Genetic epidemiology of migraine and cluster headache

Neurological and Systemic Pitfalls in the Diagnosis of Cluster Headaches: A Case-Based Review

PURPOSE OF REVIEW

To describe different pitfalls in the diagnosis of primary cluster headaches (CHs) with the guidance of seven case vignettes.

RECENT FINDINGS

The question of whether primary CHs and migraines are totally different entities has been long debated. Autonomic features can be detected in as many as 60% of migraine patients. Although some genetic similarities have been found, CACNA1A mutations have not been detected among CH patients with hemimotor aura in contrast to hemiplegic migraine. Recently, functional MRI studies have shown that the left thalamic network was the most discriminative MRI feature in distinguishing migraine from CH patients. Compared to migraine, CH patients showed decreased functional interaction between the left thalamus and cortical areas mediating interception and sensory integration. However, clinically the most significant feature had been the restlessness and agitation seen during headache attacks patients with CHs. This feature is also important in distinguishing cluster patients from other patients having other trigeminal autonomic cephalalgias except for a subset of patients with hemicrania continua. CH is an important member of the group of headache disorders characterized by their association with one or more autonomic features in the trigeminal nerve distribution and termed Trigeminal Autonomic Cephalalgias (TACs). Although CH is a relatively rare condition, judged by the distress it generally causes to the affected individual, early diagnosis and institution of appropriate therapy seem mandatory. Correct diagnosis of CHs needs avoidance of pitfalls. Such pitfalls generally include differentiation from migraine, differentiation from other side locked headache disorders, from other trigeminal autonomic cephalalgias (TACs), and lastly, recognition of rare presentations of cluster-like manifestations with hemiplegic aura and simulating trigeminal and glossopharyngeal neuralgias. Differentiation between primary and symptomatic CHs related to sellar pathologies and systemic medical conditions is of equal importance. In the present review such issues are discussed with the assistance of seven case vignettes.

Debate: Are cluster headache and migraine distinct headache disorders?

Cluster headache and migraine are regarded as distinct primary headaches. While cluster headache and migraine differ in multiple aspects such as gender-related and headache specific features (e.g., attack duration and frequency), both show clinical similarities in trigger factors (e.g., alcohol) and treatment response (e.g., triptans). Here, we review the similarities and differences in anatomy and pathophysiology that underlie cluster headache and migraine, discuss whether cluster headache and migraine should indeed be considered as two distinct primary headaches, and propose recommendations for future studies. Video recording of the debate held at the 1st International Conference on Advances in Migraine Sciences (ICAMS 2022, Copenhagen, Denmark) is available at https://www.youtube.com/watch?v=uUimmnDVTTE .

Phenotype of Cluster Headache: Clinical Variability, Persisting Pain Between Attacks, and Comorbidities-An Observational Cohort Study in 825 Patients

INTRODUCTION

Cluster headaches can occur with considerable clinical variability. The inter- and intra-individual variability could contribute to the fact that the clinical headache phenotype is not captured by too strict diagnostic criteria, and that the diagnosis and the effective therapy are thereby delayed. The aim of the study was to analyze the severity and extent of the clinical symptoms of episodic and chronic cluster headaches with regard to their variability and to compare them with the requirements of the International Classification of Headache Disorders 3rd edition (ICHD-3) diagnostic criteria.

METHODS

The study was carried out as a cross-sectional analysis of 825 patients who had been diagnosed with cluster headaches by their physician. Using an online questionnaire, standardized questions on sociodemographic variables, clinical features of the cluster headache according to ICHD-3, and accompanying clinical symptoms were recorded.

RESULTS

The majority of patients with cluster headaches have clinical features that are mapped by the diagnostic criteria of ICHD-3. However, due to the variability of the symptoms, there is a significant proportion of clinical phenotypes that are not captured by the ICHD-3 criteria for cluster headaches. In addition, change in the side of the pain between the cluster episodes, pain location, as well as persisting pain between the attacks is not addressed in the ICHD-3 criteria. In the foreground of the comorbidities are psychological consequences in the form of depression, sleep disorders, and anxiety.

CONCLUSIONS

The variability of the phenotype of cluster headaches can preclude some patients from receiving an appropriate diagnosis and effective therapy if the diagnostic criteria applied are too strict. The occurrence of persisting pain between attacks should also be diagnostically evaluated due to its high prevalence and severity as well as psychological strain. When treating patients with cluster headaches, accompanying psychological illnesses should carefully be taken into account.

Family History of Cluster Headache: A Systematic Review

Importance

Genetic and environmental factors are thought to contribute to cluster headache, and cluster headache can affect multiple members of a family. A thorough understanding of its inheritance is critical to understanding the pathogenesis of this debilitating disease.

Objective

To systematically review family history rates and inheritance patterns of cluster headache.

Evidence Review

A systematic review was performed in PubMed, Embase, and Cochrane Library. Search criteria were created by a librarian. Articles published between 1985 and 2016, after the publication date of a large review in 1985, were analyzed independently by 2 neurologists to identify family history rates and pedigrees. Pedigrees were analyzed by a genetic counselor.

