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Migraine; Clinical Aspects☆
Migraine; Clinical Aspectsq Werner J Becker, University of Calgary, Calgary, AB, Canada Ó 2017 Elsevier Inc. All rights reserved.
1 1 1 3 3 4 4 4 5 5 5 5 5 6 6
Introduction Definition and Diagnosis Epidemiology Clinical Features Migraine Without Aura Migraine With Aura Other Clinical Features of Migraine Migraine Attack Triggers Menstruation and Migraine Premonitory Symptoms The Phases of the Migraine Attack Migraine and Depression and Anxiety Conclusion Further Reading Relevant Websites
Introduction Migraine is one of the most common neurological disorders, and presents a very significant burden both for many individuals with migraine and for society. Although significant advances have been made in our understanding and treatment of migraine over the past several decades, much more needs to be learned before the pathophysiology of migraine will be fully understood.
Definition and Diagnosis Migraine is a neurological disorder that predisposes patients to recurrent attacks of headache, although attacks also include other symptoms in addition to headache as will be discussed below. Most patients with migraine have episodic migraine with intermittent headache attacks that are separated by symptom-free intervals. The clinical spectrum of migraine is broad, however; and a minority of individuals with migraine go on to develop very frequent migraine attacks. When migraine sufferers progress to headache on more than 14 days a month, with eight of these headache days meeting migraine diagnostic criteria, they are said to have chronic migraine. This article will deal only with episodic migraine, that is, with patients who have migraine with headache on 14 days a month or less. There is no definitive diagnostic test for migraine, and migraine is diagnosed using clinical diagnostic criteria. The most widely used diagnostic criteria are those of the International Classification Subcommittee of the International Headache Society (IHS). These diagnostic criteria subdivide migraine into a number of subtypes. The major subtypes that occur in adults are shown in Table 1. The most common subtypes of migraine are migraine without aura and migraine with aura. The diagnostic criteria for migraine without aura are shown in Table 2 and those for migraine with aura in Table 3. Approximately one-third of migraine sufferers experience auras. Although some experience an aura with every attack, many have both migraine with aura attacks and attacks without aura. Less commonly, patients may experience just the aura symptoms, with no headache following.
Epidemiology Migraine is so frequent that it might almost be considered normal. However, individuals with migraine do show a number of neurophysiological differences as compared with those without migraine, indicating that specific changes in brain chemistry and function must underlie the migraine disorder. Between the ages of 30 and 39 years, almost one quarter of women experience migraine attacks (Fig. 1). Overall, approximately 17% of women have migraine in population-based studies (1-year period prevalence) whereas 5%–6% of men experience migraine attacks. In the population as a whole, approximately 12% of people have
q
Change History: March 2016. WJ Becker updated Tables 1, 2, and 3 to reflect the new International Headache Society Classification (ICHD-3 Beta) published in 2013, references and websites accordingly.
Reference Module in Neuroscience and Biobehavioral Psychology
http://dx.doi.org/10.1016/B978-0-12-809324-5.03551-3
1
2
Migraine; Clinical Aspects
Table 1
Migraine subtypesa
Migraine without aura Migraine with aura Typical aura with headache Typical aura without headache Migraine with brainstem aura Hemiplegic migraine (familial and sporadic) Chronic migraine Complications of migraine Status migrainosus Migrainous infarction Probable migraine Probable migraine without aura Probable migraine with aura a Not all migraine types are shown. Modified from Headache Classification Subcommittee of the International Headache Society, 2013. The International Classification of Headache Disorders, third ed. (beta version). Cephalalgia 33, 627–808.
Table 2
Migraine without aura: diagnostic criteria
1. Patients must have had at least five attacks fulfilling the criteria below: 2. Headache attacks lasting 4–72 h untreated or unsuccessfully treated 3. Headaches must have at least two of the following: a. unilateral location b. pulsating quality c. moderate or severe pain intensity d. aggravation by or causing avoidance of routine physical activity (stair climbing, etc.) 4. During headache, at least one of the following must occur: a. nausea and/or vomiting b. photophobia and phonophobia 5. Not better accounted for by another ICHD-3 diagnosis Modified from Headache Classification Subcommittee of the International Headache Society, 2013. The International Classification of Headache Disorders, third ed. (ICHD-3) (beta version). Cephalalgia 33, 627–808.
