[Myasthenia Gravis. Register of 190 Cases in a Single Center].

Myasthenia gravis (MG) is an antibody-mediated autoimmune disease of the neuromuscular junction. The aim of this study was to evaluate clinical, epidemiological and serological features of patients with MG in a Public Hospital of Buenos Aires City. A retrospective analysis of 190 patients diagnosed with MG was performed. The mean age of MG onset was 38 years, 30% had late-onset MG (onset age > 50 years). The female/male ratio was 1.7 / 1. Disease started earlier in women than in men, mean 32 vs. 48 years (p < 0.0001). Familial autoimmune MG represented 3.2% of the cases. Most of the patients initiated their disease with a pure ocular form (52%). 12.1% (23/190) were considered ocular MG at follow-up. Thymoma-associated MG represented 11.6% of cases. 27.1% had other associated autoimmune disease, thyroid disorders were the most frequent. 81.4% were anti-acetylcholine receptor antibody (AChR-ab) positive MG; 22.7% of AChR-ab negatives were positive for anti-muscle specific kinase (MusK) antibodies. Clinical outcome was relatively good; more than half of cases were in remission or minimal manifestations at the last visit. The majority of patients required immunosuppression to control the symptoms, 78% received corticosteroids and 48%, a non-steroidal immunosuppressant.