Findings

A total of 1995 studies were found (1988 through the search criteria and 7 through other means). Forty articles met inclusion criteria: 22 large cohort studies, 1 twin-based study, and 17 case reports or small case series. Across the 22 large cohort studies, the positive family history rate of cluster headache varied between 0% and 22%, with a median of 8.2%. The largest 5 studies, of 1134, 785, 693, 609, and 500 probands each, had a positive family history in 18.0% (numerator not provided), 5.1% (40 of 785 cases), 10.0% (numerator not provided), 2.0% (12 of 609 cases), and 11.2% (56 of 500 cases), respectively. No meta-analysis was performed, given differences in methodologies. Separately, 1 twin-based study examined 37 twin pairs and reported a concordance rate of 5.4% (2 pairs). Finally, 67 pedigrees were identified. Most pedigrees (46 of 67 [69%]) were consistent with an autosomal dominant pattern, but 19 of 67 (28%) were consistent with an autosomal recessive inheritance pattern; 10 pedigrees of probable or atypical cluster headache were identified, and all were consistent with an autosomal dominant inheritance pattern. The sex ratio for cluster headache in identified pedigrees was 1.39 (103:74) in affected men and boys compared with affected women and girls, which is lower than that of the general cluster headache population.

Conclusions and Relevance

Cluster headache is an inherited disorder in a subset of families and is associated with multiple hereditary patterns. There is an unexpectedly high preponderance of women and girls with familial cluster headache; genetic subanalyses limited to female participants are necessary to further explore this observation, because these data are otherwise masked by the higher numbers of male participants with cluster headache. Overall, this systematic review supports the notion that familial cluster headache is likely the result of multiple susceptibility genes as well as environmental factors.

An Update: Pathophysiology of Migraine

Migraine is the most common disabling primary headache globally. Attacks typically present with unilateral throbbing headache and associated symptoms including, nausea, multisensory hypersensitivity, and marked fatigue. In this article, the authors address the underlying neuroanatomical basis for migraine-related headache, associated symptomatology, and discuss key clinical and preclinical findings that indicate that migraine likely results from dysfunctional homeostatic mechanisms. Whereby, abnormal central nervous system responses to extrinsic and intrinsic cues may lead to increased attack susceptibility.

Familial Cluster Headache. Is Atypical Cluster Headache in Family Members Part of the Clinical Spectrum?

Familial cluster headache (CH) was analysed in 21 Swedish families. Diagnosis was made according to The International Classification of Headache Disorders 2004. We identified 55 affected, of whom 42 had episodic or chronic CH, one had probable CH and 12 had atypical symptoms. The atypical cases did not fulfil the diagnostic criteria for CH, but had clinical symptoms with more resemblance to CH than to migraine or other trigeminal autonomic cephalgia syndromes. The overall male : female ratio was 1.8 : 1. The overall mean age at onset was significantly lower in the second/third generation than in the first generation (mean age at onset 22 vs. 31 years, SD ± 7 vs. 13 years; P < 0.01). This may be anticipation or selection bias, since individuals with late age at onset from the second/third generation may not yet have symptoms. The prevalence of migraine was 24% (13/55), i.e. similar to the prevalence in the general population. The high incidence of atypical CH cases in the Swedish families with other members affected with CH may suggest that the spectrum of CH is broader than previously thought. We suggest that atypical CH in CH families may represent an expanded spectrum of the disease with a common aetiology, i.e. a common genetic background.

The Frequent Unusual Headache Syndromes: A Proposed Classification Based on Lifetime Prevalence

BACKGROUND

There is no agreement on a single cutoff point or prevalence for regarding a given disease as rare. The concept of what is a rare headache disorder is even less clear and the spectrum from a very frequent, frequent, occasional to rare headache syndrome is yet to be established.

OBJECTIVE

An attempt has been made to estimate the lifetime prevalence of each of the headache subtypes classified in the ICHD-II.

METHOD

Using the ICHD-II, 199 different headache subtypes were identified. The following classification was made according to the estimated lifetime prevalence of each headache disorder: very frequent (prevalence >10%); frequent (between 1 and 10%); occasional (between 0.07 and 1%); and unusual or rare (<0.07%).

RESULTS

One hundred and fifty-four of 199 (77%) were categorized as unusual headache disorders, 7/199 (4%) as very frequent, 9/199 (5%) as frequent, and 29/199 (15%) as occasional forms of headache disorder.

CONCLUSION

The unusual headache syndromes do not appear to be as infrequent in clinical practice as has been generally believed. About three-fourths of the classified headache disorders found in the ICHD-II can be considered as rare. This narrative review article may be regarded as an introduction to the concept of unusual headaches and a proposed classification of all headaches (at least those listed in the ICHD-II).