Table 3 Diagnostic criteria: migraine with aura (typical aura with headache) 1. At least two attacks fulfilling the criteria below: 2. Aura consisting of visual, sensory, and/or speech/language symptoms, each fully reversible. But no motor, brainstem, or retinal symptoms 3. At least two of the following four characteristics: a. At least one aura symptom spreads gradually over 5 min, and/or two or more symptoms occur in succession b. Each individual aura symptom lasts 5–60 min c. At least one aura symptom is unilateral d. The aura is accompanied or followed within 60 min by headache 4. Not better accounted for by another ICHD-3 diagnosis, and transient ischemic attack has been ruled out Modified from Headache Classification Subcommittee of the International Headache Society, 2013. The International Classification of Headache Disorders, third ed. (ICHD-3) (beta version). Cephalalgia 33, 627–808.
Migraine; Clinical Aspects
3
30 Women
Men
25 20 15 10 5 0 12−17
18−29
40−49
30−39
50−59
60+
Age Figure 1 The 1-year point prevalence of migraine (the percentage of individuals who have migraine attacks) is shown for women and men during each of the age categories listed. Data presented in this figure is from Lipton, R.B., Bigal, M.E., Diamond, M., AMPP Advisory Group, et al., 2007. Migraine prevalence, disease burden, and the need for preventive therapy. Neurology 68, 343–349.
migraine attacks. However, migraine prevalence does differ greatly throughout the life cycle. Many females experience migraine for the first time at puberty, and after menopause many cease to have migraine attacks. Some women, however, approximately 5%, will experience migraine attacks into old age. Hormonal factors would clearly appear to be important in determining the prevalence of migraine attacks in women in different age categories, but aging itself may also play a role, as migraine prevalence in men also peaks during the fourth and fifth decades of life (although at a much lower level than in women), and falls with advancing age. As migraine is so common in the general populations, because attacks are often severe and make working difficult or impossible during attacks, and because attacks often occur from puberty until migraine sufferers are in their fifties, migraine poses a huge economic burden on many individuals and on society. If both direct costs related to treating migraine and the indirect costs related to reduced productivity and missed work days are considered, migraine is more expensive in economic terms to society than most other neurological conditions including stroke, multiple sclerosis, and Parkinson’s disease.
Clinical Features Migraine Without Aura For most individuals with migraine, headache is the most prominent feature of their migraine attacks. The pain can occur anywhere in the head, but tends to be frontal and/or temporal. It can also involve the neck, and this may lead patients to believe that the neck is the source of their headaches. The primary source of the pain in migraine is, however, believed to be nociceptive inputs from small intracranial blood vessels in the dura and on the surface of the brain. As the pain systems of the neck and the head are linked, migraine pain may radiate to involve the neck and even be associated with some neck stiffness. Headache frequency in migraine varies widely, both between different individuals and in the same individual over time. Although some individuals may have only one attack every few months, the most common migraine frequency is one or two attacks a month, with approximately 40% of migraine sufferers showing this headache frequency. Importantly, more than 13% of individuals with migraine have one attack a week or more. As discussed below, although most migraine sufferers can identify a number of triggers that will increase the likelihood of having an attack, for most individuals many of their attacks are unpredictable, and this increases the negative impact that the migraine attacks have on their lives. Although pain is the predominant clinical feature in patients with migraine without aura, other symptoms can be very troublesome for many patients as well. These are usually called “associated symptoms,” that is, associated with pain. Nausea is perhaps the most significant one, and a significant minority of individuals with migraine will vomit with some of their attacks. Light sensitivity (photophobia) and sound sensitivity (phonophobia) are also very common, and many migraine sufferers will also complain of sensitivity to odors during attacks (osmophobia). Most migraine sufferers will have photophobia and phonophobia with their attacks, and the majority will also have nausea with at least some of their attacks. The pain of the migraine attack has a number of characteristic features, although pain features can vary significantly between different migraine sufferers. Most will describe pulsating head pain and this pain is often unilateral, although it may appear on one side during one attack and on the other side during another. Attacks of bilateral head pain are also
4
Migraine; Clinical Aspects
not uncommon. An interesting feature of the typical migraine attack is that during an attack the headache is usually made worse by minor activity or exertion. This is an important diagnostic feature, and during an attack the individual with migraine will often avoid activity. This feature of the migraine attack, coupled with photophobia and phonophobia, will often cause the migraine sufferer to retreat to a bed in a quiet dark room if possible. The pain is also often severe, and this contributes further to the disability caused by the migraine attack. Affected individuals are frequently concerned that they may have a serious underlying cause for their recurrent headaches. This may lead to much unnecessary investigation (brain magnetic resonance imaging scans, etc.), and the situation is compounded in that other brain disorders (e.g., brain tumors and head trauma) can sometimes lead to headache attacks that resemble migraine without aura. This is recognized by the IHS diagnostic criteria, and these stipulate that there must be no suggestion of another cause other than migraine for the patient’s headaches. In general, however, a thorough history and neurological examination are sufficient to exclude other underlying causes of headache, and for the individual with typical migraine, other diagnostic tests including brain imaging are not necessary. Fortunately, migraine itself is by far the most common cause of headache attacks with the clinical features as described in the migraine diagnostic criteria, and although it may cause significant disability, migraine generally runs a medically benign course.
