From the Department of Neurology, Medstar Georgetown University Hospital, Washington, DC.
Abstract
- Objective: To review the epidemiology, pathophysiology, diagnosis, and treatment of migraine.
- Methods: Review of the literature.
- Results: Migraine is a common disorder associated with significant morbidity. Diagnosis of migraine is performed according to the International Classification of Headache Disorders. Comorbidities are commonly seen with migraine and include mood disorders (depression, anxiety, post-traumatic stress disorder), musculoskeletal disorders (neck pain, fibromyalgia, Ehlors-Danlos syndrome), sleep disorders, asthma, allergies, thyroid dysfunction, obesity, irritable bowel syndrome, epilepsy, stroke, and heart disease. Comorbid conditions can increase migraine disability. Management of migraine with lifestyle modifications, trigger management, and acute and preventive medications can help reduce the frequency, duration, and severity of attacks. Overuse of medications such as opiates, barbiturates, and caffeine-containing medications can increase headache frequency. Educating patients about limiting use of these medications is important.
- Conclusion: Migraine is a common neurologic disease that can be very disabling. Recognizing the condition, making an accurate diagnosis, and starting patients on migraine-specific treatments can help improve patient outcomes.
Key words: migraine; migraine without aura; migraine with aura; management of migraine.
Migraine is a common neurologic disease that affects 1 in 10 people worldwide [1]. It is 2 to 3 times more prevalent in women than in men [2]. The prevalence of migraine peaks in both sexes during the most productive years of adulthood (age 25 to 55 years) [3]. The Global Burden of Diseases, Injuries, and Risk Factors Study considers it to be the 7th most disabling disease in the world [4]. Over 36 million people in the United States have migraine [5]. However, just 56% of migraineurs have ever been diagnosed [6].
Migraine is associated with a high rate of years lived with disability [7] and the rate has been steadily increasing since 1990. At least 50% of migraine sufferers are severely disabled, many requiring bed rest, during individual migraine attacks lasting hours to days [8]. The total U.S. annual economic costs from headache disorders, including the indirect costs from lost productivity and workplace performance, has been estimated at $31 billion [9,10].
Despite the profound impact of migraine on patients and society, there are numerous barriers to migraine care. Lipton et al [11] identified 3 steps that were minimally necessary to achieve guideline-defined appropriate acute pharmacologic therapy: (1) consulting a prescribing health care professional; (2) receiving a migraine diagnosis; and (3) using migraine-specific or other appropriate acute treatments. In a study they conducted in patients with episodic migraine, 45.5% had consulted health care professional for headache in the preceding year; of these, 86.7% reported receiving a medical diagnosis of migraine, and among the diagnosed consulters, 66.7% currently used acute migraine-specific treatments, resulting in only 26.3% individuals successfully completing all 3 steps. In the recent CaMEO study [12], the proportion patients with chronic migraine that overcame all 3 barriers was less than 5%.
The stigma of migraine often makes it difficult for people to discuss symptoms with their health care providers and family members [13]. When they do discuss their headaches with their provider, often they are not given a diagnosis [14] or do not understand what their diagnosis means [15]. It is important for health care providers to be vigilant about the diagnosis of migraine, discuss treatment goals and strategies, and prescribe appropriate migraine treatment. Migraine is often comorbid with a number of medical, neurological, and psychiatric conditions, and identifying and managing comorbidities is necessary to reduce headache burden and disability. In this article, we provide a review of the diagnosis and treatment of migraine, using a case illustration to highlight key points.
Case Study
Initial Presentation
A 24-year-old woman presents for an evaluation of her headaches.
History and Physical Examination
She initially noted headaches at age 19, which were not memorable and did not cause disability. Her current headaches are a severe throbbing pain over her right forehead. They are associated with light and sound sensitivity and stomach upset. Headaches last 6 to 7 hours without medications and occur 4 to 8 days per month.
She denies vomiting and autonomic symptoms such as runny nose or eye tearing. She also denies preceding aura. She reports headache relief with intake of tablets that contain acetaminophen/aspirin/caffeine and states that she takes between 4 to 15 tablets/month depending on headache frequency. She reports having tried acetaminophen and naproxen with no significant benefit. Aggravating factors include bright lights, strong smells, and soy/ high-sodium foods.
She had no significant past medical problems and denied a history of depression or anxiety. Family history was significant for both her father and sister having a history of headaches. The patient lived alone and denied any major life stressors. She exercises 2 times a week and denies smoking or alcohol use. Review of systems was positive for trouble sleeping, which she described as difficulty falling asleep.
On physical examination, vitals were within normal limits. BMI was 23. Chest, cardiac, abdomen, and general physical examination were all within normal limits. Neurological examination revealed no evidence of papilledema or focal neurological deficits.
What is the pathophysiology of migraine?
Migraine was thought to be a primary vascular disorder of the brain, with the origins of the vascular theory of migraine dating back to 1684 [16]. Trials performed by Wolff concluded that migraine is of vascular origin [17], and this remained the predominant theory over several decades. Current evidence suggests that migraine is unlikely to be a pure vascular disorder and instead may be related to changes in the central or peripheral nervous system [18,19].
Migraine is complex brain network disorder with a strong genetic basis [19]. The trigemino-vascular system, along with neurogenically induced inflammation of the dura mater, mast cell degranulation and release of histamine, are the likely causes of migraine pain. Trigeminal fibers arise from neurons in the trigeminal ganglion that contain substance P and calcitonin gene-related peptide (CGRP) [20]. CGRP is a neuropeptide widely expressed in both peripheral and central neurons. Elevation of CGRP in migraine is linked to diminution of the inhibitory pathways which in turn leads to migraine susceptibility [21]. These findings have led to the development of new drugs that target the CGRP pathway.
In the brainstem, periaqueductal grey matter and the dorsolateral pons have been found to be “migraine generators,” or the driver of changes of cortical activity during migraine [22]. Brainstem nuclei are involved in modulating trigemino-vascular pain transmission and autonomic responses in migraine [23].
The hypothalamus has also been implicated in migraine pathogenesis, particularly its role in nociceptive and autonomic modulation in migraine patients. Schulte and May hypothesized that there is a network change between the hypothalamus and the areas of the brainstem generator leading to the migraine attacks [24].
The thalamus plays a central role for the processing and integration of pain stimuli from the dura mater and cutaneous regions. It maintains complex connections with the somatosensory, motor, visual, auditory, olfactory and limbic regions [25]. The structural and functional alterations in the system play a role in the development of migraine attacks, and also in the sensory hypersensitivity to visual stimuli and mechanical allodynia [26].
Experimental studies in rats show that cortical spreading depression can trigger neurogenic meningeal inflammation and subsequently activate the trigemino-vascular system [27]. It has been observed that between migraine episodes a time-dependent amplitude increase of scalp-evoked potentials to repeated stereotyped stimuli, such as visual, auditory, and somaticstimuli, occurs. This phenomenon is described as “deficient habituation.” In episodic migraine, studies show 2 characteristic changes: a deficient habituation between attacks and sensitization during the attack [28]. Genetic studies have hypothesized an involvement of glutamatergic neurotransmitters and synaptic dysplasticity in causing abnormal cortical excitability in migraine [27].