Abstract text (incl. figure legends and references)

Background and objective: Recurrent painful ophthalmoplegic neuropathy (RPON), formerly known as ophthalmoplegic migraine, is a rare type of cranial neuralgia characterized by attacks of unilateral headache with ipsilateral ophthalmoplegia due to paresis of one or more ocular cranial nerves. The exact pathophysiology behind RPON is unclear and the clinical presentation often resembles that of migraine disorders. The objective of this paper is to present the first reported use of erenumab in a patient with RPON.

Methods: Case description.

Results: A 31-year-old woman with a 3-year history of recurrent unilateral headache, ipsilateral ptosis, nausea, and photo- and photophobia was referred to our clinic due to suspected dural carotid-cavernous fistula observed on brain magnetic resonance imaging. Neurological examination revealed left-sided ptosis and mydriasis with a sluggish reaction to light. After excluding the presence of a dural fistula on digital subtraction angiography, the patient was diagnosed with RPON. Her symptoms subsided after receiving pulse corticosteroid therapy. She was discharged with rizatriptan for acute attacks and propranolol as prophylaxis. Over the course of the following 5 years, the patient didn"t experience a significant decrease in either intensity or frequency of her symptoms in spite of adjustments in prophylactic therapy. After numerous therapeutic failures with different classes of prophylactic drugs, including beta blockers, antidepressants and antiepileptics, erenumab was introduced in the prophylactic regimen (140 mg subcutaneously once every 28 days). While on erenumab, the patient experienced a 75% reduction in monthly headache days and this effect was sustained for 18 months.

Conclusion: The results of our case support the argument that RPON should be reclassified as a migraine variant, which would enable the use of specific prophylactic medication in patients suffering from this disorder.