Migraine With Aura The headache phase of migraine with aura is usually similar to that of migraine without aura. The aura itself is quite a distinctive symptom and of great diagnostic value. The aura usually precedes the headache phase, with the headache following promptly after the aura dissipates; although the aura may at times occur during the headache, or even occur without a following headache attack. Migraine auras usually involve visual symptoms, although less commonly they may have in addition (or instead of visual symptoms) somatosensory symptoms that usually consist of unilateral numbness and tingling. These typically involve the hand and lower face, and sometimes also the tongue. Disturbances of language and speech are also common as part of the aura. Unilateral weakness is much less common, but does occur in an uncommon migraine syndrome, hemiplegic migraine. The symptoms of the migraine aura are focal neurological symptoms that indicate direct involvement of specific regions of the brain itself. Current understanding of migraine pathophysiology is that these brain regions include portions of the cerebral cortex, which are involved by a wave of intense neuronal activation that is followed by a period of neuronal “depression” before normal neurophysiological activity can resume. These neurophysiological phenomena are thought to underlie the symptoms of the migraine aura. The aura symptoms of migraine may take a number of different forms, but certain features are characteristic and helpful in the diagnosis. First, they usually come on gradually over a few minutes, with a gradual increase in the visual symptoms from a small focus in the visual field to involvement of much of the visual field, usually on one side. Similarly, the somatosensory symptoms often spread gradually from involvement of a finger or two to involve the whole hand and then spread to the face, or the other way round. This relatively slow march of symptoms is of great diagnostic assistance, and helps to distinguish the migraine aura from transient ischemic attacks or strokes, where the symptoms usually come on more suddenly and are fully developed in a matter of a few seconds. A second characteristic feature of the migraine aura is that it usually involves positive sensory symptoms as well as negative ones. Thus, the visual symptoms usually include bright lines or scintillations as well as negative symptoms like scotomas or visual loss. The somatosensory symptoms usually involve tingling or paresthesias as well as numbness. However, as with the headache itself, the aura can be quite variable from person to person and some individuals experience primarily negative symptoms such as visual loss, during the aura. Others will have dramatic positive symptoms and even describe their auras in terms of looking into a kaleidoscope. Although the aura is often dramatic enough to cause great concern to the patient when first experienced, it is usually short, and resolves within 30 min. It does last longer in some patients, and this may cause additional concern, but in the great majority of migraine attacks aura symptoms have disappeared within an hour, and the headache phase is underway. Although individuals with migraine with aura do have a slightly increased risk of stroke, this risk is small and aura symptoms are generally benign although often recurrent for many years.
Other Clinical Features of Migraine Migraine Attack Triggers Migraine has many other features, many of which are not fully understood. Most migraine patients will report a half dozen or more factors that can “trigger” their migraine attacks; that is, can increase the probability that a migraine attack will occur in relatively close temporal relationship to the trigger. The most common migraine trigger reported is stress, but many others are also reported by individuals with migraine (Table 4). Commonly reported triggers comprise a very heterogeneous group, from red wine to weather changes. Similarly, certain aspects of the patient’s lifestyle may increase the headache frequency. It is generally accepted that irregular or insufficient sleep, skipping meals, and caffeine withdrawal can make an individual with migraine more migraine attack prone. The precise mechanisms whereby these triggers and lifestyle factors exert their effects on migraine frequency are unknown, but managing these is an important aspect of treatment.
Migraine; Clinical Aspects
Table 4
5
Patient-reported migraine triggersa
Stress Hormones (women only) Not eating Weather Sleep disturbance Perfumedodors Neck pain Lights Alcohol Smoke Sleeping late Heat Food Exercise Sexual activity a Triggers are listed in order of frequency of patient report. Reproduced from Kelman, L., 2007. The triggers or precipitants of acute migraine attack. Cephalalgia 27, 394–402.
