Myasthenia gravis is a neuromuscular immune mediated disease particularly common in adulthood. It is caused by the deleterious action of antibodies produced by the individual and directed against one or more components of the neuromuscular junction. It usually results in a fluctuating deficit in the ocular musculature and is generalized in a significant number of cases. Symptomatic treatment is based on acetylcholinesterase inhibitors and must very often be combined with a disease-modifying treatment comprising corticosteroids and / or immunosuppressants in the most severe and / or refractory forms.
In an article published in October 2020, Belgian ophthalmologists report the original observation of a 57-year-old patient treated for myasthenia gravis, first ocular then generalized, by iterative plasmapheresis and high-dose corticosteroids for several months (around 60 mg daily). The patient progressed with significant exophthalmos, repeatedly complicated by subluxation of the left eyeball. This subluxation can be explained by the weakness of the eye muscles and the excess of intra-orbital fat, two phenomena induced by the prolonged use of steroids in this patient. This is, according to the authors, the first description of such a complication in myasthenia gravis, the subluxation of the eyeball being rather a feature of another autoimmune disease, Basedow’s disease (hyperthyroidism).