Myasthenia gravis in Iranian children

Background: Considering the marked difference between the clinical course and management of juvenile myasthenia gravis, congenital/genetic myasthenia gravis and transient neonatal MG, the differential diagnosis is very important. This study was undertaken to evaluate the clinical spectrum of myasthenia gravis in children and determine the factors helping clinicians in their diagnosis and management of the disease. Methods: In a retrospective study from 1994 to 2002, all pediatric patients with myasthenia gravis (MG) admitted to Department of Pediatric Neurology in Mofid Children Hospital affiliated to Shahid Beheshti University were enrolled. Results: Of 32 children, 7 and 25 suffered from congenital and juvenile types of MG, respectively. The initial symptoms in congenital MG were ptosis (7/7), limitation of eye movement (2/7) and mild generalized weakness (6/7). Although 85% of cases with congenital MG, tested positive for Tensilon test, no myasthenia crisis or spontaneous remission was observed in any of the patients. The female to male ratio was 1.5/1 which was correlated to adult MG. In children with juvenile MG, the mean age was 5.7 +/- 4.2SD years. The most common symptoms were ptosis in 96% and generalized weakness in 76% of the cases. 32% of patients experienced one myasthenia crisis. EMG was diagnosed in 83% and tensilon test was positive in 84% of the cases. One patient had hyperthyroidism and another had hypothyroidism and both were epileptic. Eight patients underwent thymectomy microscopically. Thymic follicular hyperplasia was observed in five cases (62%), and the remaining three cases were normal. 12.5% of patients recovered completely after thymectomy and there was no need for medication during the follow up. 50% of cases showed relative improvement but it was negligible in 37% of patients. Conclusion: This study revealed that thymectomy lacks remarkable prognostic influence.