Oxygen as an abortive therapy in cluster headache: a narrative review and clinical practice aspects

Cluster headache (International Classification of Headache Disorders third edition, ICHD-3 3.1) is a primary headache disorder affecting around 0.12% of individuals. It is characterized by severe headache attacks causing significant negative impact on the lives of patients. While administration of 100% oxygen is considered to be the first-choice acute treatment, undertreatment also exists. Reasons for undertreatment may entail problems with the correct prescription of oxygen, reimbursement issues or the practical implementation of home oxygen therapy. The aim of this manuscript is to review the scientific evidence on oxygen therapy for cluster headache and provide a practical guidance for both physicians and patients to optimize its use in an acute setting. The current evidence of the administration of 100% oxygen as a safe and effective treatment for cluster headache is strong. Based on several clinical trials and surveys, the recommended flow rates range between 12 and 15 L/min via a non-rebreathing mask, for at least fifteen minutes. The frequency of cluster headache attacks and thus the need for acute treatment can be very high. Fortunately, the Belgian social security system provides a full and lifetime reimbursement of oxygen therapy for cluster headache if the diagnosis and the need for this therapy has been certified by a neurologist, neurosurgeon or neuropsychiatrist.

Oxygen Therapy in Cluster Headache, Migraine, and Other Headache Disorders

Oxygen therapy (OT) can relieve head pain in certain primary headache disorders, including cluster headache (CH). The exact underlying mechanism is currently uncertain, but suggested mechanisms include inhibition of the trigeminoautonomic reflex, modulation of neurotransmitters, and cerebral vasoconstriction. OT is the standard for acute treatment of CH, but patients with CH often experience considerable difficulties accessing home OT due to problems with insurance coverage. Inhalation of 100% oxygen at 6–12 L/min for 15–30 min using a non-rebreather face mask is one of the most effective acute therapies for CH, but several trials have indicated the superiority of higher oxygen flow rates of up to 15 L/min and/or using a demand-valve oxygen mask that can produce very high flow rates. Two randomized controlled trials have demonstrated the efficacy of OT in migraine, but obtaining reliable evidence is considered difficult because of different inhalation protocols, varying outcome measures, and small samples. There are some reports on the efficacy of OT as an adjuvant therapy in hypnic headache, primary headache in the emergency department, and even postdural puncture headache. The goal of this review article is to expand the knowledge regarding the use of oxygen in the treatment of headache disorders.

Recent advances in the diagnosis and management of cluster headache

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

Psychedelics in the Treatment of Headache and Chronic Pain Disorders

The therapeutic potential of psychedelics in headache and chronic pain disorders is documented over decades of anecdotal and early investigational reports, which have paved the way for the first controlled studies of psilocybin and lysergic acid diethylamide (LSD) in these disorders. The reported lasting clinical effects after limited dosing with psychedelics present a novel means for disease management, but considerable further study will be required to address disease-specific treatments, uncover mechanism(s) of action, and verify safety. In this chapter, these topics are reviewed with particular attention to the neurobiological systems that offer potential sources of psychedelics' unique clinical effects in headache and pain.

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

OBJECTIVE

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Effectiveness of medication in cluster headache

Background

The aim of this work is to analyze the reports on cluster headache attacks collected online in the citizen science project CLUE with respect to the effectiveness of drugs taken during the attacks. The collection of data within the framework of citizen science projects opens up the possibility of investigating the effectiveness of acute medication on the basis of a large number of individual attacks instead of a simple survey of patients.

Methods

Data from 8369 cluster headache attacks, containing information about acute medication taken and the assessment of its effect, were collected from 133 participants using an online platform and a smartphone app. Chi-square tests were used to investigate whether the effect of the three recommended acute drugs differs when distinguishing between participants with chronic or episodic cluster headache. Furthermore, it was investigated whether there are differences between smokers and non-smokers in the assessment of the effect of the acute medication.

Results

Our participants rated the effectiveness of sumatriptan 6 mg s.c. as significantly better than oxygen and zolmitriptan nasal spray. Oxygen is considered to be significantly better in episodic versus chronic cluster headache, and sumatriptan is considered to be significantly better in chronic versus episodic cluster headache. Smokers rate the effect of oxygen as significantly better than non-smokers.

Conclusions

Despite some methodological limitations, web-based data collection is able to support findings from clinical trials in a real world setting about effectiveness of acute cluster headache treatment in several situations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02195-8.

Oxygen Therapy in Headache Disorders: A Systematic Review

Background: The global active prevalence of migraines is approximately 14.7%. Oxygen therapy may reduce the use of non-steroidal anti-inflammatory drugs (NSAIDs) which often have various negative side effects. The purpose of this systematic review is to analyze the literature on the efficacy of high flow oxygen for the management of headache disorders, compared to placebo treatment. Methods: Studies were identified by PubMed, Web of Science and Scopus database from 1980 to the 30 October 2020. The search included the following terms: “oxygen therapy” and “headache” and “migraine”. Studies were included if high flow oxygen was used in the treatment of headache disorders. All selected studies were qualitatively analyzed. Results: Our literature search identified 71 studies, of which 65 were discarded and 6 were included in the meta-analysis. The random effect model did not show a pooled significant resolution of headache disorders (OR 2.08 (95% CI 0.92–4.70), p < 0.0001) in the oxygen therapy group compared to the placebo group. Conclusion: In our systematic review of six studies, there were no significant differences between high flow oxygen and placebo treatment groups.

