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.

Reduced plasma calcitonin gene-related peptide level identified in cluster headache: A prospective and controlled study.

BACKGROUND: The role of calcitonin gene-related peptide (CGRP) in the cyclic pattern of cluster headache is unclear. To acquire biological insight and to comprehend why only episodic cluster headache responds to CGRP monoclonal antibodies, we examined whether plasma CGRP changes between disease states (i.e. bout, remission and chronic) and controls. METHODS: The present study is a prospective case-control study. Participants with episodic cluster headache were sampled twice (bout and remission). Participants with chronic cluster headache and controls were sampled once. CGRP concentrations were measured in plasma with a validated radioimmunoassay. RESULTS: Plasma was collected from 201 participants diagnosed with cluster headache according to the International Classification of Headache Disorders, 3rd edition, and from 100 age- and sex-matched controls. Overall, plasma CGRP levels were significantly lower in participants with cluster headache compared to controls (p < 0.05). In episodic cluster headache, CGRP levels were higher in bout than in remission (mean difference: 17.1 pmol/L, 95% confidence interval = 9.8-24.3, p < 0.0001). CGRP levels in bout were not different from chronic cluster headache (p = 0.266). CONCLUSIONS: Plasma CGRP is unsuitable as a diagnostic biomarker of cluster headache or its disease states. The identified reduced CGRP levels suggest that CGRPs role in cluster headache is highly complex and future investigations are needed into the modulation of CGRP and its receptors.

Profile of Chinese Cluster Headache Register Individual Study (CHRIS): Clinical characteristics, diagnosis and treatment status data of 816 patients in China.

BACKGROUND: The clinical profile of cluster headache may differ among different regions of the world, warranting interest in the data obtained from the initial Chinese Cluster Headache Register Individual Study (CHRIS) for better understanding. METHODS: We conducted a multicenter, prospective, longitudinal cohort study on cluster headache across all 31 provinces of China, aiming to gather clinical characteristics, treatment approaches, imaging, electrophysiological and biological samples. RESULTS: In total 816 patients were enrolled with a male-to-female ratio of 4.33:1. The mean age at consultation was 34.98 ± 9.91 years, and 24.89 ± 9.77 years at onset. Only 2.33% were diagnosed with chronic cluster headache, and 6.99% had a family history of the condition. The most common bout was one to two times per year (45.96%), lasting two weeks to one month (44.00%), and occurring frequently in spring (76.23%) and winter (73.04%). Of these, 68.50% experienced one to two attacks per day, with the majority lasting one to two hours (45.59%). The most common time for attacks was between 9 am and 12 pm (75.86%), followed by 1 am and 3 am (43.48%). Lacrimation (78.80%) was the most predominant autonomic symptom reported. Furthermore, 39.22% of patients experienced a delay of 10 years or more in receiving a correct diagnosis. Only 35.67% and 24.26% of patients received common acute and preventive treatments, respectively. CONCLUSION: Due to differences in ethnicity, genetics and lifestyle conditions, CHRIS has provided valuable baseline data from China. By establishing a dynamic cohort with comprehensive multidimensional data, it aims to advance the management system for cluster headache in China.

One-year prevalence of cluster headache, hemicrania continua, paroxysmal hemicrania and SUNCT in Norway: a population-based nationwide registry study.

BACKGROUND: There is lack of population-based studies evaluating the prevalence of paroxysmal hemicrania, hemicrania continua and short-lasting unilateral neuralgiform headache attacks. OBJECTIVES: The aim of this study was to investigate the gender-specific 1-year prevalence of cluster headache, paroxysmal hemicrania, hemicrania continua, and short-lasting unilateral neuralgiform headache attacks. METHODS: A nationwide study was conducted from January 1 2022 and December 31 2022 by linking diagnostic codes from Norwegian Patient Registry and prescription of relevant drugs from Norwegian Prescription Database on an individual basis. The 1-year prevalence with 95% confidence intervals (CI) of cluster headache, paroxysmal hemicrania, hemicrania continua and short-lasting unilateral neuralgiform headache attacks are estimated based on the combination of diagnostic codes, prescription of drugs and corresponding reimbursement codes. RESULTS: Among 4,316,747 individuals aged ≥ 18 years, the 1-year prevalence per 100,000 was 14.6 (95% CI 13.5-15.8) for cluster headache, 2.2 (95% CI 1.8-2.7) for hemicrania continua, 1.4 (95% CI 1.0-1.8) for paroxysmal hemicrania, and 1.2 (95% CI 0.8-1.4) for short-lasting unilateral neuralgiform headache attacks. For all the trigeminal autonomic cephalalgies, cluster headache included, the prevalence was higher for women than men. CONCLUSIONS: In this nationwide register-based study, we found a 1-year prevalence per 100,100 of 14.6 for cluster headache, 2.2 for hemicranias continua, 1.4 for paroxysmal hemicranias, and 1.2 for short-lasting unilateral neuralgiform headache attacks. This is the first study reporting higher prevalence of cluster headache for women than men.

