Perioperative cardiac risks in myasthenia gravis

Myasthenia gravis(MG)is an autoimmune disorder that affects the neuromuscular junction.The primary pathology in MG involves the presence of autoantibodies to acetylcholine receptors(AChRs),which results in qualitative and quantitative reductions in the availability of functional AChRs.Cardiac muscles are also affected,resulting in various perioperative cardiac complications.Antistriational antibodies are commonly reported in MG cases with cardiac involvement.In the presence of thymoma,the prevalence of cardiac manifestations in patients with MG increases to approximately 10%-15%.Cardiac involvement in MG may range from asymptomatic electrocardiogram changes to ventricular tachycardia,myocarditis,conduction disorders,heart failure,and sudden death.Increased incidence of atrial fibrillation,ventricular and supraventricular extra systoles,and prolonged QTc have also been reported in patients with MG.Clinicians should consider the evaluation of autonomic dysfunction and risk of cardiovascular disease in patients with MG.

Intraoperative cardiogenic shock induced by refractory coronary artery spasm in a patient with myasthenia gravis: A case report

BACKGROUND Coronary artery spasm(CAS)is a rare but critical condition during surgery.Clinical manifestations can vary from only subtle electrocardiography change to sudden death.In this case report,we present the case of a patient with myasthenia gravis(MG)who developed refractory CAS-related cardiogenic shock during thymoma surgery.CASE SUMMARY A 61-year-old man had a history of cigarette smoking and coronary artery disease with a bare metal stent placed.Three months ago,he suffered from coronary spasms,with three vessels involved,after surgery for cervical spine injury.He started having progressive dysphagia 4 wk prior and was diagnosed with MG via serologic tests,and computed tomography declared a thymoma in the anterior mediastinum.After the symptoms of MG subsided,he was referred for thy-mectomy.The operation was uneventful until the closing of the sternal wound.Electrocardiography showed sudden onset ST elevation,followed by ventricular tachycardia and severe hypotension.Cardiopulmonary cerebral resuscitation was initiated immediately with electrical defibrillation,extracorporeal membrane oxygenation was performed due to refractory cardiogenic shock,and the patient was transferred to an angiography room.Angiography showed diffuse CAS with three vessels involved.Intracoronary isosorbide dinitrate and adenosine were administered,and then the patient was transferred to the intensive care unit.CONCLUSION Our case highlights the importance of being prepared for clinical situations such as the one described here and suggests the necessity of developing an appropriate anesthesia plan that includes proactive analgesia and preemptive coronary vaso-dilators.

FcRn inhibitors:a novel option for the treatment of myasthenia gravis

Myasthenia gravis is an acquired,humoral immunity-mediated autoimmune disease characterized by the production of autoantibodies that impair synaptic transmission at the neuromuscular junction.The intervention-mediated clearance of immunoglobulin G(IgG)was shown to be effective in controlling the progression of the disease.The neonatal Fc receptor(FcRn)plays a key role in prolonging the serum half-life of IgG.Antagonizing FcRn to prevent its binding to IgG can accelerate the catabolism of the latter,resulting in decreased levels of IgG,including pathogenic autoantibodies,thereby achieving a therapeutic effect.In this review,we detail the substantial research progress,both basic and clinical,relating to the use of FcRn inhibitors in the treatment of myasthenia gravis.

New Progress in the Treatment of Myasthenia Gravis

In recent decades, the treatment of myasthenia gravis has been extensively developed, but a standardized standard still needs to be used. Its treatment strategy is associated with patient prognosis, economic costs, and complications. This article reviews the pathogenesis, treatment methods, and complications of myasthenia gravis, providing new ideas for diagnosing and treating myasthenia gravis and fully embodies the principle of safety and precision.

Effectiveness of progressive resistance training in improving muscle strength in myasthenia gravis:a single subject study design

Background:To investigate the effectiveness of the progressive resistance training(PRT)using thera band in improving muscle strength in myasthenia gravis(MG).Methods:In this prospective study,12 MG patients with generalised stable disease performed progressive resistance training with thera band for four times per week for 24 weeks.The isometric muscle force of shoulder abductors,biceps brachii and knee extensors using handheld dynamometer,Myasthenia Gravis Composite(MGC)score,Quantitative myasthenia gravis score(QMG),were assessed before and after the training period.Results:Progressive resistance training was well tolerated,and the isometric muscle strength was significantly improved in shoulder abductors,biceps brachii and knee extensors(P<0.05).The disease course(QMG and MGC)was slowed down and improved(P<0.05).Conclusion:Progressive resistance training is effective in improving muscle strength specifically in most affected muscles in MG.

