Presentation of myasthenia gravis mimicking blepharospasm

Abstract

About 90% of patients with MG develop ocular muscle weakness causing ptosis and diplopia. By contrast, the ocular features of blepharospasm and Meige syndrome (blepharospasm plus oromandibular dystonia) are caused by involuntary, forcible contraction of the orbicularis oculi, causing spasmodic blinking.1,2⇓ We report two patients with MG whose presentation with chronic blinking mimicking blepharospasm led to inappropriate treatment. ### Patient 1. A 73-year-old man presented to an ophthalmologist with a 2-year history of continuous involuntary blinking without symptoms or signs of ptosis or diplopia. Blepharospasm was diagnosed. Periocular injections of botulinum toxin (Botox, Allergan Ltd., Wycombe, UK) caused a complete bilateral ptosis lasting 4 weeks. Blinking returned as the ptosis improved. One year later, we noted frequent blinking and residual, nonfatigable ptosis. There was no frontalis overactivity, abnormality of eye movements, or weakness of eye closure. The rest of the neurologic examination was normal. Bilateral blinking tics were diagnosed, …