Patients with chronic cluster headache may show reduced activity energy expenditure on ambulatory wrist actigraphy recordings during daytime attacks.

OBJECTIVE: To investigate the changes in activity energy expenditure (AEE) throughout daytime cluster headache (CH) attacks in patients with chronic CH and to evaluate the usefulness of actigraphy as a digital biomarker of CH attacks. BACKGROUND: CH is a primary headache disorder characterized by attacks of severe to very severe unilateral pain (orbital, supraorbital, temporal, or in any combination of these sites), with ipsilateral cranial autonomic symptoms and/or a sense of restlessness or agitation. We hypothesized increased AEE from hyperactivity during attacks measured by actigraphy. METHODS: An observational study including patients with chronic CH was conducted. During 21 days, patients wore an actigraphy device on the nondominant wrist and recorded CH attack-related data in a dedicated smartphone application. Accelerometer data were used for the calculation of AEE before and during daytime CH attacks that occurred in ambulatory settings, and without restrictions on acute and preventive headache treatment. We compared the activity and movements during the pre-ictal, ictal, and postictal phases with data from wrist-worn actigraphy with time-concordant intervals during non-headache periods. RESULTS: Four patients provided 34 attacks, of which 15 attacks met the eligibility criteria for further analysis. In contrast with the initial hypothesis of increased energy expenditure during CH attacks, a decrease in movement was observed during the pre-ictal phase (30 min before onset to onset) and during the headache phase. A significant decrease (p < .01) in the proportion of high-intensity movement during headache attacks, of which the majority were oxygen-treated, was observed. This trend was less present for low-intensity movements. CONCLUSION: The unexpected decrease in AEE during the pre-ictal and headache phase of daytime CH attacks in patients with chronic CH under acute and preventive treatment in ambulatory settings has important implications for future research on wrist actigraphy in CH.

An atypical survey in a cluster headache patient: A case report.

Cluster headache is a rare, severe headache associated with hypothalamic dysfunction or sleep cycles. It is classified in the primary headache group in The International Classification of Headache Disorders-3-2018 (ICHD-3-2018). In this case report, we present a 62-year-old male patient whose cluster headache showed a five times longer remission interval after dental implant treatment and ceased for more than two years following cardiac stent therapy.

Translating the Cluster Headache Quality of Life Questionnaire (CHQ) from English to Dutch with the TRAPD method.

OBJECTIVE: Cluster headache is associated with a decreased quality of life (QoL). The increased focus on patient-reported outcome measures (PROMS) has led to the creation of a tailored Cluster Headache Quality of Life scale (CHQ). Our objective was to create and authenticate a Dutch version of the CHQ (CHQ-D). METHODS: The TRAPD model (Translation, Review, Adjudication, Pretesting, Documentation) was used to translate the CHQ from English to Dutch and ensure cross-cultural adaption. Pre-testing was performed in n = 31 participants, and validity was in a new sample of n = 40 participants who completed the CHQ twice at a 2-day interval. Intraclass correlation coefficient (ICC) and Cronbach's alpha were used to assess the validity and reproducibility of the CHQ-D. RESULTS: To produce the CHQ-D, we made five modifications based on pretesting. Participants finished the questionnaire in a median time of 10 min (IQR:10.0, 17.5) and 90% within 20 min. The majority of participants (74.2%) did not find it burdensome at all. The reliability of the CHQ-D was excellent (Cronbach's alpha: 0.94; ICC: 0.94). CONCLUSION: The CHQ-D is a valid and practical instrument for QoL in individuals with cluster headache. We aim to use CHQ-D as PROM in clinical research in the Netherlands to enforce international collaborations and comparisons of studies.