"You will eat shoe polish if you think it would help"-Familiar and lesser-known themes identified from mixed-methods analysis of a cluster headache survey

OBJECTIVE

To characterize patient-reported ideas and concerns about cluster headache, treatment options, and management strategies.

BACKGROUND

Cluster headache patients experience severe pain and often suffer additional consequences from their disease. Patients have identified methods to cope with and combat cluster headache that are not widely known.

METHODS

Secondary analysis was performed using deidentified data from the online Clusterbusters Medication Use survey, wherein 10 questions allowed for freely written comments. Using mixed-methods techniques, neurologists with expertise in headache medicine identified themes from these comments. Subgroup analysis sought to identify variables associated with specific themes.

RESULTS

Among 2274 free-text responses from 493 adult participants, 23 themes were identified. Themes commonly discussed in the literature included such topics as "nothing worked" (24.7%, 122/493), "side effects" (12.8%, 63/493), and difficulties with "access/cost" (2.4%, 12/493). Less widely recognized themes included the use of "illicit substances" (35.5%, 175/493) and "vitamins/supplements" (12.2%, 60/493) in disease management. Lesser-known themes included "coffee" (5.3%, 26/493) and "exercise/physical activity" (4.7%, 23/493). Using strict significance criteria, no subgroup was associated with any theme. Several poignant quotes highlighted patient thoughts and experiences.

CONCLUSIONS

This mixed-methods analysis identified challenges endured by cluster headache patients, as well as a variety of patient-directed disease management approaches. The volunteered information spotlights pharmacological, physiological, and psychological aspects of cluster headache that warrant further exploratory and interventional investigation.

Recent Advances in the Management of Cluster Headache

Purpose of review

Among the spectrum of pain conditions, cluster headache represents one of the most severe. Targeted therapies for cluster headache are evolving thus improving the available therapeutic armamentarium. A better understanding of the currently available therapies, as well as new and emerging options, may aide physicians to manage affected sufferers better by evolving treatment guidance.

Recent findings

While classic first-line medications are useful in some patients with cluster headache, they are often accompanied by significant side effects that limit their use. Recently, novel treatments with better tolerability and decreased medication interactions have proven to be effective. A remarkable example of this is the blockage of the calcitonin gene-related peptide pathway with monoclonal antibodies, which may be a key element in the future treatment of cluster headache. The sphenopalatine ganglion and vagus nerve perform a critical role in the regulation of pain and the trigeminal autonomic reflex. Neuromodulation therapies targeting these structures have shown excellent tolerability and few significant adverse events, constituting a promising form of treatment. Finally, several potential therapeutic targets are examined in this review, such as small molecule CGRP receptor antagonists, known as gepants, and serotonin receptor 5-HT1F receptor agonists: ditans.

Summary

In summary, a deepening of the understanding of cluster headache mechanisms in recent years has driven the evolution of sophisticated therapeutic approaches that could allow a new era in the treatment of this difficult condition.

Real-life treatment of cluster headache in a tertiary headache center - results from the Danish Cluster Headache Survey

BACKGROUND

Pharmacological treatment of cluster headache constitutes the core of clinical management, but evidence is sparse. We aimed to generate insight in the existing treatment and identify associations between clinical features and treatment response.

METHODS

Patients aged 18-65 diagnosed with cluster headache according to the ICHD-2 completed a questionnaire followed by a structured interview. Multiple logistic regression was used to identify associations.

RESULTS

The population consisted of 400 patients with an episodic: chronic ratio of 1.7:1. Episodic patients were more likely to respond to triptans (odds ratio = 1.77, confidence interval: 1.08-2.91, p = 0.023) and oxygen (odds ratio = 1.64, confidence interval: 1.05-2.57, p = 0.031) than chronic. Oxygen response was less likely if pain intensity was very severe (odds ratio = 0.53, confidence interval: 0.33-2.57, p = 0.006) and the risk of a poor response increased with disease duration (odds ratio = 0.79, confidence interval: 0.65-0.96, p = 0.016). Among current users of sumatriptan injection and oxygen, the proportion achieving 100% relief was higher with sumatriptan injection (p > 0.001) than with oxygen. No associations were identified regarding verapamil. Only 57% of current users of preventive medication responded at a 50% level.

CONCLUSION

Episodic cluster headache is more responsive to acute therapy than chronic. Further, sumatriptan injection was more effective than oxygen and the responder-rate was limited with verapamil. More effective acute and preventive therapies are needed for cluster headache patients.

Emerging treatments for cluster headache: hopes and disappointments

PURPOSE OF REVIEW

Cluster headache stands among the worst debilitating pain conditions. Available treatments for cluster headache have often disabling side effects, are not tolerated, or are ineffective. The management of drug-refractory chronic forms is challenging. New treatments are warranted and reported here.

