Prevalence and incidence of cluster headache in the Republic of San Marino

The Prevalence and Clinical Phenotypes of Cluster Headache in Relation with Latitude

PURPOSE OF REVIEW

Previous studies have indicated a possible link between the prevalence of cluster headache (CH) and sunlight exposure. However, this theory has yet to be tested systemically. In this article, we aim to examine how latitude affects the prevalence and phenotypes of CH.

RECENT FINDINGS

To our knowledge, there is by far no article describing the effect of latitude on disease phenotype; thus, we performed a literature review. We noted positive effects of latitude on 1-year prevalence, the proportion of chronic CH, and the proportion of miosis and/or ptosis. Latitude may affect the phenotypic presentations of cluster headache, probably partially mediated via temperature and sunlight variations. Still, other factors, such as environmental exposure to smoking and the genetic difference between the Eastern and Western populations, may participate in the pathogenesis and clinical manifestations of CH.

Epidemiology of diagnosed cluster headache in Norway

Background:

Cluster headache (CH) is one of the most painful conditions in humans and there is limited epidemiological data on this debilitating condition.

Objectives:

To describe the epidemiology of CH in Norway

Methods:

We conducted a nationwide study to investigate the prevalence, incidence, and comorbidity of CH in Norway between January 1 2008 and December 31 2016. Treatment and outcome data from the Norwegian patient registry and the Norwegian prescription database were linked on an individual basis.

Results:

Among 3,892,260 individuals ≥18 years old of age, we identified a total of 1891 patients with CH. The prevalence of CH was 48.6 per 100,000, and the male-to-female ratio was 1.47. The estimated incidence of CH was 3.0 per 100,000/year. Among patients with CH, increased age and sex adjusted odds ratios ([OR], all with p-values <0.0001, were observed for medication-induced headache (OR 50.7, 95% CI 36.7–69.9), migraine (OR 25.2, 95% CI 22.5–28.3), chronic posttraumatic headache (OR 22.2, 95% CI 12.8–38.45), history of cranial trauma (OR 1.9, 95% CI 1.5–2.4), somatoform disorders (OR 4.2, 95% CI 3.0–5.8), suicide attempt (OR 3.9, 95% CI 2.6–5.8), personality disorder (OR 3.6, 95% CI 2.6–4.9), bipolar disorder (OR 3.6, 95% CI 2.8–4.8), peptic ulcer (OR 2.8, 95% CI 2.3–3.3), depression (OR 2.8, 95% CI 2.4–3.1), substance abuse (OR 2.6, 95% CI 2.0–3.3), and cerebrovascular disease (OR 2.4, 95% CI 1.8–3.1). Use of opioid analgesics during the study period was more common among patients with CH compared to others (81% vs. 22%, sex and age adjusted OR 23.4, 95% CI 20.8–26.2, p < 0.0001).

History of cluster headache

Objective:

To summarise the history of cluster headache evolving concepts and growing insights.

Background:

Excruciating pain, activation of the parasympathetic nervous system, and circadian rhythmicity characterise cluster headache attacks.

Results:

We find the oldest descriptions of patients suffering from the disorder in case reports of the 17th and 18th centuries. Only in the 19th and early 20th centuries did physicians start hypothesizing its cause. Initially, many researchers suspected the origin of the pain in peripheral nerves or blood vessels. However, eventually, they understood that the cause of the disease lies in the brain. In 1998, Positron emission tomography studies revealed increased activity of the posterior hypothalamus, whose role remains incompletely understood. Only recently have researchers realised that being diseased implies more than dysfunction. Recent studies analysed the consequences of cluster headache for each patient. Many struggle to deal with the disorder even in the absence of pain.

Conclusion:

Physicians have been aware of this type of pain for at least 300 years. Only when researchers studied pathological anatomy and physiology did knowledge accrue. A more comprehensive picture of the disease severity emerged when they also considered its consequences.

The neurobiology of cluster headache

Cluster headache is a primary headache form occurring in paroxysmal excruciatingly severe unilateral head pain attacks usually grouped in periods lasting 1-2months, the cluster periods. A genetic component is suggested by the familial occurrence of the disease but a genetic linkage is yet to be identified. Contemporary activation of trigeminal and cranial parasympathetic systems-the so-called trigemino-parasympathetic reflex-during the headache attacks seem to cause the pain and accompanying oculo-facial autonomic phenomena respectively. At peripheral level, the increased calcitonin gene related peptide (CGRP) plasma levels suggests trigeminal system activation during cluster headache attacks. The temporal pattern of the disease both in terms of circadian rhythmicity and seasonal recurrence has suggested involvement of the hypothalamic biological clock in the pathophysiology of cluster headache. The posterior hypothalamus was investigate as the cluster generator leading to activation of the trigemino-parasympathetic reflex, but the accumulated experience after 20 years of hypothalamic electrical stimulation to treat the condition indicate that this brain region rather acts as pain modulator. Efficacy of monoclonal antibodies to treat episodic cluster headache points to a key role of CGRP in the pathophysiology of the condition.

