“Myasthenia gravis (MG) is a neuromuscular junction autoimmune disease, characterized by fatigability and fluctuating muscle weakness. Eyelid ptosis, strabismus, and diplopia are MG-presenting features in 50% of patients, defining the “ocular myasthenia” form (OMG). Approximately 30-80% of OMG patients develop generalized myasthenia gravis (GMG) within 2 years. However, predictive factors of generalization are still not recognized.
We evaluated clinical and laboratory features of 73 MG patients with purely ocular symptoms at the onset of the disease, diagnosed at our Neuromuscular Centre in the last 10 years.
Patients were followed for a mean time of 6.8 years (SD±10.2) from the onset of the disease. 41% of them experienced disease generalization after a median time of 1 year (range 1 month to 6 years) from the onset (two of them after thymectomy and another one after SARS-CoV-2 vaccination). Males were 63,3%, females 36.7%, similar to OMG patients. Among GMG patients, 70% were tested positive for AChR-Abs, 3.3% for MuSK-Abs, and 3.3% for both. Among OMG patients, 70% were AChR-Abs positive and 30% seronegative. 19% and 30% of OMG and GMG patients presented thymic abnormalities, respectively.
In the last years, GMG conversion risk factors have been largely studied, but conflicting results have been collected. Patients with AChR-Abs positivity and thymic abnormalities seem to be at a higher risk of generalization. These data have been just in part confirmed by our small cohort of patients. However, it would be worth looking more closely at possible conversion factors even for their therapeutic implications.”