Nonthymoma early-onset- and late-onset-generalized myasthenia gravis--a retrospective hospital-based study

OBJECTIVE: Acquired myasthenia gravis (MG) is predominantly due to nicotinic acetylcholine receptor (AChR) autoantibodies (Ab). Differences between nonthymoma early-onset and late-onset MG were reported. We studied the clinical and serological characteristics of nonthymoma AChR Ab-positive-generalized MG patients. PATIENTS AND METHODS: Chinese AChR Ab-positive-generalized MG patients who had generalized disease for 3 years or longer were studied. RESULTS: Among 41 such patients, 25 (61%) were female. The mean onset age was 43.5 years (range 9-78 years) and the mean follow-up duration was 7.8 years (range 3-20 years). Sixteen (39%) patients had late-onset disease (onset age >or=50 years). Compared to early-onset patients (onset age <50 years), late-onset patients were characterized by male predominance (p=0.002), absence of thymic lymphofollicular hyperplasia (p=0.036), and a higher striated muscle Ab seropositivity rate (94% versus 4%, p<0.001). Although there was no statistically significant difference in clinical severity and outcome or response to treatment between late-onset and early-onset patients, 50% and 75% of late-onset patients had moderate or severe disease at onset and worst status, respectively, compared to 28% and 52% for early-onset patients at onset and worst status, respectively. Also 63% of late-onset patients had disease progressed within first 3 years compared to only 40% of early-onset patients did. CONCLUSION: Nonthymoma late-onset-generalized MG patients were common among Hong Kong Chinese, with a statistically non-significant trend that it was clinically more severe than early-onset MG but with similar clinical outcome or response to treatment; >90% of these patients were seropositive for striated muscle Ab.     

Thymectomy in myasthenia with pure ocular symptoms.

Eighteen patients with exclusively ocular symptoms of myasthenia were thymectomised. Suspected thymoma, resistance to pyridostigmine therapy or relapse following immunosuppressive therapy were taken as indications for surgery. The mean preoperative observation period before operation was 40 months, and after operation was 26 months. There was no operative or postoperative morbidity or mortality. Histological thymic abnormalities were found in all patients (in one case, thymoma; in four, persistent thymus; in 13, thymic hyperplasia). The histological abnormalities were identical to those found in generalised myasthenia. This included the distribution of T-cell subtypes as identified by use of monoclonal antibodies. The severity of ocular symptoms was rated using a score developed for this purpose. The score progressively declined after surgery to an average of 70% of its initial amount in 80% of patients. Full remission occurred in three cases. No patient developed generalized myasthenia. Antibody titres against acetylcholine receptors if elevated preoperatively also dropped following surgery, with one exception. Clear criteria for the expected therapeutic success of thymectomy could not be identified. Based on our results, and on the assumed significance of the thymus gland for pathogenesis, thymectomy should be considered in patients with pure ocular symptoms.     

Low-dose tacrolimus for two cases of myasthenia gravis with invasive thymoma that relapsed shortly after thymectomy

Two patients with myasthenia gravis (Ossermann IIb) involving invasive thymoma who underwent extensive thymectomy manifested myasthenic crisis shortly after the procedure; however, both patients were treated with intravenous immunoglobulin and recovered from myasthenic crisis that had been deteriorating for about 1 week. Subsequently, the patients were administered a low-dose of tacrolimus (3 mg/day) in addition to prednisolone. Several months later, tacrolimus continued to control fluctuations of myasthenic symptoms and maintained remission in these patients. The serum titer of anti-Ach-receptor antibodies decreased in parallel with clinical improvement due to tacrolimus, and we accordingly reduced the dosage of prednisolone. Tacrolimus is a new immunosuppressive agent acting through the selective inhibition of helper-T-cell activation that can be reduced dosage of steroids and can maintain remission of myasthenia gravis with invasive thymoma.     

Clinical evaluation system (score) of ocular symptoms in myasthenia gravis

A new rating scheme (score) is presented for ocular symptomatology in myasthenia gravis. The score (0-10) combines separate ratings upper eyelid weakness (ptosis) and paralysis of the outer ocular muscles (double vision). It is relatively insensitive to subjective influences and to the rater's experience. It yields replicable values which are especially important for longitudinal studies, for testing new therapeutic strategies and for their statistical validation.     

Concurrence of acute autonomic and sensory neuropathy and myasthenia gravis--a case report and pathogenetic considerations

A 22-year-old woman admitted to the hospital on Mar. 19, 1985 because of syncopal attacks and numbness on the limbs. Examination revealed peripheral sympathetic as well as parasympathetic dysfunctions and loss of myelinated as well as unmyelinated fibers in a biopsied sural nerve. A diagnosis of acute autonomic and sensory neuropathy (AASN) was made. She was treated with prednisolone but did not respond to the therapy. Only L-DOPS was effective on orthostatic hypotension. Recovery of the neurological conditions was insufficient till May 1987, when she complained of easy fatigability when speaking and chewing. Pharmacological and electrodiagnostic tests showed typical myasthenic phenomenon. At this time, serum anti-ACh receptor antibody was 741nmol/l and a diagnosis of myasthenia gravis was confirmed. Anti-ACh receptor antibody was proven to be elevated in the serum collected on April 1985 when the initial symptom of AASN had appeared. A thymectomy resulted in prompt and complete remission of semiologies of both myasthenia gravis and AASN. These suggest that immunological abnormality might play an important role in the pathogenesis of AASN in this case.     

Prognosis of ocular myasthenia

A retrospective study of 108 patients with myasthenia gravis who had solely ocular symptoms and signs at onset was carried out to identify factors influencing prognosis. Increasing duration of pure ocular myasthenia was associated with a decreasing risk of late generalized symptoms; only 9 (15%) of the observed generalizations occurred after more than 2 years of solely ocular symptoms. Increasing age at onset was associated with greater risk of respiratory crisis or death caused by myasthenia, whereas patients younger at onset had a greater chance of a benign outcome. Neither systemic curare tests nor responses to repetitive nerve stimulation had prognostic value.     

