Testosterone Replacement Therapy for Treatment Refractory Cluster Headache

Compensated Hypogonadism Identified in Males with Cluster Headache: A Prospective Case-Controlled Study

OBJECTIVE

Androgens have been hypothesized to be involved in the pathophysiology of cluster headache due to the male predominance, but whether androgens are altered in patients with cluster headache remains unclear.

METHODS

We performed a prospective, case-controlled study in adult males with cluster headache. Sera were measured for hormones including testosterone, luteinizing hormone (LH), and sex hormone-binding globulin in 60 participants with episodic cluster headache (during a bout and in remission), 60 participants with chronic cluster headache, and 60 age- and sex-matched healthy controls. Free testosterone (fT) was calculated according to the Vermeulen equation. Shared genetic risk variants were assessed between cluster headache and testosterone concentrations.

RESULTS

The mean fT/LH ratio was reduced by 35% (95% confidence interval [CI]: 21%-47%, p < 0.0001) in patients with chronic cluster headache and by 24% (95% CI: 9%-37%, p = 0.004) in patients with episodic cluster headache compared to controls after adjusting for age, sleep duration, and use of acute medication. Androgen concentrations did not differ between bouts and remissions. Furthermore, a shared genetic risk allele, rs112572874 (located in the intron of the microtubule associated protein tau (MAPT) gene on chromosome 17), between fT and cluster headache was identified.

INTERPRETATION

Our results demonstrate that the male endocrine system is altered in patients with cluster headache to a state of compensated hypogonadism, and this is not an epiphenomenon associated with sleep or the use of acute medication. Together with the identified shared genetic risk allele, this may suggest a pathophysiological link between cluster headache and fT. ANN NEUROL 2024;95:1149-1161.

The Effects of Sex Hormones on Postoperative Pain in Patients with Laparoscopic Cholecystectomy

OBJECTIVE

There are many factors that affect postoperative pain. This study determines the effect of preoperative sex hormone levels on postoperative pain levels in patients undergoing laparoscopic cholecystectomy.

PATIENTS AND METHODS

This study included a total of 89 patients who met the study inclusion criteria. The patients were divided into 3 groups based on their sex and pre and postmenopausal periods: male patients (n = 28), postmenopausal female patients (n = 31), and female patients with normal cycles (n = 30). Normal-cycle women were also regrouped based on their follicular and luteal phases. Data were collected using a descriptive characteristics form, a patient follow-up form, and the Visual Analog Scale.

RESULTS

Venous blood samples taken from the patients before surgery were used to measure their levels of estradiol (EST), testosterone (TES), and progesterone levels. Male patients had lower pain levels than female patients. The male patients' Visual Analog Scale scores were inversely related and correlated strongly with their TES levels ( P < 0.05). However, subgroup analyses suggested that their EST level played a primary role in males and that the EST/TES ratio was determinant in the late postoperative period. In female patients, the EST/progesterone ratio was the most determining factor for the level of pain felt in the postmenopausal period, whereas there was no change in the premenopausal period at different stages of the menstrual cycle.

CONCLUSIONS

Sex hormones were found to be effective in predicting postoperative pain severity.

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.

Post-traumatic headaches and vision: A review

BACKGROUND: Post-traumatic headache is the most common sequela of brain injury and can last months or years after the damaging event. Many headache types are associated with visual concerns also known to stem from concussion. OBJECTIVES: To describe the various headache types seen after head injury and demonstrate how they impact or are impacted by the visual system. METHODS: We will mirror the International Classification of Headache Disorders (ICHD) format to demonstrate the variety of headaches following brain injury and relate correlates to the visual pathways. The PubMed database was searched using terms such as headache, head pain, vision, concussion, traumatic brain injury, glare, visuomotor pathways. RESULTS: Every type of headache described in the International Classification of Headache Disorders Edition III can be initiated or worsened after head trauma. Furthermore, there is very often a direct or indirect impact upon the visual system for each of these headaches. CONCLUSION: Headaches of every described type in the ICHD can be caused by brain injury and all are related in some way to the afferent, efferent or association areas of the visual system.

Clinical symptoms of androgen deficiency in men with migraine or cluster headache: a cross-sectional cohort study

Background

To compare symptoms of clinical androgen deficiency between men with migraine, men with cluster headache and non-headache male controls.

