Objective: The unfortunate association between Grave’s disease (GD) and other autoimmune disorders such as myasthenia gravis (MG) is well recognized, but there have been only a few case reports in the literature of children having both illness. We report the association of these conditions and how to treat it.
Case: A 6 years old girl presented with chief complain of bilateral eyelid ptosis. She also had palpitation with heart rate ± 125 beats per minute and diaphoresis. There was no palpable thyroid nodule. Thyroid function test showed increased free thyroxine (FT4) 2.44 ng/dl (normal range 0.96 – 1.77) and suppressed thyroid stimulating hormone (TSH) 0.57 mIU/L (normal range 0.7 – 5.97). The diagnosis of hyperthyroid was made, she was treated with thiamizole 0.3 mg/kgBW/day. During the treatment, the FT4 and TSH became normal but the bilateral eyelid ptosis worsen, fluctuative, and accompanied by bulbar muscle weakness. The Waternberg test showed positive result and pyridostigmine 1 mg/kgBW/6 hours was given. She showed a good response to this treatment hence the diagnosis of ocular MG was made. Now she was managed with thiamizole 0.1mg/kgBW/day and pyridostigmine 1mg/kgBW/6 hours. The response to treatment  is good. 
Conclusion: GD can be associated with MG since both of them are autoimmune disorders. Early diagnosis will result in effective treatment with a possible improvement in clinical course and prognosis.