重症肌无力胸腺切除术后缓解与复发的临床观察

目的探讨伴与不伴胸腺瘤重症肌无力(MG)患者胸腺切除术后预后结局的差异,分析其预后因素。方法收集2017年9月至2018年12月在作者医院行胸腺切除术的MG 67例,比较伴与不伴胸腺瘤MG患者术后不同时间节点理想状态率、复发率的差异,并分析影响预后的因素。结果 (1)非胸腺瘤-MG术后1、6、12个月与胸腺瘤-MG术后6、12个月肌力评分均较术前明显降低(P<0.05)。(2)非胸腺瘤-MG术后理想状态率1个月(5.6%)、6个月(31.1%)、12个月(54.8%)及胸腺瘤-MG术后1个月(0%)、6个月(23.1%)、12个月(42.9%)均逐渐上升,两组间比较无统计学差异。早手术(起病-手术间期<6个月)、眼肌型是MG患者术后达到理想状态的有利因素,OR(95%CI)分别为4.211(1.146~15.475)、4.813(1.430~16.203)。(3)非胸腺瘤-MG术后复发率1个月(3.7%)、6个月(33.3%)、12个月(54.8%)及胸腺瘤-MG术后1个月(30.8%)、6个月(30.8%)、12个月(57.1%)逐渐上升,两组间比较仅第1个月的差异有统计学意义(P<0.05)。手术-复发间隔时间较短者多见于乙酰胆碱受体抗体(AChR-Abs)强阳性(≥20nmol/L)MG及胸腺瘤-MG(P=0.038,P=0.001)。结论对具有一定适应证的MG患者早期行胸腺切除有助于提高理想状态率;AChR-Abs强阳性、胸腺瘤-MG患者术后早期复发风险大;伴或不伴胸腺瘤-MG术后远期预后无统计学差异。     

眼肌无力的诊断及依据

重症肌无力是乙酰胆碱受体抗体介导的,细胞免疫依赖及补体参与的神经-肌肉接头处（NMJ）传递障碍的自身免疫性疾病。眼肌症状是最为多见的首发症状,表现为上眼睑下垂、复视、斜视等,尤以眼睑下垂最多。通过典型的临床表现及临床实验即可诊断、腾喜龙试验、血清抗体检测、电子诊断可以进一步确诊。     

Evaluation of remission in childhood myasthenia gravis

By the electrophysiological methods such as supramaximal stimulation and single-fibre EMG (SF EMG) 13 children with myasthenia were studied. In only one case the results of both tests were normal. These findings confirm the presence of subclinical disturbances of neuromuscular transmission in most cases of myasthenia during remission. This may be of practical importance in the treatment of myasthenic patients.     

A case of myasthenia gravis with transient remission after influenza A virus infection

A boy with ocular type myasthenia gravis was reported. The therapeutic effect of pyridostigmine bromide and corticosteroid was insufficient. However, clinical symptoms disappeared rapidly after an influenza A virus infection. On a peripheral lymphocytes subsets analysis, the CD 3, CD 4 and CD 4/CD 45 RA positive lymphocytes increased with the therapy and decreased after the infection. By contrast, CD 19 positive lymphocytes decreased with the therapy and increased after the infection. These results suggested that influenza A may improve the clinical signs of myasthenia gravis, as is the improved case with measles.     

Treatment of ocular myasthenia with corticotrophin

Nine patients with severe myasthenia gravis, including ocular symptoms, who did not respond to anticholinesterase therapy were given prolonged courses of corticotrophin. In all patients except one there was an initial deterioration, sometimes necessitating assisted respiration, followed by a marked improvement which persisted for many weeks and occasionally months. It is concluded that corticotrophin should be continued for at least two weeks as the onset of the remission might be delayed. Repeated courses or small maintenance doses prolonged the remission. Fluid retention and hypokalaemia were common unwanted effects but necessitated stopping the treatment in only one patient.     

眼肌型重症肌无力临床分析

目的总结分析眼肌型重症肌无力患者的临床特征,以为诊断和治疗提供参考依据。方法回顾性分析113例眼肌型重症肌无力患者的临床资料。采用免疫荧光细胞染色方法检测血清乙酰胆碱受体（AChR）抗体和肌肉特异性受体酪氨酸激酶（MuSK）抗体表达水平,分析这两项免疫学指标对眼肌型重症肌无力向全身型转化的预测价值。结果成年发病的眼肌型重症肌无力好发于40岁以上男性,多以眼睑下垂（95例,84．07％）为首发症状,少数以复视（18例,15．93％）起病。疲劳试验和新斯的明试验阳性率分别为79．44％（85／107）和84．85％（84／99）．低频重复神经电刺激和血清甲状腺抗体异常率分别为44．32％（39／88）和28％（14／50）,胸腺增生和胸腺瘤阳性率分别为16．67％（17／102）和11．76％（12／102）;血清AChR抗体阳性率为62.83％（71／113）;但MuSK抗体均呈阴性。眼肌型重症肌无力向全身型转化率为12．39％（14／113）,其中血清AChR抗体强阳性者（13例,28．26％）显著高于弱阳性者（1例,4％）,二者差异有统计学意义（X^2=4．587,P=0．032）。结论成年发病的眼肌型重症肌无力好发于中年以上男性,主要表现为眼睑下垂和复视,大多数患者伴发胸腺和甲状腺异常。血清AChR抗体表达水平升高预示向全身型转化率升高,鲜有MuSK抗体阳性反应。