Epidemiology and clinical features of short-lasting unilateral neuralgiform headache attacks: A systematic review and meta-analysis.

BACKGROUND: To synthesize the available epidemiologic data on short-lasting unilateral neuralgiform headache attacks (SUNHA). This, in turn, might inform diagnostic work-up and clinical decision-making. METHODS: EMBASE and PubMed were searched for observational studies reporting on the prevalence or relative frequency of SUNHA or its individual clinical features. Two investigators independently conducted title and abstract screening, full-text review, data extraction, and risk of bias assessment, and random-effects meta-analyses were performed to estimate the prevalence or relative frequency of SUNHA and its individual clinical features. RESULTS: Fifteen clinic-based studies met our eligibility criteria. Of these, five studies reported estimates on the relative frequency of SUNHA among adults evaluated for headache or facial pain, yielding a pooled relative frequency as 0.32% (95% confidence interval = 0.17-0.62; I2 = 89.9%). Most often, SUNHA presented as episodic, side-locked stabbing headache of severe pain intensity, predominantly affecting the ophthalmic and/or maxillary branch of the trigeminal nerve. The most common cranial autonomic features were lacrimation, conjunctival injection, rhinorrhea and nasal congestion. CONCLUSIONS: SUNHA is a rare headache disorder with distinct clinical features. However, our findings must be interpreted with caution as a result of between-study heterogeneity and lack of population-based studies, underscoring the need for further epidemiologic research.

Induction of cGMP-mediated migraine attacks is independent of CGRP receptor activation.

BACKGROUND: The cAMP and cGMP pathways are implicated in the initiation of migraine attacks, but their interactions remain unclear. Calcitonin gene-related peptide (CGRP) triggers migraine attacks via cAMP, whereas the phosphodiesterase-5 inhibitor sildenafil induces migraine attacks via cGMP. Our objective was to investigate whether sildenafil could induce migraine attacks in individuals with migraine pre-treated with the CGRP-receptor antibody erenumab. METHODS: In this randomized, double-blind, placebo-controlled, cross-over study, adults with migraine without aura received a single subcutaneous injection of 140 mg erenumab on day 1. They were then randomized to receive sildenafil 100 mg or placebo on two experimental days, each separated by at least one week, between days 8 and 21. The primary endpoint was the difference in the incidence of migraine attacks between sildenafil and placebo during the 12-h observation period after administration. RESULTS: In total, 16 participants completed the study. Ten participants (63%) experienced a migraine attack within 12 h after sildenafil administration compared to three (19%) after placebo (p = 0.016). The median headache intensity was higher after sildenafil than after placebo (area under the curve (AUC) for the 12-h observation period, p = 0.026). Furthermore, sildenafil induced a significant decrease in mean arterial blood pressure (AUC, p = 0.026) and a simultaneous increase in heart rate (AUC, p < 0.001) during the first hour after administration compared to placebo. CONCLUSION: These findings provide evidence that migraine induction via the cGMP pathway can occur even under CGRP receptor blockade. TRIAL REGISTRATION: ClinicalTrials.gov: Identifier NCT05889455.

Hypersensitivity to CGRP as a predictive biomarker of migraine prevention with erenumab.

BACKGROUND: The present study aimed to investigate the predictive value of calcitonin gene-related peptide (CGRP)-induced migraine attacks for effectiveness to erenumab treatment in people with migraine. METHODS: In total, 139 participants with migraine underwent a single experimental day involving a 20-min infusion with CGRP. Following this, the participants entered a 24-week treatment period with erenumab. The primary endpoints were the predictive value of CGRP-induced migraine attacks on the effectiveness of erenumab, defined as ≥50% reduction in monthly migraine days, or ≥ 50% reduction in either monthly migraine or monthly headache days of moderate to severe intensity. RESULTS: Among participants with CGRP-induced migraine attacks, 60 of 99 (61%) achieved ≥50% reduction in monthly migraine days during weeks 13-24 with erenumab. Conversely, 13 of 25 (52%) where CGRP infusion did not induce a migraine achieved the same endpoint (p = 0.498). There were no significant differences between the ≥50% reduction in either monthly migraine or monthly headache days of moderate to severe intensity between CGRP-sensitive and non-sensitive participants (p = 0.625). CONCLUSIONS: Our findings suggest that the CGRP-provocation model cannot be used to predict erenumab's effectiveness. It remains uncertain whether this finding extends to other monoclonal antibodies targeting the CGRP ligand or to gepants.Trial Registration: The study was registered at ClinicalTrials.gov (NCT04592952).