Methods

We performed a cross-sectional study using two validated questionnaires to assess symptoms of androgen deficiency in males with migraine, cluster headache, and non-headache controls. Primary outcome was the mean difference in androgen deficiency scores. Generalized linear models were used adjusting for age, BMI, smoking and lifetime depression. As secondary outcome we assessed the percentage of patients reporting to score below average on four sexual symptoms (beard growth, morning erections, libido and sexual potency) as these items were previously shown to more specifically differentiate androgen deficiency symptoms from (comorbid) anxiety and depression.

Results

The questionnaires were completed by n = 534/853 (63%) men with migraine, n = 437/694 (63%) men with cluster headache and n = 152/209 (73%) controls. Responders were older compared to non-responders and more likely to suffer from lifetime depression.

Patients reported more severe symptoms of clinical androgen deficiency compared with controls, with higher AMS scores (Aging Males Symptoms; mean difference ± SE: migraine 5.44 ± 0.90, p <  0.001; cluster headache 5.62 ± 0.99, p <  0.001) and lower qADAM scores (quantitative Androgen Deficiency in the Aging Male; migraine: − 3.16 ± 0.50, p <  0.001; cluster headache: − 5.25 ± 0.56, p <  0.001). Additionally, both patient groups more often reported to suffer from any of the specific sexual symptoms compared to controls (18.4% migraine, 20.6% cluster headache, 7.2% controls, p = 0.001).

Conclusion

Men with migraine and cluster headache more often suffer from symptoms consistent with clinical androgen deficiency than males without a primary headache disorder.

Cluster Headache and Other Trigeminal Autonomic Cephalalgias

PURPOSE OF REVIEW

The trigeminal autonomic cephalalgias (TACs) are relatively rare, but they represent a distinct set of syndromes that are important to recognize. Despite their unique features, TACs often go undiagnosed or misdiagnosed for several years, leading to unnecessary pain and suffering. A significant proportion of TAC presentations may have secondary causes.

RECENT FINDINGS

The underlying pathophysiology of TACs is likely rooted in hypothalamic dysfunction and derangements in the interplay of circuitry involving trigeminovascular, trigeminocervical, trigeminoautonomic, circadian, and nociceptive systems. Recent therapeutic advancements include a better understanding of how to use older therapies more effectively and the identification of new approaches.

SUMMARY

TAC syndromes are rare but important to recognize because of their debilitating nature and greater likelihood for having potentially serious underlying causes. Although treatment options have remained somewhat limited, scientific inquiry is continually advancing our understanding of these syndromes and how best to manage them.

Cluster Headache: A Review and Update in Treatment

PURPOSE OF REVIEW

The treatment of cluster headache has evolved to include a handheld neuromodulation device and a monoclonal antibody in addition to more traditional agents.

RECENT FINDINGS

Galcanezumab is an approved treatment for episodic cluster headache. The non-invasive vagal nerve stimulator has been shown to be effective as a treatment for episodic cluster headache. Dedicated pituitary imaging may not be necessary with a normal MRI of the brain. Cluster headache is the most common trigeminal-autonomic cephalalgia, characterized by unilateral, frequent, debilitating attacks associated with ipsilateral autonomic symptoms. Attacks have a circadian and, often, seasonal pattern with periods of remission that can last months to years in episodic patients. Though a rare disease, an increasing number of studies have revealed novel targets for treatment. Treatment in cluster headache should focus on early intervention to reduce frequency of attacks and the length of the cycle, which improves outcomes and disability. Acute therapy is used to treat attacks, while bridging and preventive therapies are combined to reduce cycle length. Case 1: A 43-year-old man presents with the chief complaint of severe headaches. Upon general examination, he seems uncomfortable, agitated, and exhausted. He states that he hasn't "slept in over a week because of debilitating headaches." His headaches start around the same time every night: when he lays down to go to sleep. The pain is described as sharp, like a "hot poker" to his left eye. His partner has noticed that his eye droops and turns red when the pain starts. The attacks come on abruptly and prevent him from sleeping. The severe pain lasts 30 to 45 min, but he has mild-to-moderate pain that lingers for the rest of the night. He has seen his primary care physician, an allergist, and an ear, nose, and throat (ENT) specialist before coming to see a neurologist. Similar headaches occurred last year during the month of October as well. On further questioning, he reports that these headache attacks have been occurring almost yearly for the past 7 years. Each year, these headaches come on as the weather is changing and occur on a nightly basis for about 3 to 4 weeks.

