NGHIÊN CỨU BIẾN ĐỔI TEST ĐIỆN CƠ SỢI ĐƠN ĐỘC VÀ NỒNG ĐỘ KHÁNG THỂ KHÁNG THỤ CẢM THỂ ACETYLCHOLINE HUYẾT TƯƠNG Ở BỆNH NHÂN NHƯỢC CƠ

Abstract

Objective: To evaluate certain characteristics of single-fiber electromyography (SFEMG) testing and the serum concentration of anti-acetylcholine receptor (AchR) antibodies in patients with myasthenia gravis (MG). Methods: A descriptive, cross-sectional study was conducted on 116 patients with myasthenia gravis from January 2023 to December 2024. Patient data were collected using a standardized medical record form. Patients were classified clinically based on the Osserman classification and underwent testing for anti-AchR antibodies and single-fiber electromyography (SFEMG). Results: The female-to-male ratio was 1.9:1. Ptosis was observed in 70.68% of cases. Anti-AchR antibodies were positive in 83.33% of patients. SFEMG was positive in 93.33% of group I MG and 97.67% of group II MG patients. The positivity rate of anti-AchR antibodies in MG grade I patients was 58.3% before treatment, 50% during treatment, and 33.33% after stopping treatment. The concentration of anti-AchR antibodies was correlated with clinical severity based on the Osserman classification (group I: mean concentration = 5.47 nmol/l, lower than group IIa: mean = 7.57 nmol/l; lower than group IIb: mean = 8.72 nmol/l; p<0.05). The SFEMG positivity rate remained unchanged before, during, and after treatment. Conclusion: The concentration of anti-AchR antibodies is positively correlated with the clinical severity of MG as classified by Osserman (p<0.05). SFEMG sensitivity was not affected by treatment, unlike anti-AchR antibody testing (p<0.05). SFEMG demonstrated higher sensitivity compared to anti-AchR antibody testing and was significant for diagnosing ocular myasthenia gravis when compared with anti-AchR antibody testing (p<0.05).