Temporal association between SARS-CoV-2 and new-onset myasthenia gravis: is it causal or coincidental?

Several case reports of COVID-19 in patients with myasthenia gravis (MG) have been documented. However, new-onset autoimmune MG following COVID-19 has been reported very rarely. We report one such case here. A 65-year-old man presented to us with dysphagia 6 weeks following mild COVID-19. He was evaluated and diagnosed as antiacetylcholine receptor antibody (AchR) positive, non-thymomatous, generalised MG. He subsequently developed myasthenic crisis and improved after treatment with intravenous immunoglobulin, prednisolone and pyridostigmine. Systematic literature review showed eight more similar cases. Analysis of all cases including the one reported here showed these features: mean age 55.8 years, male gender (5), time interval between COVID-19 and MG (5–56 days), generalised (5), bulbar and/or ocular symptoms (4), anti-AchR antibodies (7) and antimuscle-specific kinase antibodies (2). All have improved with immunotherapy. Although, many hypothesis are proposed to explain causal relationship between the two, it could as well be sheer coincidence.

Response to eculizumab in patients with myasthenia gravis recently treated with chronic IVIg: a subgroup analysis of REGAIN and its open-label extension study

Background: In the phase III eculizumab for refractory generalized myasthenia gravis REGAIN study [ClinicalTrials.gov identifier: NCT01997229] and its open-label extension (OLE) [ClinicalTrials.gov identifier: NCT02301624], patients with treatment-refractory antiacetylcholine receptor antibody-positive generalized myasthenia gravis had clinically meaningful improvements with eculizumab versus placebo. This subgroup analysis evaluated data from patients with a recent history of chronic intravenous immunoglobulin (IVIg) use before study entry. Methods: The subgroup comprised patients who had received IVIg at least four times in 1 year, with at least one IVIg treatment cycle during the 6 months before the first REGAIN study dose. Data from REGAIN and the OLE were analyzed. Response to eculizumab versus placebo was assessed using four validated, disease-specific measures. Incidences of exacerbations and safety endpoints were recorded. Results: The subgroup had similar patient and disease characteristics as the overall REGAIN population. Clinical assessments showed sustained eculizumab efficacy during REGAIN and the OLE over 18 months. Patients receiving placebo in REGAIN experienced rapid improvements in assessment scores when treated with eculizumab in the OLE. There was a lower rate of disease exacerbations with eculizumab than with placebo during REGAIN, and eculizumab was well tolerated. Conclusion: Eculizumab treatment, compared with placebo, results in meaningful clinical improvements and fewer disease exacerbations for patients who previously received chronic IVIg. Trial registration: REGAIN [ClinicalTrials.gov identifier: NCT01997229]; REGAIN open-label extension [ClinicalTrials.gov identifier: NCT02301624].

Myasthenia Gravis Related to Thymic Carcinoma: A Case Study

Myasthenia gravis and thymoma are often presented in association with ∼10% of myasthenic cases having concomitant thymoma. Thymic carcinoma is one of the rarest/aggressive human epithelial tumors and has no correlation with myasthenia gravis hitherto. Here is provided a clinical case and review of literature on a very rare association of thymic carcinoma (with no sign of thymoma) and myasthenia gravis (antiacetylcholine receptor antibody positive). Two years after thymectomy, clinical evolution was satisfactory. This clinical case elicits hypothesis that thymic carcinoma may be related with myasthenia gravis, what may have good prognostic from oncologic and neurologic perspectives.