Biomarkers in cluster headache: A systematic review.

OBJECTIVE: To systematically investigate previously examined biomarkers in blood, urine, cerebrospinal fluid, tear fluid, and saliva of patients with cluster headache. BACKGROUND: Cluster headache is a condition with extensive clinical challenges in terms of diagnosis and treatment. Identification of a biomarker with diagnostic implications or as a potential treatment target is highly warranted. METHODS: We conducted a systematic review including peer reviewed full text of studies that measured biochemical compounds in either blood, urine, cerebrospinal fluid, tear fluid, or saliva of patients with cluster headache diagnosed after the implementation of the International Classification of Headache Disorders (1988) written in English, Danish, Swedish, or Norwegian. Inclusion required a minimum of five participants. The search was conducted in PubMed and EMBASE, in September 2022, and extracted data were screened by two authors. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for reporting systematic reviews were followed. The Newcastle-Ottawa Scale was used to assess the risk of bias in case-controlled studies. RESULTS: We included 40 studies involving 832 patients with cluster headache and 872 controls, evaluating 80 potential biomarkers. The risk of bias for case-controlled studies was a median of 6 (range: 3-8) and 20 studies out of 40 (50%) were of fair or good quality. Most studies were identified within three groups: hypothalamic-regulated hormones, inflammatory markers, and neuropeptides. Among the hypothalamic hormones, cortisol was the most frequently investigated (N = 7) and was elevated in cluster headache in most of the studies. The most frequently examined inflammatory marker was interleukin 1 (N = 3), but findings were divergent. Calcitonin gene-related peptide was the most investigated neuropeptide (N = 9) and all studies found increased levels during attacks. CONCLUSION: Biomarker findings have been inconsistent and widely non-specific for cluster headache, which explains why none of the previous studies succeeded in identifying a unique biomarker for cluster headache, but instead contributed to substantiating the underlying pathophysiologic mechanisms. Several of the examined biomarkers could hold promise as markers for disease activity but are unfit for a clear distinction from both controls and other headaches.

A prospective open label 2-8 year extension of the randomised controlled ICON trial on the long-term efficacy and safety of occipital nerve stimulation in medically intractable chronic cluster headache.

BACKGROUND: We demonstrated in the randomised controlled ICON study that 48-week treatment of medically intractable chronic cluster headache (MICCH) with occipital nerve stimulation (ONS) is safe and effective. In L-ICON we prospectively evaluate its long-term effectiveness and safety. METHODS: ICON participants were enrolled in L-ICON immediately after completing ICON. Therefore, earlier ICON participants could be followed longer than later ones. L-ICON inclusion was stopped after the last ICON participant was enrolled in L-ICON and followed for ≥2 years by completing six-monthly questionnaires on attack frequency, side effects, subjective improvement and whether they would recommend ONS to others. Primary outcome was the change in mean weekly attack frequency 2 years after completion of the ICON study compared to baseline. Missing values for log-transformed attack-frequency were imputed for up to 5 years of follow-up. Descriptive analyses are presented as (pooled) geometric or arithmetic means and 95% confidence intervals. FINDINGS: Of 103 eligible participants, 88 (85%) gave informed consent and 73 (83%) were followed for ≥2 year, 61 (69%) ≥ 3 year, 33 (38%) ≥ 5 years and 3 (3%) ≥ 8.5 years. Mean (±SD) follow-up was 4.2 ± 2.2 years for a total of 370 person years (84% of potentially 442 years). The pooled geometric mean (95% CI) weekly attack frequency remained considerably lower after one (4.2; 2.8-6.3), two (5.1; 3.5-7.6) and five years (4.1; 3.0-5.5) compared to baseline (16.2; 14.4-18.3). Of the 49/88 (56%) ICON ≥50% responders, 35/49 (71%) retained this response and 15/39 (38%) ICON non-responders still became a ≥50% responder for at least half the follow-up period. Most participants (69/88; 78% [0.68-0.86]) reported a subjective improvement from baseline at last follow-up and 70/88 (81% [0.70-0.87]) would recommend ONS to others. Hardware-related surgery was required in 44/88 (50%) participants in 112/122 (92%) events (0.35 person-year-1 [0.28-0.41]). We didn't find predictive factors for effectiveness. INTERPRETATION: ONS is a safe, well-tolerated and long-term effective treatment for MICCH. FUNDING: The Netherlands Organisation for Scientific Research, the Dutch Ministry of Health, the NutsOhra Foundation from the Dutch Health Insurance Companies, and Medtronic.

