Migraine

Editor's Note: This issue of In the Clinic has been updated. Diagnosis Migraine headache affects 18% of women and 6% of men. Three quarters of migraine sufferers have moderate-to-severe symptoms that interfere with work, school, and other normal daily activities. Despite being a significant cause of episodic but disabling symptoms, the condition remains underrecognized, underdiagnosed, and undertreated. Migraine pain was previously believed to be largely vascular in cause, but evidence now shows that it involves genetic control of the activity of some brain cells. It is hypothesized that migraine activity begins in the brainstem and ends with distention and inflammation of meningeal vessels. These events cause an instability in brain cells that triggers surges of abnormal impulses to the periphery and releases inflammatory substances. Although migraines can be highly disruptive to daily life, effective behavioral and drug treatments can prevent attacks or relieve symptoms. What clinical features are helpful in distinguishing migraine headache from tension headache? The International Classification of Headache Disorders (ICHD) classifies headache disorders (1), but several simpler diagnostic criteria have been validated against the ICHD. Five important features of migraine are headache that is unilateral, pulsatile, or throbbing; associated with nausea or vomiting; of sufficient intensity to interrupt usual daily activities; and usually lasting 4 to 72 hours if untreated. "POUND" (as in "a pounding headache") is one way to remember symptoms consistent with migraine headache: Pulsatile quality of headache described One-day duration (duration < 4 hours suggests tension-type headache) Unilateral location Nausea or vomiting Disabling intensity. Individuals with 3 of the 5 criteria listed above are likely to have migraine; those with 4 of 5 are highly likely to have migraine (2). Other diagnostic criteria perform similarly, including 1 that considers nausea, photophobia, and headache-related disability (any day in the past 3 mo); individuals who have 2 of these 3 symptoms are highly likely to have migraine (3) (Table 1). Table 1. Elements of Patient History for Clinical Diagnosis of Migraine versus Tension-Type Headache The presence of prodrome or aura distinguishes migraine from other types of headache. Prodrome is the occurrence of euphoria, depression, fatigue, hypomania, food cravings, dizziness, cognitive slowing, or asthenia that occurs up to 24 hours before headache. Aura are neurologic symptoms that occur within 1 hour of or during headache and last a few minutes to 1 hour. Aura includes such symptoms as visual changes, loss of vision, hallucinations, numbness, tingling, weakness, or confusion. Approximately 60% to 70% of patients with migraine report prodrome, and 15% to 20% report aura. What clinical features suggest that the cause of headache may be more serious than migraine? Other primary causes of headache include tension-type headache, as well as medication-overuse headache and cluster headache. Although they can be disabling, primary headache conditions are generally benign. However, clinicians should exclude secondary causes of headache. Serious secondary causes of headache include stroke, tumor, arteritis, meningitis, acute glaucoma, and subarachnoid hemorrhage. Several historical and physical examination findings are predictive of such secondary causes (See Box). "Red flag" historical findings include changes in the intensity, frequency, or pattern of headaches; blurred vision; dizziness or lack of coordination; sudden, explosive onset of headache with rapid progression; or headache pain aggravated by coughing or movement. Red flag physical findings include fever and scalp nodules or lesions. "Red Flag" or Alarm Features That Suggest Headache Is Due to Nonbenign, Secondary Causes Changes in headache pattern, frequency, or intensity Daily headache Blurred vision Dizziness, syncope, discoordination, or focal neurologic abnormality Sudden, explosive onset Pain worse with coughing or movement Change in personality or mental status Headache awakens person from sleep Onset after 50 years of age Fever Meningeal signs Diastolic blood pressure >120 mm Hg Diminished pulse or tenderness of temporal artery Papilledema Necrotic or tender scalp lesions Increased intraocular pressure Patients may suffer from more than 1 type of headache, have headaches that cannot be easily described or classified, or have had a change in headache pattern over time. The history should include questions about the onset and frequency of the headache disorder; the duration of attacks; pain location, severity, and quality; precipitating and ameliorating factors; and family history. Table 2 presents the differential diagnosis of headache. Table 2. Differential Diagnosis of Headache What is the role of physical examination in patients who present with migraine? The physical examination should evaluate for features that suggest