Hyperthyroidism, ophthalmoplegia and unilateral mydriasis

Clinical description of a 33 years-old woman, with hyperthyroidism, admitted to the emergency unit with external bilateral ophthalmoplegia and left mydriasis, unreactive to light. The external ophthalmoplegia is proven to be due to myasthenia. The left mydriatic pupil demonstrates features typical for Adie's tonic pupil. The association of a tonic pupil with an auto-immune disease is infrequent. The axiom that internal ophthalmoplegia in a patient with external ophthalmoplegia excludes myasthenia gravis should be reevaluated.