Updates on management of headache in women and transgender women

PURPOSE OF REVIEW

Gender differences exist in headache disorders. A greater understanding of the role of hormones in headache can help the clinician better approach and manage common primary headache disorders.

RECENT FINDINGS

Recent studies highlight differences in how migraine and cluster headache present in women and men. Updates to the ongoing debate of how to manage the use of hormones in women with migraine, especially with aura, have been well reviewed in the last 18 months. A new meta-analysis evaluates gender differences in response to triptans.

SUMMARY

This review will focus on recent updates on the role of gender and hormones on migraine and cluster headache and how this may influence treatment.

Male and female sex hormones in primary headaches

BACKGROUND

The three primary headaches, tension-type headache, migraine and cluster headache, occur in both genders, but all seem to have a sex-specific prevalence. These gender differences suggest that both male and female sex hormones could have an influence on the course of primary headaches. This review aims to summarise the most relevant and recent literature on this topic.

METHODS

Two independent reviewers searched PUBMED in a systematic manner. Search strings were composed using the terms LH, FSH, progesteron*, estrogen*, DHEA*, prolactin, testosterone, androgen*, headach*, migrain*, "tension type" or cluster. A timeframe was set limiting the search to articles published in the last 20 years, after January 1st 1997.

RESULTS

Migraine tends to follow a classic temporal pattern throughout a woman's life corresponding to the fluctuation of estrogen in the different reproductive stages. The estrogen withdrawal hypothesis forms the basis for most of the assumptions made on this behalf. The role of other hormones as well as the importance of sex hormones in other primary headaches is far less studied.

CONCLUSION

The available literature mainly covers the role of sex hormones in migraine in women. Detailed studies especially in the elderly of both sexes and in cluster headache and tension-type headache are warranted to fully elucidate the role of these hormones in all primary headaches.

Cluster Headache and Other Trigeminal Autonomic Cephalalgias

PURPOSE OF REVIEW

This article covers the clinical features, differential diagnosis, and management of the trigeminal autonomic cephalalgias (TACs). The TACs are composed of five diseases: cluster headache, paroxysmal hemicrania, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT), short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA), and hemicrania continua.

RECENT FINDINGS

New classifications for the TACs have two important updates; chronic cluster headache is now defined as remission periods lasting less than 3 months (formerly less than 1 month), and hemicrania continua is now classified as a TAC (formerly classified as other primary headache). The first-line treatments of TACs have not changed in recent years: cluster headache is managed with oxygen, triptans, and verapamil; paroxysmal hemicrania and hemicrania continua are managed with indomethacin; and SUNCT and SUNA are managed with lamotrigine. However, advancements in neuromodulation have recently provided additional options for patients with cluster headache, which include noninvasive devices for abortive therapy and invasive devices for refractory cluster headache. Patient selection for these devices is key.

SUMMARY

The TACs are a group of diseases that appear similar to each other and to other headache disorders but have important differences. Proper diagnosis is crucial for proper treatment. This article reviews the pathophysiology, epidemiology, differential diagnosis, and treatment of the TACs.

Linking Cigarette Smoking/Tobacco Exposure and Cluster Headache: A Pathogenesis Theory

INTRODUCTION

To propose a hypothesis theory to establish a linkage between cigarette smoking and cluster headache pathogenesis.

BACKGROUND

Cluster headache is a primary headache syndrome grouped under the trigeminal autonomic cephalalgias. What distinguishes cluster headache from all other primary headache conditions is its inherent connection to cigarette smoking. It is undeniable that tobacco exposure is in some manner related to cluster headache. The connection to tobacco exposure for cluster headache is so strong that even if an individual sufferer never smoked, then that individual typically had significant secondary smoke exposure as a child from parental smoking behavior and in many instances both scenarios exist. The manner by which cigarette smoking is connected to cluster headache pathogenesis is unknown at present. If this could be determined this may contribute to advancing our understanding of cluster headache pathophysiology.

