Current treatment options for cluster headache: limitations and the unmet need for better and specific treatments-a consensus article

Distinct Alterations of Inflammatory Biomarkers in Cluster Headache: A Case Control Study

OBJECTIVE

Investigate the immune system's role in cluster headache by analyzing cytokines in people with cluster headache and headache-free controls, and explore if certain cytokines could predict a specific phenotype.

METHODS

We measured 45 cytokines in adult participants from the Danish Cluster Headache Biobank in a prospective case-control setup. People with cluster headache were diagnosed according to the International Classification of Headache Disorders third-edition. Controls were matched for age and sex.

RESULTS

A total of 412 were analyzed deriving from 99 with chronic cluster headache, 108 with episodic cluster headache (ECH) in bout, 105 with ECH in remission, and 100 successfully matched controls. Compared with controls, 13 cytokines were altered for ECH in bout (p < 0.05), 3 in remission (p < 0.05), and 10 for chronic cluster headache (p < 0.05). Oncostatin m was significantly elevated in all 3 disease states compared with controls (p < 0.05). Overall, the investigated cytokines showed distinct patterns of alterations between chronic cluster headache and episodic cluster headache in bout and, interestingly, IL-1β was significantly associated with having chronic cluster headache rather than episodic in bout in a logistic regression model adjusting for potential confounders (p < 0.05).

INTERPRETATION

Findings show that the immune system is altered in all 3 states of cluster headache compared with controls. Oncostatin m was elevated, constituting a promising target for future studies. The distinct alterations between episodic and chronic cluster headache are striking and urges further research of the immune system in cluster headache to better understand its potential role in prediction of disease activity and treatment response. ANN NEUROL 2025.

Current and Novel Therapies for Cluster Headache: A Narrative Review

Cluster headache (CH) is an excruciating and debilitating primary headache disorder. The prevalence is up to 1.3%, and the typical onset is around age 30. Often misdiagnosed as migraine, particularly in children, the diagnosis rate of CH has been increasing among women. CH is characterized by intense unilateral pain and autonomic symptoms, significantly impacting patients' quality of life, mental health, and productivity.Genetic associations suggest a familial risk for developing CH, with lifestyle factors also potentially playing a role. The pathophysiology involves alterations in both central and peripheral nervous system, with the hypothalamus, trigeminocervical complex, and neuropeptides such as calcitonin gene-related peptide (CGRP) being implicated.Nonpharmacological treatments focus on patient education and lifestyle modifications, while pharmacological treatments include acute therapies such as oxygen and subcutaneous or nasal sumatriptan, as well as preventive therapies like verapamil, lithium, and CGRP monoclonal antibodies. Transitional options include oral corticosteroids and greater occipital nerve injections. Emerging interventional procedures offer new avenues for managing refractory cases. Noninvasive vagal nerve stimulation and occipital nerve stimulation show promise for both acute and preventive treatment. Careful consideration of safety profiles is crucial in specific populations such as pregnant patients and children.Current treatments still leave patients highly burdened by limited efficacy and side effects. Future research continues to explore novel pharmacological targets, interventional procedures, and the potential role of psychedelics in CH management. Comprehensive, multifaceted treatment strategies are essential to improve the daily functioning and quality of life for individuals with CH.

Transcutaneous electrical nerve stimulation of the occipital nerves as treatment for chronic cluster headache

BACKGROUND

Chronic cluster headache (CCH) is an excruciatingly painful condition that can be difficult to treat sufficiently with the available medical treatment options. The greater occipital nerves (GON) are of major interest in treating CCH, and various invasive treatment modalities, such as stimulating or blocking the nerves, have been applied. Because the terminal segment of the GON has a superficial course, the nerve is also accessible for non-invasive transcutaneous stimulation. Transcutaneous electrical nerve stimulation (TENS) has been suggested as a treatment for different chronic headaches, but evidence of the efficacy in patients with CCH is scarce. Additionally, no consensus exists on the optimal placement of the transcutaneous stimulation electrodes or the treatment usage pattern.

