Clinical delineation of myasthenia gravis in the Kingdom of Bahrain.

Objectives: To report demographic and clinical data on 98 myasthenia gravis (MG) patients, seen over 5 years (January 2014-December 2018).

Methods: This was a retrospective, observational cohort study carried out at 3 hospitals in Bahrain. MG was classified into ocular or generalized types. We subdivided MG into early-onset (EOMG, ≤ 49 years) or late-onset (LOMG, > 49 years). Demographic and clinical data were recorded. The data was entered and analyzed using SPSS version 26.0.

Results: 61.2% were females. The mean age at onset was 43.8±17.7 years in males and 43.1±15.7 years in females. 72.4% had EOMG. A pure ocular presentation was most common (51%). Limb weakness was more prevalent in AChR-positive patients. The MuSK group had more severe presentation. 57.1% of patients were AChR-positive, 3.1% MuSK-positive, and 39.8% double-seronegative. Generalized disease onset was more likely with AChR. Abnormal CT chest was seen in 24/69 (35%) including thymic hyperplasia, thymoma, and thymic atrophy. Pathology findings were thymic hyperplasia (55.0%), thymoma (30%), thymolipoma (10%), and normal thymus (5%). Treatment outcomes were favorable.

Conclusion: The present study revealed that MG was more common in females, with similar age at onset between males and females. The majority of patients had EOMG with ocular disease and AChR positivity. The clinical outcomes were favorable. Following a standardized protocol for MG diagnosis and workup is recommended.