Hypersensitivity to BKCa channel opening in persistent post-traumatic headache.

BACKGROUND: Large conductance  calcium-activated potassium (BKCa) channels have been implicated in the neurobiological underpinnings of migraine. Considering the clinical similarities between migraine and persistent post-traumatic headache (PPTH), we aimed to examine whether MaxiPost (a BKCa channel opener) could induce migraine-like headache in persons with PPTH. METHODS: This is a randomized double-blind, placebo-controlled, two-way crossover study from September 2023 to December 2023. Eligible participants were adults with PPTH after mild traumatic brain injury who reported having no personal history of migraine. The randomized participants received a single dose of either MaxiPost (0.05 mg/min) or placebo (isotonic saline) that was infused intravenously over 20 minutes. The two experiment sessions were scheduled at least one week apart to avoid potential carryover effects. The primary endpoint was the induction of migraine-like headache after MaxiPost as compared to placebo within 12 hours of drug administration. The secondary endpoint was the area under the curve (AUC) values for headache intensity scores between MaxiPost and placebo over the same 12-hour observation period. RESULTS: Twenty-one adult participants (comprising 14 females and 7 males) with PPTH were enrolled and completed both experiment sessions. The proportion of participants who developed migraine-like headache was 11 (52%) of 21 participants after MaxiPost infusion, in contrast to four (19%) participants following placebo (P = .02). Furthermore, the median headache intensity scores, represented by AUC values, were higher following MaxiPost than after placebo (P < .001). CONCLUSIONS: Our results indicate that BKCa channel opening can elicit migraine-like headache in persons with PPTH. Thus, pharmacologic blockade of BKCa channels might present a novel avenue for drug discovery. Additional investigations are nonetheless needed to confirm these insights and explore the therapeutic prospects of BKCa channel blockers in managing PPTH. GOV IDENTIFIER: NCT05378074.

Elevated plasma levels of calcitonin gene-related peptide in individuals with rosacea: A cross-sectional case-control study.

BACKGROUND: Understanding the role of calcitonin gene-related peptide (CGRP) in the pathogenesis of rosacea might provide new therapeutic avenues for individuals with this disease. OBJECTIVE: To compare plasma levels of CGRP between individuals with rosacea and healthy controls. METHODS: In this cross-sectional case-control study conducted in Copenhagen, Denmark, we collected blood samples from the antecubital vein from adults with rosacea and from healthy controls. RESULTS: We enrolled 123 individuals with rosacea and 68 healthy controls. After adjusting for age and sex, plasma levels of CGRP were significantly higher in individuals with rosacea (mean, 95% confidence interval: 140.21 pmol/L, 128.50-151.92 pmol/L), compared with controls (110.77 pmol/L, 99.91-120.14 pmol/L, p = 0.002). Plasma levels of CGRP were not affected by age, sex, BMI, concomitant migraine, rosacea sub- or phenotype, concomitant disease or current treatment. LIMITATIONS: Participants were not age-, sex- and BMI-matched. CONCLUSIONS AND RELEVANCE: Elevated plasma levels of CGRP in individuals with rosacea suggest a role of CGRP in the pathogenesis of rosacea. Targeting CGRP signalling might hold therapeutic promise in people affected by this disease. GOV LISTING: NCT03872050.

Effects of PDE-3 inhibition in persistent post-traumatic headache: evidence of cAMP-dependent signaling.