Epidemiology, burden and clinical spectrum of cluster headache: a global update.

BACKGROUND: This narrative review aims to broaden our understanding of the epidemiology, burden and clinical spectrum of cluster headache based on updated findings with a global perspective. METHODS: We conducted a literature search on the following topics: (a) epidemiology; (b) burden: quality of life, disability, economic burden, job-related burden and suicidality; and (c) clinical spectrum: male predominance and its changes, age, pre-cluster and pre-attack symptoms, aura, post-drome, attack characteristics (location, severity, duration and associated symptoms), bout characteristics (attack frequency, bout duration and bout frequency), circadian and seasonal rhythmicity and disease course. RESULTS: New large-scale population-based reports have suggested a lower prevalence than previous estimations. The impact of cluster headache creates a significant burden in terms of the quality of life, disability, economic and job-related burdens and suicidality. Several studies have reported decreasing male-to-female ratios and a wide age range at disease onset. The non-headache phases of cluster headache, including pre-cluster, pre-attack and postictal symptoms, have recently been revisited. The latest data regarding attack characteristics, bout characteristics, and circadian and seasonal rhythmicity from different countries have shown variability among bouts, attacks, individuals and ethnicities. Studies on the disease course of cluster headache have shown typical characteristics of attacks or bouts that decrease with time. CONCLUSIONS: Cluster headache may be more than a "trigeminal autonomic headache" because it involves complex central nervous system phenomena. The spectrum of attacks and bouts is wider than previously recognised. Cluster headache is a dynamic disorder that evolves or regresses over time.

Clinical characteristics and treatment patterns of patients with episodic cluster headache: results from the United States, United Kingdom and Germany.

OBJECTIVE: To describe clinical characteristics and regional treatment patterns of episodic cluster headache (CH). METHODS: A point-in-time survey of physicians and their patients with CH was conducted in the United States, United Kingdom and Germany in 2017. RESULTS: Overall, 1012 patients with episodic CH were analyzed. Demographic and clinical findings were generally consistent across regions. Most patients were men (66.6%) and the mean age was 40.9 years. The greatest proportion of patients (38.3%) had ≤1 attack per day. The mean number of attacks per day (APD) was 2.4 and mean number of cluster periods per year was 2.6; the mean cluster period duration was 30.8 days. Most patients (69.3%) did not report a specific or predicable time when cluster periods occurred. Acute treatment was prescribed for 47.6% of patients, 10.3% of patients received preventive treatment, and 37.9% of patients received combined acute and preventive treatment; 4.2% of patients were not receiving treatment. Frequently prescribed acute treatments were sumatriptan, oxygen, and zolmitriptan; oxygen use varied considerably across countries and was prescribed least often in the United States. Frequently prescribed preventive treatments were verapamil, topiramate, and lithium. Lack of efficacy and tolerability were the most common reasons for discontinuing preventive treatment. CONCLUSIONS: We observed high use of acute treatments, but only half of patients used preventive treatments despite experiencing several cluster periods per year with multiple cluster APD. Further studies about the need for and benefits of preventive treatment for episodic CH are warranted.