METHODS/RESULTS

Hypothesis statement.

CONCLUSION

The hypothesis theory will include several principles: (1) the need of double lifetime tobacco exposure, (2) that cadmium is possibly the primary agent in cigarette smoke that leads to hypothalamic-pituitary-gonadal axis toxicity promoting cluster headache, (3) that the estrogenization of the brain and its specific sexually dimorphic nuclei is necessary to develop cluster headache with tobacco exposure, and (4) that the chronic effects of smoking and its toxic metabolites including cadmium and nicotine on the cortex are contributing to the morphometric and orexin alterations that have been previously attributed to the primary headache disorder itself.

Current Treatment Options: Headache Related to Menopause-Diagnosis and Management

PURPOSE OF REVIEW

Menopause is a life-changing event in numerous ways. Many women with migraine hold hope that the transition to the climacteric state will coincide with a cessation or improvement of migraine. This assumption is based mainly on common lay perceptions as well as assertions from many in the healthcare community. Unfortunately, evidence suggests this is far from the rule. Many women turn to a general practitioner or a headache specialist for prognosis and management. A natural instinct is to manipulate the offending agent, but in some cases, this approach backfires, or the concern for adverse events outweighs the desire for a therapeutic trial, and other strategies must be pursued. Our aim was to review the frequency and type of headache syndromes associated with menopause, to review the evidence for specific treatments for headache associated with menopause, and to provide management recommendations and prognostic guidance.

RECENT FINDINGS

We reviewed both clinic- and population-based studies assessing headache associated with menopause. Headache in menopause is less common than headache at earlier ages but can present a unique challenge. Migraine phenotype predominates, but presentations can vary or be due to secondary causes. Other headache types, such as tension-type headache (TTH) and cluster headache (CH) may also be linked to or altered by hormonal changes. There is a lack of well-defined diagnostic criteria for headache syndromes associated with menopause. Women with surgical menopause often experience a worse course of disease status than those with natural menopause. Hormonal replacement therapy (HRT) often results in worsening of migraine and carries potential for increased cardiovascular and ischemic stroke risk. Estrogen replacement therapy (ERT) in patients with migraine with aura (MA) may increase the risk of ischemic stroke; however, the effect is likely dose-dependent. Some medications used in the prophylaxis of migraine may be useful in ameliorating the vasomotor and mood effects of menopause, including venlafaxine, escitalopram, paroxetine, and gabapentin. Other non-medication strategies such as acupuncture, vitamin E, black cohosh, aerobic exercise, and yoga may also be helpful in reducing headache and/or vasomotor symptoms associated with menopause. The frequency and type of headache associated with menopause is variable, though migraine and TTH are most common. Women may experience a worsening, an improvement, or no change in headache during the menopausal transition. Treatment may be limited by vascular risks or other medical and psychiatric factors. We recommend using medications with dual benefit for migraine and vasomotor symptoms including venlafaxine, escitalopram, paroxetine, and gabapentin, as well as non-medication strategies such as acupuncture, vitamin E, black cohosh, aerobic exercise, and yoga. If HRT is pursued, continuous (rather than cyclical) physiological doses should be used, transdermal route of administration is recommended, and the patient should be counseled on the potential for increased risk of adverse events (AEs). Concomitant use of a progestogen decreases the risk of endometrial hyperplasia with ERT. Biological mechanisms are incompletely understood, and there is a lack of consensus on how to define and classify headache in menopause. Further research to focus on pathophysiology and nuanced management is desired.

Treatment of Cluster Headache: The American Headache Society Evidence-Based Guidelines

BACKGROUND

Cluster headache (CH), the most common trigeminal autonomic cephalalgia, is an extremely debilitating primary headache disorder that is often not optimally treated. New evidence-based treatment guidelines for CH will assist clinicians with identifying and choosing among current treatment options.

OBJECTIVES

In this systematic review we appraise the available evidence for the acute and prophylactic treatment of CH, and provide an update of the 2010 American Academy of Neurology (AAN) endorsed systematic review.