METHODS

In this explorative open-label clinical study, 36 patients with CCH were treated with TENS of the GON for 8-12 consecutive weeks between August 2021 and October 2023 as a separate part of the study protocol for a trial on stimulation of the GON (Clinicaltrials.gov identifier: NCT05023460). After a baseline period, TENS was used primarily as a preventive treatment, stimulating for 30 min twice daily at a minimum. The primary outcome was a change in attack frequency and safety with TENS treatment. Secondary outcomes were change in attack duration and pain intensity on the numeric rating scale, abortive treatments, and the Patient Global Impression of Change (PGIC) with TENS treatment. The change in attack frequency, duration, pain intensity, and use of abortive treatment was analyzed by comparing the baseline data with 4-weekly data from TENS treatment. The study aimed to systematically investigate the effect of TENS of the GON as a preventive treatment for CCH.

RESULTS

Weekly attack frequency decreased from a median of 15.7 (95% confidence interval [CI] 11.2-22.1) at baseline to 11.0 (95% CI 7.4-16.4) with TENS. In all, 13 of the 36 (36%) patients had a minimum 30% reduction in attack frequency. In the group of 30% responders, the number of weekly attacks decreased from 15.8 (95% CI 9.8-24.5) at baseline to 5.8 (95% CI 3.3-10.5) attacks with TENS. Five patients became entirely or nearly attack-free. For the entire cohort, attack duration and pain intensity were also significantly reduced with TENS. The use of oxygen was reduced by 42%, and triptan injections decreased by 55%. Overall, 15 (42%) patients reported a clinically important improvement with TENS treatment, rated on the PGIC scale. The 100 Hz stimulation programs were preferred over 10 Hz. No serious adverse events were registered.

CONCLUSION

Transcutaneous electrical nerve stimulation of the GON significantly reduced the frequency, intensity, and duration of weekly headache attacks in patients with severe CCH. Not all patients benefitted from TENS, but the treatment responders had a substantial improvement in their cluster headache. TENS treatment was well-tolerated with little or no side effects and could be a relevant supplement to conventional preventive treatment. A standard TENS apparatus is low cost, making the treatment accessible to most patients. This paper includes a detailed, comprehensive description of our clinical application of the therapy.

Rates of colorectal cancer diagnosis and mortality in people with severe mental illness: results from Australia's National Bowel Cancer Screening Programme

AIMS

Studies show that people with severe mental illness (SMI) have a greater risk of dying from colorectal cancer (CRC). These studies mostly predate the introduction of national bowel cancer screening programmes (NBCSPs) and it is unknown if these have reduced disparity in CRC-related mortality for people with SMI.

METHODS

We compared mortality rates following CRC diagnosis at colonoscopy between a nationally representative sample of people with and without SMI who participated in Australia's NBCSP. Participation was defined as the return of a valid immunochemical faecal occult blood test (iFOBT). We also compared mortality rates between people with SMI who did and did not participate in the NBCSP. SMI was defined as receiving two or more Pharmaceutical Benefits Scheme prescriptions for second-generation antipsychotics or lithium.

RESULTS

Amongst NBCSP participants, the incidence of CRC in the SMI cohort was lower than in the controls (hazard ratio [HR] 0.77, 95% confidence interval [CI] 0.61-0.98). In spite of this, their all-cause mortality rate was 1.84 times higher (95% CI 1.12-3.03), although there was only weak evidence of a difference in CRC-specific mortality (HR 1.82; 95% CI 0.93-3.57). People with SMI who participated in the NBCSP had better all-cause survival than those who were invited to participate but did not return a valid iFOBT (HR 0.67, 95% CI 0.50-0.88). The benefit of participation was strongest for males with SMI and included improved all-cause and CRC-specific survival.

CONCLUSIONS

Participation in the NBCSP may be associated with improved survival following a CRC diagnosis for people with SMI, especially males, although they still experienced greater mortality than the general population. Approaches to improving CRC outcomes in people with SMI should include targeted screening, and increased awareness about the benefits or participation.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry (Trial ID: ACTRN12620000781943).

Participation in the National Bowel Cancer Screening Program by people with severe mental illness, Australia, 2006-2019: a national data linkage study

OBJECTIVE

To compare rates of participation in the National Bowel Cancer Screening Program (NBCSP) and follow-up for people with severe mental illness with those for people without severe mental illness or not prescribed antidepressants.