Insights into real-world treatment of cluster headache through a large Italian database: prevalence, prescription patterns, and costs

Objective: This study aimed at estimating the treated cluster headache (CH) prevalence and describing prescription patterns and direct costs paid by the Italian National-Health-System.Methods: Through the ReS database (healthcare administrative data collection of a large sample of the Italian population), adults in treatment for CH (acute therapy with sumatriptan/subcutaneous or oxygen, associated with preventive therapy with verapamil or lithium) were selected. A cross-sectional analysis described the prevalence of CH-treated subjects repeated annually in 2013-2017. A longitudinal analysis of patients selected in 2013-2015 and followed for 2 years provided the prescription patterns.Results: The annual prevalence of CH-treated patients increased from 6.4×100,000 adults in 2013 to 6.7 in 2017. In 2013-2015, 570 patients (80.7% M; mean age 46) treated for CH were found. In 50.4%, the identifying CH treatment was sumatriptan/subcutaneous+verapamil. During follow-up, >1/3 changed the preventive drug and interruption was the most frequent modification, although acute treatments were still prescribed. The mean annual cost/patient ranged from €2,956 to €2,267; pharmaceuticals expenditure represented the 56.4% and 57.3%, respectively.Conclusions: This study showed an important unmet need among CH patients, carrying a high economic burden that should be considered in the evaluation of the impact of incoming therapies (e.g. Calcitonin-Gene-Related-Peptide antibodies).

Direct and indirect costs of cluster headache: a prospective analysis in a tertiary level headache centre

Background

Cluster headache (CH) is the most frequent trigemino-autonomic cephalgia. CH can manifest as episodic (ECH) or chronic cluster headache (CCH) causing significant burden of disease and requiring attack therapy and prophylactic treatment. The few data available on the economic burden of CH come from retrospective studies based on questionnaires, population surveys and medical insurance claims database. Although all these studies showed an important economic burden, they provided different estimates depending on variability of CH awareness and management, healthcare systems, available therapies and use of treatments according to different guidelines.

Methods

This prospective study aimed to quantify the total direct and indirect cost of ECH and CCH over a cluster period, both for the patient and for the National Health System (NHS), using data from subjects who consecutively attended an Italian tertiary headache centre between January 1, 2018 and December 31, 2018.

Results

A total 108 patients (89 ECH, 19 CCH) were included. Mean attack frequency was 2.3 ± 1.4 per day. Mean total cost of a CH bout was €4398 per patient and total cost of CCH was 5.4 times higher than ECH (€13,350 vs. €2487, p <  0.001). Direct costs represented the 72.1% of total cost and were covered for the 94.8% by the NHS. The costs for any item of expense were higher for CCH than for ECH (p <  0.001). Mean indirect costs for a CH bout were €1226 per patient and were higher for CCH compared to ECH (€3.538 vs. €732), but the difference was not significant. Days with reduced productive capacity impacted for the 64.6% of the total indirect costs. The analysis of the impact CH on work showed that 27%% of patients felt that CH had limited their career, 40% had changed their work pattern, 20% had changed their place of employment and 10% had lost a job due to the disease.

Conclusion

Our results provide a valuable estimate of the direct and indirect costs of ECH and CCH in the specific setting of a tertiary headache centre and confirm the high economic impact of CH on both the NHS and patients.

Systematic review of the safety and effectiveness of peripheral neurostimulation of the sphenopalatine ganglion for the treatment of refractory chronic cluster headache

INTRODUCTION

This study aimed to assess the safety and effectiveness of peripheral neurostimulation of the sphenopalatine ganglion (SPG) in the treatment of refractory chronic cluster headache.

DEVELOPMENT

Various medical databases were used to perform a systematic review of the scientific literature. The search for articles continued until 31 October 2016, and included clinical trials, systematic reviews and/or meta-analyses, health technology assessment reports, and clinical practice guidelines that included measurements of efficiency/effectiveness or adverse effects associated with the treatment. The review excluded cohort studies, case-control studies, case series, literature reviews, letters to the editor, opinion pieces, editorials, and studies that had been duplicated or outdated by later publications from the same institution. Regarding effectiveness, we found that SPG stimulation had positive results for pain relief, attack frequency, medication use, and patients' quality of life. In the results regarding safety, we found a significant number of adverse events in the first 30 days following the intervention. Removal of the device was necessary in some patients. Little follow-up data, and no long-term data, is available.

