Migraine, with or without aura, is a remarkably common condition. A study by Stewart and colleagues in the United States showed differences in the prevalence of migraine between individuals of white, African, and Asian origin of approximately 20, 16, and 9 percent, respectively, among women, and 9, 7, and 4 percent for men (see also Lipton et al). One-third of migraineurs have more than three attacks monthly if untreated and many require bed rest or severe curtailment of daily activities. Migraine may have its onset in childhood but usually begins in adolescence or young adulthood; in more than 80 percent of patients, the onset is before 30 years of age, and the physician should be cautious in attributing headaches that appear for the first time after this age to migraine, although there are many exceptions.
In younger women, the headaches may occur during the premenstrual period; in approximately 15 percent of such migraineurs, the attacks are exclusively perimenstrual Menstrual migraine (also termed catamenial migraine) discussed further on, had been considered to be solely related to the withdrawal of estradiol (based on the work of Somerville). It is now acknowledged that the influence of sex hormones on headache is more complex. Migraine tends to cease during the second and third trimesters of pregnancy in 75 to 80 percent of women, and in others they continue at a reduced frequency; less often, attacks of migraine or the associated neurologic symptoms first appear during pregnancy, usually in the first trimester.
Although migraine commonly diminishes in severity and frequency with age, it may actually worsen in some postmenopausal women, and estrogen therapy may either increase or, paradoxically, diminish the incidence of headaches. The use of birth control pills is associated with an increased frequency and severity of migraine and in rare instances has resulted in a permanent neurologic deficit (see further on and Chap. 33).
Some patients link their attacks to certain dietary items—particularly chocolate, cheese, fatty foods, oranges, tomatoes, and onions—but these connections have proved invalid in most carefully done studies and, except in the occasional persuasive individual instance. Some of these foods are rich in tyramine, which has been incriminated as a provocative factor in migraine. Alcohol, particularly red wine or port, regularly provokes an attack in some persons; in others, headaches are fairly consistently induced by exposure to glare or other strong sensory stimuli, sudden jarring of the head (“footballer’s migraine”), or by rapid changes in barometric pressure. A common trigger is excess caffeine intake or withdrawal of caffeine.
Migraine with aura may occur at any time of day, in some individuals, arising frequently after awakening. During the preceding day or so, there may have been mild changes in mood (sometimes a surge of energy or a feeling of well-being), hunger or anorexia, drowsiness, or frequent yawning. Then, abruptly, there is a disturbance of vision consisting usually of unformed flashes of white, or silver, or, rarely, of multicolored lights (photopsia). This may be followed by an enlarging blind spot with a shimmering edge (scintillating scotoma), or formations of dazzling zigzag lines (arranged like the battlements of a castle, hence the term fortification spectra, or teichopsia). Lashley’s description and drawings of his own auras over 10 min are instructive (Fig. 9-1). The expansion and movement across the visual field of the scotoma and the fortification, maintaining a consistent but expanding shape, are notable.