Acetylcholine Receptor Antibody Titers Research Articles

Ocular versus generalized myasthenia gravis: a continuum associated with acetylcholine receptor antibody titers

The aim of this study was to evaluate clinical and serological differences between the ocular myasthenia gravis (oMG) and generalized MG (gMG). This study is a retrospective chart review, in which data was collected from patients fulfilling 2 of 3 diagnostic MG criteria (positive antibodies, evidence of neuromuscular transmission defect on neurophysiological examination, positive effect of pyridostigmine treatment). 350 patients were included and data concerning demographics and MG medical history were collected. Patients with oMG accounted for 15.7 % of the included patients. The two subgroups differed significantly in oMG having a later age at onset, lower AChR antibody-titers, longer doctor-to-diagnosis delay and less intensive MG treatment. Additionally, patients with oMG were faster at reaching a well-controlled disease state. Thymus pathology, number of antibody-positive (95.9 % of gMG and 94.5 % of oMG), sex, number of other autoimmune diseases and delay before drug stability did not differ between oMG and gMG. In conclusion, oMG is presumably a milder form of gMG characterized by lower AChR antibody-titers, a milder phenotype, and a quicker response to a less aggressive treatment. But otherwise, oMG and gMG show very similar characteristics, including the same frequency of positive AChR antibodies, which seems new compared to previous reports.

Study on the clinical and electrophysiological characteristics of nerve function in myasthenia gravis patients in Vietnam.

In Vietnam, there is limited research on the role of nerve conduction in myasthenia gravis and its association with clinical features. This study aims to describe the electrophysiological features in patients with myasthenia gravis. This descriptive study was conducted from September 2019 to December 2021. The study included 33 myasthenia gravis patients who sought medical consultation or received inpatient treatment during this period. The Myasthenia Gravis Foundation of America classifies myasthenia gravis into five groups: I, IIa, IIb, IIIa, IIIb, IVa, IVb, and V. Notably, Group I involves pure ocular weakness, whereas Group a primarily impacts limb and axial muscles, and Group b mainly affects bulbar and respiratory muscles. The study revealed that motor and sensory nerve conduction in the upper and lower limbs were within normal limits for the patient group under evaluation. Repetitive nerve stimulation testing at a frequency of 3 Hz showed positive results in 66.7% of myasthenia gravis patients. Myasthenia gravis patients displayed distinct clinical symptoms, with ptosis being the most common (87.9%). Myasthenia Gravis Foundation of America classification indicated the highest proportion in subgroup IIa (24.2%), with myasthenia gravis predominating in limb and axial muscles (Group a) observed in 51.5% of cases. Needle electromyography showed no abnormalities in myasthenia gravis patients. There was an association between acetylcholine receptor antibody titers and the results of the 3 Hz repetitive nerve stimulation test in myasthenia gravis patients, with a significance of p = 0.002. Nerve conduction studies should be performed in patients with suspected neuromuscular disorders to aid in differential diagnosis and definitive diagnosis of myasthenia gravis.

Myasthenia Gravis Presenting as Sudden–onset Isolated Hypercapnic Respiratory Failure

Myasthenic crisis, which can be life-threatening due to severe respiratory failure, occurs in 15-20% of patients with myasthenia gravis. However, the crisis often develops within 1-2 years after diagnosis and is very rare as a first symptom of myasthenia gravis; isolated sudden-onset hypercapnic respiratory failure without other symptoms of myasthenia gravis is even rarer. A 63-year-old woman presented to the emergency department with fever and dizziness. Chest computed tomography showed multifocal peribronchial ground-glass opacities, and a diagnosis of pneumonia was made. Initially, the patient did not have dyspnea. However, she developed acute hypercapnic respiratory failure and was intubated. After mechanical ventilation, her hypercapnia improved initially, but worsened on initiation of weaning from the ventilator. As she had a high acetylcholine receptor antibody titer, myasthenia gravis was diagnosed. Her hypercapnia improved after treatment with pyridostigmine and methylprednisolone.