CONCLUSIONS

These results are promising, despite the limited evidence available. We consider it essential for research to continue into the safety and efficacy of SPG stimulation for patients with refractory chronic cluster headache. In cases where this intervention may be indicated, treatment should be closely monitored.

The EUROLIGHT cluster headache project: Description of methods and the study population – An Internet-based cross-sectional study of people with cluster headache

Objective:

To present the methodology and to describe the sample of a large, Internet-based survey on the burden of cluster headache (CH).

Methods:

Participants filled out a questionnaire online. Inclusion criteria were a reported diagnosis of CH and a residency in a European country; exclusion criteria were refusal to give informed consent and to complete the questionnaire.

Results:

A total of 1514 participants completed the questionnaire. Of these, 66.2% were male and 31.2% reported suffering from chronic CH. The diagnosis was validated based upon the responses in 92.9% of the participants. Other diagnoses seemed more likely in 0.8%. Among the participants with self-reported chronic CH, the International Classification of Headache Disorders-3 beta criteria for chronicity were fulfilled by 90.8%.

Conclusions:

In this article, we discuss the applied methodology as well as the properties of the sample. The overall accuracy of the self-reported diagnoses was very good as judged by our questionnaire; women and chronic CH were slightly over-represented. We will present the results of more thorough analyses in future articles and believe that these data will provide deeper insights into the burden of CH and will help to give a voice to those who endure this painful disease.

New strategies for the treatment and prevention of primary headache disorders

The primary headache disorders, which include migraine, cluster headache and tension-type headache, are among the most common diseases and leading causes of disability worldwide. The available treatment options for primary headache disorders have unsatisfactory rates of efficacy, tolerability and patient adherence. In this Review, we discuss promising new approaches for the prevention of primary headache disorders, such as monoclonal antibodies targeting calcitonin gene-related peptide (CGRP) or its receptor, and small-molecule CGRP receptor antagonists. Neuromodulation approaches employing noninvasive or implantable devices also show promise for treating primary headache disorders. Noninvasive treatments, such as transcranial magnetic stimulation and transcutaneous peripheral nerve stimulation, are delivered by devices that patients can self-administer. Implantable devices targeting the occipital nerves, sphenopalatine ganglion or high cervical spinal cord are placed using percutaneous and/or surgical procedures, and are powered either wirelessly or by surgically implanted batteries. These new and emerging treatments have the potential to address unmet patient needs and reduce headache-associated disability.

Epidemiologic study of cluster headache prevalence in a medium-size city in Brazil

ABSTRACT To determine the prevalence of cluster headache (CH) in Barbacena, a medium-size city in the State of Minas Gerais, Brazil. Methods The total population of Barbacena is 126,284 inhabitants and the Family Health Strategy Program covers 84,610 of them. In order to identify patients with cluster headache, 36,145 of these inhabitants were screened, following which, a questionnaire was completed by 181 health agents distributed throughout the 28 health posts belonging to the Family Health Strategy network. The completed questionnaires were selected based on the clinical criteria established by the International Headache Society, and those patients (18 years of age or older) with a possible CH diagnosis were later assessed by a headache specialist. This was an observational, cross-sectional study. Results In all, 15 patients were diagnosed as having CH, comprising a prevalence of 0.0414%; or 41.4/100,000 inhabitants. Conclusion The prevalence of cluster headache in Barbacena was lower than that observed in many locations worldwide.

Systematic review of the safety and effectiveness of peripheral neurostimulation of the sphenopalatine ganglion for the treatment of refractory chronic cluster headache

INTRODUCTION

This study aimed to assess the safety and effectiveness of peripheral neurostimulation of the sphenopalatine ganglion (SPG) in the treatment of refractory chronic cluster headache.

DEVELOPMENT

Various medical databases were used to perform a systematic review of the scientific literature. The search for articles continued until 31 October 2016, and included clinical trials, systematic reviews and/or meta-analyses, health technology assessment reports, and clinical practice guidelines that included measurements of efficiency/effectiveness or adverse effects associated with the treatment. The review excluded cohort studies, case-control studies, case series, literature reviews, letters to the editor, opinion pieces, editorials, and studies that had been duplicated or outdated by later publications from the same institution. Regarding effectiveness, we found that SPG stimulation had positive results for pain relief, attack frequency, medication use, and patients' quality of life. In the results regarding safety, we found a significant number of adverse events in the first 30 days following the intervention. Removal of the device was necessary in some patients. Little follow-up data, and no long-term data, is available.