Menstruation and Migraine For many women, an important migraine trigger is the drop in estrogen levels that occurs just before menstruation. As a result, they have a particularly high probability of suffering a migraine attack a day or two before the onset of their menstrual period and, for some, these attacks are prolonged and difficult to treat effectively. In contrast, during pregnancy, when the natural menstrual cycle no longer occurs, many women experience a marked improvement in their migraine frequency.
Premonitory Symptoms Some migraine sufferers report premonitory symptoms before many of their attacks. These are different from aura symptoms in that they are experienced for a number of hours before the pain phase, and usually involve more nonspecific symptoms as contrasted with the focal neurological symptoms of the aura. It is unclear what proportion of those with migraine experience premonitory symptoms, but it would appear that, at least in patients referred to headache specialists, one-third or more experience them. Reported premonitory symptoms include general symptoms such as fatigue and difficulty concentrating, mood changes such as unhappiness or anxiety, and autonomic symptoms like yawning and horripilation. Symptoms that also occur during the aura and the headache phase, such as difficulty with speech, photophobia, and nausea, are also reported by some patients as premonitory symptoms and may occur for hours before the headache begins.
The Phases of the Migraine Attack A migraine attack, therefore, consists of a number of components. For some patients, the first symptoms are the premonitory symptoms. This may be followed by the aura, or the aura may be the first symptom experienced. The pain phase or headache then follows, although for patients that have neither premonitory symptoms nor an aura, the attack begins with the headache. Finally, most patients describe a postdrome of nonspecific symptoms after the headache phase before they have fully recovered and feel normal again.
Migraine and Depression and Anxiety Individuals with migraine are more likely to suffer from depression and/or anxiety disorders than those without migraine. For example, migraine sufferers are approximately twice as likely to suffer from depression as those without migraine. Some studies have shown even higher depression tendencies in people with migraine. The reason for this association between migraine and depression and anxiety is unknown, but genetically determined changes in brain serotonin systems may underlie this association.
Conclusion Migraine is an interesting, and as yet imperfectly understood, neurological disorder that is common and which significantly impacts the lives of many in our society. Although migraine may have a slightly higher prevalence in Caucasian populations, it has a global
6
Migraine; Clinical Aspects
impact and occurs in all societies. Prevalence rates approaching 10% have been found in China and Taiwan. The degree of disability caused by migraine is often underestimated as migraine generally does not cause mortality or permanent neurological deficits. Nevertheless, as migraine is so common and often lasts the better part of a lifetime, and as many migraine sufferers find it very difficult to function productively during attacks, migraine has been ranked 19 by the World Health Organization among all causes of disability in terms of causing years lived with disability. More research is needed to understand this disorder more completely and develop better treatments.
Further Reading Andlin-Sobocki, P., Jönsson, B., Wittchen, H.U., Olesen, J., 2005. Cost of disorders of the brain in Europe. Eur. J. Neurol. 12 (Suppl. 1), 1–27. Becker, W.J., 2013. The premonitory phase of migraine and migraine management. Cephalalgia 33, 1117–1121. Goadsby, P.J., Lipton, R.B., Ferrari, M.D., 2002. Migrainedcurrent understanding and treatment. N. Engl. J. Med. 346, 257–270. Headache Classification Subcommittee of the International Headache Society, July 9, 2013. The International Classification of Headache Disorders, third ed. (beta version). Cepahalalgia 33 (9), 627–808. Kelman, L., 2007. The triggers or precipitants of the acute migraine attack. Cephalalgia 27, 394–402. Lipton, R.B., Bigal, M.E., Diamond, M., AMPP Advisory Group, et al., 2007. Migraine prevalence, disease burden, and the need for preventive therapy. Neurology 68, 343–349. Modgill, G., Jette, N., Wang, J.L., Becker, W.J., Patten, S.B., 2012. A population-based longitudinal community study of major depression and migraine. Headache 52, 422–432. Radat, F., Lantéri-Minet, M., Nachit-Ouinekh, F., et al., 2009. The GRIM2005 study of migraine consultation in France. III: psychological features of subjects with migraine. Cephalalgia 29, 338–350.
Relevant Websites http://www.achenet.org/ – American Headache Society (AHS) Committee for Headache Education. http://www.americanmigrainefoundation.org/ – The American Migraine Foundation. http://www.migrainecanada.org/ – The Canadian Headache Society (CHS).
