[Thymectomy in Chinese myasthenia gravis].

From 1972 to 1986, 80 Chinese myasthenia gravis patients with thymectomy were studied. There were 25 males, aged from 21 to 70 years old (mean age 44) and 55 females aged from 12 to 56 years old (mean age 34). According to Osserman's criteria 10 patients belonged to grade I, 28 to IIa, 31 to IIb, 4 to III, 2 to IV and 5 to V. The postoperative follow ups ranged from 1 month to 13 years. The thymic pathology showed: hyperplasia in 44 cases, atrophy in 17 cases and presence of thymoma in 19 cases. The postoperative improvement occurred in 50% in thymomatous patients, 81% in non-thymomatous patients. There was no relationship between the duration of illness before operation and the postoperative status. However the patients with age onset after 40 had higher incidence of thymoma, and a higher rate of death from myasthenia gravis despite short duration of illness before surgery. All of 18 patients in whom serum was examined, the antiacetylcholine receptor antibody was detectable. The mean titres of this antibody in 8 hyperplasia patients, 3 atrophy patients and 7 thymoma patients were all higher than the mean value of 67 myasthenia gravis patients who did not received any treatment except anticholinesterase. Seven cases had postthymectomy followups of the antibody titres, 3 cases showed decreased antibody titre after thymectomy. Ten ocular myasthenic patients received thymectomy, 3 had thymoma, 5 had hyperplasia and 2 had atrophic thymus. The improvement rate in this group was around 71%.(ABSTRACT TRUNCATED AT 250 WORDS)