CONCLUSIONS

These results are promising, despite the limited evidence available. We consider it essential for research to continue into the safety and efficacy of SPG stimulation for patients with refractory chronic cluster headache. In cases where this intervention may be indicated, treatment should be closely monitored.

Prevalence of Cluster Headache in a Population-Based Sample in Germany

A population-based sample of 6000 inhabitants of the city of Essen in Germany was screened using a standard questionnaire for possible cluster headache (CH). Fifty-six percent responded ( N = 3336, 50.5% of them women, mean age 44.7 ± 12.7 years). All suspected cases ( N = 182) were interviewed by a neurologist. Four subjects with CH (three men) were identified. The 1-year prevalence of CH was estimated to be 119/100 000 (95% confidence interval 3, 238/100 000).

Burden of Cluster Headache

The aim was to analyse the socioeconomic burden of cluster headache in patients from a tertiary headache centre. One hundred consecutive patients from the Danish Headache Centre were invited to an interview about the socioeconomic impact of cluster headache. Work absence and use of medical services were compared with a Danish population-based survey. Eighty-five patients participated; 78% reported restrictions in daily living and 13% also outside of cluster periods; 25% reported a major decrease in their ability to participate in social activities, family life and housework. The disease caused lifestyle changes for 96%, most frequently in sleeping habits and avoidance of alcohol. The absence rate among patients was 30%, which was significantly higher than 12% among the general population ( P < 0.001). Use of health services due to headache was also higher among the patients ( P < 0.001). Cluster headache, although periodic in most cases, has considerable impact on social functions, quality of life and use of healthcare.

Evidence-based treatments for cluster headache

Cluster headache (CH), one of the most painful syndromes known to man, is managed with acute and preventive medications. The brief duration and severity of the attacks command the use of rapid-acting pain relievers. Inhalation of oxygen and subcutaneous sumatriptan are the two most effective acute therapeutic options for sufferers of CH. Several preventive medications are available, the most effective of which is verapamil. However, most of these agents are not backed by strong clinical evidence. In some patients, these options can be ineffective, especially in those who develop chronic CH. Surgical procedures for the chronic refractory form of the disorder should then be contemplated, the most promising of which is hypothalamic deep brain stimulation. We hereby review the pathogenesis of CH and the evidence behind the treatment options for this debilitating condition.

Surgery for treatment of refractory chronic cluster headache: toward standard procedures

The degree of disability due to chronic cluster headache refractory to conservative treatments justifies surgical procedures as second-line treatments. Many studies and reports nowadays confirm the efficacy of the two mostly used surgical techniques in such cases. Both deep brain stimulation and occipital nerve stimulation are in fact currently utilized for this purpose but the surgical technique has not yet been standardized. We describe the surgical steps of both procedures.

Trigeminal autonomic cephalalgias

The trigeminal autonomic cephalalgias (TACs) are a group of primary headache disorders characterised by lateralized symptoms: prominent headache and ipsilateral cranial autonomic features, such as conjunctival injection, lacrimation and rhinorrhea. The TACs are: cluster headache (CH), paroxysmal hemicrania (PH), short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT)/short-lasting neuralgiform headache attacks with cranial autonomic features (SUNA) and hemicrania continua (HC). Their diagnostic criteria are outlined in the International Classification of Headache Disorders, third edition-beta (ICHD-IIIb). These conditions are distinguished by their attack duration and frequency, as well as response to treatment. HC is continuous and by definition responsive to indomethacin. The main differential when considering this headache is chronic migraine. Other TACs are remarkable for their short duration and must be distinguished from other short-lasting painful conditions, such as trigeminal neuralgia and primary stabbing headache. Cluster headache is characterised by exquisitely painful attacks that occur in discrete episodes lasting 15-180 min a few times a day. In comparison, PH occurs more frequently and is of shorter duration, and like HC is responsive to indomethacin. SUNCT/SUNA is the shortest duration and highest frequency TAC; attacks can occur over a hundred times every day.

Familial aggregation of cluster headache

Several studies suggest a strong familial aggregation for cluster headache (CH), but so far none of them have included subjects with probable cluster headache (PCH) in accordance with the International Classification of Headache Disorders.

OBJECTIVE

To identify cases of probable cluster headache and to assess the familial aggregation of cluster headache by including these subjects.

METHOD

Thirty-six patients attending a headache consultation and diagnosed with trigeminal autonomic headaches were subjected to a questionnaire-based interview. A telephone interview was also applied to all the relatives who were pointed out as possibly affected as well as to some of the remaining relatives.