Effects of intravascular photobiomodulation on motor deficits and brain perfusion images in intractable myasthenia gravis: A case report

BACKGROUND Myasthenia gravis(MG)is an autoimmune disorder caused by neuromuscular junction failure characterized by muscle weakness and fatigability.We herein report a case of MG that received intravascular laser irradiation of blood(ILIB)interventions and regained muscle power and better quality of life.To our knowledge,no previous study has investigated the benefits of ILIB treatment on patients with MG.We also evaluated the changes in brain perfusion scan and the MG activities of daily living(MG-ADL)and quantitative MG(QMG)scales.CASE SUMMARY A 59-year-old man presented to our outpatient hospital experiencing ptosis,diplopia,fibromyalgia,muscle fatigue,and fluctuating weakness in his limbs for 1 year.Based on his history,physical examination,and laboratory investigations,the final diagnosis was a flare-up of MG with poor endurance and muscle fatigue.The patient agreed to receive ILIB.Brain single-photon emission computed tomography(SPECT)was performed both before and after ILIB therapy.After receiving three courses of ILIB,the brain SPECT images showed greatly increased perfusion of the frontal lobe and anterior cingulate gyri.The patient’s MG-ADL scale score decreased markedly from 17/24 to 3/24.The QMG scale score also decreased remarkably from 32/39 to 9/39.The symptoms of MG became barely detectable and the patient was able to perform his activities of daily living and regain muscle power.CONCLUSION ILIB might have beneficial effects on MG,and brain SPECT images provided direct evidence of a positive correlation between ILIB and clinical performance.

Myasthenia gravis and pregnancy

Myasthenia gravis (MG) is an autoimmune disorder of neuromuscular junctionthat has higher incidence in younger women than men, which could be related todifferences in sex hormones physiology and immune system functioning betweenmales and females. MG can first present during pregnancy and variably affectpregnancy, labor, and postpartum period. In this paper, we had an updatedoverview on our understanding about MG presentation and its effect onpregnancy and vice versa, therapeutic options for MG pregnant women,management of pregnancy or labor complications in MG patients, and finally fetaland neonatal considerations in MG pregnant women. A multidisciplinaryapproach, involving obstetricians/gynecologists, neurologists, and anesthesiologists,plays a pivotal role in improving the clinical outcomes in both MGmothers and their infants during pregnancy, delivery and postpartum.

Surgical approaches for stage Ⅰ and Ⅱ thymoma-associated myasthenia gravis:feasibility of complete video-assisted thoracoscopic surgery (VATS) thymectomy in comparison with trans-sternal resection

Complete resection could be achieved in virtually all myasthenic patients with Masaoka stage I and II thymoma us- ing the trans-sternal technique. Whether this is appropriate for minimally invasive approach is not yet clear. We evalu- ated the feasibility of complete video-assisted thoracoscopic surgery （VATS） thymectomy for the treatment of Ma- saoka stage I and Ⅱ thymoma-associated myasthenia gravis, compared to conventional trans-sternal thymectomy. We summarized 33 patients with Masaoka stage I and II thymoma-associated myasthenia gravis between April 2006 and September 2011. Of these, 15 patients underwent right-sided complete VATS （the VATS group） by us- ing adjuvant pneuomomediastinum, comparing with 18 patients using the trans-sternal approach （the T3b group）. No intraoperative death was found and no VATS case required conversion to median sternotomy. Significant differences between the two groups regarding duration of surgery and volume of intraoperative blood loss （P = 0.001 and P 〈 0.001, respectively） were observed. Postoperative morbidities were 26.7% and 33.3% for the VATS and T3b groups, respectively. All 33 patients were followed up for 12 to 61 months in the study. The cumulative probabilities of reaching complete stable remission and effective rate were 26.7% （4/15） and 93.3% （14/15） in the VATS group, which had a significantly higher complete stable remission and effective rate than those in the T3b group （P = 0.026 and P = 0.000, respectively）. We conclude that VATS thymectomy utilizing adjuvant pneuomo- mediastinum for the treatment of stage I and II thymoma-associated myasthenia gravis is technically feasible but deserves further investigation in a large series with long-term follow-up.

