Family History of Cluster Headache: A Systematic Review

Cluster headache: understandings of current knowledge and directions for whole process management

Cluster headache (CH) is a common primary headache that severely impacts patients' quality of life, characterized by recurrent, severe, unilateral headaches often centered around the eyes, temples, or forehead. Distinguishing CH from other headache disorders is challenging, and its pathogenesis remains unclear. Notably, patients with CH often experience high levels of depression and suicidal tendencies, necessitating increased clinical attention. This comprehensive assessment combines various reports and the latest scientific literature to evaluate the current state of CH research. It covers epidemiology, population characteristics, predisposing factors, and treatment strategies. Additionally, we provide strategic insights into the holistic management of CH, which involves continuous, individualized care throughout the prevention, treatment, and rehabilitation stages. Recent advances in the field have revealed new insights into the pathophysiology of CH. While these findings are still evolving, they offer a more detailed understanding of the neurobiological mechanisms underlying this disorder. This growing body of knowledge, alongside ongoing research efforts, promises to lead to the development of more targeted and effective treatments in the future.

Recent advances in diagnosing, managing, and understanding the pathophysiology of cluster headache

Cluster headache, characterised by attacks of severe, recurrent, unilateral headache and ipsilateral cranial autonomic symptoms, remains a primary headache with an elusive pathophysiology. Recent advances have introduced effective treatments and broadened understanding of the clinical features of cluster headache. These features are similar in patients globally, but regional differences in prevalence and burden exist. International collaborations have led to identification of eight genetic loci associated with cluster headache. The pathophysiological mechanisms are still not fully understood but recent studies show that targeting the trigeminal autonomic reflex by neurostimulation, or targeting the neuropeptide calcitonin gene-related peptide (CGRP), might lessen the attack burden. The US Food and Drug Administration has approved galcanezumab, a monoclonal antibody targeting CGRP, as the first specific preventive treatment for episodic cluster headache. However, a preventive effect was not replicated in chronic cluster headache, and the European Medicines Agency did not approve galcanezumab, restricting its availability in Europe. Owing to the low prevalence of cluster headache, continued collaboration through multicentre clinical trials and data sharing will be imperative for further breakthroughs in understanding and management.

The location of pain in cluster headache: Data from the International Cluster Headache Questionnaire

OBJECTIVE

To identify the most common locations of cluster headache pain from an international, non-clinic-based survey of participants with cluster headache, and to compare these locations to other cluster headache features as well as to somatotopic maps of peripheral, brainstem, thalamic, and cortical areas.

BACKGROUND

Official criteria for cluster headache state pain in the orbital, supraorbital, and/or temporal areas, yet studies have noted pain extending beyond these locations, and the occipital nerve appears relevant, given the effectiveness of suboccipital corticosteroid injections and occipital nerve stimulation. Furthermore, cranial autonomic features vary between patients, and it is not clear if the trigeminovascular reflex is dermatome specific (e.g., do patients with maxillary or V2 division pain have more rhinorrhea?). Finally, functional imaging studies show early activation of the posterior hypothalamus in a cluster headache attack. However, the first somatosensory area to be sensitized is unclear; the first area can be hypothesized based on the complete map of pain locations.

METHODS

The International Cluster Headache Questionnaire was an internet-based cross-sectional survey that included a clickable pain map of the face. These data were compared to several other datasets: (1) a meta-analysis of 22 previous publications of pain location in cluster headache (consisting of 6074 patients); (2) four cephalic dermatome maps; (3) participants' survey responses for demographics, autonomic features, and effective medications; and (4) previously published somatotopic maps of the brainstem, thalamus, primary somatosensory cortex, and higher order somatosensory cortex.

