DISCUSSION
Migraine, though commonly encountered in clinical practice, is a complex disorder. For women, migraine headaches have been recognized by the World Health Organization as the 12th leading cause of “life lived with a disabling condition.”3 Pure menstrual migraine and menstrually related migraine will be the focus of discussion here.
Etiology
Menstrually related migraine (comparable to pure menstrual migraine, although the latter is distinguished by occurring only during the perimenstrual period1) is recognized as a distinct type of migraine associated with perimenstrual hormone fluctuations.4 Of women who experience migraine, 42% to 61% can associate their attacks with the perimenstrual period5; this is defined as two days before to three days after the start of menstruation.
It has also been determined that women are more likely to have migraine attacks during the late luteal and early follicular phases (when there is a natural drop in estrogen levels) than in other phases (when estrogen levels are higher).6 Despite clinical evidence to support this estrogen withdrawal theory, the pathophysiology is not completely understood. It is possible that affected women are more sensitive than other women to the decrease in estrogen levels that occurs with menstruation.7
History and Physical Findings of Menstrual Migraines
Almost every woman with perimenstrual migraines reports an absence of aura.7 In the evaluation of headache, the same criteria for migraine without aura pertain to the classifications of pure menstrual migraine (PMM) or menstrually related migraine (MRM).1 Correlation of migraine attacks to the onset of menses is the key finding in the patient history to differentiate menstrual migraine from migraine without aura in women.8 Furthermore, perimenstrual migraines are often of longer duration and more difficult to treat than migraines not associated with hormone fluctuations.9
In order to distinguish between PMM and MRM, it is important to understand that pure menstrual migraine attacks take place exclusively in the five-day perimenstrual window and at no other times of the cycle. The criteria for MRM allow for attacks at other times of the cycle.1
In addition to causing physical pain, menstrual migraines can impact work performance, household activities, and personal relationships. The MIDAS questionnaire is a disability assessment tool that can reveal to the practitioner how migraines have affected the patient’s life over the previous three months.10 This is a useful method to identify patients with disabling migraines, determine their need for treatment, and monitor treatment efficacy.
Diagnosis
Menstrual migraine is a clinical diagnosis made by findings from the patient’s history. The International Headache Society has established specific diagnostic criteria in the ICHD-II for both PMM and MRM.1 An accurate and detailed migraine history is invaluable for the diagnosis of menstrual migraine. Although a formal questionnaire can serve as a good screening tool, it relies on the patient’s ability to recall specific times and dates with accuracy.11 Recall bias can be misleading in any attempt to confirm a diagnosis. The patient’s conscientious use of a daily headache diary or calendar (see Figure 2, for example) can lead to a precise record of the characteristics and timing of migraines, overcoming these obstacles.
Brain imaging is necessary if the patient’s symptoms suggest a critical etiology that requires immediate diagnosis and management. Red flags include sudden onset of a severe headache, a headache characterized as “the worst headache of the patient’s life,” a change in headache pattern, altered mental status, an abnormal neurologic examination, or fever with neck stiffness.12
Treatment Options for Menstrual Migraine
There is no FDA-approved treatment specific for menstrual migraines; however, medications used for management of nonmenstrual migraines are also those most commonly prescribed for women with menstrual migraine headaches.13 Because these headaches are frequently more severe and of longer duration than nonmenstrual migraine headaches, a combination of intermittent preventive therapy, hormone manipulation, and acute treatment strategies is often necessary.4
Acute therapy is aimed to treat migraine pain quickly and effectively with minimal adverse effects or need for additional medication. Triptans have been the mainstay of menstrual migraine treatment and have been proven effective for both acute attacks and prevention.4 Sumatriptan has a rapid onset of action and may be given orally as a 50- or 100-mg tablet, as a 6-mg subcutaneous injection, or as a 20-mg nasal spray.14
Abortive therapies are most effective when taken at the first sign of an attack. Patients can repeat the dose in two hours if the headache persists or recurs, to a maximum of two doses in 24 hours.15 Rizatriptan is another triptan used for acute treatment of menstrual migraine headaches. Its initial 10-mg dose can be repeated every two hours, to a maximum of 30 mg per 24 hours. NSAIDs, such as naproxen sodium, have also been recommended in acute migraine attacks. They seem to work synergistically with triptans, inhibiting prostaglandin synthesis and blocking neurogenic inflammation.15