Pathophysiology,epidemiology, and impact of migraine

Despite a decade of progress, migraine headache remains prevalent, disabling, underdiagnosed, and undertreated in the United States. Migraine affects ∼12% of the population, and the economic burden in terms of annual cost of labor lost to migraine disability is between $5.6 and $17.2 billion. The threshold for migraine may be genetically determined, although recent genetic and neurophysiologic studies point to migraine as possibly a channelopathy. Cerebral cortical and brain stem changes occur in migraine. Head pain and associated symptoms of migraine can be explained by activation of the trigeminal vascular system. Evidence has also been accumulated that suggests the release of nitric oxide is an important trigger mechanism. Introduction of the triptans has dramatically advanced acute migraine pharmacotherapy, and preventive therapy has greatly improved; however, public health initiatives may be needed to further advance diagnosis and treatment of this common and disabling disorder.     

Pathophysiology of migraine headache

The underlying mechanism of migraine and pain has been unraveled recently with the advent of neuroimaging. In this article mechanism of migraine aura and the pain of migraine are discussed. In addition, interictal studies demonstrating hyperexcitability in migraine are reviewed.     

Pathophysiology of migraine and cluster headaches

There have been remarkable advances in the last decade in unraveling the mystery of primary headache disorders such as migraine and cluster. The vascular theory has been superseded by the neurovascular phenomenon, which seems to be the permissive triggering factor in migraine and cluster headache. This has been achieved through new imaging modalities such as positron imaging tomography (PET) and functional magnetic resonance imaging (fMRI). Prior to these imaging techniques, it was not possible to study the primary headache disorders because there was no structural basis. There is now an increasing body of evidence that the brain is primarily involved in cluster and migraine and that vessel dilation is an epiphenomenon.     

Pathophysiology of migraine and clinical implications

Migraine pathophysiology is determined by genetic and environmental factors. Based on altered cerebral habituation and low serotonin levels, certain triggers can elicit a migraine attack. Following initial unspecific prodromi, an aura follows in many patients which most often consists of visual symptoms. Cortical spreading depression is the electrophysiological correlate of the aura and can activate the trigemino-vascular system. This is one potential mechanism initiating the pain process. The characteristic unilateral pulsating headache is caused by a neurogenic inflammation in the meninges. Neck pain as reported by some patients is a migraine-specific feature, the anatomical basis being the trigemino-cervical complex. Functional changes in the pain processing system maintain the headache. Among these are sensitization of trigeminal nucleus caudalis neurons and an altered antinociception descending from the periaquaductal grey. Triptans have a peripheral and central mode of action, but they are no longer effective once central sensitization has occurred.     

Hungarian migraine epidemiology

OBJECTIVE: A population-based epidemiological survey of migraine without aura and migraine with aura completed by mailed questionnaire in Hungary. The diagnosis and classification of migraine was according to the criteria of the International Headache Society. METHODS: The validity of the self-administered headache questionnaire was evaluated by a neurologist using clinical interviews. The study population was a random sample of 2000 men and women aged between 15 and 80 years. The questionnaire was completed by 813 of 1910 people (392 men and 421 women), providing a 42.6% participation rate. RESULTS: Sixty-seven percent of these people experienced some kind of headache during their lives. The 1-year prevalence of migraine without aura was 7.6% (the female/male ratio was 3:1), while the 1-year prevalence of migraine with aura was 2% (female/male ratio was 2:1). Most migraineurs experienced headache attacks 1 to 4 times monthly, which lasted 24 hours. The most characteristic accompanying signs were nausea and phonophobia. Stress, sleep deprivation, hot weather, and fasting were the most common precipitating factors of a migraine attack. In the migraine with aura group, the most common aura was a visual disturbance. Only 43% of migraineurs had ever consulted a physician for headache, and only 15% of patients had missed work or school because of a migraine attack in the previous year. Most of the patients suffering from migraine without aura were between 20 and 40 years old, while migraineurs with aura were over 40 years old. According to this investigation, the prevalence of migraine was not lower than in Western countries.     

Gallstone disease. Pathophysiology, epidemiology, natural history, and treatment options.

In 1991, only symptomatic gallstones should be treated. The treatment of choice for all gallstones continues to be surgical removal. Except for stones in the common bile duct, which are amenable to removal by endoscopic papillotomy, nonsurgical treatment of gallstones should be investigated further before it can have widespread applicability. The major challenge in the future may be medical prevention of gallstone formation in susceptible individuals. Laparoscopic cholecystectomy seems to have moved to the forefront of surgical therapy in patients who are candidates for the procedure.     

Diagnosis,epidemiology, and impact of tension-type headache

Although tension-type headache is the most prevalent headache and affects 78% of the general population, the substantial societal and individual burden associated with this primary headache has been overlooked. In contrast to migraine headache, there has been limited focus on tensiontype headache. Most patients with the chronic form of tension-type headache, which affects 3% of the population, are left virtually without any specific treatment. Chronic tensiontype headache differs from the episodic form in frequency, lack of effect to most treatment strategies, more medication overuse, and more loss of quality of life. Daily or near daily headaches also constitute a major diagnostic and therapeutic problem and distinguishing chronic tension-type headache from migraine headache and from medication-induced headache is a substantial diagnostic challenge because management strategies are completely different. Considerable benefits for the society can be gained by specific strategies leading to reductions in the amount of sickness absence and impaired working abilities. The burden on the affected patients’ and their families’ quality of life also may be improved by a general acceptance of the disorder and by the development of a specific treatment strategy.     