RESULTS

One thousand five hundred eighty-nine participants completed the pain map portion of the survey, and the primary locations of pain across all respondents was the orbital, periorbital, and temporal areas with a secondary location in the lower occiput; these primary and secondary locations were consistent with our meta-analysis of 22 previous publications. Of the four cephalic dermatomes (V1, V2, V3, and a combination of C2-3), our study found that most respondents had pain in two or more dermatomes (range 85.7% to 88.7%, or 1361-1410 of 1589 respondents, across the four dermatome maps). Dermatomes did not correlate with their respective autonomic features or with medication effectiveness. The first area to be sensitized in the canonical somatosensory pathway is either a subcortical (brainstem or thalamus) or higher order somatosensory area (parietal ventral or secondary somatosensory cortices) because the primary somatosensory cortex (area 3b) and somatosensory area 1 have discontinuous face and occipital regions.

CONCLUSIONS

The primary pain locations in cluster headache are the orbital, supraorbital, and temporal areas, consistent with the official International Classification of Headache Disorders criteria. However, activation of the occiput in many participants suggests a role for the occipital nerve, and the pain locations suggest that somatosensory sensitization does not start in the primary somatosensory cortex.

Ketamine as Treatment for Cluster Headache: A Systematic Review of Literature and a Case Series

INTRODUCTION

Cluster headache is a severe and debilitating neurological condition characterized by intense, excruciating pain with a significant impact on patients' wellbeing. Although different treatment options are available, many patients continue to experience inadequate relief. Therefore, experimental strategies are increasingly studied. One of the more promising approaches is the use of ketamine. We present the currently available evidence and our own data.

METHODS

In this mixed-methods paper, we first summarize the available evidence of ketamine for treatment of cluster headache based on a systematic review of literature in MEDLINE, EMBASE and the Cochrane library of systematic reviews. As the level of evidence is quite limited, we report our own cohort study with ten patients treated with ketamine infusions for cluster headache. They were followed up to investigate the patients' experience of treatment success and quality of life.

RESULTS

The search and review of literature identified four reports with a total of 68 patients. All were uncontrolled case series. The current literature suggests that ketamine might decrease cluster headache. However, as the applied regimes and reported outcomes are highly heterogeneous, further analysis was futile. Our own data show high patient satisfaction with ketamine treatment.

CONCLUSION

Despite the limited evidence, ketamine might be considered a potential therapeutic approach for cluster headache. Therefore, further research including randomized controlled trials should be encouraged.

CLOCK gene circannual expression in cluster headache

BACKGROUND

Cluster headache is a primary headache disorder characterized by bouts with circadian and circannual patterns. The CLOCK gene has a central role in regulating circadian rhythms. Here, we investigate the circannual CLOCK expression in a population of cluster headache patients in comparison to matched controls.

METHODS

Patients with cluster headache were sampled two to four times over at least one year, both in or outside bouts, one week after each solstice and equinox. The expression of CLOCK was measured by quantitative real-time polymerase chain reaction (RT-PCR) in the peripheral blood.

RESULTS

This study included 50 patients and 58 matched controls. Among the patient population, composed of 42/50 males (84%) with an average age of 44.6 years, 45/50 (90%) suffered from episodic cluster headache. Two to four samples were collected from each patient adding up to 161 samples, 36 (22.3%) of which were collected within a bout. CLOCK expression for cluster headache patients was considerably different from that of the control population in winter (p-value mean = 0.006283), spring (p-value mean = 0.000006) and summer (p-value mean = 0.000064), but not in autumn (p-value mean = 0.262272). For each season transition, the variations in CLOCK expression were more pronounced in the control group than in the cluster headache population. No statistically significant differences were found between bout and non-bout samples. No individual factors (age, sex, circadian chronotype, smoking and coffee habits or history of migraine) were related to CLOCK expression.

CONCLUSIONS

We observed that CLOCK expression in cluster headache patients fluctuates less throughout the year than in the control population. Bout activity and lifestyle factors do not seem to influence CLOCK expression.

Cluster Headache, SUNCT, and SUNA

OBJECTIVE

This article reviews the epidemiology, clinical features, differential diagnosis, pathophysiology, and management of three types of trigeminal autonomic cephalalgias: cluster headache (the most common), short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT), and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA).