Role of Methadone in Induction and/or Exacerbation of Cluster Headache in Patients Treated for Opioid Addiction

Methadone is a potent opioid agonist widely used in opioid maintenance therapy. In some countries, methadone is available for pain treatment. We report the cases of two patients with history of substance abuse (mainly heroin), who presented with cluster headache possibly related to high-dose methadone. One possible explanation for the severe pain described in these cases is hyperalgesia induced by high doses of methadone.

Genetic and Environmental Influences on Expression of Recurrent Headache as a Function of the Reporting Age in Twins

To explore age-related mechanisms in the expression of recurrent headache, we evaluated whether genetic and environmental influences are a function of the reporting age using questionnaire information that was gathered in 1973 for 15- to 47-year-old Swedish twins (n =12,606 twin pairs). Liability to mixed headache (mild migraine and tension-type headache) was explained by non-additive genetic influences (49%) in men aged from 15 to 30 years and additive genetic plus shared environmental influences (28%) in men aged from 31 to 47 years. In women, the explained proportion of variance, which was mainly due to additive genetic effects, ranged from 61% in adolescent twins to 12% in twins aged from 41 to 47 years, whereas individual specific environmental variance was significantly lower in twins aged from 15 to 20 years than in twins aged from 21 to 30 years. Liability to migrainous headache (more severe migraine) was explained by non-addi-tive genetic influences in men, 32% in young men and 45% in old men, while total phenotypic variance was significantly lower in young men than in old men. In women, the explained proportion of variance ranged from 91% in the youngest age group to 37% in the oldest age group, with major contributions from non-additive effects in young and old women (15–20 years and 41–47 years, respectively) and additive genetic effects in intermediate age groups (21–40 years). While total variance showed a positive age trend, genetic variance tended to be stable across age groups, whereas individual specific environmental variance was significantly lower in adolescent women as compared to older women.

Genetics of menstrual migraine: the epidemiological evidence

Approximately one of every three to five women with migraine without aura experience migraine attacks in relation to menstruation. The International Classification of Headache Disorders, 2nd Edition provides appendix diagnoses for pure and menstrually related migraine without aura that need further validation. Probands with menstrual migraine might have more affected relatives than probands with nonmenstrual migraine. However, precise epidemiological, family, and twin data still are lacking.

Biological correlates of migraine and cluster headaches: an overview of their potential use in diagnosis and treatment

Current diagnostic criteria for headaches are based on the International Classification for Headache Disorders, second edition, which is largely built on data obtained from clinical examinations and patients' medical histories. Despite decades of vigorous basic and clinical research, we still lack reliable clinical laboratory diagnostic markers for headaches, which clearly obstructs the physician's ability to optimize and follow the patient's response to treatment protocols as well as holds back the discovery and implementation of new therapeutic modalities. In this paper, we review and discuss current efforts to identify and characterize biochemical and immunological changes in biological fluids and tissue that may be specifically associated with the etiology and/or pathophysiology of migraine and cluster headaches; we also discuss some of the recent genetic findings and ion channel modulation studies that may help to distinguish among various headache populations.

Current and emerging treatment options for migraine and other primary headache disorders

Primary headache disorders are highly prevalent worldwide. The impact of primary headaches to the individual is significant and reflects physical suffering and decreased social and occupational functioning. The economic burden to society is enormous and represents direct healthcare costs and the indirect costs associated with decreased workplace productivity and work absences. The last decade has witnessed tremendous advances both in our understanding of the biology of headache and in our therapeutic armamentarium. This review outlines how these developments may be rationally implemented by highlighting individual treatment options and general treatment strategies. The state-of-the-art methods for the abortive and prophylactic treatment of tension-type headache, migraine and cluster headache are reviewed.

Management of headache patients

Headache is a very common complaint, in both primary care and in specialist settings. Headache patients account for around 20% of all outpatients seen in neurological practices and their management, particularly when they present with intractable headache, or are suspected of having secondary headaches, can be a challenge for the clinician. All the guidelines agree that the diagnosis of headache is merely clinical and that testing is not recommended if the individual is not significantly more likely than anyone else in the general population to have a significant abnormality. A full history of the temporal profile of the headache should be gathered first: when it first started, the circumstances of its onset, whether it has remained the same over time, and, if not, in what way it has changed. The patient should be questioned carefully about the specific characteristics of the attacks (frequency, duration, severity of the pain, efficacy of the treatments). It is also necessary to establish whether there is a history of other diseases and to investigate gynecological and psychological history, and family history. History alone allows a diagnosis of probable primary headache. Signs of a possible secondary headache must be carefully sought in all patients, even in apparently clear-cut cases. The guidelines recommend careful investigation of new headaches or those whose features have recently changed in order to exclude secondary headache. Once a secondary headache has been reasonably ruled out, it can help the patient to investigate possible comorbid pathologies and suggest appropriate lifestyle changes.