People with cluster headache (CH) experience headache attacks of excruciating stabbing pain, usually on one side of the head around the eye. These headache attacks typically last between 15 min and 3 h, and come in clusters (or bouts) occurring up to several times a day for a few weeks or months at a time. This greatly impacts a patient's quality of life.We surveyed doctors and their patients across the United States, the United Kingdom and Germany, looking at symptoms that occurred during CH attacks, how long the headache attacks lasted, how often the patient had them, and what medicines were being given.Our results showed that patients with CH suffered from clusters (bouts) of headache attacks several times a year. Nearly, a third of patients had a wrong diagnosis before being diagnosed with CH. Patients experienced stress, agitation, restlessness, difficulty relaxing and depression during a headache attack, especially those who had more CH attacks each day.Although many patients were taking medication, only half of patients were prescribed medicines to prevent their headache attack from starting. Side effects and the medicines not working were the most common reasons patients stopped taking medicine to prevent their headache attacks. The differences seen in medicines prescribed between countries suggest differences in guidance, or in doctors' awareness of current medication guidelines. Further studies about the need for and benefits of medicines to prevent CH attacks are needed.

Validation of the Italian version of the Cluster Headache Impact Questionnaire (CHIQ).

BACKGROUND: The Cluster Headache Impact Questionnaire (CHIQ) is a specific and easy-to-use questionnaire to assess the current impact of cluster headache (CH). The aim of this study was to validate the Italian version of the CHIQ. METHODS: We included patients diagnosed with episodic CH (eCH) or chronic CH (cCH) according to the ICHD-3 criteria and included in the "Italian Headache Registry" (RICe). The questionnaire was administered to patients through an electronic form in two sessions: at first visit for validation, and after 7 days for test-retest reliability. For internal consistency, Cronbach's alpha was calculated. Convergent validity of the CHIQ with CH features and the results of questionnaires assessing anxiety, depression, stress, and quality of life was evaluated using Spearman's correlation coefficient. RESULTS: We included 181 patients subdivided in 96 patients with active eCH, 14 with cCH, and 71 with eCH in remission. The 110 patients with either active eCH or cCH were included in the validation cohort; only 24 patients with CH were characterized by a stable attack frequency after 7 days, and were included in the test-retest cohort. Internal consistency of the CHIQ was good with a Cronbach alpha value of 0.891. The CHIQ score showed a significant positive correlation with anxiety, depression, and stress scores, while showing a significant negative correlation with quality-of-life scale scores. CONCLUSION: Our data show the validity of the Italian version of the CHIQ, which represents a suitable tool for evaluating the social and psychological impact of CH in clinical practice and research.

Oxygen inhalation has no effect on provoked cranial autonomic symptoms using kinetic oscillation stimulation in healthy volunteers.

OBJECTIVE: Inhalation of oxygen is highly effective in cluster headache, a subtype of trigeminal autonomic cephalgias. Since oxygen has no effect on nociceptive pain, the mechanism of action is still unknown. The present study investigated whether oxygen inhalation modifies the trigeminal autonomic reflex arc in healthy volunteers. METHODS: 21 healthy volunteers participated in a randomized, placebo controlled, double-blind, cross-over, and within-subject study design. In a randomized order demand valve inhalation of 100% oxygen or medical air were administered. Capillary blood samples were collected to control for blood gas changes. Cranial parasympathetic output (lacrimation) was provoked using kinetic oscillation stimulation of the nasal mucosa. Standardized measurement of lacrimation between baseline and kinetic oscillation stimulation served as a measure of induced cranial autonomic output. RESULTS: There was no significant difference in parasympathetic output after oxygen inhalation when compared to inhalation of medical air. CONCLUSION: The inhalation of 100% oxygen does not affect the parasympathetic reflex arc of the trigeminal autonomic reflex.

Intra- and interindividual attack frequency variability of chronic cluster headache.

BACKGROUND: The lack of knowledge about the intra- and interindividual attack frequency variability in chronic cluster headache complicates power and sample size calculations for baseline periods of trials, and consensus on their most optimal duration. METHODS: We analyzed the 12-week baseline of the ICON trial (occipital nerve stimulation in medically intractable chronic cluster headache) for: (i) weekly vs. instantaneous recording of attack frequency; (ii) intra-individual and seasonal variability of attack frequency; and (iii) the smallest number of weeks to obtain a reliable estimate of baseline attack frequency. RESULTS: Weekly median (14.4 [8.2-24.0]) and instantaneous (14.2 [8.0-24.5]) attack frequency recordings were similar (p = 0.20; Bland-Altman plot). Median weekly attack frequency was 15.3 (range 4.2-140) and highest during spring (p = 0.001) compared to the other seasons. Relative attack frequency variability decreased with increasing attack frequency (p = 0.010). We tabulated the weekly attack frequency estimation accuracies compared to, and the associated deviations from, the 12-week gold standard for different lengths of the observation period. CONCLUSION: Weekly retrospective attack frequency recording is as good as instantaneous recording and more convenient. Attack frequency is highest in spring. Participants with ≥3 daily attacks show less attack frequency variability than those with <3 daily attacks. An optimal balance between 90% accuracy and feasibility is achieved at a baseline period of seven weeks.The ICON trial is registered in ClinicalTrials.gov under number NCT01151631.