RECENT FINDINGS

In cluster headache acute treatment, delivery systems like Demand Valve Oxygen or nonrebreather-type masks could enhance the effectiveness of inhaled oxygen therapy. Noninvasive vagus nerve stimulation relieves cluster headache pain at short-term in episodic patients. Sphenopalatine ganglion stimulation combines acute and preventive properties in subsets of patients and is of interest in selected refractory chronic forms. In cluster headache prevention, 'hypothalamic' deep brain stimulation is being refined using slightly different stereotactic coordinates or lower risk methods like endoventricular stimulation. Anti-CGRP monoclonal antibodies provide interesting results in episodic cluster headache, have a good safety profile, but do not appear effective in chronic cluster headache.

SUMMARY

These novel approaches provide additional alternatives to conventional cluster headache management, but results obtained in chronic forms are often disappointing. Research on cluster headache is often hampered by the lack of awareness in the medical world and by the relatively low prevalence of cluster headache compared with migraine. However, common features shared by these two primary headaches could help developing disease-specific therapies.

Effectiveness of Oxygen and Other Acute Treatments for Cluster Headache: Results From the Cluster Headache Questionnaire, an International Survey

OBJECTIVE

To assess the effectiveness and adverse effects of acute cluster headache medications in a large international sample, including recommended treatments such as oxygen, commonly used medications such as opioids, and emerging medications such as intranasal ketamine. Particular focus is paid to a large subset of respondents 65 years of age or older.

BACKGROUND

Large international surveys of cluster headache are rare, as are examinations of treatments and side effects in older cluster headache patients. This article presents data from the Cluster Headache Questionnaire, with respondents from over 50 countries and with the vast majority from the United States, the United Kingdom, and Canada.

METHODS

This internet-based survey included questions on cluster headache diagnostic criteria, which were used as part of the inclusion/exclusion criteria for the study, as well as effectiveness of medications, physical and medical complications, psychological and emotional complications, mood scores, and difficulty obtaining medications. The diagnostic questions were also used to create a separate group of respondents with probable cluster headache. Limitations to the methods include the use of nonvalidated questions, the lack of a formal clinical diagnosis of cluster headache, and the grouping of some medications (eg, all triptans as opposed to sumatriptan subcutaneous alone).

RESULTS

A total of 3251 subjects participated in the questionnaire, and 2193 respondents met criteria for this study (1604 cluster headache and 589 probable cluster headache). Of the respondents with cluster headache, 68.8% (1104/1604) were male and 78.0% (1245/1596) had episodic cluster headache. Over half of respondents reported complete or very effective treatment for triptans (54%, 639/1139) and oxygen (54%, 582/1082). Between 14 and 25% of respondents reported complete or very effective treatment for ergot derivatives (dihydroergotamine 25%, 42/170; cafergot/ergotamine 17%, 50/303), caffeine and energy drinks (17%, 7/41), and intranasal ketamine (14%, 5/37). Less than 10% reported complete or very effective treatment for opioids (6%, 30/541), intranasal capsaicin (5%, 7/151), and intranasal lidocaine (2%, 5/241). Adverse events were especially low for oxygen (no or minimal physical and medical complications 99%, 1077/1093; no or minimal psychological and emotional complications 97%, 1065/1093), intranasal lidocaine (no or minimal physical and medical complications 97%, 248/257; no or minimal psychological and emotional complications 98%, 251/257), intranasal ketamine (no or minimal physical and medical complications 95%, 38/40; no or minimal psychological and emotional complications 98%, 39/40), intranasal capsaicin (no or minimal physical and medical complications 91%, 145/159; no or minimal psychological and emotional complications 94%, 150/159), and caffeine and energy drinks (no or minimal physical and medical complications 89%, 39/44; no or minimal psychological and emotional complications 91%, 40/44). This is in comparison to ergotamine/cafergot (no or minimal physical and medical complications 83%, 273/327; no or minimal psychological and emotional complications 89%, 290/327), dihydroergotamine (no or minimal physical and medical complications 81%, 143/176; no or minimal psychological and emotional complications 91%, 160/176), opioids (no or minimal physical and medical complications 76%, 416/549; no or minimal psychological and emotional complications 77%, 423/549), or triptans (no or minimal physical and medical complications 73%, 883/1218; no or minimal psychological and emotional complications 85%, 1032/1218). A total of 139 of 1604 cluster headache respondents (8.7%) were age 65 and older and reported similar effectiveness and adverse events to the general population. The 589 respondents with probable cluster headache reported similar medication effectiveness to respondents with a full diagnosis of cluster headache.

CONCLUSIONS

Oxygen is reported by survey respondents to be a highly effective treatment with few complications in cluster headache in a large international sample, including those 65 years or over. Triptans are also very effective with some side effects, and newer medications deserve additional study. Patients with probable cluster headache may respond similarly to acute medications as patients with a full diagnosis of cluster headache.