Migraine, one of the most common human diseases, is a brain disorder that is characterized by attacks of throbbing often unilateral headache that can be accompanied by neurological symptoms such as nausea and vomiting, as well as hypersensitivity to light and sound . There are two main types of migraines: migraine with aura and migraine without aura.
Migraine affects nearly 10 % of people in the world . In the United States about 18 % of women and 6 % of men suffer from migraine yearly with a corresponding lifetime prevalence of 43 % and 18 % respectively. According to Europe declarement 12-28 % of people at some time in their lives suffer from migraine which rises during adolescence and falls in the early 50s. According to studies, the range of one-year prevalence of migraine is 14-35 % in adult women and 6-15 % in adult men (Figure 1.). Beside specific differences between genders, the life time prevalence also significantly differs with age; about 5 of children under 12 suffer from migraine, with nearly no difference between girls and boys.
Classification and diagnosis criteria for migraine were established by the International Headache Society (IHS). Its International Classification of Headache Disorders, 3rd edition (ICHD-3), clarified a basis to make the nomenclature for different types of headache and migraine standardized; it provides a well explanation of symptoms for each type of migraine. The categorization distinguishes six subclasses of migraine .
The primary headaches
1.1. Migraine without aura (MO)
1.2. Migraine with aura (MA)
1.2.1. Migraine with typical aura
18.104.22.168. Typical aura with headache
22.214.171.124. Typical aura without headache
1.2.2. Migraine with brainstem aura
1.2.3. Hemiplegic migraine
126.96.36.199.Familial hemiplegic migraine (FHM)
188.8.131.52.1. Familial hemiplegic migraine type 1 (FHM1)
184.108.40.206.2. Familial hemiplegic migraine type 2 (FHM2)
220.127.116.11.3. Familial hemiplegic migraine type 3 (FHM3)
18.104.22.168.4. Familial hemiplegic migraine, other loci
22.214.171.124. Sporadic hemiplegic migraine
1.2.4. Retinal migraine
1.3. Chronic migraine
1.4. Complications of migraine
1.5. Probable migraine
1.6. Episodic syndromes that may be associated with migraine
Migraine with and without aura, are the most common types that themselves are divided into various subtypes. Their characteristics are described below.
Migraine without aura
Migraine without aura is a recurrent headache disorder manifesting in attacks lasting 4–72 hours. Typical characteristics of this kind of headache are pulsating quality, unilateral location, moderate or severe intensity, getting aggravated by ordinary physical activity and association with nausea and/or phonophobia and photophobia.
A. At least five attacks, fulfilling criteria B–D
B. Headache attacks lasting 4–72 hours (when untreated or unsuccessfully treated)
C. Headache has at least two of the following four characteristics:
1. Unilateral location
2. Pulsating quality
3. Moderate or severe pain intensity
4. Aggravation by or causing avoidance of routine physical activity (e.g. walking or climbing stairs)
D. During headache at least one of the following:
1. Nausea and/or vomiting
2. Photophobia and phonophobia
E. Not better accounted for by another ICHD-3 diagnosis.
Migraine attacks may also be associated with cranial autonomic symptoms and cutaneous allodynia symptoms. In young children, phonophobia and photophobia may be inferred from their behavior. A minority of women (<10%) have migraine attacks in association with the majority of their menstrual cycles; most of them are without aura. Attacks during menstruation are usually longer and accompanied by more severe nausea than attacks outside the menstrual cycle.
Migraine with Aura
Migraine with aura is described as recurrent attacks, which last minutes, of unilateral reversible sensory, visual or other symptoms of central nervous system that usually develop gradually and are followed by headache and associated migraine symptoms.
A. At least two attacks fulfilling criteria B and C
B. One or more of the following fully reversible aura symptoms:
3. Speech and/or language
C. At least three of the following six characteristics:
1. At least one aura symptom spreads gradually over ≥ 5 minutes
2. Two or more aura symptoms occur in succession
3. Each individual aura symptom lasts 5–60 minutes
4. At least one aura symptom is unilateral
5. At least one aura symptom is positive
6. The aura is accompanied, or followed within 60 minutes, by headache D. Not better accounted for by another ICHD-3 diagnosis
Familial and Sporadic Hemiplegic Migraine
IHCD-3 classified the hemiplegic types of migraine as subtypes of migraine with aura. The symptoms are similar to MA, but with preceding or associating hemiplegic symptoms, such as sensory disturbances and motor weakness during the aura. The IHS classifies cases of hemiplegic migraine without any affected relatives as sporadic, whereas the cases with at least one affected person as a first or second degree relative are called familial hemiplegic migraine (FHM).
Therefore, familial hemiplegic migraine has a very strong genetic component; in fact, it is the only type of migraine which inheritates in an autosomal dominant mode. Because of its monogenic appearance, FHM is of special interest for migraine studies. The affected neuronal ion channels give us a considerable knowledge of mechanisms in migraine.
The economic importance of migraine is related to its great prevalence. According to the World Health Organization, migraine is among the three disorders with the highest prevalence (43). Prevalence rates of migraine, as mentioned earlier, is different with age and gender, but irrespective of all these variabilities, migraine is to be seen a common disease affecting much people at some points in their lives. However, not each prevalent disease has such a great economic influence, in reverse, very rare diseases put high costs on patients. Various categories of costs have to be taken into consideration when considering the economic effect of disease:
- costs for the individual
- costs for medical care
- costs for the economy of the country
The costs to the individual mainly is because of spending on OTC drugs (basically NSAIDs) and deductibles on prescribed drugs. For migrainers, these costs should be bearable, because especially NSAIDs are mostly accessible as generic drugs. Nevertheles, the considerable costs of migraine are because of the medical care system and economy detraction. The smaller portion of these socio-economic costs is the result of the hospitalization, health care provider visits, medication. Researches evaluate the economic impact of migraine as an annual total direct costs of 696 € per patient with episodic migraine (about 15 days of headache per month) in Germany. Figures for other countries such as Italy, UK, Spain and France is in a comparable range.
Migraine can impair patients’ ability to do their job properly, it can force affected persons to go home earlier or even become absent from work. Absence from workplace due to migraine may extend from few days to several weeks or even a month in each year. A British research reports the average of 5.7 working days which are lost per year for every student or working migraineur. In another study, the indirect financial impact of migraine on US employers was evaluated to be nearly $12 billion per year (mainly as a result of absenteeism).