Horner syndrome
C. Magnetic resonance angiography of the brain and neck
There is a broad differential diagnosis for symptoms of headache, anisocoria, and ptosis. An edrophonium test (choice A) aids in diagnosing myasthenia gravis, while sumatriptan injections (choice D) can treat cluster headache. Although myasthenia gravis and cluster headache may present with acute ptosis, a patient with this constellation of symptoms must first be evaluated for life-threatening causative mechanisms. Myasthenia gravis typically does not present with a headache and anisocoria, while new migraines1 or cluster headaches2 in a 56-year-old patient are atypical. Lastly, a diagnosis of blepharoptosis and referral for surgical repair (choice B) should be made only after more lethal diagnoses have been excluded.