1 1 1 3 3 4 4 4 5 5 5 5 5 6 6
Introduction Definition and Diagnosis Epidemiology Clinical Features Migraine Without Aura Migraine With Aura Other Clinical Features of Migraine Migraine Attack Triggers Menstruation and Migraine Premonitory Symptoms The Phases of the Migraine Attack Migraine and Depression and Anxiety Conclusion Further Reading Relevant Websites
Introduction Migraine is one of the most common neurological disorders, and presents a very significant burden both for many individuals with migraine and for society. Although significant advances have been made in our understanding and treatment of migraine over the past several decades, much more needs to be learned before the pathophysiology of migraine will be fully understood.
Definition and Diagnosis Migraine is a neurological disorder that predisposes patients to recurrent attacks of headache, although attacks also include other symptoms in addition to headache as will be discussed below. Most patients with migraine have episodic migraine with intermittent headache attacks that are separated by symptom-free intervals. The clinical spectrum of migraine is broad, however; and a minority of individuals with migraine go on to develop very frequent migraine attacks. When migraine sufferers progress to headache on more than 14 days a month, with eight of these headache days meeting migraine diagnostic criteria, they are said to have chronic migraine. This article will deal only with episodic migraine, that is, with patients who have migraine with headache on 14 days a month or less. There is no definitive diagnostic test for migraine, and migraine is diagnosed using clinical diagnostic criteria. The most widely used diagnostic criteria are those of the International Classification Subcommittee of the International Headache Society (IHS). These diagnostic criteria subdivide migraine into a number of subtypes. The major subtypes that occur in adults are shown in Table 1. The most common subtypes of migraine are migraine without aura and migraine with aura. The diagnostic criteria for migraine without aura are shown in Table 2 and those for migraine with aura in Table 3. Approximately one-third of migraine sufferers experience auras. Although some experience an aura with every attack, many have both migraine with aura attacks and attacks without aura. Less commonly, patients may experience just the aura symptoms, with no headache following.
Epidemiology Migraine is so frequent that it might almost be considered normal. However, individuals with migraine do show a number of neurophysiological differences as compared with those without migraine, indicating that specific changes in brain chemistry and function must underlie the migraine disorder. Between the ages of 30 and 39 years, almost one quarter of women experience migraine attacks (Fig. 1). Overall, approximately 17% of women have migraine in population-based studies (1-year period prevalence) whereas 5%–6% of men experience migraine attacks. In the population as a whole, approximately 12% of people have
q
Change History: March 2016. WJ Becker updated Tables 1, 2, and 3 to reflect the new International Headache Society Classification (ICHD-3 Beta) published in 2013, references and websites accordingly.
Reference Module in Neuroscience and Biobehavioral Psychology
http://dx.doi.org/10.1016/B978-0-12-809324-5.03551-3
1
2
Migraine; Clinical Aspects
Table 1
Migraine subtypesa
Migraine without aura Migraine with aura Typical aura with headache Typical aura without headache Migraine with brainstem aura Hemiplegic migraine (familial and sporadic) Chronic migraine Complications of migraine Status migrainosus Migrainous infarction Probable migraine Probable migraine without aura Probable migraine with aura a Not all migraine types are shown. Modified from Headache Classification Subcommittee of the International Headache Society, 2013. The International Classification of Headache Disorders, third ed. (beta version). Cephalalgia 33, 627–808.
Table 2
Migraine without aura: diagnostic criteria
1. Patients must have had at least five attacks fulfilling the criteria below: 2. Headache attacks lasting 4–72 h untreated or unsuccessfully treated 3. Headaches must have at least two of the following: a. unilateral location b. pulsating quality c. moderate or severe pain intensity d. aggravation by or causing avoidance of routine physical activity (stair climbing, etc.) 4. During headache, at least one of the following must occur: a. nausea and/or vomiting b. photophobia and phonophobia 5. Not better accounted for by another ICHD-3 diagnosis Modified from Headache Classification Subcommittee of the International Headache Society, 2013. The International Classification of Headache Disorders, third ed. (ICHD-3) (beta version). Cephalalgia 33, 627–808.