METHODS

Medline, PubMed, and EMBASE databases were searched for double-blind, randomized controlled trials that investigated treatments of CH in adults. Exclusion and inclusion criteria were identical to those utilized in the 2010 AAN systematic review.

RESULTS AND RECOMMENDATIONS

For acute treatment, sumatriptan subcutaneous, zolmitriptan nasal spray, and high flow oxygen remain the treatments with a Level A recommendation. Since the 2010 review, a study of sphenopalatine ganglion stimulation was added to the current guideline and has been administered a Level B recommendation for acute treatment. For prophylactic therapy, previously there were no treatments that were administered a Level A recommendation. For the current guidelines, suboccipital steroid injections have emerged as the only treatment to receive a Level A recommendation with the addition of a second Class I study. Other newly evaluated treatments since the 2010 guidelines have been given a Level B recommendation (negative study: deep brain stimulation), a Level C recommendation (positive study: warfarin; negative studies: cimetidine/chlorpheniramine, candesartan), or a Level U recommendation (frovatriptan).

CONCLUSIONS

This AHS guideline can be utilized for understanding which therapies have superiority to placebo or sham treatment in the management of CH. In clinical practice, these recommendations should be considered in concert with other variables including safety, side effects, patient preferences, clinician experience, cost, and the invasiveness of the intervention. Given the lack of Class I evidence and Level A recommendations, particularly for a number of commonly used preventive therapies, further studies are warranted to demonstrate safety and efficacy for established and emerging therapies.

Sex Differences in Pain

Females greatly outnumber males as sufferers of chronic pain. Although social and psychological factors certainly play a role in the differences in prevalence and incidence, biological differences in the functioning of the immune system likely underlie these observed effects. This Review examines the current literature on biological sex differences in the functioning of the innate and adaptive immune systems as they relate to pain experience. With rodent models, we and others have observed that male mice utilize microglia in the spinal cord to mediate pain, whereas females preferentially use T cells in a similar manner. The difference can be traced to differences in cell populations, differences in suppression by hormones, and disparate cellular responses in males and females. These sex differences also translate into human cellular responses and may be the mechanism by which the disproportionate chronic pain experience is based. Recognition of the evidence underlying sex differences in pain will guide development of treatments and provide better options for patients that are tailored to their physiology. © 2016 Wiley Periodicals, Inc.

Migraine and Adiponectin: Is There a Connection?

Migraine is a common disorder, characterized by recurrent episodes of headache and associated symptoms. The full pathophysiology of migraine is incompletely delineated. Current theories suggest that it is a neurovascular disorder involving cortical depression, neurogenic inflammation and vasodilation. Various neuropeptides and cytokines have been implicated in the pathophysiology of migraine including calcitonin gene-related peptide, interleukin (IL)-1, IL-6 and tumour necrosis factor (TNF)-α. There is evidence demonstrating an association between migraine and processes associated with inflammation, atherosclerosis, immunity and insulin sensitivity. Similarly, adiponectin, an adipocytokine secreted by adipose tissue, has protective roles against the development of insulin resistance, dyslipidaemia and atherosclerosis and exhibits anti-inflammatory properties. The anti-inflammatory activities of adiponectin include inhibition of IL-6 and TNF-induced IL-8 formation, as well as induction of the anti-inflammatory cytokines IL-10 and IL-1 receptor antagonist. Adiponectin levels are also inversely correlated with C-reactive protein (CRP), TNF-α and IL-6 levels. Likewise, recent studies have shown a possible correlation between CRP, TNF-α and IL-6 and migraine attacks. In addition, insulin sensitivity is impaired in migraine and obesity is a risk factor for the transformation from episodic to chronic migraine. In this review we discuss the basic science of adiponectin and its potential connection to the pathophysiology of migraine. Future research may focus on how adiponectin levels are potentially altered during migraine attacks, and how that information can be potentially translated into migraine therapy.

Pharmacotherapy options for cluster headache

INTRODUCTION

Cluster headache (CH) is a primary headache disorder and the most common trigeminal autonomic cephalalgia. Patients suffer from very severe unilateral headache attacks accompanied by ipsilateral trigeminal autonomic symptoms. Previous studies described a high burden of disease due to its impact on social life as well as an increased suicide ideation rate. The mean time to diagnosis in western industrialized countries is estimated at 4 years.