RESULTS

Twenty-four probands fulfilled the criteria for CH or PCH; they had 142 first-degree relatives, of whom five were found to have CH or PCH, including one case of CH sine headache. The risk for first-degree relatives was observed to be increased by 35- to 46-fold.

CONCLUSION

Our results suggest a familial aggregation of cluster headache in the Portuguese population.

Trigeminal autonomic cephalalgias: A review of recent diagnostic, therapeutic and pathophysiological developments

The trigeminal autonomic cephalalgias (TACs) are a group of primary headache disorders that are characterized by strictly unilateral trigeminal distribution pain occurring in association with ipsilateral cranial autonomic symptoms. This group includes cluster headache, paroxysmal hemicrania and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing. These disorders are very painful, often considered to be some of the most painful conditions known to mankind, and consequently are highly disabling. They are distinguished by the frequency of attacks of pain, the length of the attacks and very characteristic responses to medical therapy, such that the diagnosis can usually be made clinically, which is important because it dictates therapy. The management of TACs can be very rewarding for physicians and highly beneficial to patients.

Headache in pregnancy: a nuisance or a new sense?

Headache is a very commonly encountered symptom in pregnancy and is usually due to primary headache disorders which are benign in nature. It can however be quite debilitating for some women who may need therapeutic treatment of which there are several options safe to use in pregnancy. It is equally important though to recognise that headache may be a sign of serious underlying pathology. This paper aims to provide a clinically useful guidance for differentiation between primary and secondary headaches in pregnancy. The primary headache disorders and their management in pregnancy are explored in depth with brief overviews of the causes for secondary headaches and their further investigation and management.

Secondary chronic cluster headache due to trigeminal nerve root compression

A 50-year-old woman had a gradual onset of chronic headache located in the right temporal region and a burning sensation in the root of the tongue which over a year evolved into chronic cluster headache with a milder chronic headache in-between the severe cluster headache attacks. A cerebral magnetic resonance imaging (MRI) showed vascular compression of the trigeminal nerve root on the pain side. Neurosurgery microvascular decompression relieved the patient's chronic cluster headache, the chronic intermittent headache and the burning tongue sensation. The effect was persistent at a 1 year follow-up. Patients with atypical symptoms of cluster headache should be examined with cerebral MRI angiography of arteries and veins to exclude symptomatic causes.

Deep brain stimulation of the posteromedial hypothalamus: indications, long-term results, and neurophysiological considerations

OBJECT

The aim of this study was to review the indications for and results of deep brain stimulation (DBS) of the posterior hypothalamus (pHyp) in the treatment of drug-refractory and severe painful syndromes of the face, disruptive and aggressive behavior associated with epilepsy, and below-average intelligence. The preoperative clinical picture, functional imaging studies, and overall clinical results in the literature are discussed.

METHODS

All patients underwent stereotactic implantation of deep-brain electrodes within the pHyp. Data from several authors have been collected and reported for each clinical entity, as have clinical results, adverse events, and neurophysiological characteristics of the pHyp.

RESULTS

The percentage of patients with chronic cluster headache who responded to DBS was 50% in the overall reported series. The response rate was 100% for short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing and for chronic paroxysmal hemicrania, although only 2 patients and 1 patient, respectively, have been described as having these conditions. None of the 4 patients suffering from refractory neuropathic trigeminal pain benefited from the procedure (0% response rate), whereas all 5 patients (100%) affected with refractory trigeminal neuralgia (TN) due to multiple sclerosis (MS) and undergoing pHyp DBS experienced a significant decrease in pain attacks within the first branch of cranial nerve V. Six (75%) of 8 patients presenting with aggressive behavior and mental retardation benefited from pHyp stimulation; 6 patients were part of the authors' series and 2 were reported in the literature.

CONCLUSIONS

In carefully selected patients, DBS of the pHyp can be considered an effective procedure for the treatment of refractory trigeminal autonomic cephalalgias, aggressive behavior, and MS-related TN in the first trigeminal branch. Only larger and prospective studies along with multidisciplinary approaches (including, by necessity, neuroimaging studies) can lead us to better patient selection that would reduce the rate of nonresponders.

Mode of occurrence of traumatic head injuries in male patients with cluster headache or migraine: Is there a connection with lifestyle?

Introduction: Our study objective was to investigate the mode of occurrence of traumatic head injury in episodic cluster headache and migraine patients.

Methods: We conducted a retrospective study on 400 male patients, 200 with cluster headache (cases) and 200 with migraine (controls). We investigated the frequency and mode of occurrence of traumatic head injury and some lifestyle habits.