Cluster headache in children--experience from a specialist headache clinic

BACKGROUND

Cluster headache is a primary headache disorder with the distinct clinical features: unilaterality, extreme pain, cranial autonomic features and periodicity. The prevalence of the disorder is 0.1% in adults and with a male predominance. The age of onset is usually in the second and third decade of life but the onset in the first decade is recognised. We describe our experience of cluster headache in children and review the literature. We have attempted to define the clinical features of cluster headache in children as compared to adults, the role of clinical investigations, reliability of clinical diagnosis, effective treatment and management options.

METHODS

A retrospective casenotes review was conducted on all children with suspected cluster headache seen in our centre from 2000 to 2005. Case ascertainment was conducted using International Headache Society guidelines, and by telephone interviews with the parents.

RESULTS

Eleven children were identified, (seven male and four female). The median age of onset was 8.5 years (range 2-14). The median age at diagnosis was 11.5 years (range 7-17). Eight children had episodic and 3 children had chronic cluster headaches. The average attack duration was 72 min. The commonest reported bout frequency was one per day. Several children had circadian and circumannual periodicity and most displayed the other features of the disorder, such as agitated movement and cranial autonomic activation. Oxygen, methysergide, verapamil, zolmitriptan and dihydroergotamine were the drugs which were effective in terminating the headache. Paracetamol, ibuprofen and paracetamol/codeine combinations were not.

CONCLUSION

We describe our experience with cluster headache in eleven children who all presented before the age of 16.

Psychiatric disorders and headache familial recurrence: a study on 200 children and their parents

The main aim of the study was to examine the relationship between headache and familial recurrence of psychiatric disorders in parents and their children. Headache history and symptomatology have been collected in a clinical sample of 200 patients and their families, using a semi-structured interview (ICHD-II criteria). Psychiatric comorbidity was assessed by DSM-IV criteria. Chi squares and a loglinear analysis were computed in order to evaluate the main effects and interactions between the following factors: frequency and headache subtypes (migraine/not-migraine) in children, headache (migraine/not-migraine-absent/present) in parents, headache (absent/present) in grandparents, and psychiatric comorbidity (absent/present) have been analyzed: 94 mothers (47%) and 51 fathers (25.5%) had at least one psychiatric disorder, mainly mood and anxiety disorders. Considering the significant prevalence of Psi-co in children (P < 0.0001), we compared it with the presence of familiarity to headache: a significant interaction has been found (P < 0.05) showing that migraineurs with high familial recurrence of headache had a higher percentage (74.65%) of psychiatric disorders, than no-migraineurs (52.17%). Absence of headache familial loading seems to be related to psi-co only in no-migraine headache (87.5 vs. 45.5%). The occurrence of psychiatric disorders is high in children with headache, but a very different pattern seems to characterize migraine (familial co-transmission of migraine and Psi-Co?) if compared with non-migraine headache.

Migraine as a cause of persistent nausea or vomiting in palliative care: a case series

Migraine is common, underdiagnosed, and frequently inadequately treated in the general population. Nausea and vomiting are common reasons for patients to be referred for symptom control. Nausea can be the most prominent feature of migraine; the International Classification of Headache Disorders (ICHD) recognizes cyclical vomiting syndrome as a migraine variant in children, and there is increasing evidence for a similar entity in adults. We present three patients with troublesome nausea uncontrolled by conventional antiemetic therapy. On questioning, all three had other symptoms suggestive of migraine, and two had a family history. Their symptoms settled with the use of various antimigraine therapies. Amitriptyline appears to be particularly useful. A therapeutic trial of prophylaxis may be indicated for patients whose nausea and vomiting may be attributed to migraine.

A vertical VAS is a valid instrument for monitoring headache pain intensity

Visual analogue scales (VAS) are well-validated instruments for assessing pain intensity, but have an impractical format. The aim of the study was to validate a vertical against a horizontal VAS for pain intensity registration. Out-patients with headache or non-headache pain were included. Participants completed a horizontal and a vertical VAS. Both were completed twice for test-retest. Headache was diagnosed according to the International Classification of Headache Disorders, 2nd edition. The results on vertical and horizontal VAS did not differ significantly in the different headache or chronic pain groups. For test-retest evaluation, effect sizes and Cohen's delta values were < 0.029 with < 1.5% change from test to retest (P < 0.01). Correlation coefficients were > 0.95. Bland-Altman analysis showed good agreement between vertical and horizontal scores with correlation coefficients > 0.84. A vertical VAS is equally valid as a horizontal VAS for registration of pain intensity in headache and non-headache patients.

Refractory migraine and chronic migraine: pathophysiological mechanisms

Despite increased understanding of primary headaches and their treatment, the underlying causes of refractory migraine remain unknown. This note considers potential genetic, structural, functional and pharmacological factors that could contribute to this relatively intractable condition. Further understanding of refractory migraine will require the use of medical imaging technologies, clinical experimental medicine studies on novel pharmacological agents and astute observations in clinical practice to direct potential novel therapeutic approaches.