AREAS COVERED

Many treatment options for CH exist, but due to the rarity of the disease, controlled randomized clinical studies remain difficult to perform. This review summarizes the current knowledge about the treatment of CH including internationally accepted treatment guidelines, and an additional MEDLINE search (1 February 2015).

EXPERT OPINION

International treatment recommendations and official guidelines give reassurance about specific pharmacotherapy options for CH, but only few of these are backed by sufficient scientific evidence. The limited therapeutic efficacy in some patients leads to the use of alternative, complementary, but also illicit drugs to better cope with the disease. Many single cases, case series and uncontrolled studies were performed with different substances in an attempt to find a better way to treat or prevent the excruciatingly painful attacks associated with CH. Large-scale, randomized controlled clinical trials are desperately needed in order to further increase the quality of patient care for this outstanding but terrifying disease.

Clomiphene citrate as a preventive treatment for intractable chronic cluster headache: a second reported case with long-term follow-up

OBJECTIVE

To describe a second case of treatment refractory chronic cluster headache responsive to clomiphene citrate and with long-term follow-up.

METHODS

Case report with 7-year evaluation.

CASE

A 63-year-old man with a 17-year history of chronic cluster headache preceded to have significant adverse events or was nonresponsive to multiple cluster headache preventive medications including verapamil, lithium, valproic acid, topiramate, baclofen as well as greater occipital nerve blocks and inpatient hospitalization. The patient experienced 3-5 headaches per day. On clomiphene citrate 100 mg/day he became 100% pain-free and remained so for 3.5 years with only mild fatigue as a side effect. He then had cluster headache recurrence and did well on gabapentin for another 3 years with repeat headache recurrence. Clomiphene was restarted, and he became pain-free once again.

DISCUSSION

This is the second reported case of the effective use of clomiphene citrate for the preventive treatment of medicinal refractory chronic cluster headache. This is the first case to report long-term follow-up of this neurohormonal treatment. Clomiphene citrate appears to be safe for extended use in chronic cluster headache even in an elderly sufferer and has a minimal side effect profile. The mechanism of action of how clomiphene prevents cluster headache may involve both its ability to enhance testosterone production and its ability to bind to hypothalamic estrogen receptors. Clomiphene citrate should join the list of alternative cluster headache prophylactic treatments to be considered by headache specialists when conventional cluster headache preventives are ineffective.

Mechanisms of pain modulation by sex hormones in migraine

A number of pain conditions, acute as well as chronic, are much more prevalent in women, such as temporomandibular disorder (TMD), irritable bowel syndrome, fibromyalgia, and migraine. The association of female sex steroids with these nociceptive conditions is well known, but the mechanisms of their effects on pain signaling are yet to be deciphered. We reviewed the mechanisms through which female sex steroids might influence the trigeminal nociceptive pathways with a focus on migraine. Sex steroid receptors are located in trigeminal circuits, providing the molecular substrate for direct effects. In addition to classical genomic effects, sex steroids exert rapid nongenomic actions to modulate nociceptive signaling. Although there are only a handful of studies that have directly addressed the effect of sex hormones in animal models of migraine, the putative mechanisms can be extrapolated from observations in animal models of other trigeminal pain disorders, like TMD. Sex hormones may regulate sensitization of trigeminal neurons by modulating expression of nociceptive mediator such as calcitonin gene-related peptide. Its expression is mostly positively regulated by estrogen, although a few studies also report an inverse relationship. Serotonin (5-Hydroxytryptamine [5-HT]) is a neurotransmitter implicated in migraine; its synthesis is enhanced in most parts of brain by estrogen, which increases expression of the rate-limiting enzyme tryptophan hydroxylase and decreases expression of the serotonin re-uptake transporter. Downstream signaling, including extracellular signal-regulated kinase activation, calcium-dependent mechanisms, and cAMP response element-binding activation, are thought to be the major signaling events affected by sex hormones. These findings need to be confirmed in migraine-specific animal models that may also provide clues to additional ion channels, neuropeptides, and intracellular signaling cascades that contribute to the increased prevalence of migraine in women.

