The role of estrogen in migraine: a review and hypothesis

Exteroceptive silent period of temporalis muscle in menstrual headaches

The second exteroceptive silent period (ES2) of temporalis muscle was recorded on days 1 and 15 of the menstrual cycle in 17 women, 9 of whom suffered regularly from tension-type headaches during menstruation. Mean duration of temporalis ES2 was significantly shorter on day 1 of the cycle than on day 15. This difference was due to a marked menstrual reduction of ES2 in the headache subgroup. A positive correlation was found between ES2 durations and oestradiol/progesterone ratios. We hypothesize that the variations of ES2 during the ovarian cycle result from the modulatory effects of oestrogens on descending aminergic pathways that control excitability of inhibitory brainstem interneurons mediating exteroceptive suppression of jaw-closing motoneurons.

Event-related slow potentials and associated catecholamine function in migraine

Plasma norepinephrine and dopamine and event-related slow potentials were measured at menses and ovulation in migraine with and without aura relative to normal subjects. The results indicated that at menses, but not ovulation, plasma dopamine was increased and norepinephrine was decreased relative to normal. This catecholamine imbalance was greater in migraine without aura than in migraine with aura. Conversely, event-related slow potentials measured over the posterior cortex at ovulation but not at the menses was altered relative to normal. Early epoch negativity was reduced in migraine with aura, whereas late epoch negativity was reduced in migraine without aura. The results suggested that (a) migraine without aura may involve dynamic shifts in the function of both norepinephrine and dopamine responsive neurons; (b) pathophysiology of migraine with aura is less dependent on catecholamine imbalance (norepinephrine alone affected); (c) these pathophysiological mechanisms are most prevalent in or restricted to posterior cortical regions but may be modulated by brainstem mechanisms.

Migraine and menstruation: a pilot study

OBJECTIVE

To define the term "menstrual" migraine and to determine the prevalence of "menstrual" migraine in women attending the City of London Migraine Clinic.

DESIGN

Women attending the clinic were asked to keep a record of their migraine attacks and menstrual periods for at least 3 complete menstrual cycles.

RESULTS

Fifty-five women completed the study. "Menstrual" migraine was defined as "migraine attacks which occur regularly on or between days -2 to +3 of the menstrual cycle and at no other time". Using this criterion, 4 (7.2%) of the women in our population had "menstrual" migraine. All 4 women had migraine without aura. A further 19 (34.5%) had an increased number of attacks at the time of menstruation in addition to attacks at other times of the cycle. Eighteen (32.7%) had attacks occurring throughout the cycle but with no increase in number at the time of menstruation. Fourteen (25.5%) had no attacks within the defined period during the 3 cycles studied.

DISCUSSION

A small percentage of women have attacks only occurring at the time of menstruation, which can be defined as true "menstrual" migraine. This group is most likely to respond to hormonal treatment. The group of 34.5% who have an increased number of attacks at the time of menstruation in addition to attacks at other times of the month could be defined as having "menstrually related" migraine and might well respond to hormonal therapy. The 32.7% who have attacks throughout the menstrual cycle without an increase at menstruation are unlikely to respond to hormonal therapy. The 25.5% who do not have attacks related to menstruation almost certainly will not respond to hormonal therapy.

Ovarian hormones and the circulation

Ovarian steroids have effects on blood circulation involving the mechanisms which control blood flow and the changes that occur in the pathogenesis of atherosclerosis. Estrogens appear to protect women from cardiovascular disease through their effects on lipid metabolism as well as more direct effects on arterial walls which appear to inhibit atherosclerotic plaque formation. There is increasing evidence that estrogen replacement after menopause can markedly reduce female mortality due to vascular disease. Effects of hormone imbalance and deficiency on vasomotor control are clinically significant and hormone treatment appears to be effective in the management of a variety of conditions due to abnormal blood flow including vasomotor instability, migraine, vaginal dryness and, perhaps, some forms of angina. Most review articles have focused on the effects of ovarian steroids and lipid metabolism as well as the findings of recent epidemiologic studies. This is understandable as those investigations have proved so valuable in understanding the protective effects of estrogens. The present discussion, in contrast, focuses on the effects of ovarian steroids, estrogens in particular, on circulatory mechanisms. At the present time there is increasing interest in these studies. Findings thus far appear to contribute to understanding estrogen cardioprotection and also raise awareness of a variety of clinical conditions in which estrogen treatment could be indicated because of its effects on circulation.

Ovarian steroid levels in migraine with and without aura

Radioimmunoassays were used to measure interictal levels of ovarian steroids (oestradiol, total oestrogens and progesterone) in migraine patients at the onset of menses and coincident with the luteinizing hormone surge preceding ovulation. Results of these verified biochemically-contrasting points of the ovarian cycle were used to compare 13 migraine patients without aura and 6 migraine patients with aura with 17 non-migraine women. No group differences were found for physiological basal levels of ovarian steroids measured at menses. Preceding ovulation elevation in oestradiol levels relative to normal was found in migraine patients with aura but not in migraine patients without aura. These results suggest that a variation in oestradiol levels is an important factor in the different clinical expressions of migraine.

Migraine-related stroke: brain infarction in superior cerebellar artery territory demonstrated by nuclear magnetic resonance

We report 4 cases of migraine-related stroke in young females. Two patients were taking oral contraceptives and one was pregnant. The results of the computerized tomography of the brain were negative in 3 patients and partially positive in one, while NMR showed ischemic lesions in the posterior fossa in each case. We would like to highlight the value of NMR in the assessment of migraine associated with prolonged focal neurologic deficiencies when the clinical examination revealed brain stem or cerebellar signs and the peculiar localization of the ischemic lesion that corresponded in all 4 cases to the area irrigated by the superior cerebellar artery. An hormonal factor is suspected as the precipitating event of this complication in 3 of these patients.