Melatonin treatment decreases c-fos expression in a headache model induced by capsaicin

The aim of the present work was to analyze c-fos response within the trigeminal nucleus caudalis (TNC) of pinealectomized rats and animals that received intraperitoneal melatonin, after intracisternal infusion of capsaicin, used to induce intracranial trigeminovascular stimulation. Experimental groups consisted of animals that received vehicle solution (saline-ethanol-Tween 80, 8:1:1, diluted 1:50) only (VEI, n=5); animals that received capsaicin solution (200 nM) only (CAP, n=6); animals submitted to pinealectomy (PX, n=5); sham-operated animals (SH, n=5); animals submitted to pinealectomy followed by capsaicin stimulation (200 nM) after 15 days (PX + CAP, n=7); and animals that received capsaicin solution (200 nM) and intraperitoneal melatonin (10 mg/kg) (CAP + MEL, n=5). Control rats, receiving vehicle in the cisterna magna, showed a small number of c-fos-positive cells in the TNC (layer I/II) as well as the sham-operated and pinealectomized rats, when compared to animals stimulated by capsaicin. On the other hand, pinealectomized rats, which received capsaicin, presented the highest number of c-fos-positive cells. Animals receiving capsaicin and melatonin treatment had similar expression of the vehicle group. Our data provide experimental evidence to support the role of melatonin and pineal gland in the pathophysiology of neurovascular headaches.

Refractory migraine and chronic migraine: pathophysiological mechanisms

Migraine is a complex disorder of the brain whose mechanisms are only now being unravelled. It is common, disabling, and economically costly. Brain imaging has suggested a role for the brainstem. While the disorder is almost certainly inherited, the degree to which this contributes to a treatment refractory state is not clear. Indeed, no specific structural or pharmacological explanation can be seen from the data as they have been generated. It is clear that patients with more frequent headache are very likely to go on to even more frequent headache, but again these data are complex. A challenge going forward is to establish the biology of these very challenging patients who undoubtedly have substantial disability.

Genetics of migraine headache in children

A family history of migraine is very frequently noted when evaluating a child for recurrent headaches. This implies an inherited or genetic basis as a component to the underlying pathophysiology. A variety of techniques have begun to elucidate this contribution, including historical observation, population-based studies including family and twin studies, gene polymorphism association studies, and specific gene identification for isolated migraine subtypes. This line of investigation should progress in the future to a better understanding of migraine and clarification of the diagnostic subtypes for a genotype-phenotype association.

Genetics in primary headaches

This tutorial describes different methods and results of genetic studies of primary headaches. A positive family history is imprecise, because it does not specify the number of affected, family size or relation to the proband. Nor does it include an interview of the possibly affected family members. Calculation of the familial aggregation after confirmation of the diagnosis by a physician is more precise. Compared to the general population, first-degree relatives of probands with migraine without aura, migraine with aura, chronic tension-type headache and cluster headache has a significantly increased risk of the proband's disorder. These data are confirmed in twin studies. The primary headaches are caused by a combination of genetic and environmental factors. A major breakthrough was identification of 3 different genes all causing the rare autosomal dominant inherited familial hemiplegic migraine. The genes encode ion channels. So far no genes have been identified to cause the more common types of primary headaches.

Cluster headache and head trauma: Is there an association?

This article discusses what is known of and written regarding the possible association of cluster headache and head trauma. There is additional discussion of conditions other than direct head trauma that are also seen in association with cluster headache. These conditions bring into question the concept of primary versus secondary cluster headache and raise the possible need to expand the category of secondary cluster headache. With increasing knowledge of the pathophysiology of cluster headache, the potentially causative role of head trauma in the development of cluster headache may become better defined.

Targeting neuronal hyperexcitability for antimigraine drug development

Migraine is among the most prevalent neurological disorders worldwide, afflicting up to 16% of the population. Because it mostly affects patients between the most productive ages of 25 and 50 years, migraine costs employers more than US$13 billion per year in reduced productivity and missed days. It is therefore important to prevent and treat migraine attacks. Triptans were introduced in the early 1990s and effectively alleviate symptoms in most patients. Their success was based on the existence of the operational hypothesis implicating the trigemino-vascular system. Prophylactic medications have been available since beta-blockers, followed by agents belonging to other therapeutic classes. Most of them were found serendipitously to be effective. However, progress in the development of preventative agents has been hampered by the lack of animal models mimicking the early events of migraine pathophysiology. This review will examine how a recent theory on the origin of migraine attacks is likely to lead to the development of new animal models.

Influence of MTHFR Genotype on Contingent Negative Variation And MRI Abnormalities in Migraine

BACKGROUND

The MTHFR C677T genotype has been associated with increased risk of migraine, particularly of migraine with aura (MA) in selected clinical samples and with elevated homocysteine. The hyper-homocysteinemia may favor the vascular and neuronal mechanism underlying migraine, and the risk of stroke.

