[Myasthenia gravis in old age. A retrospective study of 58 patients]

The course in 58 cases of myasthenia gravis in subjects over 50 years of age is reported. They total about 30% of cases in all age-groups. 36.2% of the patients died after an average period of illness of 3.4 years. 58.6% initially showed only ocular symptoms and in 58.8% of these the myasthenia was likewise located only in the eyes in the further course of the illness. The prognosis of ocular myasthenia is very good if the myasthenic process does not extend to other muscle groups in the first or second year of illness. 41.2% of primary ocular myasthenia turned into other types, in most cases a generalized type, and these had a poor prognosis. 69.2% of these patients died after an average period of illness of 1.5 years due to myasthenia-induced complications. Cases of myasthenia which initially are of the generalized type, in which the average duration is only 2.7 years until death, and to some extent the bulbar types, also have a poor prognosis. Ocular myasthenic cases generally need only small doses of cholinesterase inhibitors. Some patients had no medical treatment because there was no subjective or objective need for it. Several patients were given doses of cholinesterase inhibitors which were too large; excessive doses are to be avoided because of the proven negative influence of cholinesterase inhibitors on the myoneural system. It is recommended that types of myasthenia with a poor prognosis be treated early with corticoids, ACTH or azathioprin, if the cholinesterase inhibitors have proved ineffective or it their effect is unsatisfactory. Thymectomy is advisable only in patients under 60 years of age.