Headache and a pupil-sparing third nerve palsy.

CLINICAL HISTORY A 48-year-old woman presented with a 5-day history of right, retroorbital, dull aching or stabbing and throbbing pain occasionally felt in the right side of the nose. The headache started out mild and became severe over the first day. She was seen in an emergency department 3 days after headache onset. A computed tomography (CT) scan of the brain was negative. She was prescribed hydrocodone, which only dulled the pain. The day prior to consultation, she developed horizontal and vertical diplopia. On the morning of the visit, she noted drooping of her right eyelid. There was a past medical history of bronchial asthma and gastroesophageal reflux, but no history of hypertension, diabetes, ischemic heart or cerebrovascular disease. The blood pressure was 130/90 mm Hg. Neurologic examination was normal except for a pupilsparing, partial, right third nerve palsy. The pupils were 3 mm, equal, and reactive to light. A magnetic resonance imaging (MRI) scan of the brain with intracranial magnetic resonance angiography (MRA) was normal. An erythrocyte sedimentation rate (ESR) was 10 mm/h. A lipid profile and glycosylated hemoglobin level were normal. On follow-up 1 week later, she reported that she had not been able to open her right eye for several days and complained of the same persistent headache, rated in intensity as 7 to 8/10. Hydrocodone was of minimal benefit. The pain was worse with looking up and could awaken her from sleep. Examination revealed a pupil-sparing, complete, right third nerve palsy. Questions.— What is the cause of the third nerve palsy? Is further testing such as a cerebral arteriogram, lumbar puncture, or additional blood work indicated? What are the features of headache associated with ischemic third nerve palsies? What medications might be helpful for the headache? What is her prognosis for recovery of third nerve function?