LATEST DEVELOPMENTS

The first-line treatments for trigeminal autonomic cephalalgias have not changed in recent years: cluster headache is managed with oxygen, triptans, and verapamil, and SUNCT and SUNA are managed with lamotrigine. However, new successful clinical trials of high-dose prednisone, high-dose galcanezumab, and occipital nerve stimulation provide additional options for patients with cluster headache. Furthermore, new genetic and imaging tests in patients with cluster headache hold promise for a better understanding of its pathophysiology.

ESSENTIAL POINTS

The trigeminal autonomic cephalalgias are a group of diseases that appear similar to each other and other headache disorders but have important differences. Proper diagnosis is crucial for proper treatment.

Cluster headache: an update on clinical features, epidemiology, pathophysiology, diagnosis, and treatment

Cluster headache (CH) is one of the worst primary headaches that remain underdiagnosed and inappropriately treated. There are recent advances in the understanding of this disease and available treatments. This paper aims to review CH's recent clinical and pathophysiological findings, diagnosis, and treatment. We performed a narrative literature review on the socio-demographics, clinical presentations, pathophysiological findings, and diagnosis and treatment of CH. CH affects 0.1% of the population with an incidence of 2.07-9.8/100,00 person-years-habitants, a mean prevalence of 53/100,000 inhabitants (3-150/100,000 inhabitants). The male-to-female ratio remains inconclusive, as the ratio of 4.3:1 has recently been modified to 1.3-2.6, possibly due to previous misdiagnosis in women. Episodic presentation is the most frequent (80%). It is a polygenetic and multifactorial entity that involves dysfunction of the trigeminovascular system, the trigeminal autonomic reflex, and the hypothalamic networks. An MRI of the brain is mandatory to exclude secondary etiologies. There are effective and safe pharmacological treatments oxygen, sphenopalatine, and great occipital nerve block, with the heterogeneity of clinical trial designs for patients with CH divided into acute, transitional, or bridge treatment (prednisone) and preventive interventions. In conclusion, CH remains underdiagnosed, mainly due to a lack of awareness within the medical community, frequently causing a long delay in reaching a final diagnosis. Recent advances in understanding the principal risk factors and underlying pathophysiology exist. There are new therapeutic possibilities that are effective for CH. Indeed, a better understanding of this challenging pathology will continue to be a subject of research, study, and discoveries in its diagnostic and therapeutic approach.

Combined genotype of HCRTR2 and CLOCK variants in a large family of cluster headache with familial periodicity phenotype

PURPOSE

Cluster headache (CH) is a debilitating condition with severe and recurrent headaches characterized by circannual and circadian rhythms. A genetic contingent was suggested, and several loci were described in large cohorts. However, no variant associated with CH for multiplex families has been described. The purpose of our study was to examine candidate genes and new genetic variants in a multigenerational family of cluster headaches in which two members have original chronobiological characteristics that we have called the phenomenon of "family periodicity".

METHODS AND RESULTS

We performed a whole genome sequencing in four patients in a large multigenerational family of cluster headache to identify additional loci associated with CH. This allowed us to replicate the genomic association of HCRTR2 and CLOCK as candidate genes. In two family members with the same phenotypic circadian pattern (familial periodicity) the association of polymorphism NM_001526.4:c.922G > A was shown in the HCRTR2 gene, and NM_004898.4:c.213T > C in the CLOCK gene.

INTERPRETATION

This whole genome sequencing reproduced two genetic risk loci for CH already involved in its pathogenicity. This is the first time that the combination of HCRTR2 and CLOCK gene variants is identified in a multigenerational family of CH with striking periodicity characteristics. Our study supports the hypothesis that the combination of HCRTR2 and CLOCK gene variants can contribute to the risk of cluster headache and offer the prospect of a new area of research on the molecular circadian clock.

Sex Differences in Clinical Features, Treatment, and Lifestyle Factors in Patients With Cluster Headache

BACKGROUND AND OBJECTIVES

Cluster headache is considered a male-dominated disorder, but we have previously suggested that female patients may display a more severe phenotype. Studies on sex differences in cluster headache have been conflicting; therefore, this study, with the largest validated cluster headache material at present, gives more insights into sex-specific characteristics of the disease. The objective of this study was to describe sex differences in patient demographics, clinical phenotype, chronobiology, triggers, treatment, and lifestyle in a Swedish cluster headache population.