Table 3 Diagnostic criteria: migraine with aura (typical aura with headache) 1. At least two attacks fulfilling the criteria below: 2. Aura consisting of visual, sensory, and/or speech/language symptoms, each fully reversible. But no motor, brainstem, or retinal symptoms 3. At least two of the following four characteristics: a. At least one aura symptom spreads gradually over 5 min, and/or two or more symptoms occur in succession b. Each individual aura symptom lasts 5–60 min c. At least one aura symptom is unilateral d. The aura is accompanied or followed within 60 min by headache 4. Not better accounted for by another ICHD-3 diagnosis, and transient ischemic attack has been ruled out Modified from Headache Classification Subcommittee of the International Headache Society, 2013. The International Classification of Headache Disorders, third ed. (ICHD-3) (beta version). Cephalalgia 33, 627–808.
Migraine; Clinical Aspects
3
30 Women
Men
25 20 15 10 5 0 12−17
18−29
40−49
30−39
50−59
60+
Age Figure 1 The 1-year point prevalence of migraine (the percentage of individuals who have migraine attacks) is shown for women and men during each of the age categories listed. Data presented in this figure is from Lipton, R.B., Bigal, M.E., Diamond, M., AMPP Advisory Group, et al., 2007. Migraine prevalence, disease burden, and the need for preventive therapy. Neurology 68, 343–349.
migraine attacks. However, migraine prevalence does differ greatly throughout the life cycle. Many females experience migraine for the first time at puberty, and after menopause many cease to have migraine attacks. Some women, however, approximately 5%, will experience migraine attacks into old age. Hormonal factors would clearly appear to be important in determining the prevalence of migraine attacks in women in different age categories, but aging itself may also play a role, as migraine prevalence in men also peaks during the fourth and fifth decades of life (although at a much lower level than in women), and falls with advancing age. As migraine is so common in the general populations, because attacks are often severe and make working difficult or impossible during attacks, and because attacks often occur from puberty until migraine sufferers are in their fifties, migraine poses a huge economic burden on many individuals and on society. If both direct costs related to treating migraine and the indirect costs related to reduced productivity and missed work days are considered, migraine is more expensive in economic terms to society than most other neurological conditions including stroke, multiple sclerosis, and Parkinson’s disease.
Clinical Features Migraine Without Aura For most individuals with migraine, headache is the most prominent feature of their migraine attacks. The pain can occur anywhere in the head, but tends to be frontal and/or temporal. It can also involve the neck, and this may lead patients to believe that the neck is the source of their headaches. The primary source of the pain in migraine is, however, believed to be nociceptive inputs from small intracranial blood vessels in the dura and on the surface of the brain. As the pain systems of the neck and the head are linked, migraine pain may radiate to involve the neck and even be associated with some neck stiffness. Headache frequency in migraine varies widely, both between different individuals and in the same individual over time. Although some individuals may have only one attack every few months, the most common migraine frequency is one or two attacks a month, with approximately 40% of migraine sufferers showing this headache frequency. Importantly, more than 13% of individuals with migraine have one attack a week or more. As discussed below, although most migraine sufferers can identify a number of triggers that will increase the likelihood of having an attack, for most individuals many of their attacks are unpredictable, and this increases the negative impact that the migraine attacks have on their lives. Although pain is the predominant clinical feature in patients with migraine without aura, other symptoms can be very troublesome for many patients as well. These are usually called “associated symptoms,” that is, associated with pain. Nausea is perhaps the most significant one, and a significant minority of individuals with migraine will vomit with some of their attacks. Light sensitivity (photophobia) and sound sensitivity (phonophobia) are also very common, and many migraine sufferers will also complain of sensitivity to odors during attacks (osmophobia). Most migraine sufferers will have photophobia and phonophobia with their attacks, and the majority will also have nausea with at least some of their attacks. The pain of the migraine attack has a number of characteristic features, although pain features can vary significantly between different migraine sufferers. Most will describe pulsating head pain and this pain is often unilateral, although it may appear on one side during one attack and on the other side during another. Attacks of bilateral head pain are also
4
Migraine; Clinical Aspects
not uncommon. An interesting feature of the typical migraine attack is that during an attack the headache is usually made worse by minor activity or exertion. This is an important diagnostic feature, and during an attack the individual with migraine will often avoid activity. This feature of the migraine attack, coupled with photophobia and phonophobia, will often cause the migraine sufferer to retreat to a bed in a quiet dark room if possible. The pain is also often severe, and this contributes further to the disability caused by the migraine attack. Affected individuals are frequently concerned that they may have a serious underlying cause for their recurrent headaches. This may lead to much unnecessary investigation (brain magnetic resonance imaging scans, etc.), and the situation is compounded in that other brain disorders (e.g., brain tumors and head trauma) can sometimes lead to headache attacks that resemble migraine without aura. This is recognized by the IHS diagnostic criteria, and these stipulate that there must be no suggestion of another cause other than migraine for the patient’s headaches. In general, however, a thorough history and neurological examination are sufficient to exclude other underlying causes of headache, and for the individual with typical migraine, other diagnostic tests including brain imaging are not necessary. Fortunately, migraine itself is by far the most common cause of headache attacks with the clinical features as described in the migraine diagnostic criteria, and although it may cause significant disability, migraine generally runs a medically benign course.