BACKGROUND: Phosphodiesterase 3 (PDE-3) inhibition have been implicated in the neurobiologic underpinnings of migraine. Considering the clinical similarities between migraine and persistent post-traumatic headache (PPTH), we aimed to ascertain whether PDE-3 inhibition can elicit migraine-like headache in persons with PPTH. METHODS: We tested cilostazol, which inhibits PDE-3, in a randomized, double-blind, placebo-controlled, two-way crossover study involving persons with PPTH attributed to mild traumatic brain injury. The randomized participants were allocated to receive oral administration of either 200-mg cilostazol or placebo (calcium tablet) on two separate experiment days. The primary end point was the incidence of migraine-like headache during a 12-hour observation window post-ingestion. The secondary endpoint was the area under the curve (AUC) for reported headache intensity scores during the same observation window. RESULTS: Twenty-one persons underwent randomization and completed both experiment days. The mean participants' age was 41.4 years, and most (n = 17) were females. During the 12-hour observation window, 14 (67%) of 21 participants developed migraine-like headache post-cilostazol, in contrast to three (14%) participants after placebo (P =.003). The headache intensity scores were higher post-cilostazol than after placebo (P <.001). CONCLUSIONS: Our results provide novel evidence showing that PDE-3 inhibition can elicit migraine-like headache in persons with PPTH. Given that PDE-3 inhibition increases intracellular cAMP levels, our findings allude to the potential therapeutic value of targeting cAMP-dependent signaling pathways in the management of PPTH. Further investigations are imperative to substantiate these insights and delineate the importance of cAMP-dependent signaling pathways in the neurobiologic mechanisms underlying PPTH. GOV IDENTIFIER: NCT05595993.

Differences in Cortical Morphology in People With and Without Migraine: A Registry for Migraine (REFORM) MRI Study.

BACKGROUND AND OBJECTIVES: Structural imaging can offer insights into the cortical morphometry of migraine, which might reflect adaptations to recurring nociceptive messaging. This study compares cortical morphometry between a large sample of people with migraine and healthy controls, as well as across migraine subtypes. METHODS: Adult participants with migraine and age-matched and sex-matched healthy controls attended a single MRI session with magnetization-prepared rapid acquisition gradient echo and fluid-attenuated inversion recovery sequences at 3T. Cortical surface area, thickness, and volume were compared between participants with migraine (including subgroups) and healthy controls across the whole cortex within FreeSurfer and reported according to the Desikan-Killiany atlas. The analysis used cluster-determining thresholds of p < 0.0001 and cluster-wise thresholds of p < 0.05, adjusted for age, sex, and total intracranial volume. RESULTS: A total of 296 participants with migraine (mean age 41.6 years ± 12.4 SD, 261 women) and 155 healthy controls (mean age 41.1 years ± 11.7 SD, 133 women) were included. Among the participants with migraine, 180 (63.5%) had chronic migraine, 103 (34.8%) had migraine with aura, and 88 (29.7%) experienced a migraine headache during the scan. The total cohort of participants with migraine had reduced cortical surface area in the left insula, compared with controls (p < 0.0001). Furthermore, participants with chronic migraine (n = 180) exhibited reduced surface area in the left insula (p < 0.0001) and increased surface area in the right caudal anterior cingulate cortex (p < 0.0001), compared with controls. We found no differences specific to participants with aura or ongoing migraine headache. Post hoc tests revealed a positive correlation between monthly headache days and surface area within the identified anterior cingulate cluster (p = 0.014). DISCUSSION: The identified cortical changes in migraine were limited to specific pain processing regions, including the insula and caudal anterior cingulate gyrus, and were most notable in participants with chronic migraine. These findings suggest persistent cortical changes associated with migraine. TRIAL REGISTRATION INFORMATION: The REFORM study (clinicaltrials.gov identifier: NCT04674020).

Guidelines of the International Headache Society for controlled trials of pharmacological preventive treatment for persistent post-traumatic headache attributed to mild traumatic brain injury.

