Effective treatment of infantile myasthenia gravis by combined prednisone and thymectomy.

Myasthenia gravis developed in two children at 2 and 3 years of age respectively. Minimal improvement followed chronic oral administration of cholinesterase inhibitors. Patient 1 had ptosis and ophthalmoplegia but no clinical or electromyographic involvement of muscles of the extremities, although a quadriceps muscle biopsy revealed lymphorrhages. Patient 2 had progressive generalized myasthenia for 3 1/2 years. Both children were given a 3-month course of prednisone followed by thymectomy. They both are in remission, 12 and 8 months after thymectomy, with only minimal residual ocular weakness, but this weakness is much more responsive to anticholinesterase drugs than before thymectomy. Long-term administration of steroids, with the attendant complication of growth retardation, is avoided.