The natural history and ophthalmic involvement in childhood myasthenia gravis at the hospital for sick children

Objective: To characterize signs, symptoms, and the natural history of myas thenic syndromes in pediatric patients. Design: Retrospective noncomparative case series. Participants: Thirty-four patients with a diagnosis of myasthenia were iden tified from either the hospital's or treating physician's database. Methods: Retrospective chart review, clinical examination, and telephone in terview. Main Outcome Measures: Information pertaining to the ophthalmologic and neu rologic examination, diagnostic interventions, and treatment was noted. Pat ients with active disease, attending during the study period, were examined at their outpatient visits. Those who no longer attended the hospital were contacted by means of a telephone interview to complete their follow-up. Results: Thirty-four children were found to have myasthenia. Two had transi ent neonatal myasthenia, which resolved quickly. Seven (20.6%) patients had congenital myasthenic syndromes (CMS) and 25 (73.5%, 19 females) were affe cted with autoimmune myasthenia gravis (AMG). In those patients with severe CMS, three showed signs of generalized weakness, including failure to thri ve, frequent apneas, and aspirations. In four patients with mild CMS, eye s igns were relatively more prominent. In all patients with CMS, strabismus, ophthalmoplegia, and ptosis were the main ophthalmologic signs and remained relatively constant. Fourteen (56%) patients with AMG had ocular signs and symptoms, and five of them progressed to systemic involvement in 7.8 month s on average (range, 1-23). The remaining nine patients with ocular AMG had either strabismus or ptosis and were treated with pyridostigmine (nine pat ients) and prednisone (two patients). Patients with ocular AMG were seen at 78 months on average, those with systemic AMG at 85.6 months. Systemic AMG was seen in 16 patients. No thymomas were found in 14 patients who underwe nt thymectomy. Of the 25 patients with AMG, 8 are still being treated, 8 ar e in remission for an average of 65.2 months and are asymptomatic, 4 patien ts are receiving long-term immunosuppressants (1 has likely sustained perma nent damage to her extraocular muscles with complete ophthalmoplegia and pt osis), and 4 have been lost to follow-up. Finally, one patient died after a spiration because of bulbar weakness. Conclusions: Patients with CMS varied in the degree of severity. Apneic att acks, aspiration, and failure to thrive may obscure the diagnosis. Compared with AMG, their ophthalmologic signs and symptoms were usually permanent. Visual signs and symptoms were usually prominent in those patients with act ive AMG, but those in remission were asymptomatic. More than half of the pa tients with juvenile AMG had ocular symptoms. Generalization occurred in a minority in an average of 7.8 months. Patients entered remission after appr oximately 2 years of treatment and were visually asymptomatic. This study s uggests that long-term permanent damage to the extraocular muscles as a res ult of juvenile AMG is rare. Myasthenia gravis is a life-threatening diseas e as evidenced by the death of one of our patients. Many of these patients are first seen by the ophthalmologist who can aid the diagnosis, screen for amblyopia, and monitor the patient's response to therapy. (C) 2000 by the American Academy of Ophthalmology.