Ocular myasthenia gravis is a localized form of myasthenia gravis, which is a postsynaptic disorder of the neuromuscular junction that causes fluctuating weakness of extraocular muscles resulting from autoimmune mechanisms. In women with myasthenia, changes in sex hormone levels and administration of corticosteroids can trigger or worsen symptoms of myasthenia gravis.
To describe a case of seronegative ocular myasthenia gravis whose first symptom appeared a day after in vitro fertilization procedure.
A 37-year-old woman suddenly developed mild ptosis and fluctuating diplopia that worsened in the evening. Before the development of symptoms, she had undergone in vitro fertilization procedure and had taken oral steroids. Ocular motility examination revealed an intermittent exotropia in primary gaze at both distance and near. The neostigmine test confirmed her diagnosis as ocular myasthenia gravis.
When taking a history for young women with sudden onset of binocular diplopia, steroids and sex hormones should be taken into account, which may trigger or exacerbate symptoms of ocular myasthenia gravis.