UNEXPLAINED OCULOMOTOR PALSY AND MYASTHEN IA-GRAVIS

Three cases of ocular myasthenia gravis were observed. The first patie nt, a 74-year-old man was found to have complete left ophthalmoplegia and ptosis unchanged at examination one month after onset. The second patient, a 42-year-old man, developed incomplete right ophthalmoplegia with peudoanterior internuclearis ophthalmoplegia, then ptosis two da ys later. The third patient, a 70-year-old man, presented with sudden onset complete right palsy of the third nerve. Diabetes mellitus or in tra-cranial lesions were suspected in all three patients although labo ratory tests, tomodensitometry, nuclear magnetic resonance imaging, or arteriography gave no confirmation. Ptosis was relieved and eye movem ent was improved after the intravenous edrophonium test, but electromy ography was negative. The three patients were treated with anticholine sterase agents and showed unequivocal improvement. The second patient underwent thymectomy. Clinicians should inform patients of the contrai ndications of drugs in this disease. The diagnosis of pure oculomotor forms of myasthenia gravis is sometimes difficult to establish and sho uld be suspected in cases of unexplained oculomotor palsy.