Possible implications of dysregulated nicotinic acetylcholine receptor diffusion and nanocluster formation in myasthenia gravis

Myasthenia gravis is a rare and invalidating disease affecting the neuromuscular junction of voluntary muscles.The classical form of this autoimmune disease is characterized by the presence of antibodies against the most abundant protein in the neuromuscular junction,the nicotinic acetylcholine receptor.Other variants of the disease involve autoimmune attack of non-receptor scaffolding proteins or enzymes essential for building or maintaining the integrity of this peripheral synapse.This review summarizes the participation of the above proteins in building the neuromuscular junction and the destruction of this cholinergic synapse by autoimmune aggression in myasthenia gravis.The review also covers the application of a powerful biophysical technique,superresolution optical microscopy,to image the nicotinic receptor in live cells and follow its motional dynamics.The hypothesis is entertained that anomalous nanocluster formation by antibody crosslinking may lead to accelerated endocytic internalization and elevated turnover of the receptor,as observed in myasthenia gravis.

Effectiveness of Thymectomy in Non-thymomatous Myasthenia Gravis: a Systematic Review

There is continuous debate regarding the effectiveness of thymectomy in the treatment of non-thymomatous myasthenia gravis （MG）. This systematic review was undertaken to determine whether thymectomy was effective in non-thymomatous MG. We retrieved articles published between January 1980 and September 2013. Sixteen cohort studies were included. Given the considerable het- erogeneity, we used a descriptive method instead of statistical synthesis. The median relative rates （RRs） and their interquartile ranges were used to estimate the magnitude of benefit. Compared to conserva- tively treated MG patients, thymectomized patients had higher survival, clinical remission, pharma- cologic remission and improvement rates, and RRs were 1.07 （1.01-1.17）, 1.83 （0.82-2.99）, 1.55 （1.22-1.95） and 1 （1.00-1.09）, respectively. Subgroup analyses showed that patients with moderate to severe generalized MG benefited more from thymeetomy, with RRs of survival and pharmacologic re- mission increasing to 1.35 （1.24-1.49） and 2.68 （1.73-4.17）, respectively. These results suggested that thymectomy might be an effective procedure in non-thymomatous MG patients. The patients with mod- erate to severe generalized MG might benefit more. Taking into account the poor methodological qual- ity of present studies, more well-designed prospective randomized controlled trials （RCTs） are still re- quired to reach uneouivocal conclusion.

Investigation on the Mechanism of Exacerbation of Myasthenia Gravis by Aminoglycoside Antibiotics in Mouse Model

To investigate the underlying mechanism of the exacerbation of myasthenia gravis by aminoglycoside antibiotics. C57/BL6 mice were immunized with acetylcholine receptor (AChR), extracted from electric organ of Narcine timilei according to Xu Haopeng's methods, in complete Fruend's adjuvant (CFA) to establish experimental autoimmune myasthenia gravis (EAMG). EAMG mice were divided randomly into 5 groups: MG group, NS group and three antibiotics groups. The clinical symptom scores of mice were evaluated on d7 after the last immunization and d14 of antibiotics treatment. Repetitive nerve stimulation (RNS) was performed and the levels of anti-AChR antibody (AChR-Ab) were tested at the same time. The mean clinical symptom grades of gentamycin group (1.312, 2.067), amikacin group (1.111, 1.889) and etimicin group (1.263, 1.632) were significantly higher than those of MG group (1.000, 1.200) (P<0.05). The positive rates of RNS of three antibiotics groups were 69.23 %, 58.82 % and 63.16 % respectively, which were significantly higher than those of MG group and NS group (40.00 %, 40.00 %, P<0.05). The AChR-Ab level in serum and the expression of AChR on neuromuscular junction (NMJ) of mice in three antibiotics groups were also higher than those of MG group. Our results indicated that aminoglycoside antibiotics could aggravate the symptom of myasthenia gravis. The exacerbation of myasthenia gravis by these antibiotics probably involves competitively restraining the release of acetylcholine from presynaptic membrane, impairing the depolarization of postsynaptic membrane, depressing the irritability of myocyte membrane around the end-plate membrane and consequently leading to the blockade of neuromuscular junction.