Significance of Acetylcholine Receptor Antibody Titers in Acetylcholine Receptor Antibody-Positive Ocular Myasthenia Gravis: Generalization and Presence of Thyroid Autoimmune Antibodies and Thymoma.

To evaluate the association in acetylcholine receptor (AChR) antibody-positive ocular myasthenia gravis (OMG) subjects between AChR antibody titers and conversion to generalized myasthenia gravis (GMG), the presence of thyroid autoimmune antibodies, and the presence of thymoma. A total of 118 subjects with AChR antibody-positive OMG were included. Demographic data, clinical characteristics, serology tests, presence of thymoma, treatment, and conversion to GMG were retrospectively reviewed. The presence of thyroid autoimmune antibodies was defined as the presence of at least one of the following: (1) thyroid peroxidase antibody; (2) thyroglobulin antibody; (3) thyroid-stimulating hormone receptor antibody. Univariate and multivariate logistic regression analyses were used as methods of evaluating association. AChR antibody titers were determined in all subjects with a median of 3.33 (0.46-141.09) nmol/L. The median follow-up period was 14.5 (3-113) months. At the final follow-up time-point, 99 subjects (83.90%) remained with a diagnosis of pure OMG, while 19 subjects (16.10%) had converted to GMG. An AChR antibody titer ≥8.11 nmol/L was associated with the conversion to GMG (odds ratio (OR) 3.66, 95% CI: 1.19-11.26; p = 0.023). Of the 79 subjects with available thyroid autoimmune antibodies data, 26 subjects (32.91%) displayed the presence of thyroid autoimmune antibodies. An AChR antibody titer ≥2.81 nmol/L was associated with the presence of thyroid autoimmune antibodies (OR 6.16, 95% CI: 1.79-21.22; p = 0.004). Finally, of the 106 subjects with available thoracic computed tomography (CT) data, only 9 subjects (8.49%) demonstrated the presence of thymoma. An AChR antibody titer ≥15.12 nmol/L was associated with the presence of thymoma (OR 4.97, 95% CI: 1.10-22.48; p = 0.037). AChR antibody titers should be considered in AChR antibody-positive OMG patients. Those with AChR antibody titers ≥8.11 nmol/L, who are at a greater risk of conversion to GMG, should be closely monitored and encouraged to be aware of early clinical signs of life-threatening GMG. In addition, serum thyroid autoimmune antibodies and thoracic CT screening for thymoma should be performed in AChR antibody-positive OMG patients, particularly in those with AChR antibody titers ≥2.81 nmol/L and ≥15.12 nmol/L, respectively.

Role of soluble forms of follicular helper T-cell membrane molecules in the pathogenesis of myasthenia gravis

This study examined the role of Tfh and Treg associated molecules also known as checkpoint molecules, their ligands, and IL-21 in myasthenia gravis (MG) pathogenesis. Serum levels of sPD-1, sPD-L1, sICOS, sICOSLG, sCTLA4, and IL-21 were measured in 39 patients with acetylcholine receptor (AChR) antibody-positive generalized MG and 27 controls. sPD-1 and IL-21 levels were higher in MG patients than in controls. Additionally, sPD-1 levels correlated positively with the levels of IL-21, sICOSLG, sCTLA4, and AChR antibody titers. sICOS are correlated with MGADL and AChR antibody titers. These Tfh associated molecules could be used as biomarkers of MG disease activity.

The coincidence of Guillain‐Barré syndrome and myasthenia gravis

Background The occurrence of both Guillain-Barré syndrome (GBS) and Myasthenia Gravis (MG) conditions in the same individual is rare. The underlying pathophysiology was assumed to be an autoimmune humoral mechanism. A molecular mimicry in which a cross-reaction between autoantibodies and myelin sheath of peripheral nerves and acetylcholine receptors of the neuromuscular junction (NMJ) cannot be excluded as an underlying cause. Case presentation An 18-year-old female patient was examined. She was presented with symptoms of generalized weakness and distal weakness in both upper and lower extremities, more pronounced on the right side and with associated right foot drop and bilateral ptosis. The electrophysiological study was performed and the AChR antibody titre was determined. The patient was diagnosed with GBS and MG. Conclusions In conclusion, GBS and MG are two different neurological entities with different pathophysiology. New onset or persistence of symptoms in a patient with GBS treated with IVIG or plasmapheresis should probe for another autoimmune neurological illness, preferably autoimmune neuromuscular disorders like MG.