BACKGROUND: Persistent headache attributed to traumatic injury to the head is divided into two subtypes, one attributed to moderate or severe traumatic injury and another attributed to mild traumatic injury (i.e., concussion). The latter is much more prevalent, in part because more than 90% of cases with traumatic brain injury are classified as mild. The pathophysiology of persistent post-traumatic headache is poorly understood and the underlying mechanisms are likely multifactorial. There is currently no approved treatment specifically for persistent post-traumatic headache, and management strategies rely on medications used for migraine or tension-type headache. Therefore, high-quality trials are urgently needed to support clinical decision-making and optimize management strategies. International guidelines can facilitate appropriate trial design and ensure the acquisition of high-quality data evaluating the efficacy, tolerability, and safety of available and novel pharmacological therapies for the preventive treatment of persistent post-traumatic headache. METHODS: The development of this guideline was based on a literature review of available studies in MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials, along with a review of previously published guidelines for controlled trials of preventive treatment for episodic and chronic migraine. The identified literature was critically appraised, and due to the scarcity of scientific evidence, recommendations were primarily based on the consensus of experts in the field. OBJECTIVE: To provide guidelines for designing state-of-the-art controlled clinical trials aimed at evaluating the effectiveness of preventive treatments for persistent post-traumatic headache attributed to mild traumatic brain injury.

Postdromal symptoms in migraine: a REFORM study.

BACKGROUND: Migraine is a multiphasic neurovascular disorder, where headache can be succeeded by postdromal symptoms. However, there are limited research on postdromal symptoms. This study aimed to investigate the proportion of individuals with migraine from a tertiary care unit reporting postdromal symptoms in adherence with the ICHD-3 definition. We also aimed to examine how the means of enquiry might influence the estimated proportions. Additionally, we explored whether any clinical features might affect the likelihood of reporting postdromal symptoms. Finally, we assessed to what extend the postdromal symptoms might impact the disease burden. METHODS: In a cross-sectional study, we enrolled adult participants diagnosed with migraine who were asked to report their postdromal symptoms (i.e., unprompted reporting). Subsequently, a 16-item list was used to further ascertain the occurrence of postdromal symptoms (i.e., prompted reporting). Clinical characteristics were obtained through a semi-structured interview. Moreover, electronic questionnaires were used to assess the disease burden, i.e., the Six-Item Headache Impact Test (HIT-6), Migraine Disability Assessment (MIDAS), and the World Health Organization Disability Assessment 2.0 (WHODAS 2.0). RESULTS: Among 631 participants with migraine, a higher proportion experienced at least one postdromal symptom when prompted (n = 509 [80.7%]) compared with unprompted reporting (n = 421 [66.7%], P < 0.001). Furthermore, the total number of postdromal symptoms experienced was greater with prompted than unprompted reporting (medians 3 [IQR 1 - 6] versus 1 [IQR 0 - 2]; P < 0.001). Furthermore, the likelihood of reporting postdromal symptoms increased with the presence of premonitory symptoms and decreased with higher number of monthly migraine days. Weak correlations were identified between the number of postdromal symptoms reported and both HIT-6 (ρ = 0.14; P < 0.001) and WHODAS scores (ρ = 0.15; P < 0.001), whilst no correlation was observed with MIDAS score (ρ = 0.08; P = 0.054). CONCLUSIONS: Postdromal symptoms are prevalent in individuals with migraine from a tertiary care unit. However, reported estimates warrant cautious interpretation as they depend on the means of enquiry, presence of premonitory symptoms, and frequency of monthly migraine days. Moreover, a weak correlation was identified between the number of postdromal symptoms and both HIT-6 and WHODAS scores, indicating only a marginal influence on the disease burden.

Clinical features of migraine with aura: a REFORM study.