Results: The number of traumatic head injuries was significantly higher in cases than in controls (adjusted odds ratio [OR] = 2.0; 95% confidence interval [CI] = 1.5–2.8). Cases were more often responsible for the head traumas (adjusted OR = 2.6; 95% CI = 1.3–4.9) and reported a significantly higher proportion of injuries during scuffles or brawls (OR = 6.5; 95% CI = 2.9–14.8). Compared with other cluster headache patients, cases responsible for traumatic head injuries were more frequently heavy alcohol ( p = .000), heavy tobacco ( p = .03) and heavy coffee consumers ( p = .003).

Conclusions: Cluster headache patients (a) had traumatic head injuries more frequently than migraineurs; and (b) were more often responsible for them, perhaps due to particular behaviours related to their lifestyles.

Epidemiology of headache

Epidemiological studies conducted in the general population point to average headache prevalence rates of 46% for 1-year prevalence and of 64% for lifetime prevalence. For migraine, most studies conducted in the adult general population of western Europe and North America indicate rates between 5% and 9% in men, and between 12% and 25% in women. Non-western countries report lower figures. Migraine shows no gender differences in children, while in the elderly its frequency appears much reduced in both genders. About one-third of migraineurs suffer from migraine with aura. For tension-type headache, prevalence data reports in the literature are few and conflicting: rates range from 11% in Singapore to 20-40% in the USA and over 80% in Denmark. It is worth noting that the highest figures are found in studies where a personal interview has been employed. This probably indicates that the prevalence of this headache subtype is particularly sensitive to the method of data collection. Cluster headache occurs in 1-3 per thousand of the general population, with a gender (M:F) ratio of about 3:1. About 4% of the adult general population suffers from chronic daily headache.

Efficacy of oxygen inhalation in sumatriptan refractory "high altitude" cluster headache attacks

We describe the case of a 40-year-old woman, affected by episodic cluster headache, who presented with a cluster headache triggered by exposure to high altitude. Her attacks were refractory to sumatriptan, very effective at sea level, but responded to oxygen. A pathophysiological mechanism is proposed.

Pathophysiology of trigeminal autonomic cephalalgias

Cluster headache, paroxysmal hemicrania, and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) are primary headaches recently classified together as trigeminal autonomic cephalalgias (TACs). The causes of these headaches have long been debated, with "peripheral" hypotheses in opposition to "central" hypotheses. The available information indicates that the pain originates from within the brain in cluster headache. The hypothalamic activation observed during TAC attacks by use of functional neuroimaging, and the success of hypothalamic stimulation as a treatment, confirm that the posterior hypothalamus is crucial in the pathophysiology of these headaches. The posterior hypothalamus is now known to modulate craniofacial pain, and hypothalamic activation occurs in other pain disorders, suggesting that this brain area is likely to have a more complex role in the pathophysiology of TACs than that of a mere trigger. Hypothalamic activation might play a part in terminating rather than triggering attacks, and might also give rise to a central permissive state, allowing attacks to take place.

Lessons from 8 years' experience of hypothalamic stimulation in cluster headache

Neuroimaging studies in cluster headache (CH) patients have increased understanding of attack-associated events and provided clues to the pathophysiology of the condition. They have also suggested stimulation of the ipsilateral posterior inferior hypothalamus as a treatment for chronic intractable CH. After 8 years of experience, stimulation has proved successful in controlling the pain attacks in almost 60% of chronic CH patients implanted at various centres. Although hypothalamic implant is not without risks, it has generally been performed safely. Implantation affords an opportunity to perform microrecordings of individual posterior hypothalamic neurons. These studies are at an early stage, but suggest the possibility of identifying precisely the target site by its electrophysiological characteristics. Autonomic studies of patients undergoing posterior hypothalamic stimulation provide further evidence that long-term stimulation is safe, revealing that it can cause altered modulation of the mechanisms of orthostatic adaptation without affecting the baroreflex, cardiorespiratory interactions or efferent sympathetic and vagal functions. Chronically stimulated patients have an increased threshold for cold pain at the site of the first trigeminal branch ipsilateral to the stimulated side; when the stimulator is switched off, changes in sensory and pain thresholds do not occur immediately, suggesting that long-term stimulation is required to induce sensory and nociceptive changes. Posterior inferior hypothalamic stimulation is now established as a treatment for many chronic CH patients. The technique is shedding further light on the pathophysiology of the disease, and is also providing clues to functioning of the hypothalamus itself.