METHODS

Study participants were identified by screening medical records from 2014 to 2020, requested from hospitals and neurology clinics in Sweden for the ICD-10 code G44.0 for cluster headache. Each study participant answered a detailed questionnaire on clinical information and lifestyle, and all variables were compared with regard to sex.

RESULTS

A total of 874 study participants with a verified cluster headache diagnosis were included. Of the participants, 575 (66%) were male and 299 (34%) were female, and biological sex matched self-reported sex for all. Female participants were to a greater extent diagnosed with the chronic cluster headache subtype compared with male participants (18% vs 9%, p = 0.0002). In line with this observation, female participants report longer bouts than male participants (p = 0.003) and used prophylactic treatment more often (60% vs 48%, p = 0.0005). Regarding associated symptoms, female participants experienced ptosis (61% vs 47%, p = 0.0002) and restlessness (54% vs 46%, p = 0.02) more frequently compared with male participants. More female than male study participants had a positive family history of cluster headache (15% vs 7%, p = 0.0002). In addition, female participants reported diurnal rhythmicity of their attacks more often than male participants (74% vs 63%, p = 0.002). Alcohol as a trigger occurred more frequently in male participants (54% vs 48%, p = 0.01), whereas lack of sleep triggering an attack was more common in female participants (31% vs 20%, p = 0.001).

DISCUSSION

With this in-depth analysis of a well-characterized cluster headache population, we could demonstrate that there are significant differences between male and female participants with cluster headache, which should be regarded at the time of diagnosis and when choosing treatment options. The data suggest that female patients generally may be more gravely affected by cluster headache than male patients.

No significant association between SNPs in the CLOCK and ADH4 genes and susceptibility to cluster headaches: A systematic review and meta-analysis

BACKGROUND

The circadian locomotor output cycles kaput (CLOCK) gene and the alcohol dehydrogenase 4 (ADH4) gene are promising candidates for susceptibility to cluster headaches (CH). Associations of the three single nucleotide polymorphisms (SNPs)-CLOCK SNP rs1801260 and ADH4 SNPs rs1800759, and rs1126671-with CH were studied previously, but the results were inconsistent.

METHODS

Associations between the three SNPs (rs1801260, rs1126671, and rs1800759) and CH risk were separately assessed by pooled odds ratios (ORs) along with 95% confidence intervals (95% CIs) based on five different genetic models. Methodological quality was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). All statistical analyses were carried out with RevMan 5.3 software.

RESULTS

Eight studies involving 1437 CH patients and 2541 healthy controls were selected for quantitative synthesis, from five studies on CLOCK rs1801260, five on ADH4 rs1800759, and three on ADH4 rs1126671. Our pooled data did not support associations between the three SNPs (rs1801260 in the CLOCK gene, rs1800759 and rs1126671 in the ADH4 gene) and susceptibility to CH (rs1801260: OR 1.10, 95% CI: 0.95-1.28; p = 0.19; rs1800759: OR 1.06, 95% CI: 0.93-1.22; p = 0.37; and rs1126671: OR 1.09, 95% CI: 0.92-1.28; p = 0.32).

CONCLUSION

We found no significant associations between the three SNPs (rs1801260 in the CLOCK gene and rs1800759 and rs1126671 in the ADH4 gene) and the susceptibility to CH across both Caucasian and Asian ethnicities in our meta-analysis.

Recent advances in the diagnosis and management of cluster headache

Cluster headache, a primary headache disorder, consists of short (15-180 minutes), frequent (up to eight a day), unilateral attacks of facial pain with associated ipsilateral autonomic features and restlessness. The attacks are suspected to be one of the most painful human experiences, and the disorder is associated with a high rate of suicidal ideation. Proper diagnosis is key, as some of the most effective treatments, such as high flow oxygen gas, are rarely used in other headache disorders. Yet diagnostic delay is typically years for this disorder, as it is often confused with migraine and trigeminal neuralgia, and secondary causes may be overlooked. This review covers the clinical, pathophysiologic, and therapeutic features of cluster headache. Recent updates in diagnosis include the redefinition of chronic cluster headache (remission periods lasting less than three months instead of the previous one month), and recent advances in management include new treatments for episodic cluster headache (galcanezumab and non-invasive vagus nerve stimulation).