BACKGROUND: About one-third of persons with migraine experience transient neurologic symptoms, referred to as aura. Despite its widespread prevalence, comprehensive clinical descriptions of migraine with aura remain sparse. Therefore, we aimed to provide an in-depth phenotypic analysis of aura symptoms and characteristics in a cross-sectional study of a large sample of adults diagnosed with migraine with aura. METHODS: Data were extracted from the baseline characteristics of participants in the Registry for Migraine (REFORM) study - a single-center, prospective, longitudinal cohort study. Participants were adults diagnosed with migraine aura, reporting ≥ 4 monthly migraine days in the preceding 3 months. Trained personnel conducted in-person semi-structured interviews, capturing details on the nature, duration, localization, and progression of individual aura symptoms. RESULTS: Of the 227 enrolled participants with migraine with aura, the mean age was 41.1 years, with a predominant female representation (n = 205 [90.3%]). Visual aura was present in 215 (94.7%) participants, somatosensory aura in 81 (35.7%), and speech and/or language aura in 31 (13.7%). A single type of aura was observed in 148 (65.2%) participants, whilst 79 (34.8%) reported multiple aura types. Most participants (n = 220 [96.9%]) described their aura symptoms as positive or gradually spreading. Headache in relation to aura was noted by 218 (96.0%) participants, with 177 (80.8%) stating that the onset of aura symptoms preceded the onset of headache. CONCLUSIONS: This study offers a detailed clinical depiction of persons with migraine with aura, who were predominantly enrolled from a tertiary care unit. The findings highlight potential gaps in the available literature on migraine with aura and should bolster clinicians' acumen in diagnosing migraine with aura in clinical settings.

Premonitory symptoms in migraine: A REFORM Study.

BACKGROUND: Estimates of proportions of people with migraine who report premonitory symptoms vary greatly among previous studies. Our aims were to establish the proportion of patients reporting premonitory symptoms and its dependency on the enquiry method. Additionally, we investigated the impact of premonitory symptoms on disease burden using Headache Impact Test (HIT-6), Migraine Disability Assessment (MIDAS) and World Health Organization Disability Assessment 2.0 (WHODAS 2.0), whilst investigating how various clinical factors influenced the likelihood of reporting premonitory symptoms. METHODS: In a cross-sectional study, premonitory symptoms were assessed among 632 patients with migraine. Unprompted enquiry was used first, followed by a list of 17 items (prompted). Additionally, we obtained clinical characteristics through a semi-structured interview. RESULTS: Prompted enquiry resulted in a greater proportion reporting premonitory symptoms than unprompted (69.9% vs. 43.0%; p < 0.001) and with higher symptom counts (medians 2, interquartile range = 0-6 vs. 1, interquartile range = 0-1; p < 0.001). The number of symptoms correlated weakly with HIT-6 (ρ = 0.14; p < 0.001) and WHODAS scores (ρ = 0.09; p = 0.041). Reporting postdromal symptoms or triggers increased the probability of reporting premonitory symptoms, whereas monthly migraine days decreased it. CONCLUSIONS: The use of a standardized and optimized method for assessing premonitory symptoms is necessary to estimate their prevalence and to understand whether and how they contribute to disease burden.

Epidemiology and clinical features of paroxysmal hemicrania: A systematic review and meta-analysis.

OBJECTIVE: To assess the prevalence or relative frequency of paroxysmal hemicrania and its clinical features in the adult general population and among adult patients evaluated for headache in tertiary care. BACKGROUND: Paroxysmal hemicrania is a rare trigeminal autonomic cephalalgia with characteristic attacks of headache, associated cranial autonomic symptoms and signs, and an absolute response to indomethacin. Its epidemiological burden remains unknown in both the adult general population and among adult patients evaluated for headache in a tertiary care setting. Moreover, the frequencies of the clinical features associated with paroxysmal hemicrania have not been well established. METHODS: A literature search of PubMed and Embase was conducted from January 1, 1988, to January 20, 2023. Eligible for inclusion were observational studies reporting the point prevalence or relative frequency of paroxysmal hemicrania or its clinical features in the adult general population or among adult patients evaluated for headache in tertiary care. Two independent investigators (M.J.H. and J.G.L.) performed the title, abstract, and full-text article screening. Each included study's risk of bias was critically appraised using the Joanna Briggs Institute Critical Appraisal Checklist for Studies Reporting Prevalence Data. Estimates of prevalence or relative frequency were calculated using a random-effects meta-analysis. The between-study heterogeneity was assessed using the I2 statistic and further explored with meta-regression. This study was pre-registered on PROSPERO (identifier: CRD42023391127). RESULTS: A total of 17 clinic-based studies and one population-based study met the eligibility criteria. Importantly, an overall high risk of bias was observed across the eligible studies. The relative frequency of paroxysmal hemicrania was estimated to be 0.3% (95% CI, 0.2%-0.5%) among adult patients evaluated for headache in tertiary care with considerable heterogeneity (I2 = 76.4%). No cases with paroxysmal hemicrania were identified among 1,838 participants in a population-based sample. Moreover, the most prevalent cranial autonomic symptoms were lacrimation (77.3% [95% Cl, 62.7%-87.3%]), conjunctival injection (75.0% [95% Cl, 60.3%-85.6%]), and nasal congestion (47.7% [95% Cl, 33.6%-62.3%]). CONCLUSIONS: Our findings suggest that paroxysmal hemicrania is a rare disorder among adults evaluated for headache in tertiary care, while its prevalence in the general population remains unknown. Further studies focusing on the clinical features of paroxysmal hemicrania are warranted.