Cluster headache

Cluster headache (CH) is a primary headache disease characterized by recurrent short-lasting attacks (15 to 180 minutes) of excruciating unilateral periorbital pain accompanied by ipsilateral autonomic signs (lacrimation, nasal congestion, ptosis, miosis, lid edema, redness of the eye). It affects young adults, predominantly males. Prevalence is estimated at 0.5–1.0/1,000. CH has a circannual and circadian periodicity, attacks being clustered (hence the name) in bouts that can occur during specific months of the year. Alcohol is the only dietary trigger of CH, strong odors (mainly solvents and cigarette smoke) and napping may also trigger CH attacks. During bouts, attacks may happen at precise hours, especially during the night. During the attacks, patients tend to be restless. CH may be episodic or chronic, depending on the presence of remission periods. CH is associated with trigeminovascular activation and neuroendocrine and vegetative disturbances, however, the precise cautive mechanisms remain unknown. Involvement of the hypothalamus (a structure regulating endocrine function and sleep-wake rhythms) has been confirmed, explaining, at least in part, the cyclic aspects of CH. The disease is familial in about 10% of cases. Genetic factors play a role in CH susceptibility, and a causative role has been suggested for the hypocretin receptor gene. Diagnosis is clinical. Differential diagnoses include other primary headache diseases such as migraine, paroxysmal hemicrania and SUNCT syndrome. At present, there is no curative treatment. There are efficient treatments to shorten the painful attacks (acute treatments) and to reduce the number of daily attacks (prophylactic treatments). Acute treatment is based on subcutaneous administration of sumatriptan and high-flow oxygen. Verapamil, lithium, methysergide, prednisone, greater occipital nerve blocks and topiramate may be used for prophylaxis. In refractory cases, deep-brain stimulation of the hypothalamus and greater occipital nerve stimulators have been tried in experimental settings. The disease course over a lifetime is unpredictable. Some patients have only one period of attacks, while in others the disease evolves from episodic to chronic form.

Headache and pregnancy

BACKGROUND

Many women who suffer from migraine and tension-type headaches (TTHs) have an improvement in the frequency of these headaches during pregnancy. At the same time pregnancy predisposes women to a number of potentially life-threatening conditions which can present with headache. Accurate diagnosis and treatment of headache during pregnancy is essential.

REVIEW SUMMARY

The primary objectives of this review are to: (1) Summarize the natural history of primary headache disorders, including migraine, tension-type, and cluster headaches during pregnancy, as well as the impact of migraine on pregnancy outcomes and complications.(2) Summarize the therapeutic options and strategies for managing headaches in pregnancy and (3) Discuss the causes of secondary headaches and the diagnostic evaluation for new onset headache during pregnancy.

CONCLUSION

Primary headache disorders, in particular TTHs and migraines, generally improve during pregnancy. However the frequency of improvement varies greatly. Because the pathophysiology of both migraines and TTHs is poorly understood, this limits our ability to predict improvement. Future research should be focused on headache pathophysiology and the effect of ovarian hormones and the pregnant state on headache pathogenesis.

The Incidence and Prevalence of Cluster Headache: A Meta-Analysis of Population-Based Studies

Cluster headache is a trigemino-autonomic cephalgia with a low prevalence. Several population-based studies on its prevalence and incidence have been performed, but with different methodology resulting in different figures. We analysed all available population-based epidemiological studies on cluster headache and compared the data in a meta-analysis. The pooled data showed a lifetime prevalence of 124 per 100 000 [confidence interval (CI) 101, 151] and a 1-year prevalence of 53 per 100 000 (CI 26, 95). The overall sex ratio was 4.3 (male to female), it was higher in chronic cluster headache (15.0) compared with episodic cluster headache (3.8). The ratio of episodic vs. chronic cluster headache was 6.0. Our analysis revealed a relatively stable lifetime prevalence, which suggests that about one in 1000 people suffers from cluster headache, the prevalence being independent of the region of the population study. The sex ratio (male to female) is higher than published in several patient-based epidemiological studies.

The global burden of headache: a documentation of headache prevalence and disability worldwide

This study, which is a part of the initiative 'Lifting The Burden: The Global Campaign to Reduce the Burden of Headache Worldwide', assesses and presents all existing evidence of the world prevalence and burden of headache disorders. Population-based studies applying International Headache Society criteria for migraine and tension-type headache, and also studies on headache in general and 'chronic daily headache', have been included. Globally, the percentages of the adult population with an active headache disorder are 46% for headache in general, 11% for migraine, 42% for tension-type headache and 3% for chronic daily headache. Our calculations indicate that the disability attributable to tension-type headache is larger worldwide than that due to migraine. On the World Health Organization's ranking of causes of disability, this would bring headache disorders into the 10 most disabling conditions for the two genders, and into the five most disabling for women.

