Myasthenia gravis (MG) is a rare autoimmune disease. Transient neonatal myasthenia gravis (TNMG) is caused by pathogenic maternal autoantibodies that cross the placenta and disrupt signaling at the neuromuscular junction. This is a systematic review of this transient immunoglobulin G (IgG)-mediated disease. TNMG affects 10-20% of children born to mothers with MG. The severity of symptoms ranges from minor feeding difficulties to life-threatening respiratory weakness. Minor symptoms might go unnoticed but can still interfere with breastfeeding. Acetylcholine-esterase inhibitors and antibody-clearing therapies such as immunoglobulins can be used to treat TNMG, but most children do well with observation only. TNMG is self-limiting within weeks as circulating antibodies are naturally cleared from the blood. In rare cases, TNMG is associated with permanent skeletal malformations or permanent myopathy. The mother\'s antibodies can also lead to spontaneous abortions. All healthcare professionals meeting pregnant or birthing women with MG or their neonates should be aware of TNMG. TNMG is hard to predict. Reoccurrence is common among siblings. Pre-pregnancy thymectomy and intravenous immunoglobulins during pregnancy reduce the risk. Neonatal fragment crystallizable receptor (FcRn) blocking drugs for MG might reduce TNMG risk.

BACKGROUND: Generalized myasthenia gravis (MG) with antibodies against the acetylcholine receptor is a chronic disease causing muscle weakness. Access to novel treatments warrants authoritative treatment recommendations. The Nordic countries have similar, comprehensive health systems, mandatory health registers, and extensive MG research.
METHODS: MG experts and patient representatives from the five Nordic countries formed a working group to prepare treatment guidance for MG based on a systematic literature search and consensus meetings.
RESULTS: Pyridostigmine represents the first-line symptomatic treatment, while ambenonium and beta adrenergic agonists are second-line options. Early thymectomy should be undertaken if a thymoma, and in non-thymoma patients up to the age of 50-65 years if not obtaining remission on symptomatic treatment. Most patients need immunosuppressive drug treatment. Combining corticosteroids at the lowest possible dose with azathioprine is recommended, rituximab being an alternative first-line option. Mycophenolate, methotrexate, and tacrolimus represent second-line immunosuppression. Plasma exchange and intravenous immunoglobulin are used for myasthenic crises and acute exacerbations. Novel complement inhibitors and FcRn blockers are effective and fast-acting treatments with promising safety profiles. Their use depends on local availability, refunding policies, and cost-benefit analyses. Adapted physical training is recommended. Planning of pregnancies with optimal treatment, information, and awareness of neonatal MG is necessary. Social support and adaptation of work and daily life activities are recommended.
CONCLUSIONS: Successful treatment of MG rests on timely combination of different interventions. Due to spontaneous disease fluctuations, comorbidities, and changes in life conditions, regular long-term specialized follow-up is needed. Most patients do reasonably well but there is room for further improvement. Novel treatments are promising, though subject to restricted access due to costs.

Transient neonatal myasthenia gravis (TNMG) is an acquired disease which occurs in 10 to 20% of infants born to a mother with myasthenia gravis. Even though it is a self-limiting disorder, it may potentially be life-threatening if prompt diagnosis is not made, and expedient supportive respiratory management is not initiated when required.
Here we describe three infants with TNMG. Two of them developed symptoms of TNMG within 24 hours of life, but one developed symptoms at 43 hours of life. One of the patients had an atypical form of TNMG with contracture and hypotonia. The other two infants survived a typical form of TNMG with hypotonia and poor sucking. All cases resolved spontaneously by one to two weeks of life with conservative management.
Infants born to mothers with myasthenia gravis need to be monitored closely for symptoms of TNMG for the first 48 to 72 hours of life. However, the majority of infants with TNMG traverse a benign course and resolve spontaneously with expectant care.

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Antibodies to acetylcholine receptor (AChR) are detected in the vast majority of patients with generalized myasthenia gravis (MG) and are rarely detected in significant titer in other autoimmune diseases. We report a patient with an axonal predominately sensory neuropathy for over 12 years with persistent binding and modulating AChR antibodies as well as striational muscle antibodies with no evidence of MG or any neoplastic disease.