Activation of ATP-sensitive potassium channels triggers migraine attacks independent of calcitonin gene-related peptide receptors: a randomized placebo-controlled trial.

BACKGROUND: The present study aimed to investigate whether levcromakalim, a KATP channel opener, induces migraine attacks in people with migraine pre-treated with erenumab, a monoclonal CGRP receptor antibody. METHODS: In this double-blind, placebo-controlled, two-way cross-over study, adults with migraine without aura received a subcutaneous injection of 140 mg of erenumab on day 1. Subsequently, they were randomized to receive a 20-minute infusion of 0.05 mg/ml levcromakalim or placebo on two experimental days separated by at least one week (between days 8 and 21). The primary endpoint was the difference in the incidence of migraine attacks between levcromakalim and placebo during the 12-hour post-infusion period. RESULTS: In total, 16 participants completed the study. During the 12-hour observation period, 14 (88%) of 16 participants experienced migraine attacks after levcromakalim, compared to two (12%) after placebo (p < 0.001). The area under the curve for median headache intensity was greater after levcromakalim than placebo (p < 0.001). Levcromakalim elicited dilation of the superficial temporal artery during the first hour after infusion, a response absent following placebo (p < 0.001). CONCLUSIONS: The induction of migraine attacks via opening of KATP channels appears independent of CGRP receptor activation.Trial Registration: ClinicalTrials.gov, Identifier NCT05889442.

Pharmacotherapies for Migraine and Translating Evidence From Bench to Bedside.

Migraine is a ubiquitous neurologic disorder that afflicts more than 1 billion people worldwide. Recommended therapeutic strategies include the use of acute and, if needed, preventive medications. During the past 2 decades, tremendous progress has been made in better understanding the molecular mechanisms underlying migraine pathogenesis, which in turn has resulted in the advent of novel medications targeting signaling molecule calcitonin gene-related peptide or its receptor. Here, we provide an update on the rational use of pharmacotherapies for migraine to facilitate more informed clinical decision-making. We then discuss the scientific discoveries that led to the advent of new medications targeting calcitonin gene-related peptide signaling. Last, we conclude with recent advances that are being made to identify novel drug targets for migraine.

Hypersensitivity to PACAP-38 in post-traumatic headache: a randomized clinical trial.

Pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38), known for its role in migraine pathogenesis, has been identified as a novel drug target. Given the clinical parallels between post-traumatic headache (PTH) and migraine, we explored the possible role of PACAP-38 in the pathogenesis of PTH. To this end, we conducted a randomized, double-blind, placebo-controlled, two-way crossover trial involving adult participants diagnosed with persistent PTH resulting from mild traumatic brain injury. Participants were randomly assigned to receive a 20-min continuous intravenous infusion of either PACAP-38 (10 pmol/kg/min) or placebo (isotonic saline) on two separate experimental days, with a 1-week washout period in between. The primary outcome was the difference in incidence of migraine-like headache between PACAP-38 and placebo during a 12-h observational period post-infusion. The secondary outcome was the difference in the area under the curve (AUC) for baseline-corrected median headache intensity scores during the same 12-h observational period. Of 49 individuals assessed for eligibility, 21 were enrolled and completed the trial. The participants had a mean age of 35.2 years, and 16 (76%) were female. Most [19 of 21 (90%)] had a migraine-like phenotype. During the 12-h observational period, 20 of 21 (95%) participants developed migraine-like headache after intravenous infusion of PACAP-38, compared with two (10%) participants after placebo (P < 0.001). Furthermore, the baseline-corrected AUC values for median headache intensity scores during the 12-h observational period was higher after PACAP-38 than placebo (P < 0.001). These compelling results demonstrate that PACAP-38 is potent inducer of migraine-like headache in people with persistent PTH. Thus, targeting PACAP-38 signalling might be a promising avenue for the treatment of PTH.