The clinical characteristics of familial cluster headache

Background

A positive family history predisposes to the development of cluster headache. The distinct characteristics of familial cluster headache have yet to be confirmed, however, evidence suggests a younger age of onset and higher proportion of females in this subgroup.

Objectives

To assess the rate and mode of inheritance of familial cluster headache in a tertiary referral centre for headache. To describe the clinical features of familial cluster headache.

Methods

A retrospective study conducted between 2007 and 2017. Cluster headache was confirmed in probands and affected relatives. Differences in demographics, clinical characteristics, and response-to-treatment in familial cluster headache were delineated through multivariate analysis using a control cohort of 597 patients with sporadic cluster headache.

Results

Familial cluster headache was confirmed in 48 (7.44%) patients and predominantly reflected an autosomal dominant mode of inheritance with reduced penetrance. Familial cases were more likely to report nasal blockage (OR 4.06, 95% CI; 2.600–6.494, p < 0.001) during an attack and a higher rate of concurrent short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (OR 3.76, 95% CI; 1.572–9.953, p = 0.004).

Conclusion

These findings add to evidence suggesting a genetic component to cluster headache. Here, we demonstrated prominent nasal blockage, and a higher occurrence of concomitant short-lasting unilateral neuralgiform headache with conjunctival injection and tearing in this subgroup, further delineating the phenotype.

Using the Biopsychosocial Model to Guide Patient-Centered Neurological Treatments

The biopsychosocial model was defined by George L. Engel to propose a holistic approach to patient care. Through this model, physicians can understand patients in their context to aid the development of tailored, individualized treatment plans that consider relevant biological, psychological, and social-cultural-spiritual factors impacting health and longitudinal care. In this article, we advocate for the use of the biopsychosocial model in neurology practice across outpatient and inpatient clinical settings. To do so, we first present the history of the biopsychosocial model, and its relationships to precision medicine and deep phenotyping. Then, we bring the neurologist up-to-date information on the components of the biopsychosocial clinical formulation, including predisposing, precipitating, perpetuating, and protective factors. We conclude by detailing illustrative neurological case examples using the biopsychosocial model, emphasizing the importance of considering relevant psychological and social factors to aid the delivery of patient-centered clinical care in neurology.

Cluster Headache and Associated Risk Factors: A Systemic Review and Meta-Analysis

Cluster headache (CH) has always been associated with several risk factors, including hereditary, environmental, and lifestyle habits. This study focuses on important risk factors, including family history, smoking, alcohol consumption, male predominance, and head trauma associated with CH. The present study aimed at investigating the available literature on cluster headaches and evaluating their associated risk factors. A systematic data search was designed, and scientific data were collected from renowned databases, including PubMed, Cochrane, Embase, Cumulative Index of Nursing and Allied Health Literature (CINAHL), and Google Scholar. Thirty-two studies were selected to execute a systemic review, and 26 studies, consisting of 6,065 CH patients, qualified for a meta-analysis. Statistical analyses were conducted by using MedCalc, version 16.8.4; (MedCalc Software, Ostend, Belgium; http://www.medcalc.org) and Rapidminer statistical software, version 9.6.0 (www.rapidminer.com). We conclude the evidence of family history, smoking, alcohol consumption, male predominance, and head trauma are associated with cluster headaches. However, sex discrimination in familial cases needs to be revisited because of the female predominance reported by familial history and CH association studies.

Cluster headache epidemiology including pediatric onset, sex, and ICHD criteria: Results from the International Cluster Headache Questionnaire

OBJECTIVE

To validate the diagnoses and to investigate epidemiological data from an international, non-clinic-based, and large (n = 1604) survey of participants with cluster headache.