Sex-related differences in pain

This article provides an overview of sex-related differences in musculoskeletal pain and the role sex hormones and response to analgesic drugs may play in these differences. Some common pain conditions that include temporomandibular disorders, rheumatoid arthritis, fibromyalgia syndrome and tension-type and migraine headaches, show fairly marked sex-related differences in their occurrence, however, with the exception of rheumatoid arthritis, these pain conditions are also characterized by a lack of understanding of their basic underlying pathophysiology. The association of pain symptoms of these musculoskeletal pain conditions with the reproductive cycle of women is strongly suggestive of a role of the estrogens and/or progesterones, the main female sex hormones, in sex-related differences in pain. Nevertheless, an alternative suggestion that testosterone, the major male sex hormone, protects men from these chronic musculoskeletal pain conditions, has also been made. Indeed, emerging evidence suggests that both male and female sex hormones may contribute to the marked sex-related differences in the occurrence of certain musculoskeletal pain conditions. Men and women also appear to differ in response to pain treatment with certain analgesic drugs. The mechanistic basis for these sex-related differences is not entirely understood but sex hormones are thought to be one of the influencing factors. An improved understanding of mechanisms which underlie sex-related differences in musculoskeletal pain and response to analgesic drugs should permit improved pain management strategies for male and female musculoskeletal pain patients in the clinical setting.

Refractory headache: historical perspective, need, and purposes for an operational definition

The study of migraine has yielded many benefits for headache patients. Little research, however, has been performed on refractory migraine (RM) headache, a term often used interchangeably with intractable migraine. This may be a consequence of a lack of a well-accepted definition. In a survey performed by the Refractory Headache Special Interest Section (RHSIS) on the American Headache Society (AHS) in 2006, 58% of the members agreed that a definition for refractory headache should be added to the International Classification of Headache Disorders-2. A PubMed search identified 21 articles that defined refractory or intractable headache/migraine. Sixteen (76%) defined the term "refractory" and 5 (24%) defined the term "intractable." Many of these definitions did not address the need for an adequate trial of a preventive medicine, disability, and medication overuse. An operational definition will allow us to better characterize the disorder, address unmet medical needs, and identify the most effective treatments. RHSIS of the AHS has proposed a definition of RM. It is our hope that this definition will spur interest in this entity and will lead to further research in the area.

Clomiphene citrate for treatment refractory chronic cluster headache

A treatment refractory chronic cluster headache patient is presented who became cluster-free on clomiphene citrate. The author has previously reported a SUNCT patient responding to clomiphene citrate. Hypothalamic hormonal modulation therapy with clomiphene citrate may become a new preventive choice for trigeminal autonomic cephalalgias. The possible mechanism of action of clomiphene citrate for cluster headache prevention will be discussed.

Trigeminal autonomic cephalalgias. Part 1: cluster headache

Cluster headache is characterized by severe, strictly unilateral pain attacks lasting 15 to 180 minutes localized to orbital, temporal, and midface areas accompanied by ipsilateral autonomic features. It represents 1 of 3 primary headaches classified as trigeminal autonomic cephalalgias. While its prevalence is small, it is not uncommon for cluster headache patients to present at dental offices seeking relief for their pain. It is important for oral health care providers to recognize cluster headache and render an accurate diagnosis. This will avoid the pitfall of implementing unnecessary and inappropriate traditional dental treatments in hopes of alleviating this neurovascular pain. The following article is part 1 of a review on trigeminal autonomic cephalalgias and focuses on cluster headache. Aspects of cluster headache including its prevalence and incidence, genetics, pathophysiology, clinical presentation, classification and variants, diagnosis, medical management, and dental considerations are discussed.

Cluster headache treatment dilemmas: the experts respond

When conventional treatment approaches to cluster headache are unsuccessful, expert recommendations are relevant but may not be easily accessible to treating clinicians. We conducted a study of expert recommendations in response to standardized vignettes. Ten expert headache clinicians were asked what treatment they would recommend for a hypothetical 55-year-old male cluster headache patient in the following five situations: 1) known coronary artery disease with response only to sumatriptan; 2) strictly unilateral headaches unresponsive to preventive treatment; 3) effective abortive treatment not covered by insurance; 4) patient request to obtain methysergide from Canada; and 5) headaches responsive only to steroid treatment.