Migraine With Aura The headache phase of migraine with aura is usually similar to that of migraine without aura. The aura itself is quite a distinctive symptom and of great diagnostic value. The aura usually precedes the headache phase, with the headache following promptly after the aura dissipates; although the aura may at times occur during the headache, or even occur without a following headache attack. Migraine auras usually involve visual symptoms, although less commonly they may have in addition (or instead of visual symptoms) somatosensory symptoms that usually consist of unilateral numbness and tingling. These typically involve the hand and lower face, and sometimes also the tongue. Disturbances of language and speech are also common as part of the aura. Unilateral weakness is much less common, but does occur in an uncommon migraine syndrome, hemiplegic migraine. The symptoms of the migraine aura are focal neurological symptoms that indicate direct involvement of specific regions of the brain itself. Current understanding of migraine pathophysiology is that these brain regions include portions of the cerebral cortex, which are involved by a wave of intense neuronal activation that is followed by a period of neuronal “depression” before normal neurophysiological activity can resume. These neurophysiological phenomena are thought to underlie the symptoms of the migraine aura. The aura symptoms of migraine may take a number of different forms, but certain features are characteristic and helpful in the diagnosis. First, they usually come on gradually over a few minutes, with a gradual increase in the visual symptoms from a small focus in the visual field to involvement of much of the visual field, usually on one side. Similarly, the somatosensory symptoms often spread gradually from involvement of a finger or two to involve the whole hand and then spread to the face, or the other way round. This relatively slow march of symptoms is of great diagnostic assistance, and helps to distinguish the migraine aura from transient ischemic attacks or strokes, where the symptoms usually come on more suddenly and are fully developed in a matter of a few seconds. A second characteristic feature of the migraine aura is that it usually involves positive sensory symptoms as well as negative ones. Thus, the visual symptoms usually include bright lines or scintillations as well as negative symptoms like scotomas or visual loss. The somatosensory symptoms usually involve tingling or paresthesias as well as numbness. However, as with the headache itself, the aura can be quite variable from person to person and some individuals experience primarily negative symptoms such as visual loss, during the aura. Others will have dramatic positive symptoms and even describe their auras in terms of looking into a kaleidoscope. Although the aura is often dramatic enough to cause great concern to the patient when first experienced, it is usually short, and resolves within 30 min. It does last longer in some patients, and this may cause additional concern, but in the great majority of migraine attacks aura symptoms have disappeared within an hour, and the headache phase is underway. Although individuals with migraine with aura do have a slightly increased risk of stroke, this risk is small and aura symptoms are generally benign although often recurrent for many years.
Other Clinical Features of Migraine Migraine Attack Triggers Migraine has many other features, many of which are not fully understood. Most migraine patients will report a half dozen or more factors that can “trigger” their migraine attacks; that is, can increase the probability that a migraine attack will occur in relatively close temporal relationship to the trigger. The most common migraine trigger reported is stress, but many others are also reported by individuals with migraine (Table 4). Commonly reported triggers comprise a very heterogeneous group, from red wine to weather changes. Similarly, certain aspects of the patient’s lifestyle may increase the headache frequency. It is generally accepted that irregular or insufficient sleep, skipping meals, and caffeine withdrawal can make an individual with migraine more migraine attack prone. The precise mechanisms whereby these triggers and lifestyle factors exert their effects on migraine frequency are unknown, but managing these is an important aspect of treatment.
Migraine; Clinical Aspects
Table 4
5
Patient-reported migraine triggersa
Stress Hormones (women only) Not eating Weather Sleep disturbance Perfumedodors Neck pain Lights Alcohol Smoke Sleeping late Heat Food Exercise Sexual activity a Triggers are listed in order of frequency of patient report. Reproduced from Kelman, L., 2007. The triggers or precipitants of acute migraine attack. Cephalalgia 27, 394–402.