Induction of cluster headache after opening of adenosine triphosphate-sensitive potassium channels: a randomized clinical trial.

ABSTRACT: Activation of adenosine triphosphate-sensitive potassium (K ATP ) channels has been implicated in triggering migraine attacks. However, whether the opening of these channels provoke cluster headache attacks remains undetermined. The hallmark of cluster headache is a distinct cyclical pattern of recurrent, severe headache episodes, succeeded by intervals of remission where no symptoms are present. In our study, we enrolled 41 participants: 10 with episodic cluster headaches during a bout, 15 in the attack-free remission period, and 17 diagnosed with chronic cluster headaches. Over 2 distinct experimental days, participants underwent a continuous 20-minute infusion of levcromakalim, a K ATP channel opener, or a placebo (isotonic saline), followed by a 90-minute observational period. The primary outcome was comparing the incidence of cluster headache attacks within the postinfusion observation period between the levcromakalim and placebo groups. Six of 10 participants (60%) with episodic cluster headaches in bout experienced attacks after levcromakalim infusion, vs just 1 of 10 (10%) with placebo ( P = 0.037). Among those in the remission phase, 1 of 15 participants (7%) reported attacks after levcromakalim, whereas none did postplacebo ( P = 0.50). In addition, 5 of 17 participants (29%) with chronic cluster headache had attacks after levcromakalim, in contrast to none after placebo ( P = 0.037). These findings demonstrate that K ATP channel activation can induce cluster headache attacks in participants with episodic cluster headaches in bout and chronic cluster headache, but not in those in the remission period. Our results underscore the potential utility of K ATP channel inhibitors as therapeutic agents for cluster headaches.

Epidemiology and clinical features of hypnic headache: A systematic review and meta-analysis.

BACKGROUND: Hypnic headache is a neurological disorder characterized by recurrent headache attacks that occur exclusively during sleep, leading to awakening. Synthesizing the available epidemiological data might inform clinical decision-making. METHODS: We searched PubMed and Embase for observational studies on hypnic headache published between 1 May 2004, and 22 December 2022. Two investigators independently screened titles, abstracts, and full-text articles. We performed a random-effects meta-analysis with meta-regression to estimate the prevalence of hypnic headache and its clinical features based on epidemiologic data from population-based and clinic-based studies. RESULTS: Fourteen studies, one population-based and 13 clinic-based, met our eligibility criteria. The population-based study did not identify any people with hypnic headache. From 11 clinic-based studies, the pooled relative frequency of hypnic headache was 0.21% (95%CI, 0.13 to 0.35%; I2 = 87%) in adult patients evaluated for headache. The pooled mean age of onset was 60.5 years, with a slight female predisposition. Hypnic headache was typically bilateral (71%), pressing (73%), of moderate (38%) or severe (44%) pain intensity, and lasted about 115 minutes per attack. CONCLUSIONS: Our data should be cautiously interpreted due to between-study heterogeneity. The identified clinical presentation of hypnic headache can guide clinical diagnosis, in addition to the International Classification of Headache Disorders.

Hypersensitivity to opening of ATP-sensitive potassium channels in post-traumatic headache.

