmyasthenia gravis despite the absence of randomized clinical trials (1). Myasthenia gravis is uncommonly reported in monozygous twins; disease concordance occurs in approximately one third of such identical twin pairs; and treatment for myasthenia gravis, when described,is usually concordant in identical twin pairs (2). OBJECTIVE: To report an 11-year clinical course of a pair of identical twins concordant for generalized acetylcholine receptor antibody­positive nonthymomatous myasthenia gravis in whom only 1 was treated with extended transsternal thymectomy. CASE REPORT: Twin A was a 19-year-old white woman who presented with an 8-week history of intermittent leg weakness, causing her to fall during activities, such as climbing stairs. On examination,she had moderately severe fatigable proximal muscle weakness and ptosis. Her weakness improved with intravenous edrophonium administration.Initial binding acetylcholine receptor antibody titer was 1.22 nmol/L (normal value, 0.03 nmol/L). Repetitive 2-Hz nerve(median, ulnar, and facial) stimulation studies demonstrated up to a 16% decremental response. Chest computed tomography showed residual thymic tissue without thymoma. An extended transsternal thymectomy was performed 11 weeks after the onset of symptoms.

Preparation, in vitro screening and molecular modelling of symmetrical bis-quinolinium cholinesterase inhibitors--implications for early myasthenia gravis treatment.

This paper describes the preparation and in vitro evaluation of 18 newly prepared bis-quinolinium inhibitors on human recombinant acetylcholinesterase (AChE) and human plasmatic butyrylcholinesterase (BChE). Their inhibitory (IC(50)) and was compared to the chosen standards ambenonium dichloride, edrophonium chloride, BW284c51 and ethopropazine hydrochloride. One novel compound was found to be a promising inhibitor of hAChE (in nM range) and was better than edrophonium chloride or BW284c51, but was worse than ambenonium chloride. This compound also showed selectivity towards hAChE and it was confirmed as a non-competitive inhibitor of hAChE by kinetic analysis. A molecular modelling study further confirmed its binding to the peripheral active site of hAChE via apparent π-π or π-cationic interactions.

Rapid chemical antagonism of neuromuscular blockade by L-cysteine adduction to and inactivation of the olefinic (double-bonded) isoquinolinium diester compounds gantacurium (AV430A), CW 002, and CW 011.

BACKGROUND: The ultra-short-acting neuromuscular blocker gantacurium is chemically degraded in vitro by rapid adduction of L-cysteine to its central olefinic double bond. Preliminary data have suggested that exogenous (intravenous) L-cysteine abolishes gantacurium blockade. Two new analogues of gantacurium (CW 002 and CW 011) have been synthesized to undergo slower L-cysteine adduction, yielding intermediate duration. L-cysteine adduction to and antagonism of these novel agents is further defined herein. METHODS: Comparative reaction half-time for L-cysteine adduction in vitro of the three compounds was determined by high-performance liquid chromatography. ED95 for twitch inhibition in monkeys under isoflurane was calculated, and duration at approximately 4-5x ED95 was correlated with reaction half-time for adduction. Speed of L-cysteine antagonism was contrasted with anticholinesterase reversal. Potencies of CW 002 and its adduction product were compared to provide a basis for L-cysteine antagonism. RESULTS: Rate of L-cysteine adduction in vitro (reaction half-time) was 11.4 and 13.7 min for CW 002 and CW 011 versus 0.2 min for gantacurium, and was inversely related to duration of block (P < 0.0001). CW 002 and CW 011 were 3x longer acting than gantacurium (28.1 and 33.3 min vs. 10.4 min), but only half the duration of cisatracurium. The adduct of CW 002 was approximately 70x less potent than CW 002. L-cysteine (10-50 mg/kg intravenously) given 1 min after approximately 4-5x ED95 doses of all the three compounds abolished block within 2-3 min. CONCLUSIONS: L-cysteine adduction occurs at different rates by design in olefinic isoquinolinium diester neuromuscular blockers, yielding corresponding durations of action. Antagonism by exogenous L-cysteine is superior to anticholinesterases, inducing inactivation of the active molecules to restore function rapidly at any time.