OBJECTIVE

The first aim of the present study was to examine the Contingent Negative Variation (CNV) amplitude and habituation pattern in a migraine sample versus non-migraine subjects, at the light of the MTHFR genotype, according to an unrelated and clinical based case-control panel. The second aim was to compare the frequency of Magnetic Resonance Imaging (MRI) subclinical brain lesions across the different C677 genotypes in the same migraine sample, selected for the young age and the absence of any cardiovascular risk factor.

METHODS

One hundred and five 18-45 year old out-patients, 90 affected by migraine without aura (MO) and 15 by MA, and 97 non-migraine healthy subjects, age and sex matched, were selected for the genetic analysis. All subjects had a common ethnic origin from Puglia. Sixty-four migraine subjects and 33 control subjects were submitted to the recording of the CNV. All migraine subjects underwent the MRI evaluation.

RESULTS

The frequency of homozygosis was 14.33% in normal subjects, versus 25.7% in MA + MO group (chi2-test: 10.80 P= .001). The frequency of homozygosis in MO patients, was 25.5% (MA versus N: chi2-test: 9 P= .003), in MA group it was 26.6%. Considering the MTHFR genotype in migraine patients and controls, the C677TT subjects exhibited a reduced habituation index of the early CNV (iCNV), in respect with both C677TC and C677CC; in the migraine group, there was a significant decrease of CNV habituation in patients with homozygosis and a positive correlation between the habituation index values and the homocysteine levels. Nineteen migraine patients exhibited subclinical brain lesions (18.05%): patients with C677T homozygosis did not exhibit a higher risk for MRI abnormalities.

CONCLUSIONS

This unrelated and clinical based case-control study showed that genetically induced hyper-homocysteinemia may favor the neuronal factors predisposing to migraine, while it does not influence the presence of subclinical vascular brain lesions probably linked with increased risk of stroke.

Craniomandibular muscles, intraoral orthoses and migraine

Intraoral splints are effective in migraine prevention. In this review, changes in the quality of life of migraineurs treated with a palatal nonoccluding splint were measured. Using the Migraine Specific Quality of Life Instrument (Version 2.1), it was found that the palatal nonoccluding splint significantly improved the quality of life of migraineurs. The role of the craniomandibular muscles in the pathophysiology of migraine is also discussed.

Cluster headache: Myths and the evidence

Although cluster headache (CH) has been the focus of a great deal of research, it also has been the focus of a great deal of speculations that have been repeated commonly as fact. The authors conducted a thorough review of the literature and an informal poll of several noted headache experts to investigate the truth behind common myths and hypotheses regarding CH. They then present an overview of some of these more common hypotheses, observations, and myths, and offer a brief review of the existing evidence supporting or negating the theories. These include gender, genetics, suicidality, homicidality, physical appearance, personality, and psychologic features of the patient with CH.

Headache in schoolchildren: association with other pain, family history and psychosocial factors

Limited information exist about associations between different headache types and other pains, family history of pain, and psychosocial factors among children from the general population suffering from less severe headache. We interviewed 130 schoolchildren together with a parent to find out whether such factors differ between children with mainly infrequent and moderate migraine or tension-type headache as compared to those without primary headache. Children with headache, especially those with migraine reported other pains and physical symptoms more frequently than children without primary headache. Coherently, parents of children suffering from migraine reported their children to have significantly more somatic symptoms than parents of children without primary headache. In addition, first-degree relatives of children with headache suffered from more migraine, other pains, and physical symptoms compared with first-degree relatives of children without primary headache. Children with migraine visited the school nurse, used medication and were absent from school because of headache more often than those with tension-type headache. Few other differences in psychosocial factors were found between the three groups. Migraine among first-degree relatives and the total sum of physical symptoms in children were the strongest predictors of headache in logistic regression analysis. It is concluded that in schoolchildren with mainly infrequent and moderate headache, pain and physical symptoms cluster within individuals as well as their families, however, psychological and social problems are uncommon.

Genomic abnormalities in patients with migraine and chronic migraine: preliminary blood gene expression suggests platelet abnormalities

BACKGROUND

Migraine has strong genetic and environmental components and may also be a significant contributor to chronic migraine (CM). It is hypothesized that gene expression changes in peripheral blood cells can be used to detect the interaction of these influences.

OBJECTIVE

Distinct genomic expression patterns for migraine and CM will be present. These genomic profiles will help clarify the interactions of inheritance and environment. This initial study begins to examine the feasibility of peripheral blood cell genomic analysis to assist in the understanding of the pathophysiology of migraine and CM.

METHODS

Blood samples from patients were obtained either during an acute migraine or CM. Genomic expression patterns were analyzed using Affymetrix U95A microarrays.

RESULTS

Expression patterns of 7 migraine and 15 CM patients were compared to four distinct control groups (total patients, n=56) including healthy subjects. A group of platelet genes were upregulated in both migraine and CM samples. Different gene expression patterns were also seen between migraine and CM. A group of immediate early genes including c-fos and cox-2 were expressed at higher levels in migraine, whereas specific mitochondrial genes were expressed at higher levels in CM.