OBJECTIVE: To investigate whether levcromakalim (a KATP channel opener) induces migraine-like headache in people with persistent post-traumatic headache who had no known history of migraine. METHODS: In a randomized, double-blind, placebo-controlled, 2-way crossover trial, participants were randomly assigned to receive a 20-minute continuous intravenous infusion of levcromakalim (50 µg/mL) or placebo (isotonic saline) on two separate experimental days with a 1-week wash-out period in between. The primary endpoint was the difference in incidence of migraine-like headache between levcromakalim and placebo during a 12-hour observational period after infusion start. The secondary endpoint was the difference in area under the curve for baseline-corrected median headache intensity scores between levcromakalim and placebo during the 12-hour observational period. RESULTS: A total of 21 participants with persistent post-traumatic headache were randomized and completed the trial. During the 12-hour observational period, 12 (57%) of 21 participants reported experiencing migraine-like headache following the levcromakalim infusion, compared with three after placebo (P = 0.013). Moreover, the baseline-corrected median headache intensity scores were higher following the levcromakalim infusion than after placebo (P = 0.003). CONCLUSION: Our findings suggest that KATP channels play an important role in the pathogenesis of migraine-like headache in people with persistent post-traumatic headache. This implies that KATP channel blockers might represent a promising avenue for drug development. Further research is warranted to explore the potential therapeutic benefits of KATP channel blockers in managing post-traumatic headache.Trial Registration: ClinicalTrials.gov Identifier: NCT05243953.

What proportion of people with migraine report postdromal symptoms? A systematic review and meta-analysis of observational studies.

BACKGROUND: Postdromal symptoms, following headache resolution, are said to constitute a distinct phase of the migraine attack. We question the evidence for this, with regard both to the nature of such symptoms and to how often they are reported to occur. METHODS: We searched the Pubmed and Embase databases for relevant articles from their inception until 25 May 2023. We included observational studies recording the proportions of participants with migraine reporting one or more postdromal symptoms or specific individual symptoms. Two reviewers independently screened studies for relevance (agreeing on those to be included), extracted data and assessed risk of bias. Data were analyzed using random-effects meta-analysis to establish the proportions of those with migraine reporting one or more postdromal symptoms, whether among the general population or patients in clinic-based samples. RESULTS: Large majorities of participants in either case reported postdromal symptoms: 97% in the only population-based study, and a mean of 86% (95% CI: 71-94%) in four clinic-based studies. The most commonly reported specific symptoms were fatigue (52%; 95% CI: 44-60%), concentration difficulties (35%; 95% CI: 14-65%) and mood changes (29%; 95% CI: 9-64%), none of these being clearly described. These estimates could not be considered reliable: they were subject to substantial study heterogeneity, none of the studies applied International Classification of Headache Disorders definitions of postdromal symptoms, and all had high risk of bias. CONCLUSION: Postdromal symptoms in migraine appear to be very commonly reported, but the data are unreliable with regard both to their nature and to how often they occur. Further studies are needed to conclude that they constitute a distinct phase of migraine.

An exploratory analysis of clinical and sociodemographic factors in CGRP-induced migraine attacks: A REFORM study.

OBJECTIVE: To investigate whether clinical and sociodemographic factors are associated with calcitonin gene-related peptide (CGRP) induced migraine attacks. METHODS: A total of 139 participants with migraine received a 20-minute intravenous infusion of CGRP (1.5 µg/min) on a single experiment day. The incidence of CGRP-induced migraine attacks was recorded using a headache diary during the 12-hour observational period post-infusion. Univariable and multivariable regression analyses were conducted to examine potential predictors' relationship with CGRP-induced migraine attacks. RESULTS: CGRP-induced migraine attacks were reported in 110 (79%) of 139 participants. Univariable analysis revealed that participants with cutaneous allodynia had higher odds of developing CGRP-induced migraine attacks, compared with those without allodynia (OR, 2.97, 95% CI, 1.28 to 7.43). The subsequent multivariable analysis confirmed this association (OR, 3.26, 95% CI, 1.32 to 8.69) and also found that participants with migraine with aura had lower odds of developing CGRP-induced migraine attacks (OR, 0.32, 95% CI, 0.12 to 0.84). CONCLUSION: Our results suggest that cutaneous allodynia and aura play a role in CGRP-induced migraine attacks, while other clinical and sociodemographic factors do not seem to have any noticeable impact. This indicates that the CGRP provocation model is robust, as the CGRP hypersensitivity remained unaffected despite differences among a heterogeneous migraine population.Trial Registration: ClinicalTrials.gov Identifier: NCT04592952.