Management of Trigeminal Autonomic Cephalalgias Including Chronic Cluster: A Review.

Importance: Trigeminal autonomic cephalalgias (TACs) comprise a unique collection of primary headache disorders characterized by moderate or severe unilateral pain, localized in in the area of distribution of the first branch of the trigeminal nerve, accompanied by cranial autonomic symptoms and signs. Most TACs are rare diseases, which hampers the possibility of performing randomized clinical trials and large studies. Therefore, knowledge of treatment efficacy must be based only on observational studies, rare disease registries, and case reports, where real-world data and evidence play an important role in health care decisions. Observations: Chronic cluster headache is the most common of these disorders, and the literature offers some evidence from randomized clinical trials to support the use of pharmacologic and neurostimulation treatments. Galcanezumab, a monoclonal antibody targeting the calcitonin gene-related peptide, was not effective at 3 months in a randomized clinical trial but showed efficacy at 12 months in a large case series. For the other TACs (ie, paroxysmal hemicrania, hemicrania continua, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing, and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms), only case reports and case series are available to guide physicians in everyday management. Conclusions and Relevance: The accumulation of epidemiologic, pathophysiologic, natural history knowledge, and data from case series and small controlled trials, especially over the past 20 years from investigators around the world, has added to the previously limited evidence and has helped advance and inform the treatment approach to rare TACs, which can be extremely challenging for clinicians.

Comorbidity or combination - more evidence for cluster-migraine?

BACKGROUND: While migraine and cluster headache share some clinical features and therapies, they differ considerably in the frequency and duration of the headache, as well as the inter-attack, or inter-bout, pathophysiology. Neither is fully understood, with their shared pathways being of interest. FINDINGS: Five patients for whom it was difficult to distinguish migraine from cluster headache are presented. They had aspects of their phenotypes, which could be attributed to both disorders. Each patient was thoroughly examined, excluding secondary causes of headache, and had been treated with a number of medicines. CONCLUSION: A correct diagnosis is key to the appropriate treatment approach. Especially, if treatment is not successful for the suspected headache type, and enlargement of the diagnostic and therapeutic range, respectively, should be evaluated. Whether in such settings there is shared or different pathophysiology can only be speculated upon.

Clinical Reasoning: A Teenager With Right-Sided Headache and Periorbital Changes.

While migraine is the most common headache disorder in children and adolescents presenting to a neurologist, other primary headache disorders are important to recognize. Trigeminal autonomic cephalalgias represent a rare group of primary headache disorders with different characteristics, workup, and management. In this study, we present an adolescent with 1 common and 1 unique headache phenotype, followed by a guided discussion of the differential diagnoses, workup, treatments, and a brief summary of further management considerations.

Unilateral corneal arcus and conjunctival vessel alterations in cranial autonomic dysregulation: A case report.

BACKGROUND: Cranial autonomic dysregulation is a common symptom of patients suffering from cluster headache or migraine. The peripheral vascular dysfunction may increase the risk for ischemic or hemorrhagic strokes, myocardial infarction, retinal vasculopathy, cardiovascular mortality, and peripheral artery diseases. Furthermore, it may also manifest with ocular symptoms, e.g., increased lacrimation, conjunctival injection, and facial swelling. CASE PRESENTATION: We here report a case of a patient with migraine and ocular signs of a vascular dysregulation that have led to persisting changes of conjunctival vessels and to a corneal arcus. CONCLUSIONS: Autonomic vascular dysregulation may not only cause headaches but also persisting changes of ocular tissues, e.g., conjunctival vessel alterations and a corneal arcus.

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.