Computer Aided Study of Mechanism of Immunoadsorbent for Myasthenia Gravis

Myasthenia Gravis (MG) is an organ specific autoimmune disease mediated by autoantibodies (AChR Ab) against the acetylcholine receptor (AChR). Literature reported that the AChR Ab can be removed by absorbent linked with tryptophan. It was studied in detail in our lab. With the aid of computer, we docked some ligands into AChR Ab, and the results from scores of docking under different generations showed that there was no specific binding between tryptophan and scFv fragment just as the binding between antigen-antibody. The interaction between Trp and immunoglobulin was a broad-spectrum binding.

“Warming yang and invigorating qi” acupuncture alters acetylcholine receptor expression in the neuromuscular junction of rats with experimental autoimmune myasthenia gravis

Myasthenia gravis is an autoimmune disorder in which antibodies have been shown to form against the nicotinic acetylcholine nicotinic postsynaptic receptors located at the neuromuscular junction.＂Warming yang and invigorating qi＂ acupuncture treatment has been shown to reduce serum inflammatory cytokine expression and increase transforming growth factor beta expression in rats with experimental autoimmune myasthenia gravis.However,few studies have addressed the effects of this type of acupuncture on the acetylcholine receptors at the neuromuscular junction.Here,we used confocal laser scanning microscopy to examine the area and density of immunoreactivity for an antibody to the nicotinic acetylcholine receptor at the neuromuscular junction in the phrenic nerve of rats with experimental autoimmune myasthenia gravis following ＂warming yang and invigorating qi＂ acupuncture therapy.Needles were inserted at acupressure points Shousanli（LI10）,Zusanli（ST36）,Pishu（BL20）,and Shenshu（BL23） once daily for 7 consecutive days.The treatment was repeated after 1 day of rest.We found that area and the integrated optical density of the immunoreactivity for the acetylcholine receptor at the neuromuscular junction of the phrenic nerve was significantly increased following acupuncture treatment.This outcome of the acupuncture therapy was similar to that of the cholinesterase inhibitor pyridostigmine bromide.These findings suggest that ＂warming yang and invigorating qi＂ acupuncture treatment increases acetylcholine receptor expression at the neuromuscular junction in a rat model of autoimmune myasthenia gravis.

Fusion protein of single-chain variable domain fragments for treatment of myasthenia gravis

Single-chain variable domain fragment （scFv） 637 is an antigen-specific scFv of myasthenia gravis. In this study, scFv and human serum albumin genes were conjugated and the fusion pro-tein was expressed in Pichia pastoris. The afifnity of scFv-human serum albumin fusion protein to bind to acetylcholine receptor at the neuromuscular junction of human intercostal muscles was detected by immunolfuorescence staining. The ability of the fusion protein to block myas-thenia gravis patient sera binding to acetylcholine receptors and its stability in healthy serum were measured by competitive ELISA. The results showed that the inhibition rate was 2.0-77.4%, and the stability of fusion protein in static healthy sera was about 3 days. This approach suggests the scFv-human serum albumin is a potential candidate for speciifc immunosuppressive therapy of myasthenia gravis.

Case report of a healthy,elderly man with long-term high titers for anti-acetylcholine receptor antibody without myasthenia gravis

Anti-acetylcholine receptor antibodies （AAR） are considered pathognomonic and pathogenetic for myasthenia gravis （MG）. AAR detection confirms clinical diagnosis of MG. However, AAR is rarely detected in patients without MG. The underlying pathophysiological mechanisms in a normal subject without MG have not been adequately addressed in previous studies. The present study reports on a case study of a healthy, elderly man with high AAR titers for 14 years. Pathophysiological mechanisms could be due to AAR heterogeneity in specificity, affinity, and multiform, and to muscle variability in response to AAR.

