Development of Generalized Disease at 2 Years in Patients With Ocular Myasthenia Gravis

Abstract

THE INITIAL SYMPTOMS or signs of myasthenia gravis are ptosis, extraocular muscle weakness, or ocular misalignment in up to 65% of patients. Clinically apparent generalized disease is reported to develop in approximately 53% of patients with ocular myasthenia gravis and in 44% within 2 years.^1,2 Although not predictive of generalized myasthenia gravis, abnormal findings of standard repetitive nerve stimulation electromyography of systemic muscles³ and abnormal serum acetylcholine receptor (AChR) antibody levels in up to 50% of patients suggest that subclinical systemic disease occurs in a significant minority of patients with ocular myasthenia gravis.^2,4 In addition, abnormal findings of single fiber electromyography of the upper extremity is more common in patients with ocular myasthenia gravis in whom generalized disease develops.⁵ Limb muscle end-plate injury on ultrastructural examination has also been reported in patients with ocular myasthenia gravis.⁶