Endocrine Abstracts

About 1% of the patients with Graves’ disease develop myasthenia gravis, however, euthyroid Graves’ ophtalmopathy has only rarely been associated with myasthenia gravis and especially with isolated ocular myasthenia gravis. A 63-year old, male patient with vitiligo presented double vision and right ptosis, shortly followed by left ptosis. On the ophthalmological examination there was bilateral ptosis and orbito-ocular ultrasonography yielded a thickening of the left lateral recti. Electromiographic and extensive biochemistry examinations were normal. Thyroid dysfunction was absent with normal TSH receptor antibodies but antithyroid peroxidase antibodies titers were 82.88 IU/ml (normal <34). Thyroid ultrasound examination showed a nodular goiter presenting diffuse decreased echogenicity. The ocular manifestations were interpreted as euthyroid-associated orbitopathy in the context of Hashimoto thyroiditis and the patient received a course of corticotherapy. Two months later he was admitted with bilateral exophtalmos and sclera and conjunctival injection and received combined glucocorticoid and radiotherapy. Two weeks after the corticotherapy was stopped, the patient experienced exacerbation of diplopia and bilateral palpebral ptosis. At a new neurologic assessment, repetitive nerve stimulation of the ulnar nerve recording from abductor digiti minimi of the right hand revealed a decremental response and serum acetylcholine receptor antibody was positive at 5 nmol/l (normal <0.4). Chest X-ray and chest computed tomography did not reveal any thymic hyperplasia or thymoma. TSH was slightly reduced at 0.158 μU/ml and anti-thyroglobulin antibody levels were 845 IU/l (normal ≤115). Pyridostigmine and intermittent glucocorticoid treatment was recommended. At 2-years follow-up visit, no signs of generalized myasthenia were detected. We report a case of euthyroid Graves ophthalmopathy associated with isolated ocular myasthenia gravis appearing in a patient with longstanding vitiligo, compatible with an autoimmune polyglandular syndrome-3C phenotype. The coexistence of these two entities, in the absence of overt thyroid dysfunction or generalized features of myasthenia gravis may cause diagnostic confusion.