Recurrent Headache With Diplopia: A Common Presentation of an Uncommon Entity.

Recurrent painful ophthalmoplegic neuropathy (RPON) is a rare headache syndrome, the diagnosis of which can be daunting to those who are not familiar with it. It presents characteristically with recurrent ocular motor weakness and ipsilateral head pain without an underlying etiology and often has unique imaging findings. Even after the successful diagnosis of this entity, there are no published management guidelines. Here, we present the case of a 31-year-old man whom we diagnosed with RPON following two episodes of unilateral headache with ophthalmoplegia over a three-month period and treated successfully with high-dose steroids on both occasions. We highlight the lack of prior migraine history and seeming antecedent viral infection as potential supporting evidence that this condition has a unique pathophysiology different from migraine. We also highlight his dramatic and reproducible response to steroids as additional evidence that steroids are good acute treatment options for this condition. Finally, as our patient lacked the expected cranial nerve imaging abnormalities on head MRI, we suggest that cranial nerve thickening and/or enhancement on MR imaging is not a sine qua non for this diagnosis, contrary to the opinion of some experts.