Myasthenia gravis in infancy. A report of 12 cases

INTRODUCTION: Myasthenia gravis (MG) shows specific clinical features in children. It is essential to know this and also the use of diagnostic techniques used in infancy and childhood for correct diagnosis. OBJECTIVES: To analyze the clinical behaviour of this disorder and the use of complementary tests in the diagnosis of paediatric patients. PATIENTS AND METHODS: We studied a group of 12 children diagnosed as having MG, who were admitted to the Instituto de Neurolog a y Neurocirug a de Ciudad de La Habana (Cuba) between March 1997 and June 2001. Data were obtained from the clinical histories regarding the clinical picture, anticholinesterase test, repetitive stimulation test (RST), simple fibre test (SFT), computerized axial tomography (CAT) of the mediastinum and the treatment given in each case. RESULTS: Juvenile myasthenia gravis (JMG) presented in 91% of the patients studied. The average age of onset of JMG was 7.45 years, with no difference in presentation in the two sexes. The extrinsic muscles of the eye were most affected and the form with generalized clinical involvement predominated at the time of admission. The RST was positive in four of the nine patients in whom it was done (44%) and the SFT was positive in the six cases in which it was done. No changes were found in the mediastinum on CAT scanning. Mestinon and prednisone were the most commonly used drugs. CONCLUSION: In our group JMG was the most frequent form seen. Neurophysiological studies were very useful diagnostic tools.