BACKGROUND

There are several limitations in current epidemiological data in cluster headache including a lack of large non-clinic-based studies. There is also limited information on several aspects of cluster headache, such as pediatric incidence.

METHODS

The International Cluster Headache Questionnaire was an internet-based survey that included questions on cluster headache demographics, criteria from the International Classification of Headache Disorders (ICHD), and medications.

RESULTS

A total of 3251 subjects participated in the survey, and 1604 respondents met ICHD criteria for cluster headache. For validation, we interviewed a random sample of 5% (81/1604) of participants and confirmed the diagnosis of cluster headache in 97.5% (79/81). Pediatric onset was found in 27.5% (341/1583) of participants, and only 15.2% (52/341) of participants with pediatric onset were diagnosed before the age of 18. Men were more likely to have episodic cluster headache between ages 10 and 50, but the sex ratio was approximately equal for other ages. An overwhelming majority of respondents had at least one autonomic feature (99.0%, 1588/1604) and had restlessness (96.6%, 1550/1604), but many also had prototypical migrainous features including photophobia or phonophobia (50.1%, 804/1604), pain aggravated by physical activity (31.4%, 503/1604), or nausea and vomiting (27.5%, 441/1604). Interestingly, the first-line medications for acute treatment (oxygen) and preventive treatment (calcium channel blockers) were perceived as significantly less effective in chronic cluster headache (3.2 ± 1.1 and 2.1 ± 1.0 respectively on a 5-point ordinal scale) compared with episodic cluster headache (3.5 ± 1.0 and 2.4 ± 1.1, respectively, p < 0.001 for both comparisons).

CONCLUSIONS

Cluster headache often occurs in the pediatric population, although they are typically not diagnosed until adulthood. The onset of cluster headache is the inverse of that in migraine; in migraine women are more likely to have migraine between ages 10 and 50 but the sex ratio is approximately equal otherwise. Prototypical migrainous features are not useful in differentiating cluster headache from migraine. Participant data from a large international study also suggest that chronic cluster headache is not only less responsive to newer treatments (like noninvasive vagus nerve stimulation and galcanezumab), but to traditional first-line treatments as well.

Evidence That HFE H63D Variant Is a Potential Disease Modifier in Cluster Headache

Cluster headache (CH) is a primary headache disorder with a complex genetic background. Several studies indicate a potential link between iron homeostasis and the pathophysiology of primary headaches. The HFE gene encodes for a protein involved in iron metabolism, while genetic variants in HFE have been associated with hereditary hemochromatosis (HH), an iron overload disorder. The objective of the current study was to examine the association of the more common HFE H63D variant, with the susceptibility to develop CH and diverse clinical phenotypes in a population of Southeastern European Caucasian (SEC) origin. Genomic DNA samples from 128 CH patients and 294 neurologically healthy controls were genotyped for the HFE rs1799945 (H63D) variant. H63D genotypic and allelic frequency distribution did not differ significantly between patients and controls (p > 0.05). Subgroup analysis revealed a significantly more frequent occurrence of the variant G allele in chronic compared to episodic CH patients, indicative for a possible correlation of the HFE gene with the susceptibility for disease chronification. Although homozygosity for the less prevalent H63D variant G allele was minimal in the CH cohort, the results of the present study are in accordance with previous studies in CH and migraine patients, suggesting that HFE H63D variant modifies the disease clinical characteristics. Hence, despite the absence of a per se association with CH susceptibility in the current SEC cohort, variability in HFE gene may be potentially regarded as a disease modifier genetic factor in CH.

Hemicrania continua in a family: A report of two cases

OBJECTIVE

To report two cases of hemicrania continua (HC) in a mother and daughter.

BACKGROUND

HC is a rare primary headache disorder belonging to the family of trigeminal autonomic cephalalgias (TACs). Unlike migraine, familial cases of TACs are rare, and we know relatively little of their inheritance pattern and genetic mechanisms.

METHODS

We present a mother and daughter with HC. We compare the similarities and differences between this family and the first report of familial HC and discuss the implications for future studies.