UNASSIGNED: To analyze radiological characteristics of the extraocular muscles (EOMs) in myasthenia gravis (MG) patients with ocular manifestations.
UNASSIGNED: This retrospective case-control study included all MG cases with ocular manifestations, who attended a neuro-ophthalmology clinic at a university hospital, Bangkok, from April 2009 to June 2018. They experienced double vision and ophthalmoplegia. Control participants had normal eye movements. Orbital scans were thoroughly reviewed. We measured muscle thickness (MT) of the superior rectus, inferior rectus, medial rectus and lateral rectus muscles in both eyes using magnetic resonance imaging or computed tomography scan. The sum of the muscle thickness at all sites was calculated (MTsum). Comparisons of the mean MT of each muscle type and the mean MTsum between the MG and control groups were performed by using Student\'s t-test. MRI signal intensities of the EOMs were also recorded.
UNASSIGNED: Twenty MG cases and 20 controls were included in the study. The mean MTsum was 23.7 (standard deviation 4.8) mm in the MG group and 32.6 (3.5) mm in the controls. There were statistically significant differences between the two groups with respect to the mean MT and mean MTsum (p <0.001). In the MG group, there was a negative correlation between the MTsum and disease duration (p= 0.03). By using coronal T2-weighted orbital MRI with fat suppression (T2W/FS), the most frequent finding was isointensity with central hypointensity of the EOMs in the MG group.
UNASSIGNED: Atrophic EOMs were frequently found in the MG group, particularly in chronic cases. Isointensity with central hypointensity of EOMs on T2W/FS was also common in the MG group. These findings highlight the importance of muscle involvement in MG and may be helpful for clinical decision-making.

To investigate the correlation between acetylcholine receptor antibodies (AChR-Ab) concentration levels and individualized clinical symptoms in patients with AChR myasthenia gravis (AChR-MG) in China.
ELISA was used to determine the concentration of AChR-Ab in patients with MG. The Myasthenia Gravis Foundation of America (MGFA) Clinical Classification, Quantitative Myasthenia Gravis (QMG) score, and MG-specific activities of daily living (MG-ADL) scoring systems were used to evaluate the clinical status of patients. Spearman correlation analysis was used to determine the correlation between the AChR-Ab concentration and clinical score. The changes in the antibody concentration and clinical score are shown in MGFA-antibody concentration-treatment plots.
Autoantibody detection tests were performed in 67 patients, and their clinical scores were recorded. Forty-nine patients received immunosuppressive therapy, 17 patients received pyridostigmine only, and 1 patient under thymectomy without any medication. The AChR-Ab concentration correlated with the MGFA Classification in 5 (29.4%) patients in the pyridostigmine-only group and 15 (30.6%) patients in the immunosuppressive drug group. The changes in the MGFA Classification preceded the changes in the AChR-Ab concentration in 4 (23.5%) patients treated with pyridostigmine and 10 (20.4%) patients on immunosuppressive drugs. In patients on oral non-steroidal immunosuppressants, the AChR-Ab concentration changed by more than 50%, whereas the MGFA Classification did not increase. The AChR-Ab concentration decreased in 17/32 (53.1%) patients after thymectomy, and then increased, whereas the AChR-Ab concentration increased in 15/32 (46.9%) patients and the MGFA Classification decreased in 27/32 (81.8%) patients after thymectomy. The AChR-Ab concentration presented a slight correlation with the corresponding MGFA, QMG, and MG-ADL in patients with thymoma.
In the Chinese AChR-MG population, the Changes in the AChR-Ab concentration in individuals with AChR-MG did not consistently correlate with the severity of clinical symptoms.

