Clinical Outcomes of Myasthenia Gravis with Thymoma and Thymic Hyperplasia Undergoing Extended Transsternal Thymectomy: A Single-Center Experience

Comparison of Short-Term Post-Thymectomy Outcomes by Time-Weighted Dosages of Drug Requirements between Thymoma and Non-Thymoma Myasthenia Gravis Patients

(1) Background: Early thymectomy is suggested in all clinically indicated myasthenia gravis (MG) patients. However, short-term clinical response after thymectomy in MG patients has been limitedly described in the literature. This study aimed to compare the 5-year post-thymectomy outcomes between thymoma (Th) and non-thymoma (non-Th) MG patients. (2) Methods: MG patients aged ≥18 years who underwent transsternal thymectomy and had tissue histopathology reports in Songklanagarind Hospital between 2002 and 2020 were enrolled in a retrospective review. The differences in the baseline demographics and clinical characteristics between ThMG and non-Th MG patients were studied. We compared the time-weighted averages (TWAs) of daily required dosages of pyridostigmine, prednisolone or azathioprine to efficiently maintain daily living activities and earnings between the MG patient groups during 5 consecutive years following thymectomy. Post-thymectomy clinical status, exacerbations or crises were followed. Descriptive statistics were used for analysis with statistical significance set at p < 0.05. (3) Results: ThMG patients had significantly older ages of onset and shorter times from the MG diagnosis to thymectomy. Male gender was the only significant factor associated with ThMG. TWAs of the daily MG treatment drug dosages required showed no differences between the groups. Additionally, the rates of exacerbations and crises were not different, but decremental trends were shown in both groups after the thymectomies. (4) Conclusions: The daily dosage requirements of MG treatment drugs were not different. There was a trend of decreasing adverse event rates despite no statistically significant differences during the first 5 years after thymectomy in ThMG and non-ThMG patients.

Prevalence and risk factors of myasthenia gravis recurrence post-thymectomy

Objectives:

To evaluate the prevalence and the factors associated with recurrence of myasthenia gravis following thymectomy.

Methods:

Six electronic databases which reported on recurrence of myasthenia gravis following thymectomy and/or its risk factors from 1985 to 2018 were searched. Summary prevalence and risk values obtained based on the random effect models were reported.

Results:

Seventy (70) papers containing 7,287 individuals with myasthenia gravis who received thymectomy as part of their management were retrieved. The patients had a mean follow-up of 4.65 years post-thymectomy. The prevalence of myasthenia gravis recurrence post-thymectomy was 18.0% (95% CI 14.7–22.0%; 1865/7287). Evident heterogeneity was observed (I²=93.6%; p<0.001). Recurrence rate was insignificantly higher in male compared with female patients (31.3 vs. 23.8%; p=0.104). Pooled recurrence rates for thymomatous (33.3%) was higher than the rate among non-thymomatous (20.8%) myasthenia gravis patients (Q=4.19, p=0.041). Risk factors for recurrence include older age, male sex, disease severity, having thymomatous myasthenia gravis, longer duration of the myasthenia gravis before surgery, and having an ectopic thymic tissue.

Conclusion:

A fifth of individuals with myasthenia gravis experience recurrence after thymectomy. Closer monitoring should be given to at-risk patients and further studies are needed to understand interventions to address these risks.

Early onset myasthenia gravis in a Malawian woman: Challenges in managing myasthenia gravis in a low-resource setting

Myasthenia gravis is a rare autoimmune disease, which presents with ocular or generalised symptoms. Few publications describe its prevalence in African populations. We describe a young woman who was diagnosed with myasthenia gravis in a Malawian public hospital and outline the challenges encountered in managing this condition in a low-resource setting.

Subgroup stratification and outcome in recently diagnosed generalized myasthenia gravis

OBJECTIVE

To describe disease outcomes of myasthenia gravis (MG) subgroups and which factors influence outcomes by reviewing individual patient records of a representative cohort.

METHODS

We performed a retrospective analysis of 199 patients with generalized MG and disease onset after the year 2000 who were treated at 2 tertiary referral centers in Austria. We stratified patients as early- and late-onset acetylcholine receptor antibody-positive, muscle-specific tyrosine kinase (MuSK) antibody-positive, and seronegative patients and patients with thymoma regardless of antibody status. We evaluated patients' symptom severity and treatment regimens and the occurrence of life-threatening events at yearly time points for up to 10 years.

RESULTS

Minimal manifestation status or better was eventually achieved and sustained for >1 year by 125 (63%) patients. Forty percent (66 of 165 patients) showed an early response to treatment, which predicted a benign disease course later on. In contrast, 19% of patients, who remained symptomatic for 2 years after disease onset despite immunosuppressive therapy, were more treatment resistant in the following years. The strongest predictor of outcome was the diagnostic subgroup. Patients with MuSK-MG had a much better outcome than previously reported.

CONCLUSION

Our data give an update on the disease course of generalized MG in the new century. Diagnostic subgroups and response to treatment within the first 2 years help to predict the long term outcome.

Malignant thymoma with metastasis associated with paraneoplastic myasthenia gravis

We describe a patient who initially presented with a mixed thymic tumor and developed myasthenia gravis 8 years following thymectomy with recurrence of metastatic disease. Metastasis to the pleura, mediastinum, and cervical spine was identified with a positron emission tomography scan when this patient presented with recurring pneumonias and atrial fibrillation. The presentation and diagnosis were clouded by multiple courses of prednisone and chemotherapy for respiratory complications and metastatic disease, respectively. Classical myasthenia gravis symptoms emerged when his prednisone was tapered. The delayed presentation of paraneoplastic disease and the rare metastatic site make this case particularly unusual.