Factors predicting surgical outcome of thymectomy in myasthenia gravis

Aim of the study is to evaluate predictors of outcome after thymectomy in the management of non thymomatous myasthenia gravis. One hundred patients who underwent thymectomy for myasthenia gravis in the period between June 2019 and September 2021 in Kasr Alainy hospitals were recruited to this study.
 Preoperative assessment included age, gender, co morbidities, MGFA classification, duration of symptoms from time of diagnosis till surgery, preoperative medication, preoperative plasmapheresis. All patients performed CT chest, electromyography, and acetyl choline receptor antibody titer before and after surgery. Thymectomy was performed either by transsternal or VATS approach with documentation of the extent of resection; primary outcome was assessment of improvement by MGFA classification and need for medication. Secondary outcome was postoperative complications. Complete stable remission was achieved in 5 patients, clinical and pharmacological improvements were achieved in 71 patients, 21 patients didn’t improve and only 3 patients worsen after surgery. Finally, we found that early onset MG, absent preoperative comorbidity, performing extended thymectomy and reduction of postoperative Acetyl choline receptor antibody titer were significant predictors of improvement of MG symptoms after thymectomy.

Changes in antibody titers and clinical course in myasthenia gravis retrospective study

Myasthenia gravis (MG) is a rare, long‐term autoimmune disorder that causes muscle weakness; the condition typically has phases when it remits and phases when it relapses. Even though treatment response with regards to immunosuppressive therapies in MG patients is classically monitored by clinical scores, identification of a serological biomarker that monitors treatment response could be helpful. Here, the authors explore the correlation between acetylcholine receptor (AChR) antibody titers with changes in clinical severity in patients with MG and discuss the implications for clinical practice.

Relationship between Low and High Anti-acetylcholine Receptor Antibody Titers and Clinical Severity in Myasthenia Gravis.

To determine the frequency of low and high anti-AChR (acetylcholine receptor) antibody titers and to evaluate their relationship with clinical severity in myasthenia gravis. Cross-sectional, observational study. Department of Neurology, King Edward Medical University/Mayo Hospital, Lahore from April 2017 to March 2018. Fifty-six seropositive patients, aged between 18-75 years, were included. A blood sample was obtained from each patient to assess for the anti-AChR antibody titers by enzyme-linked immunosorbent assay (ELISA) technique and classified as low (0.4-<50 nmol/L) and high AChR antibody titers (>50 nmol/L). Clinical severity was graded according to the Osserman's classification. Out of 56 patients, 51.79% (n=29) were males and 48.21% (n=27) were females, and mean age was 32.73 +8.48 years. Mean anti-AChR antibody titer was found 40.45 + 13.54; 60.71% (n=34) had low and 39.29% (n=22) had high titers. Upon grading the severity, 1.79% (n=1) had grade I, 25% (n=14) had grade IIa, 26.79% (n=15) had grade IIb, 37.5% (n=21) had grade III, and 8.93% (n=5) had grade IV. These grades were significantly associated with high/low titers of anti-AChR antibody (p<0.001) but no significant association was found with age and gender (p=0.39 and 0.19 respectively). Serum concentration of anti-AChR antibodies has significant association with the clinical severity in myasthenia gravis. Key Words: Anti-acetylcholine receptor antibody, Myasthenia gravis, Neuromuscular junction diseases.

The clinical utility of neostigmine administration in the diagnosis of acquired myasthenia gravis.