STUDY DESIGN

Retrospective cohort study; analysis of de-identified linked NBCSP, Pharmaceutical Benefits Scheme (PBS), and Medicare Benefits Schedule (MBS) data.

SETTING

Australia, 2006-2019.

PARTICIPANTS

People aged 50-74 years (NBCSP-eligible) with severe mental illness, defined as those dispensed two or more prescriptions for second generation antipsychotics or for lithium (PBS data), and a random sample of people aged 50-74 years eligible for Medicare-subsidised services but never prescribed psychotropic medications (antipsychotics, lithium, antidepressants).

MAIN OUTCOME MEASURES

NBCSP participation (returned faecal occult blood test sample), valid test result, positive test result, and follow-up colonoscopy rates.

RESULTS

A total of 119 475 people with severe mental illness and 1 090 574 control group people were included in our analyses. The proportion of women was larger in the severe mental illness group (51.3%) than the control group (48.7%), as were the proportions who lived in inner regional areas (23.5% v 19.1%) or in areas in the lowest socio-economic quintile (21.8% v 14.7%). The NBCSP participation rate was lower among people with severe mental illness (adjusted incidence rate ratio [IRR], 0.70; 95% confidence interval [CI], 0.69-0.84). The proportion of valid test results was smaller for people with severe mental illness (95.9% v 98.7%; adjusted IRR, 0.97; 95% CI, 0.96-0.99), and the positive test result proportion larger (12.3% v 6.6%; adjusted IRR, 2.01; 95% CI, 1.94-2.09). The proportion of positive test results followed by colonoscopy was smaller for people with severe mental illness (71.7% v 82.6%; adjusted IRR, 0.88; 95% CI, 0.85-0.92).

CONCLUSIONS

People with severe mental illness were less likely to participate in the NBCSP or to undergo colonoscopy after a positive test result than other Australians. These differences may contribute to higher colorectal cancer mortality among people with severe mental illness. The contributions of differences in cancer stage at diagnosis and subsequent treatment to higher colorectal cancer mortality require further study.

Cluster Headache and Hypoxia: Breathing New Life into an Old Theory, with Novel Implications

Cluster headache is a severe, poorly understood disorder for which there are as yet virtually no rationally derived treatments. Here, Lee Kudrow's 1983 theory, that cluster headache is an overly zealous response to hypoxia, is updated according to current understandings of hypoxia detection, signaling, and sensitization. It is shown that the distinctive clinical characteristics of cluster headache (circadian timing of attacks and circannual patterning of bouts, autonomic symptoms, and agitation), risk factors (cigarette smoking; male gender), triggers (alcohol; nitroglycerin), genetic findings (GWAS studies), anatomical substrate (paraventricular nucleus of the hypothalamus, solitary tract nucleus/NTS, and trigeminal nucleus caudalis), neurochemical features (elevated levels of galectin-3, nitric oxide, tyramine, and tryptamine), and responsiveness to treatments (verapamil, lithium, melatonin, prednisone, oxygen, and histamine desensitization) can all be understood in terms of hypoxic signaling. Novel treatment directions are hypothesized, including repurposing pharmacological antagonists of hypoxic signaling molecules (HIF-2; P2X3) for cluster headache, breath training, physical exercise, high-dose thiamine, carnosine, and the flavonoid kaempferol. The limits of current knowledge are described, and a program of basic and translational research is proposed.

Non-Migraine Head Pain and Botulinum Toxin

Botulinum toxin A (BT-A), a potential neurotoxin produced by the bacterium Clostridium botulinum, is known for its ability to prevent the release of acetylcholine at the neuromuscular synapse, leading to temporary muscle paralysis. BT-A is used for a wide range of therapeutic applications. Several studies have shown mechanisms beyond the inhibition of acetylcholine release for pain control. BT-A inhibits the release of neurotransmitters associated with pain and inflammation, such as glutamate, CGRP, and substance P. Additionally, it would be effective in nerve entrapment leading to neuronal hypersensitivity, which is known as a new pathogenesis of painful conditions. BT-A has been applied to the treatment of a wide variety of neurological disorders. Since 2010, BT-A application has been approved and widely used as a chronic migraine prophylaxis. Moreover, due to its effects on pain through sensory modulation, it may also be effective for other headaches. Several studies using BT-A, at different doses and administration sites for headaches, have shown beneficial effects on frequency and severity. In this review, we provide an overview of using BT-A to treat primary and secondary headache disorders.