Myasthenia gravis (MG) with symptoms limited to eye muscles [ocular MG (OMG)] is a rare disease. OMG incidence varies according to ethnicity and age of onset. In recent years, both an increase in incidence rate, particularly in the elderly, and a lower risk for secondary generalization may have contributed to the growing disease prevalence in Western countries. OMG should be considered in patients with painless ptosis and extrinsic ophthalmoparesis. Though asymmetric muscle involvement and symptom fluctuations are typical, in some cases, OMG can mimic isolated cranial nerve paresis, internuclear ophthalmoplegia, and conjugate gaze palsy. Diagnostic confirmation can be challenging in patients negative for anti-acetylcholine receptor and anti-muscle-specific tyrosine kinase antibodies on standard radioimmunoassay. Early treatment is aimed at relieving symptoms and at preventing disease progression to generalized MG. Despite the absence of high-level evidence, there is general agreement on the efficacy of steroids at low to moderate dosage; immunosuppressants are considered when steroid high maintenance doses are required. The role of thymectomy in non-thymoma patients is controversial. Prolonged exposure to immunosuppressive therapy has a negative impact on the health-related quality of life in a proportion of these patients. OMG is currently excluded from most of the treatments recently developed in generalized MG.

Juvenile myasthenia gravis is a pediatric autoimmune disorder of the neuromuscular junction associated with substantial morbidity, for which standard therapies are not always efficacious. The objective of our study was to assess the tolerability and efficacy of rituximab use in children with refractory juvenile myasthenia gravis.
We conduced a retrospective cohort study at a single tertiary care referral center to evaluate children with juvenile myasthenia gravis who were treated with rituximab. The clinical status of these participants before and after initiation of rituximab therapy was measured, focusing on numbers of hospital admissions, numbers of immunomodulatory or immunosuppressive medications needed, and Myasthenia Gravis Foundation of America severity class.
Five children with juvenile myasthenia gravis were ascertained who received rituximab as part of their regimen, four of whom had elevated acetylcholine receptor antibodies and one of whom had elevated muscle-specific kinase antibodies. After initiation of rituximab therapy, all participants experienced reduced numbers of immunomodulatory medications during the follow-up period (mean 11.6 months). Four of the five subjects experienced fewer juvenile myasthenia gravis-related hospital admissions and reduced (improved) Myasthenia Gravis Foundation of America classes, with no subjects having moderate or severe symptoms following treatment with rituximab. No significant adverse events were recorded for any of the participants.
Rituximab was well-tolerated and efficacious in this juvenile myasthenia gravis cohort. The beneficial effect of rituximab was most pronounced in the one participant with muscle-specific kinase antibodies.

UNASSIGNED: Completion thymectomy may be performed in patients with non-thymomatous refractory myasthenia gravis (MG) to allow a complete and definitive clearance from residual thymic tissue located in the mediastinum or in lower neck. Hereby we present our short- and long-term results of completion thymectomy using subxiphoid video-assisted thoracoscopy.
UNASSIGNED: Between July 2010 and December 2017, 15 consecutive patients with refractory non-thymomatous myasthenia, 8 women and 7 men with a median age of 44 [interquartile range (IQR) 38.5-53.5] years, underwent video-thoracoscopic completion thymectomy through a subxiphoid approach.
UNASSIGNED: Positron emission tomography (PET) showed mildly avid areas [standardized uptake value (SUV) more than or equal to 1.8] in 11 instances. Median operative time was 106 (IQR, 77-141) minutes. No operative deaths nor major morbidity occurred. Mean 1-day postoperative Visual Analogue Scale value was 2.53±0.63. Median hospital stay was 2 (IQR, 1-3.5) days. A significant decrease of the anti-acetylcholine receptor antibodies was observed after 1 month [median percentage changes -67% (IQR, -39% to -83%)]. Median follow-up was 45 (IQR, 21-58) months. At the most recent follow-up complete stable remission was achieved in 5 patients. Another 9 patients had significant improvement in bulbar and limb function, requiring lower doses of corticosteroids and anticholinesterase drugs. Only one patient remained clinically stable albeit drug doses were reduced. One-month postoperative drop of anti-acetylcholine receptor antibodies was significantly correlated with complete stable remission (P=0.002).
UNASSIGNED: This initial experience confirms that removal of ectopic and residual thymus through a subxiphoid approach can reduce anti-acetylcholine receptor antibody titer correlating to good outcome of refractory MG.