Childhood abuse and migraine: epidemiology, sex differences, and potential mechanisms

Migraine and maltreatment are both common conditions that are more prevalent in women. Epidemiological evidence supports an association between childhood abuse and headache, as well as pain in general, although some controversy exists based on methodological concerns of studying the influence of remote, traumatic, stigmatizing events in an often depressed population. There is a growing scientific body of knowledge regarding the neurobiological effects of abuse on brain function and structure that suggest a possible role of early life stress in the pathogenesis of migraine, and a differential impact based on sex. Advances in our understanding of the basic mechanisms by which an adverse environment interacts with and changes the genome, may suggest new treatment strategies.     

Post-traumatic stress disorder and migraine: epidemiology, sex differences, and potential mechanisms

Migraine is a common, often disabling disorder associated with a significant personal and societal burden. The presence of post-traumatic stress disorder (PTSD) may increase this disability substantially. Migraine and PTSD are both up to 3 times more common in women than in men. The divergence in prevalence rates of migraine and PTSD that occurs between the sexes after puberty suggests that gonadal hormones play an important role. In addition, the preponderance of PTSD in women may be related to their higher rates of interpersonal trauma, the most common cause of PTSD. However, recent data suggest that although the odds of PTSD are increased in both women and men with episodic migraine, this association is stronger in men than women. In this paper, we examine the epidemiology of PTSD and migraine, with an emphasis on the known sex differences. We then discuss the neurobiological changes associated with PTSD, the current hypotheses for the mechanisms relating PTSD and migraine, and the treatment implications of these findings.     

Economic and social impact of migraine

We sent an anonymous self-administered questionnaire to 4200 employees of a Trust hospital, 1903 of whom returned it. We identified 158 migraine sufferers according to International Headache Society (IHS) criteria. These sufferers estimated 2.0 days/year absence from work, and an equivalent of 5.5 days/year lost by reduced effectiveness at work, caused by their migraine at an estimated financial cost of over 50,000 pounds to the Trust. An additional 220 individuals who had received a diagnosis of migraine from a doctor but fulfilled only 3/4 IHS criteria lost the equivalent of 6.7 days off work at a further cost of 63,000 pounds). Few patients had consulted their general practitioner about their migraines in the last 3 months. Most (78%) were using only over-the-counter medication. Migraine patients should be encouraged to seek medical attention.      

Overview on the prevalence and impact of migraine

Migraine is a highly prevalent headache disorder that has a substantial impact on the individual and society. Over the past decade, substantial advances in research have increased understanding of the pathophysiology, diagnosis, epidemiology, and treatment of the disorder. This article reviews the burden of migraine, emphasizing the population-based studies that used standardized diagnostic criteria.     

Body mass index, migraine, migraine frequency and migraine features in women

We evaluated the association of body mass index (BMI) with migraine and migraine specifics in a cross-sectional study of 63 467 women aged ≥ 45 years, of whom 12 613 (19.9%) reported any history of migraine and 9195 had active migraine. Compared with women without migraine and a BMI < 23 kg/m², women with a BMI ≥ 35 kg/m² had adjusted odds ratios (ORs) (95% confidence intervals) of 1.03 (0.95, 1.12) for any history of migraine. Findings were similar for active migraineurs. Women with a BMI of ≥ 35 kg/m² had increased risk for low and high migraine frequency, with the highest estimate for women who reported daily migraine. Compared with women with the lowest associated risk (migraine frequency < 6 times/year; BMI between 27.0 and 29.9 kg/m²), women with a BMI ≥ 35 kg/m² had an OR of daily migraine of 3.11 (1.12, 8.67). Among the women with active migraine, a BMI ≥ 35 kg/m² was associated with increased risk of phonophobia and photophobia and decreased risk of a unilateral pain characteristic and migraine aura. Our data confirm previous findings that the association between BMI with migraine is limited to migraine frequency and specific migraine features.     

The epidemiology of migraine: a retrospective study in Italian emergency departments

This study was conducted to measure the frequency of contact with emergency departments in Italy because of migraine, and to compare the initial diagnosi s of headache with the diagnosis after application of the International Headache Society (IHS) criteria. A retrospective observational method was used, consisting of an analysis of the records of patients admitted to nine Italian emergency departments during different 4-month periods in 1994. Comparison of the initial diagnosis with the diagnosis after application of the IHS diagnostic criteria was performed. More than 31 million emergency department contacts were reported in Italy during 1994. In the same year, 543 630 patients visited the nine emergency departments enrolled in the study, with 169 569 of these contacts occurring in the 4-month period analyzed in the study. We excluded from the analysis all cases of secondary headache fully recognized at the emergency department admission (ie, traumas, intracranial pathology, systemic diseases). The total number of patients included in our analysis was 1043 (0.6%). The 934 patients who could be fully evaluated were initially classified as having migraine; cluster headache; headache not otherwise specified; or diagnosed in the emergency department as suffering from headache, but reclassified by other departments as suffering from a different disease. After retrospective application of the IHS classification, the diagnostic distribution was modified, revealing that 18% of patients with migraine and 5% with cluster headaches had previously been classified as having headache not otherwise specified; a further 6% of cases with migraine and 0.4% of patients with cluster headache had previously been classified as having secondary headaches. The diagnosis of headache not otherwise specified was made with notable frequency, indicating the limits of emergency department logs and the difficulty in carrying out a retrospective analysis and reassessment of diagnosis. The majority (88%) of patients assessed had not taken drugs for headache in the 48 hours before the emergency department contact, suggesting that in Italy emergency departments are used instead of a visit to the general practitioner. Nonsteroidal anti-inflammatory drugs were the most frequently prescribed drugs in the emergency departments for this group of diagnoses. The research revealed, on the one hand, that headache is a numerically significant phenomenon in the emergency department setting and, on the other, the need to apply prospective designs to this kind of survey.