To assess the clinical utility of neostigmine methylsulfate administration in the diagnosis of suspected acquired myasthenia gravis (MG) in dogs and cats. Retrospective study (2017-2019). Five university teaching hospitals and 2 private referral hospitals. Twenty-two dogs and 3 cats. Criteria for inclusion were clinical signs consistent with acquired MG, performance of a neostigmine challenge and acetylcholine receptor antibody titers. None. The route of neostigmine administration was recorded. Response to neostigmine challenge was determined via sequential evaluation of muscle strength and ambulation following administration of neostigmine methylsulfate. Response to neostigmine challenge was compared to acetylcholine receptor antibody titers, which were used as the biochemical gold standard in this study. Sixteen out of 22 dogs were diagnosed with acquired MG. Thirteen of 16 had a strong positive response to neostigmine challenge whereas 3 of 16 had no response. Two out of 3 dogs with polymyositis also had a strong positive response to neostigmine challenge. Weak positive results were seen with intracranial neoplasia (n=1) and a dog with dilated cardiomyopathy and coxofemoral joint disease (n=1). One cat was diagnosed with acquired MG and had a positive response to neostigmine challenge. Two cats had no response to neostigmine challenge and were diagnosed with alternate conditions. Two cats were premedicated with glycopyrrolate, one of which had a mild adverse response to neostigmine challenge (sialorrhea and mild transient tremors). Three out of 22 dogs had minimal adverse effects (sialorrhea and 1 dog with muscle tremors). The neostigmine challenge appears to be safe and viable alternative to the previously utilized edrophonium challenge, particularly when weak positive responses are considered negative for acquired MG. Polymyositis cases may have a false positive response to neostigmine challenge.

Disease Severity Assessment and Short-Term Outcome in Patients with Myasthenia Gravis.

Background:Myasthenia gravis (MG) is an autoimmune disorder with a chronic fluctuating course. The outcome measures encapsulate disease severity, functional impact at diagnosis, and objective evaluation of clinical benefit from therapeutic interventions.Aims and Objective:To assess the disease severity, correlation between various outcome measures, and to evaluate the short-term outcome at 3 months and 6 months in a cohort of MG patients.Materials and Methods:Quantitative myasthenia gravis (QMG) score, myasthenia gravis composite (MGC) score, and myasthenia gravis quality of life-15 (MG-QoL-15) score were applied to 54 patients at first visit, 3 months and 6 months follow-up.Results:Mean quality of life-15 (QoL-15) score at base line was 15.241. Mean QMG and MGC scores at baseline were 14.63 ± 8.37 and 15.87 ± 9.14, respectively. QMG score showed a strong positive correlation with both MGC and MG-QoL-15 scores. QMG and MGC scores showed a moderate correlation with acetylcholine receptor antibody (AChR Ab) titers. Mean QMG at follow-up was 9.95 ± 5.49 at 3 months and 6.74 ± 4.74 at 6 months. Mean MGC at follow-up was 10.75 ± 5.58 at 3 months and 6.51 ± 4.36 at 6 months.Conclusion:The combination of physician-evaluated and patient-reported outcome measures provided a more discerning picture of patient status and response to treatment. Incorporating MG outcome measures into clinical practice would aid in modulating therapies.

Surgical treatment of an oesophageal achalasia in a small breed dog

A 6-year-old, male Yorkshire Terrier dog presented with persistent regurgitation and severe weight loss. Based on the clinical signs, physical and other various diagnostic examinations, including fluoroscopy, were performed. Myasthenia gravis was ruled out through a serum acetylcholine receptor antibody titre measurement and a negative response to neostigmine bromide (0.02 mg/kg) within 4 hours of injection. The dog was diagnosed with idiopathic oesophageal achalasia. As a treatment, a modified Heller’s oesophagomyotomy was performed, and the dog recovered well with no signs of recurrence for 18 months.

Management and resolution of acquired myasthenia gravis in a carbimazole-treated hyperthyroid domestic shorthair cat

An 11-year-old male neutered domestic shorthair cat presented with acute onset signs of generalised weakness and neck ventroflexion. He had been diagnosed with hyperthyroidism two months previously and been treated...

