Clinical Reasoning: A 47-Year-Old with Headache, Vertigo, and Double Vision

A 47-year-old man with a history of isolated, severe, recurrent episcleritis of the left eye, on adalimumab and methotrexate for the past 2 years, presented with acute vertigo. Two days later, in addition to ongoing vertigo, he developed a mild headache behind his right eye, which intensified over 5 days and worsened with Valsalva maneuver and when lying down. He denied nausea, vomiting, light or sound sensitivity, or a history of headaches. On the fifth day of symptoms, he developed double vision, which persisted regardless of the severity of the headache and was worse when looking to the right. On examination, vital signs were normal without evidence of fever. Extraocular movements were notable for mildly restricted gaze of the right eye when looking toward the right side. Pupils were reactive, ophthalmoscopic examination did not show papilledema, and finger to nose test was normal. Mental status, strength, sensation, and reflexes were normal.