Four Decades of Occipital Nerve Stimulation for Headache Disorders: A Systematic Review

PURPOSE OF REVIEW

Chronic headaches are a significant source of disability worldwide. Despite the development of conventional strategies, a subset of patients remain refractory and/or experience side effects following these treatments. Hence, occipital nerve stimulation (ONS) should be considered as an alternative strategy for intractable chronic headaches. This review aims to provide a comprehensive overview of the effectiveness, safety, mechanisms and practical application of ONS for the treatment of headache disorders.

RECENT FINDINGS

Overall response rate of ONS is 35.7-100%, 17-100%, and 63-100% in patients with cluster headache, chronic migraine and occipital neuralgia respectively. Regarding the long-term effectivity in all groups, 41.6-88.0% of patients remain responders after ≥ 18.3 months. The most frequently reported adverse events include lead migration/fracture (13%) and local pain (7.3%). Based on our results, ONS can be considered a safe and effective treatment for chronic intractable headache disorders. To support more widespread application of ONS, additional research with larger sample sizes should be conducted.

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

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

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

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

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Use of Prescribed and Non-Prescribed Treatments for Cluster Headache in a Swedish Cohort

BACKGROUND

Cluster headache (CH) is a debilitating condition, but current therapies leave CH patients in pain. The extent of this problem in Sweden is unknown.

METHODS

An anonymized questionnaire was sent to 479 Swedish CH patients to investigate patterns and perceived effects of treatments.

RESULTS

Three hundred fourteen answers were analyzed. The population was representative regarding age of onset and sex. Less than half (46%) were satisfied with their abortive treatments, 19% terminated functioning abortive treatments due to side effects. Additionally, 17% of chronic CH patients had not tried the first-line preventive drug verapamil. A small subset had tried illicit substances to treat their CH (0-8% depending on substance). Notably, psilocybin was reported effective as an abortive treatment by 100% (n = 8), and with some level of effect as a preventive treatment by 92% (n = 12). For verapamil, some level of preventive effect was reported among 68% (n = 85).

CONCLUSIONS

Our descriptive data illustrate that many Swedish CH patients are undertreated, lack functional therapies, and experience side effects. Further studies are warranted to search for new treatment strategies as well as a revision of current treatment guidelines with the aim of reducing patient disease burden to the greatest extent possible.

Hyperalgesia, Increased Temporal Summation and Impaired Inhibitory Mechanisms in Episodic and Chronic Cluster Headache: An Observational Study

Cluster Headache (CH) is a primary headache that causes severe pain. Some evidence suggests that central mechanisms might be involved. The objective of this study was (1) to compare hyperalgesia signs, temporal summation and conditioned pain modulation among episodic (ECH) and chronic CH (CCH) patients and controls, (2) to compare these factors between sides in the patient groups and (3) to compare the psychophysical variables between the groups. This cross-sectional study included 71 subjects divided into three groups (ECH, CCH and controls). Pressure pain thresholds, temporal summation, conditioned pain modulation and other psychosocial variables were measured. The ANOVA showed differences for all physical outcome measures (p < 0.05). Bonferroni post hoc analyses showed differences when comparing the patient groups with the healthy subjects (p < 0.05), with large effect sizes (d > 0.8). No differences between the patient groups were found for almost all the variables (p > 0.05). Significant differences for all the variables were detected when comparing the symptomatic and non-symptomatic sides in both the ECH and CCH groups (p < 0.05). The ECH and CCH groups showed mechanical hyperalgesia, increased temporal summation and impaired inhibitory mechanisms compared to the controls. Side-to-side differences were also detected within the patient groups. Patients with CCH had poorer sleep quality and quality of life than the controls.