Menstruation and Migraine For many women, an important migraine trigger is the drop in estrogen levels that occurs just before menstruation. As a result, they have a particularly high probability of suffering a migraine attack a day or two before the onset of their menstrual period and, for some, these attacks are prolonged and difficult to treat effectively. In contrast, during pregnancy, when the natural menstrual cycle no longer occurs, many women experience a marked improvement in their migraine frequency.
Premonitory Symptoms Some migraine sufferers report premonitory symptoms before many of their attacks. These are different from aura symptoms in that they are experienced for a number of hours before the pain phase, and usually involve more nonspecific symptoms as contrasted with the focal neurological symptoms of the aura. It is unclear what proportion of those with migraine experience premonitory symptoms, but it would appear that, at least in patients referred to headache specialists, one-third or more experience them. Reported premonitory symptoms include general symptoms such as fatigue and difficulty concentrating, mood changes such as unhappiness or anxiety, and autonomic symptoms like yawning and horripilation. Symptoms that also occur during the aura and the headache phase, such as difficulty with speech, photophobia, and nausea, are also reported by some patients as premonitory symptoms and may occur for hours before the headache begins.
The Phases of the Migraine Attack A migraine attack, therefore, consists of a number of components. For some patients, the first symptoms are the premonitory symptoms. This may be followed by the aura, or the aura may be the first symptom experienced. The pain phase or headache then follows, although for patients that have neither premonitory symptoms nor an aura, the attack begins with the headache. Finally, most patients describe a postdrome of nonspecific symptoms after the headache phase before they have fully recovered and feel normal again.
Migraine and Depression and Anxiety Individuals with migraine are more likely to suffer from depression and/or anxiety disorders than those without migraine. For example, migraine sufferers are approximately twice as likely to suffer from depression as those without migraine. Some studies have shown even higher depression tendencies in people with migraine. The reason for this association between migraine and depression and anxiety is unknown, but genetically determined changes in brain serotonin systems may underlie this association.
Conclusion Migraine is an interesting, and as yet imperfectly understood, neurological disorder that is common and which significantly impacts the lives of many in our society. Although migraine may have a slightly higher prevalence in Caucasian populations, it has a global
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impact and occurs in all societies. Prevalence rates approaching 10% have been found in China and Taiwan. The degree of disability caused by migraine is often underestimated as migraine generally does not cause mortality or permanent neurological deficits. Nevertheless, as migraine is so common and often lasts the better part of a lifetime, and as many migraine sufferers find it very difficult to function productively during attacks, migraine has been ranked 19 by the World Health Organization among all causes of disability in terms of causing years lived with disability. More research is needed to understand this disorder more completely and develop better treatments.
Further Reading Andlin-Sobocki, P., Jönsson, B., Wittchen, H.U., Olesen, J., 2005. Cost of disorders of the brain in Europe. Eur. J. Neurol. 12 (Suppl. 1), 1–27. Becker, W.J., 2013. The premonitory phase of migraine and migraine management. Cephalalgia 33, 1117–1121. Goadsby, P.J., Lipton, R.B., Ferrari, M.D., 2002. Migrainedcurrent understanding and treatment. N. Engl. J. Med. 346, 257–270. Headache Classification Subcommittee of the International Headache Society, July 9, 2013. The International Classification of Headache Disorders, third ed. (beta version). Cepahalalgia 33 (9), 627–808. Kelman, L., 2007. The triggers or precipitants of the acute migraine attack. Cephalalgia 27, 394–402. Lipton, R.B., Bigal, M.E., Diamond, M., AMPP Advisory Group, et al., 2007. Migraine prevalence, disease burden, and the need for preventive therapy. Neurology 68, 343–349. Modgill, G., Jette, N., Wang, J.L., Becker, W.J., Patten, S.B., 2012. A population-based longitudinal community study of major depression and migraine. Headache 52, 422–432. Radat, F., Lantéri-Minet, M., Nachit-Ouinekh, F., et al., 2009. The GRIM2005 study of migraine consultation in France. III: psychological features of subjects with migraine. Cephalalgia 29, 338–350.
Relevant Websites http://www.achenet.org/ – American Headache Society (AHS) Committee for Headache Education. http://www.americanmigrainefoundation.org/ – The American Migraine Foundation. http://www.migrainecanada.org/ – The Canadian Headache Society (CHS).