Clinical manifestation and humoral immuno-function of myasthenia gravis patients with abnormal and normal thymus gland

BACKGROUND： Myasthenia gravis （MG） is an autoimmune disease which mainly affects neuromuscular junctions. The ages, modified Osserman classification and clinical manifestation and humoral immunol function of MG with and without thymic abnormality are different. OBJECTIVE： To explore the clinical manifestation and humoral immuno-function of MG with abnormal and normal thymus gland. DESIGN ： Contrast observation SETTTNG ： Department of Neurology, the Third Affiliated Hospital of Sun Yat-sen University PARTZCZPANTS ： A total of 49 inpatients with MG were selected from the Third Affiliated Hospital of Sun Yat-sen University from March 2000 to August 2005. All the patients had typical clinical manifestation of MG and positive neostigmine test. All the patients knew and agreed the laboratory examinations. There were 22 males and 27 females of 2-69 years old. Chest MRI or CT scan were performed to reveal thymus gland abnormality. According to whether there was tumor in superior mediastinum, all patients were divided into 2 groups, abnormal and normal groups. Normal thymus gland group （n=30） contained 16 males and 14 females of 6-43 years old. Abnormal thymus gland group （n=19） contained 6 male and 13 female of 2-69 years old, METHODS： ① All patients were questioned about initial symptoms. Meanwhile, main clinical manifestations were recorded at hospital admission. ② 7180A automatic biochemical analyzer and automatic microplate reader were used in detecting seroimmunity index. The levels of C3, C4, IgG, IgA, IgM and CH50 in blood serum were analyzed by nephelometry. ③ Clinical classification is based on modified Osserman classification. The patients with MG were divided into six types： I （Ocular myasthenia）, Ⅱ a （Mild generalized myasthenia）, Ⅱb （Moderately severe generalized myasthenia）, Ⅲ （Acute fulminating myasthenia）, Ⅳ（Late se- vere myasthenia）. MAZN OUTCOME MEASURES： ① Differences of initial symptoms and clinical manifestation of two group patients. ② Differences of age of onset and modified Osserman classification of two groups. ③The humoral immuno-functions of two groups were compared. RESULTS： All the 49 patients were involved in the final analysis of results. ① Differences of initial symptoms： Ptosis was the most common initial symptoms in both groups. Patients with ptosis of normal thymus gland were 25 （83%, 25/30）. Patients with ptosis of abnormal thymus gland were 13 （68%, 13/19）. Patients with normal thymus gland： dysphagia 2 （7%, 2/30）, diplopia 4 （13%, 4/30）, fatigue 4 （13%, 4/30）, dysarthria 3, （10 %, 13/30）. Patients with abnormal thymus gland： dysphagia 3 （16%, 3/19）, diplopia 6 （32%, 6/19）, fatigue 3 （16%, 3/19）, dysarthria 2 （10%, 2/19）. ② Differences of clinical manifestation of two groups： Ptosis was the most common clinical manifestation in both groups. Patients with ptosis of normal thymus gland were 29 （97%, 29/30）. Patients with ptosis of abnormal thymus gland were 15 （79%, 15/19）. The rates of fatigue and breathing disorder in patients with abnormal thymus gland were higher than patients with normal thymus gland. Myasthenia crisis occurred in 3 patients （16 %, 3/19） in abnormal thymus gland group, with 1 （3%, 1/30） in abnormal thymus gland group. ③ Differences of age of onset and modified Osserman classification： The rate of type ｜ （63%, 19/30） in patients with normal thymus gland was higher than patients （42%, 8/19） with abnormal thymus gland. The rates of type Ⅱ a, Ⅱ b and Ⅲ （58 %） in patients with abnormal thymus gland were higher than patients （37%, 8/19） with normal thymus gland. But no differences were found between two groups （P 〉 0.05）. Patient number of onset from 20 to 29 year old in abnormal group （47%） was higher than that in normal group （20%）. Comparison of two groups was X2=4.10 and P 〈 0.05.④ Comparison of the humoral immunol indexes of two groups： The levels of IgG, IgA, C3 and CH50 in abnormal group were higher than those in normal group. But no differences were found between two groups （P 〉 0.05）. CONCLUSZON： ① Ptosis was the most common initial symptom and clinical feature in both groups. ② Clinical manifestation in abnormal group were more severe, and ages of onset in abnormal group were more young.③ The humoral immuno indexes of two groups were not significantly different.