Long-term effect of thymectomy plus prednisone versus prednisone alone in patients with non-thymomatous myasthenia gravis: 2-year extension of the MGTX randomised trial

The Thymectomy Trial in Non-Thymomatous Myasthenia Gravis Patients Receiving Prednisone (MGTX) showed that thymectomy combined with prednisone was superior to prednisone alone in improving clinical status as measured by the Quantitative Myasthenia Gravis (QMG) score in patients with generalised non-thymomatous myasthenia gravis at 3 years. We investigated the long-term effects of thymectomy up to 5 years on clinical status, medication requirements, and adverse events. We did a rater-blinded 2-year extension study at 36 centres in 15 countries for all patients who completed the randomised controlled MGTX and were willing to participate. MGTX patients were aged 18 to 65 years at enrolment, had generalised non-thymomatous myasthenia gravis of less than 5 years' duration, had acetylcholine receptor antibody titres of 1·00 nmol/L or higher (or concentrations of 0·50-0·99 nmol/L if diagnosis was confirmed by positive edrophonium or abnormal repetitive nerve stimulation, or abnormal single fibre electromyography), had Myasthenia Gravis Foundation of America Clinical Classification Class II-IV disease, and were on optimal anticholinesterase therapy with or without oral corticosteroids. In MGTX, patients were randomly assigned (1:1) to either thymectomy plus prednisone or prednisone alone. All patients in both groups received oral prednisone at doses titrated up to 100 mg on alternate days until they achieved minimal manifestation status. The primary endpoints of the extension phase were the time-weighted means of the QMG score and alternate-day prednisone dose from month 0 to month 60. Analyses were by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00294658. It is closed to new participants, with follow-up completed. Of the 111 patients who completed the 3-year MGTX, 68 (61%) entered the extension study between Sept 1, 2009, and Aug 26, 2015 (33 in the prednisone alone group and 35 in the prednisone plus thymectomy group). 50 (74%) patients completed the 60-month assessment, 24 in the prednisone alone group and 26 in the prednisone plus thymectomy group. At 5 years, patients in the thymectomy plus prednisone group had significantly lower time-weighted mean QMG scores (5·47 [SD 3·87] vs 9·34 [5·08]; p=0·0007) and mean alternate-day prednisone doses (24 mg [SD 21] vs 48 mg [29]; p=0·0002) than did those in the prednisone alone group. 14 (42%) of 33 patients in the prednisone group, and 12 (34%) of 35 in the thymectomy plus prednisone group, had at least one adverse event by month 60. No treatment-related deaths were reported during the extension phase. At 5 years, thymectomy plus prednisone continues to confer benefits in patients with generalised non-thymomatous myasthenia gravis compared with prednisone alone. Although caution is appropriate when generalising our findings because of the small sample size of our study, they nevertheless provide further support for the benefits of thymectomy in patients with generalised non-thymomatous myasthenia gravis. National Institutes of Health, National Institute of Neurological Disorders and Stroke.

Factors predicting remission in thymectomized patients with acetylcholine receptor antibody-positive myasthenia gravis.

Although thymectomy is an important therapeutic option for myasthenia gravis (MG), factors predicting remission after thymectomy are not well known. We retrospectively reviewed patients with acetylcholine receptor antibody (AChR-Ab)-positive MG who had undergone thymectomy. Prognostic factors predicting remission were investigated. Changes in AChR-Ab titer before and after thymectomy were also evaluated. Among the 179 patients, 52.5% achieved complete stable or pharmacologic remission. Nonthymomatous pathology and mild preoperative status were favorable predictors of remission. The decrease in AChR-Ab titer after thymectomy was significant in nonthymomatous MG but not in thymomatous MG. Nonthymomatous pathology and mild preoperative status are prognostic factors that may predict remission after thymectomy. The decrease in AChR-Ab titer after thymectomy was significant in nonthymomatous MG but not in thymomatous MG, suggesting that the pathogenic role of the thymus differs according to pathology. Muscle Nerve 58:796-800, 2018.