CONCLUSIONS

Increased expression of platelet genes in patients with migraine and CM suggests similar underlying pathophysiology. The differences seen between migraine and CM in other genes suggest an overlapping but not identical pathophysiology. Further genomic profiling studies will help define these relationships and provide further insights into headache pathogenesis.

Migraine Pathophysiology

A combination of basic science and human physiology, particularly functional neuroimaging, has radically altered our understanding of migraine with a focus on brain mechanisms for this common and disabling disorder. Genetic studies have begun to provide plausible targets for the basic molecular defect in terms of ion channels, albeit thus far in the rare condition of familial hemiplegic migraine (FHM). Migraine pathophysiology involves the trigeminovascular system and central nervous system modulation of the pain-producing structures of the cranium. The degree to which head pain results from the activation of the nociceptors of pain-producing intracranial structures, or to the facilitation or lack of inhibition of afferent signals, is not clear at this time. An understanding of the pain mechanism is likely to provide insights into the mechanisms underlying the more generalized sensory dysfunction that is so typical of migraine.

Hereditary patterns of Belgrade university female students with migraine and nonmigraine primary headache

Various studies have provided evidence that migraine is a multifactorial genetic disorder. The aim of the present study was to compare hereditary patterns of female students with migraine (245 subjects) and non-migraine primary headaches (1053 subjects). The prevalence study was performed combined with a case-control study. Migraineurs had significantly more frequently one or more first-degree and/or second-degree relatives with migraine. Students with menstrual migraine, in comparison with other subtypes of migraine (with the exception of premenstrual migraine), had significantly more frequently > or = 2 relatives with migraine. Among students with non-migraine primary headaches, those with menstrually related headache had more frequently relatives with migraine in comparison with students suffering from menstrually unrelated nonmigraine headache. The results obtained are in line with the results of genetic epidemiologic studies suggesting that genetic factors play a role in the occurrence of migraine.

Epidemiology and genetics of cluster headache

Cluster headache, the most severe primary headache, is characterised by unilateral pain, ipsilateral autonomic features, and, in many cases, restlessness. Recent epidemiological studies indicate that the prevalence of cluster headache is about one person per 500. Genetic epidemiological surveys indicate that first-degree relatives are five to 18 times-and second-degree relatives, one to three times-more likely to have cluster headache than the general population. Inheritance is likely to be autosomal dominant with low penetrance in some families, although there may also be autosomal recessive or multifactorial inheritance in others. To date, no molecular genetic clues have been identified for cluster headache. Identification of genes for cluster headache is likely to be difficult because most families reported have few affected members and genetic heterogeneity is likely. Future focus should be on ion channel genes and clock genes. This review summarises the epidemiology and genetics of cluster headache.

Toward a molecular genetic classification of familial hemiplegic migraine

The genetics of migraine is a fascinating and rapidly moving research area. Familial hemiplegic migraine, a rare subtype of migraine with a Mendelian pattern of inheritance, is caused by mutations in the chromosome 19 CACNA1A gene or in the chromosome 1 ATP1A2 gene. Familial migraine variants are classified on the basis of clinical, descriptive criteria, but this is insufficient. In the future, a diagnostic classification based on mutation-analysis is needed.

Familial retinal migraines

Approximately 25% of sufferers of retinal migraine are thought to have a positive family history. Retinal migraines can cause both transient, and rarely permanent, unilateral monocular visual loss. This report of familial retinal migraines furthers our understanding of this particular migraine subtype. Two families with retinal migraines are reported suggesting an autosomal-dominant inheritance pattern with variable expression and penetrance.

Cluster headache mimics

This article discusses cluster headache and a variety of cluster mimics, with the intention of aiding the practitioner in differentiating between primary cluster headache and secondary forms of cluster. Secondary causes of cluster headache include infections, tumors, vascular abnormalities, and head trauma. In addition, other trigeminal autonomic cephalgias occasionally can be difficult to distinguish from primary cluster headache.

Recognition and treatment of cluster headache in the emergency department

Cluster headache has a dramatic presentation marked by rapidly escalating intensity of pain and prominent signs of autonomic dysfunction. Despite its distinctive features, diagnostic delay and misdiagnosis are common. Prompt recognition of this headache disorder provides an opportunity for effective treatment. This article provides a practical approach to the diagnosis and management of patients with cluster headache in the emergency room setting.

Migraine and asthma in childhood: evidence for specific asymmetric parent-child interactions in migraine and asthma families

In spite of the fact that migraine often manifests as a familial disorder, the role of the family in migraine has not been adequately explored. In this study parent-child interactions in 20 families with a child suffering from migraine were analysed and compared with 20 healthy families and 20 families with an asthma child. The families had to solve a puzzle within a limited time. Parent-child interactions within migraine and asthma families were asymmetric, revealing a disease-specific interpersonal context in the family. Communication with the affected child in migraine families was significantly more directive, with more specific instructions and less help, towards migraineurs than with the healthy siblings. Dominance of parents and submissive behaviour of children were the main features of interactions. In asthma families interactions were more conflicting and less cooperative. This study demonstrated a specific, asymmetric, pattern of family interactions predisposing children either to migraine or asthma.

