Clinical Reasoning: A 54-year-old woman with transient episodes of headache and neurologic dysfunction

A 54-year-old woman with a 13-year history of resected oligodendroglioma (treated with resection and whole brain radiation therapy with focus on brain tumor [40 Gy]) was admitted with acute left hemiparesis (Medical Research Council [MRC] 2/5), left hemineglect, confusion, and multiple episodes of throbbing right parietal headache lasting for hours. Blood pressure levels were normal (<140/90 mm Hg) on repeat measurements. The patient was afebrile and neurologic examination disclosed no signs of meningeal irritation. The patient reported having a similar episode (mild left hemiparesis [MRC 4/5] following a right parietal throbbing headache) 11 years ago. The episode lasted less than 24 hours and the patient recovered completely from her symptoms. Her treating physician considered this episode as a focal seizure, ordered no further diagnostic workup, and changed her antiepileptic medication from phenytoin (100 mg TID) to phenobarbital (50 mg BID). The patient had no history of headaches before the diagnosis of her brain tumor. She had no family history of migraine. One year after the radiation therapy, she started developing episodes of migraine of moderate to severe intensity with a frequency of 2–6 attacks per year. The headache attacks were typically unilateral (right-sided) and lasted for several hours (5–53 hours). The pain was of pulsating nature and was aggravated by physical activity. The patient occasionally reported that the headache was accompanied by nausea or vomiting. She had no sensitivity to light or sound. Usually, the migraine attacks were …