Experimental Study on Induction of Tolerance to Experimental Autoimmune Myasthenia Gravis by Immature Dendritic Cells

Summary: To investigate the effect of immature dendritic cells (iDCs) on experimental autoimmune myasthenia gravis (MG), iDCs were generated in low dose of GM-CSF, and then they were pulsed with acetylcholine receptor (AchR) and transferred to allogeneic rats. After 3 weeks, all rats were immunized with AchR and complete Freund's adjuvant (CFA) and observed for the corresponding indices of MG for 7 weeks. Our results showed that compared with mature DCs (mDCs) generated at high dose of GM-CSF plus additional stimulation by lipopolysaccharide, iDCs expressed significantly lower levels of MHC-Ⅱ, CD80 and CD86, and their ability to uptake FITC-Dextran was stronger but the ability of stimulating proliferation of allogeneic T cells were weaker. Like controls, after immunization, all rats transferred with iDCs, mDCs and AchR-pulsed mDCs showed typical symptoms in 4 to 7 weeks. The amplitude of electromyogram wave dropped obviously, the level of serum AchRab increased and neuromuscular junction showed typical damage of MG. In contrast, no conspicuous changes were noted in rats transferred with AchR-pulsed iDCs. The results suggest that iDCs could be generated by inducing bone marrow precursors in low dose of GM-CSF, AchR-pulsed iDCs could induce tolerance of EAMG. The dysfunction of DCs may play an important role in the initiation and maintenance of normal immune response in MG.

Comparison of diagnosis value for new onset myasthenia gravis by many clinical auxiliary examinations

BACKGROUND： The clinical values of neostigmine test, clinical electrophysiologic study and acetylcholine receptor antibody detection in diagnosing myasthenia gravis （MG） found newly are unclear in China.OBJECTIVE： To investigate the reference value of common clinical diagnosis parameters in correctly diagnosing untreated MG found newly.DESIGN： Retrospective case analysis.SETTING： Department of Neurology, Beijing Hospital, Ministry of Health.PARTICIPANTS： Totally 156 outpatients with MG admitted to Department of Neurology, Beijing Hospital,Ministry of Health between January 1999 and December 2002. The involved patients, 72 males and 84 females, were aged 2 - 79 years. They were classified according to Osserman＇s criteria： ⅡA 72, ⅡB 76, Ⅲ3 and Ⅳ 5. They were all subjected to being inquired of disease history, neostigmine test, and acetylcholine receptor antibody detection, met the diagnosis criteria of Neuroimmunology Committee of China, and confirmed by clinical electrophysiologic detections; Informed consents were obtained from all the involved subjects.METHODS： ①After admission, every patient was intramuscularly injected with 1.5 mg neostigmine; If the patient was a child, the injection dose was decreased according to his/her age. If his/her score of any observation index after injection was improved ≥ 50% as compared with before injection , his positive index was Set as positive. Positive neostigmine test was set if there was one positive index. ②Repetitive nerve stimulation and single fiber electromyography were performed with Dantec Keypoint electromyogram （EMG） apparatus. ③Acetylcholine receptor antibody was detected by ELISA method.MAIN OUTCOME MEASURES： Clinical absolute and relative scores of MG, acetylcholine receptor antibody level, and repetitive nerve stimulation and single fiber electromyography examination results.RESULTS： The positive rates of neostigmine test, repetitive nerve stimulation and single fiber electromyography examination for MG were 86.5%, 82.6%, and 69.2%, respectively, and the positive rate of acetylcholine receptor antibody was 78.8%.CONCLUSION： Standardized neostigmine test has the highest sensitivity to diagnose MG.

Sympathetic skin response in patients with myasthenia gravis: A comparative analysis