Epidemiology of cluster headache

Cluster headache is rare, occurring in less than 1% of the population. Studies suggest that, in addition to the pain and associated autonomic disturbances recognized to be characteristic of the syndrome, patients also may experience nausea, photophobia, behavioral agitation, or restlessness. A decreasing male:female ratio also has been noted, perhaps attributable to lifestyle trends adopted by more women that were previously associated with men, such as tobacco use, alcohol consumption, and working outside of the home. The relationship between cluster headache and hormonal events does not appear to be strong. Hormonal influences on the chronic form of cluster headache in women are a subject of investigation. The emerging understanding of the genetics of cluster headache increasingly suggests a genetic component, with familial transmission now recognized to be more common than previously appreciated. Head trauma, coronary artery disease, and migraine appear to be present in more patients with cluster headache than can be explained by chance alone. Ethnic and racial differences in prevalence are less well understood.

Shared rearing environment in migraine: results from twins reared apart and twins reared together

BACKGROUND

Studies of twins who are separated from each other early in life and are reared in different environments offer the opportunity to resolve variation in liability to disease.

OBJECTIVE

To evaluate the importance of genetic and environmental influences in migraine; in particular, addressing the role of the shared rearing environment.

METHODS

A population-based cohort of twins, including a subsample of 314 pairs reared apart and 364 matched control pairs reared together, was drawn from the Swedish Twin Registry. Data on lifetime migraine was collected via self-administered questionnaires mailed to twins aged 42 to 81 years. Quantitative genetic models and regression models were used to analyze sources of twin similarity.

RESULTS

We found nonsignificant shared rearing environmental influences on migraine for men (17%) and no rearing effects at all for women. The heritability of migraine was estimated at 38% (95% confidence interval, 0 to 73) for men and 48% (95% confidence interval, 27 to 65) for women. Among monozygotic twins reared apart, those separated at 3 years of age or earlier were more similar for lifetime migraine than those separated later, and this was especially true for women.

CONCLUSION

In agreement with previous twin data, family resistance in migraine is mainly due to genetic factors, whereas environmental influences make family members different, not similar.

Familial occurrence of migraine with aura in a population-based study

OBJECTIVE

To better define a possible genetic basis for migraine with aura (MWA).

METHODS

We investigated the familial occurrence of migraine with aura in a sample of (MWA) subjects recruited from an epidemiologic study of migraine with aura involving the general population. The sample with migraine with aura (n = 26) was selected out of a total of 1392 subjects (842 women and 550 men) representative of the general population aged 18 to 65 years in the southern Italian town of San Severo. A family history of migraine with aura was determined via direct interviews with all living first-degree relatives of the 26 subjects who could be reached by investigators, 119 people: 71 women and 48 men. The diagnosis of migraine with aura was made according to the 1988 International Headache Society (IHS) criteria.

RESULTS

Of the 26 subjects with migraine with aura, 7 (6 women and 1 man) had a positive family history, with a total of 7 first-degree relatives affected by the disease (1 mother, 2 fathers, 1 brother, 1 sister, and 2 children). Based on the lifetime prevalence rate of migraine with aura (1.6%) in the San Severo general population, the relative risk of migraine with aura in the first-degree relatives of the subjects was 3.68 (4.16 for women and 2.77 for men).

CONCLUSION

Our subjects' relative risk rate for familial occurrence of migraine with aura was similar to that reported by one investigator, but markedly lower than that reported by another group.

Analysis of nitric oxide synthase genes in cluster headache

The aetiology of cluster headache is still not yet completely understood, but the potential relevance of genetic factors has been recognized during recent years. Nitric oxide (NO) plays a critical role in the regulation of vasodilation, neurotransmission, inflammation and many other events throughout the body. NO also appears to be an important mediator of vascular headache pathophysiology. In this study we have performed an association analysis of five polymorphic microsatellite markers in the three different NO synthase (NOS) genes; nNOS (NOS1), iNOS (NOS2A) and eNOS (NOS3). Ninety-one cluster headache patients diagnosed according to International Headache Society criteria and 111 matched controls were studied. Phenotype and allele frequencies were similarly distributed in patients and controls except for an iNOS (NOS2A) pentanucleotide repeat allele which was significantly more common in controls. We observed a higher phenotype frequency of this allele in our control group compared with rates in control groups of other studies, whereas the frequency in our patients was similar to that in controls from previous reports. Thus, we conclude that it is unlikely that genetic variations within the NOS genes contribute greatly to cluster headache susceptibility.

Intractable cluster headaches in a migraineur

Some migraineurs have the additional misfortune of suffering from cluster headaches; this situation can be challenging.