RESULTS

Both the mother and daughter presented with a constant, side-locked headache of moderate intensity, with episodic exacerbations of more severe pain that are associated with ipsilateral cranial autonomic activation. After negative workup, both patients were started on indomethacin and achieved absolute response at different doses, confirming HC.

CONCLUSIONS

Our report further corroborates other reports of familial TACs that TACs are primary headaches possibly attributable to genetic factors, albeit detailed mechanisms remain elusive. Nevertheless, whether clinical presentation and treatment responses would be substantially different between sporadic and familial HCs remain unclear.

Clinical Features of Cluster Headache: A Hospital-Based Study in Taiwan

Most previous studies on cluster headache (CH) focus on Western populations. This study aimed to investigate the clinical characteristics of CH in a neurology outpatient population in Taiwan. A cross-sectional survey was conducted from July 2015 to June 2019 in a medical college affiliated with a tertiary care hospital (Tri-Service General Hospital) in Taiwan. All consecutive patients reporting headache as their chief complaint were asked to participate in a face-to-face interview with a qualified headache specialist and to complete a detailed self-administered questionnaire. The diagnosis of CH was made according to the Third edition of the International Classification of Headache Disorders. The subjects comprised 80 consecutive new CH patients (13 women and 67 men; ratio, 1:5). The mean age at presentation was 36.0 ± 10.8 years (range, 16-64 years), mean age at onset was 27.2 ± 12.1 years (range, 5-65 years), and mean time lag before diagnosis was 9.3 ± 10.5 years (range, 0-46.4 years). Of the total CH patients, 25.3% reported feelings of restlessness during headache episodes. A seasonal predilection was reported by 18% of the CH patients. The use of tobacco was the most common (44/80 patients). Chronic CH was only observed in 5% of the patients and only one patient (1.3%) reported both a positive family history for CH and aura. Features of CH in Taiwanese patients differed from that of Caucasian patients; a lower prevalence of chronic CH, positive family history of CH, and occurrence of aura may be less common in the former than in the latter.

Current Understanding of the Chronobiology of Cluster Headache and the Role of Sleep in Its Management

Cluster headache is uniquely rhythmic in its occurrence both diurnally and annually. This has implications for the clinical approach to the patient but also for our understanding of the role of central structures in its pathological basis. Many intrinsic and extrinsic factors seem to influence CH rhythmicity, including genetics. The proclivity for attacks to occur at night and the possible association with particular sleep phenomena, including sleep apnea, have motivated a number of studies which has improved our understanding but many questions remain unanswered. The sleep-headache interaction seems to be bidirectional and possibly both direct and indirect. The latter could involve more disperse networks of homeostatic regulation, which may better encompass recent observations. Treatment of the headache patient with concurrent sleep problems can be particularly challenging, especially considering side-effects and interactions of commonly used medications. While current treatment guidelines do not incorporate chronotherapeutic thinking, some evidence may suggest that application of such principles on an individual level may be beneficial.

Chronic Cluster Headache Update and East-West Comparisons: Focusing on Clinical Features, Pathophysiology, and Management

PURPOSE OF REVIEW

This review provides an update on chronic cluster headache (CH) focusing on clinical features, pathophysiology, and management as well as comparisons between Eastern and Western populations.

RECENT FINDINGS

Chronic CH in Eastern populations was relatively rare, compared to that in Western populations. Lacrimation and/or conjunctival injection is the most frequently reported cranial autonomic symptom, and visual aura is predominant in chronic CH patients. Neuroimaging evidence in both ethnic groups suggests that CH pathophysiology involves the hypothalamus and pain-modulatory areas, with dynamic alternations between CH episodes. Recent evidence indicates that midbrain dopaminergic systems may participate in CH chronicity. Noteworthy advances have emerged in neuromodulatory therapies for chronic CH, but treatment with calcitonin gene-related peptide (CGRP) monoclonal antibodies has been unsuccessful. Recent evidence shows divergence of chronic CH between Eastern and Western populations. Neuromodulatory therapies but not CGRP inhibition is effective in this intractable patient group.