Validation of a questionnaire for the detection of cluster headache

BACKGROUND

In the absence of biological markers, the diagnosis of cluster headache (CH) rests on clinical evidence as reported through ad-hoc interviews.

OBJECTIVE

The aim of this study was to validate a 16-item self-administered questionnaire designed to screen CH cases.

METHODS

The questions were based on the second edition of the International Headache Society classification (ICHD-II) criteria for CH (n = 12) and on specific disease features (n = 3). Answers to each question were either "Yes,""No," or "Don't know." The validity of this screening tool was assessed using a two-step procedure. In Step 1, the 16 questions were submitted to 30 healthy subjects with different cultural backgrounds to verify content clarity. In Step 2, the questionnaire was given to 71 patients (32 women and 39 men) aged 15 to 78 years (mean 37.5 years), who were seen at the University of Parma Headache Center with a diagnosis of CH (episodic, 17; chronic, 13), migraine (without aura, 18; with aura, 3), and tension-type headache (episodic, 16; chronic, 4) according to the ICHD-II criteria. Sensitivity, specificity, and the positive and negative predictive values were calculated for each question as measures of validity.

RESULTS

Severity, unilaterality, and location of pain had the highest sensitivity (100%), but low (34.1%) or fairly low specificity (61.0% and 58.5%, respectively). In contrast, a positive response to lithium or verapamil had a 66.7% sensitivity and a 97.6% specificity. Sensitivity and specificity were 100% and 90.2% for duration of attacks (<180 to 240 minutes), and 90.0% and 92.7% for compulsory movements, respectively. The best discriminatory pattern for symptom detection was unilaterality of pain and the presence of at least five of the following seven features: pain severity and location, duration, frequency and daily recurrence of attacks, rhinorrhea and restlessness as accompanying symptoms.

CONCLUSIONS

Our findings confirm that this questionnaire is a useful method for CH screening in epidemiological studies.

Enucleation and development of cluster headache: a retrospective study

Background

Cluster headache (CH) is a neurovascular, primary headache disorder. There are, however, several case reports about patients whose CH started shortly after a structural brain disease or trauma. Motivated by a patient who developed CH 3 weeks after the removal of an eye and by similar case reports, we tested the hypothesis that the removal of an eye is a risk factor for CH.

Methods

A detailed headache questionnaire was filled out by 112 patients on average 8 years after enucleation or evisceration of an eye.

Results

While 21 % of these patients experienced previously unknown headaches after the removal of an eye, no patient fulfilled the diagnostic criteria for CH.

Conclusion

Our data does not suggest that the removal of an eye is a major risk factor for the development of CH.

Decreasing Incidence of Cluster Headache: A Population‐Based Study in Olmsted County, Minnesota

The incidence of medically recognized cluster headache within Olmsted County, Minnesota, from 1989 through 1990, was determined by using modified International Headache Society criteria. The results were compared with previously published incidence data from 1979 through 1981. The overall age- and sex-adjusted incidence decreased from 9.8/100,000 person-years in 1979-1981 to 2.07/100,000 person-years in 1989-1990.

Intranasal medications for the treatment of migraine and cluster headache

Intranasal medications for the treatment of headache have recently received increased attention. This paper reviews intranasal formulations of a variety of available medications (dihydroergotamine mesylate [dihydroergotamine mesilate], sumatriptan, zolmitriptan, butorphanol, capsaicin and lidocaine [lignocaine]) and one experimental medication (civamide, a cis-isomer of capsaicin) for the treatment of migraine and cluster headache. Although the efficacy of intranasal agents varies with the product used, intranasal delivery may be both convenient and more effective than other modes of drug delivery for a variety of reasons: (i) intranasal administration bypasses small bowel gastrointestinal tract absorption, which is often significantly delayed during the acute phase of a migraine attack; (ii) nauseated patients may prefer non-oral formulations as they decrease the chance of vomiting and are more rapidly effective; (iii) intranasal administration causes no pain or injection site reaction and is easier and more convenient to administer than injection or suppository and so may be used earlier in a migraine attack, resulting in better efficacy; (iv) intranasal medication produces the same number or fewer adverse events than injections; and (v) intranasal formulations offer a more rapid onset of action than oral medications, for some of the above reasons and, as such, may be more useful in patients with cluster headache, although this needs to be verified. However, it is important to emphasise that a preference study showed that most patients prefer oral tablets to an intranasal formulation. Also, some nasal preparations have significant adverse effects or are not well absorbed and therefore do not work consistently; others are more challenging to administer as a result of their delivery apparatus. Nevertheless, it is our opinion that nasal preparations increase therapeutic options and may result in faster response times and better efficacy than oral formulations and better patient satisfaction than injectable preparations.

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.