RESUMO
A 54 year-old woman presented with bilateral fatigable blepharoptosis with diurnal fluctuation and diplopia for 10 days. She had a 3 year history of hypertension and showed symptoms of bilateral ptosis, supranuclear upward gaze palsy, and vertical diplopia with the pupils promptly constricting to light. Bell's phenomenon and vertical oculocephalic responses were intact but an impaired convergence was noted in both eyes. A intramuscular neostigmine test was negative. T1 and T2-wighted MRI of the brain showed a small round high signal intensity lesion in the periaqueductal gray (PAG) region. Therefore, she was diagnosed with a midbrain ptosis due to midbrain hemorrhage. The PAG lesion was suggested as contributing to the fatigable blepharoptosis and supranuclear upward gaze palsy in the patient. We recommend that patients with clinical features of myasthenia limited to the ocular muscles and, having risk factors for cerebrovascular disease, be thoroughly evaluated for intracranial lesions if warranted.