Acetylcholine Receptor Antibody Titers and Clinical Course after Influenza Vaccination in Patients with Myasthenia Gravis: A Double-Blind Randomized Controlled Trial (ProPATIent-Trial)

BackgroundIt is a continuous matter of discussion whether immune activation by vaccination in general and Influenza vaccination in particular increases the risk for clinical deterioration of autoimmune diseases. This prospective study investigated the serological and clinical course of autoimmune Myasthenia gravis (MG) after a seasonal influenza vaccination. MethodsThis randomized, placebo-controlled, double-blind study enrolled MG patients with antibodies against acetylcholine-receptors (AChR-ab). They were allocated to receive seasonal influenza vaccine or placebo. The primary endpoint was the relative change of AChR-ab-titer over 12weeks. A relative increase of 20% was set as non-inferiority margin. Secondary endpoints were clinical changes in the modified Quantitative Myasthenia Gravis Score (QMG), increase of anti-influenza-ELISA-antibodies, and changes of treatment. The study is registered with Clinicaltrialsregister.eu, EudraCT number 2006-004374-27. Findings62 patients were included. Mean±standard deviation (median) in the vaccine and placebo group were AChR-ab-titer changes of −6.0%±23.3% (−4.0%) and −2.8%±22.0% (−0.5%) and QMG score changes of −0.08±0.27 (0.17) and 0.11±0.31 (0.00), respectively. The difference between groups (Hodges-Lehmann estimate with 95% CI) was - for the AChR-ab-titer change 4·0% [−13.3%, 4.5%] (p=0.28 for testing a difference, p<0.0001 for testing non-inferiority) and for the QMG change 0·00 [−0.17, 0.00] (p=0.79 for testing a difference). The occurrence of 74 adverse events (AE) was comparable between groups. The most common AE was flu-like symptoms. One serious AE (hospitalisation following gastrointestinal haemorrhage) in the verum group was not related to the vaccine. InterpretationInfluenza vaccination in MG is safe. Uprating the potential risk of a severe course of MG exacerbation during influenza infection compared to the 95% CI differences for the endpoints, vaccination is principally indicated in this patient population.

Spontaneous remission of localized myasthenia gravis manifested as megaesophagus in a dog

A 2.5-year-old male German shepherd-cross dog was admitted for progressively deteriorating regurgitations ofone-month duration. Physical examination was unremarkable, apart from a poor body condition; also, neurological examination did not reveal any abnormality. In thoracic survey radiographs, a generalized esophageal dilation, consistent with megaesophagus, was well visualized. An increased nicotinic acetylcholine receptor antibody titer confirmed the diagnosis of acquired focal myasthenia gravis expressed as megaesophagus in this patient. The only help offered to the dog was a modification of its feeding habits (upright position, small and frequent meals). Within two months of the initial admission and prior to institution of specific treatment for myasthenia gravis, the dog experienced spontaneous and complete clinical remission and remained healthy for the next two years, eating again the normal way, but unfortunately was lost to follow-up. The favourable outcome of megaesophagus due to localized myasthenia gravis is discussed accordingly.

Correlation of antimuscarinic acetylcholine receptor antibody titers and antidesmoglein antibody titers with the severity of disease in patients with pemphigus

Acetylcholine receptor (AchR) antibody levels significantly correlate with disease severity at initial pemphigus diagnosis and during follow-up. However, it is not clear if they are just an epiphenomenon or a potential trigger of the known pathogenic process in pemphigus vulgaris. We sought to assess the changes in anti-muscarinic (M3) AchR and anti-desmoglein (Dsg) antibody titers with therapy. This was a hospital-based cohort study involving 45 patients with active pemphigus. Disease was graded clinically using Pemphigus Disease Area Index. Antibody titers were estimated using enzyme-linked immunosorbent assay at baseline, 3months, and 15months. All patients with pemphigus had significantly higher anti-M3 AchR titers when compared with a control group. Only 95.5% of patients had anti-Dsg1 antibodies and 84.4% of patients had anti-Dsg3 antibodies. A statistically significant reduction in all 3 antibody titers from baseline to follow-up with treatment was observed. There was a good correlation between all 3 antibody titer and Pemphigus Disease Area Index score at baseline and after therapy and between anti-M3 AchR and anti-Dsg1 antibody titers. Sample size was small and follow-up period was short. Anti-M3 AchR antibodies are strongly associated with pemphigus. They significantly correlate with disease activity and their titers decline with therapy along with anti-Dsg antibodies.

