Appearance of anti-acetylcholine receptor antibodies after COVID-19

Objectives: In this paper, we report a case of Myasthenia Gravis (MG) exacerbated by COVID-19 that was initially anti-acetylcholine receptor (AChR) negative and after 9 months became positive for anti-AChR antibodies. Methods: We performed a review of the medical records and clinical follow-up of a patient followed at the Neurology service of Walter Cantídio University Hospital. Results: A 37-year-old female patient presented with mild dysphonia, ptosis and diplopia. Three months later, she was admitted to the hospital with respiratory failure associated with COVID-19. The patient received a clinical diagnosis of MG and anti-AChR and MuSK antibodies were negative at that moment. Nine months after initial presentation, serum anti-AChR antibodies were positive. Conclusion: We reported a patient who presented seroconversion for anti-AChR antibodies after COVID-19. There have been some reports of possible viral triggers for myasthenia, but controversy over this matter still remains.