New-onset Myasthenia Gravis after SARS-CoV-2 infection: case report and literature review

Abstract

We report the case of a 19-year-old female patient who developed Myasthenia Gravis 13 days after SARS-CoV-2 infection with positive RT-PCR testing. Her symptoms initially involved the oculo-bulbar district, but they gradually worsened in 3 months converting into a generalized form of Myasthenia Gravis complicated with a myasthenic crisis. A high level of anti-acetylcholine receptor antibodies was found in the serum, while anti-MuSK antibodies were negative; Repetitive Nerve Stimulation and Single-fiber Electromyography were suggestive of Myasthenia Gravis. Intravenous immunoglobulin courses and specific therapy were able to improve her symptoms, but thymic resection was needed to control the disease. This is a report of new-onset Myasthenia Gravis correlated to COVID-19 in which thymic resection was described and the histologic analysis of the thymus was performed showing thymic hyperplasia despite negative thoracic Magnetic Resonance Imaging. SARS-CoV-2 infection releases inflammatory cytokines that could dysregulate the immune system and lead to Myasthenia Gravis in susceptible subjects.

Autoimmune myasthenia gravis and COVID-19. A case report-based review

“…20 In a third case, while chest MRI showed no thymic abnormalities, histological analysis after thymic resection confirmed thymic hyperplasia. 27 The median time interval between COVID-19 and the clinical onset of MG was 17 days (range 5-56 days). In one case study, MG onset emerged post COVID-19 infection which followed an anti-SARS-CoV-2 booster dose vaccination.…”

“…59 Our literature search identified 14 publications that reported 18 cases in the specified time frame (Table 1). [15][16][17][18][19][20][21][22][23][24][25][26][27][28] An additional publication that presented the case of an 86-year-old man with generalized muscle weakness, diplopia, ocular ptosis and dyspnoea in the subacute phase of COVID-19 was inconclusive. 60 For this patient, the diagnosis of MG was not supported by paraclinical investigations (i.e., no data were provided on RNS, SF-EMG or edrophonium/ neostigmine test, and AchR and MuSK antibodies were within the normal range).…”

“…13,14 Conversely, cases of new-onset autoimmune MG have been reported worldwide by several groups, following COVID-19 or any type of vaccination against it. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] Moreover, one study reported a case in which MG appeared as an initial symptom of COVID-19. 35 The purpose of this present review was to assess the relationship between COVID-19 infection and new onset MG by reviewing case studies published between 01 December 2019 and 30 June 2023 identified by a search of PubMed/Medline database.…”

Ocular Myasthenia Gravis: A Current Overview

“…Myasthenia manifested as generalized muscle weakness in 11 patients; three presented with pure OMG, and only one presented with oculo-bulbar myasthenia. 74 Cases of myasthenia following covid-19 vaccination are much less reported than covid-19 infection, with only 4 cases reported, one of whom had been diagnosed with myasthenia 5 years before vaccination. 75 Given the small number of cases reported, there is no conclusive evidence that myasthenia is necessarily a complication of the COVID-19 vaccines, and the benefits of receiving the vaccine outweigh the potential risks.…”

Neuromuscular Disorders Associated With COVID-19

“…They surmised that the immune dysregulation created by infection with SARS-CoV2 resulted in histologically verified thymic dysfunction, resulting in the expression of anti-acetylcholine receptor antibodies. 59,60 The other systematic review reported the outcomes of the studies that it included. 61 They summarized that MGFA class greater than IV, 62 older age, and long-term use of corticosteroids 63 were associated with more severe COVID-19.…”