Analysis of mortality and related factors in 2195 adult myasthenia gravis patients in a 10-year follow-up study

To analyze the mortality and potential risk factors for death in myasthenia gravis (MG) patients. A total of 2195 adult patients with MG (aged older than 18 years) diagnosed during the period between 2003 and 2013 were followed-up and retrospectively reviewed. During the 10-year follow-up, 129 patients died and the total mortality rate was 5.88%. The risk factors associated with MG-related deaths were duration of the disease, occurrence of myasthenic crisis, severity of disease that included the Myasthenia Gravis Foundation of America (MGFA) grade III and IV at onset, elevation of acetylcholine receptor antibody (AchR-abs) titers, presence of thymic pathology, and failure of administrating immunosuppressants (P < 0.05). In addition, the non-MG related factors, including the history of preceding strokes, and the presence of chronic obstructive pulmonary disease (COPD), diabetes mellitus, atrial fibrillation, hyperlipidemia, myocardial infarction, and malignant tumors, were closely linked with death in the MG population (the hazard ratios [HRs] were 3.251, 4.173, 3.738, 3.886, 1.945, 2.177, and 14.7, respectively; P< 0.05). The severity of disease at entry, presence of AchRabs, thymic pathology, and duration of the disease predict a higher risk for death. Systemic illnesses including stroke, COPD, diabetes mellitus, atrial fibrillation, hyperlipidemia, myocardial infarction, and malignant tumor, which may also increase the risk of death, should be carefully monitored and managed.

Single-fiber Electromyography in the Extensor Digitorum Communis for the Predictive Prognosis of Ocular Myasthenia Gravis: A Retrospective Study of 102 Cases.

Background:Single-fiber electromyography (SFEMG) abnormality in the extensor digitorum communis (EDC) was reported in ocular myasthenia gravis (OMG), which indicated subclinical involvement beyond extraocular muscles in OMG patients. The relationship between the abnormal findings of SFEMG in EDC and the probability for OMG to develop generalized myasthenia gravis (GMG) is unknown. This retrospective study aimed to determine the predictive value of abnormality of SFEMG in EDC of OMG patients.Methods:One-hundred and two OMG patients underwent standard clinical diagnosis process and SFEMG test in EDC muscle when diagnosed and were clinically followed up for 5 years. The SFEMG data were compared between different clinical groups according to thymus status, onset age, and different outcome of OMG developing. Chances of progressing to GMG were compared between two different groups according to SFEMG and repetitive nerve stimulation (RNS) results, acetylcholine receptor antibody (AchRAb) titer, thymus status, and onset age.Results:Abnormal SFEMG results were observed in 84 (82.4%) patients. The mean jitter, percentage of jitter >55 μs (%), and blocking were higher in OMG patients than in healthy volunteers. There were no statistical differences in jitter analysis between thymoma group and non-thymoma group (P = 0.65), or between the later OMG group and the later GMG group (P = 0.31), including mean jitter, percentage of jitter >55 μs (%), and blocking. Elderly group (≥45 years old) had a higher mean jitter than younger group (t = 2.235, P = 0.028). Total 55 OMG developed GMG, including 47 in abnormal SFEMG group while 8 in normal SFEMG group. There was no statistical difference in the conversion rates between the two groups (χ2 = 0.790, P = 0.140). RNS abnormality, AchRab titer, or onset age had no correlation with OMG prognosis (P = 0.150, 0.070, 0.120, respectively) while thymoma did (χ2 = 0.510, P = 0.020).Conclusion:SFEMG test in the EDC showed high abnormality in OMG, suggesting subclinical involvement other than extraocular muscles. Nevertheless, the abnormal jitter analysis did not predict the prognosis of OMG according to clinical follow-up.