Migraine
- Episodic headache often preceded by neurologic manifestation called "aura"
- Most common aura: sparkling zigzag that migrates across visual hemifield and obscures it ("scintillating scotoma")
- Visual aura starts as tiny scotoma appearing to both eyes adjacent to fixation
- Scotoma enlarges across one hemifield with sparkling leading edge, blocking vision as it goes
- Visual episode lasts 20 to 30 minutes
- Headache, fatigue, nausea, mild confusion follow visual aura and last for hours to days
- Visual aura may occur without other manifestations ("acephalgic migraine"), especially after age 50
- Posterior circulation (vertebrobasilar) transient ischemic attack (TIA), but episode lasts seconds to minutes and scotoma does not migrate
- Occipital lobe seizure, but duration of visual symptoms very variable and scotoma does not migrate
- Vitreoretinal tug, but visual symptom is non-migrating flash lasting less than second
- Retinal or optic nerve disorders, but visual symptom usually flickering lights
- Consider alternative diagnoses if symptoms do not match migraine perfectly
- Refer to ophthalmologist, who may refer patient to neurologist or internist, depending on findings
- Advise patients with migraine and visual aura to avoid smoking and oral contraceptives, which increase risk of migrainous stroke
- Recognize difficulty of excluding TIA or seizure, which are potentially life-threatening
- Migraine may be disruptive if attacks frequent and painful, requiring medication