a secondary headache, such as fever, meningeal or other signs of infection, neurologic abnormalities, changes in visual acuity, increased intraocular pressure, elevated blood pressure, and mental status changes. What is the role of diagnostic testing, including imaging studies and electroencephalography, in patients with suspected migraine? Neuroimaging, such as magnetic resonance imaging (MRI) or computed tomography, is not usually warranted for patients with migraine symptoms and a normal neurologic examination. A meta-analysis of studies of patients with migraine and a normal neurologic examination found a 0.18% rate of significant intracranial lesions (4). Clinicians should apply a lower threshold for obtaining neuro-imaging for patients with atypical headache features, substantial change in headache pattern, or symptoms or signs of neurologic abnormalities (5). For instance, MRI is indicated in patients with a long history of migraine headache who develop substantial changes in headache pattern or in any patient with headache and focal neurologic signs or symptoms. In patients with new onset headache after 50 years of age, it is important to obtain an erythrocyte sedimentation rate (ESR) to evaluate for secondary causes of headache, particularly temporal arteritis or other vasculitides, even if symptoms are consistent with migraine. An elevated ESR (>30 mm/h) suggests temporal arteritis but lacks specificity, making a temporal artery biopsy necessary in patients in whom temporal arteritis is suspected. Headache is the predominant symptom in 65% to 80% of patients with temporal arteritis (6), and the combination of new-onset headache, jaw claudication, and abnormal (nodular or tender) arteries is highly predictive of temporal arteritis (7). Electroencephalography (EEG) is not routinely used in evaluation of headache, and should be considered only if associated symptoms suggest a seizure disorder, such as atypical migrainous aura or episodic loss of consciousness. A systematic review found no increased prevalence of EEG abnormalities in patients with headache, no useful headache subgroups defined by EEG, and no ability of EEG to identify patients whose headaches have a structural cause (8). Clinical Bottom Line: Diagnosis In patients with normal neurologic examination, evaluation of symptoms distinguishes migraine from tension or other types of headache. Migraines are typically pulsatile, are unilateral, last 4 to 72 hours, are associated with nausea or vomiting, and make it necessary for patients to alter their usual activities. Neuroimaging is not usually warranted for patients with normal neurologic examination, and EEG has not been shown to be useful. Clinicians should ask patients about features that suggest serious secondary causes of headache and conduct appropriate evaluation for these causes. Treatment What is the role of diet in the management of patients with migraine? Dietary triggers for migraine are idiosyncratic and can be difficult to identify. However, some foods are known to be associated with migraines (see Box). About 20% of patients with migraine report dietary triggers (9, 10). Clinicians should encourage patients to identify and avoid dietary factors that may contribute to headaches. There is also some controversy over the role of aspartame in triggering migraine. Common Dietary Triggers for Migraine Caffeine withdrawal Nitrates and nitrites in preserved meats Phenylethylamines, tyramines, xanthines in aged cheeses, red wine, beer, champagne, chocolate Monosodium glutamate in some Asian and prepared foods Dairy products Fatty foods Researchers at the Montefiore Medical Center Headache Unit questioned 190 consecutive patients about the effect of alcohol, carbohydrates, and aspartame in triggering their headaches. Of the 171 patients who completed the survey, 49.7% reported alcohol as a precipitating factor, 8.2% reported aspartame, and 2.3% reported carbohydrates. Patients with migraine were significantly more likely to report alcohol as a triggering factor and reported aspartame as a precipitant 3 times more often than those having other types of headache (11). There is some evidence of a causal relationship between food and migraine through elimination diets, reintroduction, and double-blind rechallenge (12, 14). In these studies, elimination diets decreased symptoms substantially in some individuals. The findings suggested that greater efforts are needed to educate patients about the possible benefits of adjusting diet to decrease headache frequency. An investigation of the awareness and impact of dietary risk factors on patients with chronic headache found that three quarters of the 130 participants were aware of the possible link between certain foods and headache, although most did not report hearing about this from their doctor. Notably, knowledge of the possible link did not prompt changes in food consumption practices (15). Is behavioral therapy effective in the management of m