Background: Myasthenia gravis is infrequently encountered in pediatric ophthalmology practice. The purpose of this study is to evaluate the clinical spectrum of this condition in children and to identify factors that may aid the clinician in its diagnosis and management.
Subjects and methods: A retrospective chart review was performed on all pediatric patients presenting with myasthenia gravis to the Departments of Pediatric Ophthalmology and Neuro- ophthalmology at the Texas Children's Hospital from 1989-1999. Information regarding mode of presentation, myasthenic classification, ocular and systemic involvement, diagnostic investigations, therapy and outcome was collected and evaluated.
Results: Fourteen patients were included in the study whose ages ranged from 1-17 years at presentation. One patient had congenital myasthenia gravis and 13 had juvenile myasthenia gravis. Thirteen of 14 (93%) patients presented with ocular findings; two of whom had associated systemic disease at presentation. Six of 14 (43%) patients had systemic involvement during the course of their illness, of whom three (21%) had respiratory compromise requiring assisted ventilation. Thirteen of 14 (93%) patients received pyridostigmine as first line treatment. Ten of 14 (71%) patients had a favorable response. A favorable response was defined as improvement in the extraocular motility to within 10 prism diopters of orthotropia with resolution of the blepharoptosis. Three of 14 patients (21%) received a combination of pyridostigmine and steroids, all of whom had a favorable response. Seven of 14 patients (50%) underwent thymectomy; all had a favorable response. Two of 14 patients (14%) required both blepharoptosis and strabismus surgery.
Conclusion: Pediatric myasthenia gravis may present initially to the ophthalmologist and should be considered in any pediatric patients with blepharoptosis and an ocular motility disturbance. Prompt diagnosis may be associated with significant reduction in morbidity. A favorable response to medical and surgery therapy was noted in most of our patients.