Clinical analysis of patients with myasthenia gravis from Hospital Universitário Clementino Fraga Filho (HUCFF)

Abstract

Background: Myasthenia gravis (MG) is an autoimmune disorder characterized by the production of autoantibodies that impair neuromuscular transmission, leading to fluctuating muscle weakness. Although diagnosis and treatment have evolved over recent decades, clinical presentation, laboratory findings, and therapeutic management can vary significantly among patients of distinct populations. Objective: To describe the clinical, serological, and therapeutic profile of MG patients followed at the HUCFF outpatient clinic, emphasizing the time interval between symptom onset and diagnosis, antibody profile, instituted therapies, and symptom control. Methods: A prospective outpatient study analyzing 46 patients diagnosed with MG. Data was collected regarding the time up to diagnosis, presence of specific antibodies (Anti-AChR, Anti-MuSK, Anti-LRP4), history of thymectomy, use of corticosteroids and immunosuppressants, episodes of exacerbation, and symptom control measured by the MG Composite scale. Results: Of the 46 patients evaluated, 26 were diagnosed within a year of symptom onset, 12 within two years, and 8 were diagnosed after more than two years of symptoms. Regarding the serological profile, 17 patients were Anti-AChR positive, 3 were Anti-MuSK positive and none were Anti-LRP4 positive. Three patients had indeterminate titers, and 14 have still pending tests. Seven patients were double-seronegative (Anti-AChR and Anti-MuSK negative), with the diagnosis confirmed by electroneuromyography (ENMG) and therapeutic response. Thymectomy was performed in 25 patients, including 3 non-AChR positive cases. Only 3 of these procedures occurred after 2018’s update to the International Consensus Guidance for Management of Myasthenia Gravis. Regarding drug therapy, 33 patients were using corticosteroids (16 at a dose of 5 mg/day), with 24 patients requiring steroid-sparing immunosuppressive therapy: 19 used azathioprine, 1 methotrexate, and 4 mycophenolate mofetil. Fifteen patients presented exacerbations since the initial diagnosis; 14 received intravenous immunoglobulin (IVIG) and 1 underwent plasmapheresis. At the last consultation, 35 patients achieved total symptom control (0 points on the MG composite scale), 5 scored 1 or 2 points, and 6 scored more than 3 points. Seven patients presented associated autoimmune comorbidities, including Sjögren’s syndrome, vitiligo, Graves' disease, and Parsonage-Turner syndrome. Conclusion: The majority of patients showed early diagnosis and good clinical control despite serological and therapeutic variability. Corticosteroids and immunosuppressants remain central management strategies, and monitoring therapeutic response is essential, especially in patients with indeterminate antibodies or multiple exacerbations. This outpatient profile highlights the importance of multidisciplinary follow-up and individualized treatment adjustment.