BACKGROUND： The examination of sympathetic skin response is an important index for assessing the autonomic nerve function, and patients with myasthenia gravis are always accompanied by dysautonomia. Therefore, it will be important to know whether sympathetic skin response can be used as the index for the clinical evaluation of myasthenia gravis. OBJECTIVE： To investigate the diagnostic value of sympathetic skin response in the damage of autonomic nerve function of patients with myasthenia gravis. DESIGN： A case-controlled comparative observation. SETTING： Department of Neurology and Room of Nerve Electromyogram, the Affiliated Hospital of North Sichuan Medical College. PARTICIPANTS： Thirty outpatients or inpatients with myasthenia gravis were selected from the Department of Neurology, the Affiliated Hospital of North Sichuan Medical College from May 2006 to May 2007, including 9 males and 21 females, aged 8 - 72 years with a mean age of （28 ± 5） years old. They were all accorded with the diagnostic standards of myasthenia gravis, accompanied by different severity of autonomic nerve symptoms, including poor skin nutrition, sweating of hands and feet, pyknocardia, persistent hypotension, abdominal pain, constipation, etc. They all had not taken any drug affecting the autonomic nerve function before the examination. Informed consents were obtained from all the patients. Meanwhile, 30 healthy physical examinees were enrolled as the normal control group, including 10 males and 20 females, aged 10 - 75 years with a mean age of （31 ±5） years old. Approval was obtained from the hospital ethic committee. METHODS： After admission, the patients were examined with sympathetic skin response using DANTEC keypoint 2.0 electromyography evoked potential apparatus （Danmark）. The changes of the latency and wave amplitude of sympathetic skin response were observed. The subjects in the normal control group were examined with the same methods at physical examination. Abnormality was judged by the disappearance of wave form, latency longer than that in the normal control group by Mean＋2.5SD, or wave amplitude lower than the average value in the normal control group by 50%. MAIN OUTCOME MEASURES： The results of the latency and wave amplitude of sympathetic skin response were compared between the patients with myasthenia gravis and normal controls. RESULTS： All the 30 patients with myasthenia gravis and 30 healthy physical examinees were involved in the final analysis of results. There were no significant differences between the left and right upper and lower limbs in both the myasthenia gravis group and normal control group （P 〉 0.05）. In the myasthenia gravis group, the abnormal rate of sympathetic skin response was 37% （11/30）, the latency was prolonged and the wave amplitude was decreased as compared with those in the normal control group, and there were significant differences （P 〈 0.01）. CONCLUSION： Sympathetic skin response can be used as an electrophysiological index for judging the damages of autonomic nerve function in patients with myasthenia gravis.

Studying the relationship between clinical features and mental health among late-onset myasthenia gravis patients

BACKGROUND Mental disorders are common comorbidities among individuals with neurological diseases, and the prevalence of depressive and anxiety-related symptoms in newly referred patients at neurology outpatient clinics is high. There have been few studies on the mental health of patients with late-onset myasthenia gravis(MG).AIM To examine the relationship between clinical features and the mental health symptoms within late-onset MG patients.METHODS A total of 105 patients diagnosed with MG were recruited consecutively from a neuromuscular outpatient clinic between December 2020 and February 2021. Patients were classified into two groups: early-onset MG(age at onset < 50 years, n = 63) and late-onset MG(age at onset ≥ 50 years, n = 42). Social demographic data and information about marital status, education level, clinical symptoms, serum antibody levels, and therapies used were collected for all participants. Participants were also evaluated using the Myasthenia Gravis Composite scale, the Myasthenia Gravis Activities of Daily Living scale, the Myasthenia Gravis Quality of Life 15(MG-QOL-15) questionnaire, the 17-item version of the Hamilton Depression Rating Scale(HAM-D) and the Hamilton Anxiety Rating Scale(HAM-A). The relationship between clinical features and mental health in late-onset MG patients was examined using multivariate logistic regression analyses.RESULTS Late-onset MG patients were more prone to dyspnea, had higher levels of serum anti-acetylcholine receptor antibodies, and higher total scores on the MG-QOL-15, HAM-D, and HAM-A questionnaires, than early-onset MG patients had(P < 0.05). Among those with late-onset MG, female patients had higher total HAM-D and HAM-A scores than male patients had(P < 0.05). High scores on the QOL-15 questionnaire were associated with higher incidences of anxiety and depression, and the association was found to be independent after adjusting for confounding risk factors. In the late-onset subgroup, the areas under the receiver operating characteristic curves for the MG-QOL-15 score-based diagnostic accuracy for anxiety and depression state were 0.816(P = 0.001) and 0.983(P < 0.001), respectively.CONCLUSION Higher MG-QOL-15 scores were a risk factor for anxiety and depression in late-onset MG, and women with late-onset MG were more likely to have anxiety and depression than men were.