A study of myasthenia gravis in patients with and without thymoma

This study was undertaken to compare the clinical, neurophysiological, radiological and prognostic features of myasthenia gravis with and without thymoma. 37 patients with myasthenia gravis (27 males, 10 females), with age range of 4.5 to 72 (mean 39) years, were managed at a tertiary care centre in India. Four patients were below 15 years of age and 6 above 55 years. Most of the patients were in stage II (34). There were 2 patients in stage III and 1 in stage I. 27 patients underwent thymectomy. Thymoma was detected in 10 cases. The decrement in patients with thymoma ranged between 11 and 62% (mean 27.9%) and nonthymoma group 10-75% (mean 28%). CT scan of thorax revealed mediastinal mass in 5 out of 10 cases of thymoma and 2 out of 27 patients without thymoma. Outcome of myasthenia gravis with thymoma was worse than without thymoma at 1 year followup. Severity of illness, extent of decrement, lack of facilitation, duration of illness and age of the patients were not related to the outcome. It is concluded the clinical and neurophysiological changes in myasthenia gravis with and without thymoma do not differ. However, patients with thymoma have a worse outcome.