Indomethacin-responsive headache syndromes

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.

Feasibility of a High-Dose Inhaled Indomethacin Dry Powder with Dual Deposition for Pulmonary and Oral Delivery

In this study we have developed a high-dose dry powder inhaler formulation of indomethacin using a novel approach to carrier-based formulations. Specifically, larger drug particles serve as the carrier for the smaller micronized drug particles, such that an inhaled dose is combined with an oral dose. To study this system, the aerosol performance of a standard indomethacin-lactose formulation was compared to carrier-free micronized indomethacin and a drug-as-carrier formulation (a micronized indomethacin-coarse indomethacin blend). Indomethacin with lactose showed a very poor aerosol performance, indicating high adhesion between the drug and carrier. The performance of the carrier-free micronized drug was significantly better, indicating low cohesion. Coarse drug particles as a carrier allowed improved powder flow and aerosol performance while also providing a potential secondary route of absorption of indomethacin, namely oral. An optimal formulation ratio of 1:1 (w/w) fine indomethacin-coarse indomethacin was developed in this study.

Complementary and Integrative Medicine for the Treatment of Trigeminal Neuralgia and Trigeminal Autonomic Cephalalgia

PURPOSE OF REVIEW

Trigeminal neuralgia (TN) and trigeminal autonomic cephalalgias (TACs) are both painful diseases which directly impact the branches of the trigeminal nerve, which supply the face. Patients who have experienced adverse effects, have not responded to mainstream treatments, or have a personal preference for nonmedication options, often turn to complementary and integrative medicine (CIM). The aim of this review is to discuss the efficacy and safety of CIM therapies available for the treatment of TN and TACs.

RECENT FINDINGS

Not only are there limited therapeutic options for TN and TAC patients, but also is there a proportion of patients who are intolerant to standard medical treatments. Recent findings have illustrated that 86% of patients with headache disorders utilize CIM modalities in combination with mainstream medical therapy. CIM modalities can be helpful for these diseases and have primarily been studied in combination with standard medical therapy. There is limited evidence for CIM and behavioral therapies in managing these conditions, and more research is needed to confirm which therapies are safe and effective.

Pharmacological treatment of migraine: Drug classes, mechanisms of action, clinical trials and new treatments

Migraine is the sixth most prevalent disease globally, a major cause of disability, and it imposes an enormous personal and socioeconomic burden. Migraine treatment is often limited by insufficient therapy response, leading to the need for individually adjusted treatment approaches. In this review, we analyse historical and current pharmaceutical development approaches in acute and chronic migraine based on a comprehensive and systematic analysis of Food and Drug Administration (FDA)-approved drugs and those under investigation. The development of migraine therapeutics has significantly intensified during the last 3 years, as shown by our analysis of the trends of drug development between 1970 and 2020. The spectrum of drug targets has expanded considerably, which has been accompanied by an increase in the number of specialised clinical trials. This review highlights the mechanistic implications of FDA-approved and currently investigated drugs and discusses current and future therapeutic options based on identified drug classes of interest.

Indomethacin-responsive headaches-A narrative review

BACKGROUND

Indomethacin is a nonsteroidal anti-inflammatory drug whose mechanism of action in certain types of headache disorders remains unknown. The so-called indomethacin-responsive headache disorders consist of a group of conditions with a very different presentation that have a particularly good response to indomethacin. The response is so distinct as to be used in the definition of two: hemicrania continua and paroxysmal hemicrania.

METHODS

This is a narrative literature review. PubMed and the Cochrane databases were used for the literature search.

RESULTS

We review the main pharmacokinetic and pharmacodynamics properties of indomethacin useful for daily practice. The proposed mechanisms of action of indomethacin in the responsive headache disorders, including its effect on cerebral blood flow and intracranial pressure, with special attention to nitrergic mechanisms, are covered. The current evidence for its use in primary headache disorders, such as some trigeminal autonomic cephalalgias, cough, hypnic, exertional or sexual headache, and migraine will be covered, as well as its indication for secondary headaches, such as those of posttraumatic origin.

CONCLUSION

Increasing understanding of the mechanism(s) of action of indomethacin will enhance our understanding of the complex pathophysiology that might be shared by indomethacin-sensitive headache disorders.

Lipid Formulations and Bioconjugation Strategies for Indomethacin Therapeutic Advances

Indomethacin (IND) is a drug which after successful clinical trials became available for general prescription in 1965 and from that time is one of the most widely used anti-inflammatory drug with the highest potencies in the in vitro and in vivo models. However, despite its high therapeutic efficacy in relieving the symptoms of certain arthritis and in treating gout or collagen diseases, administration of IND causes a number of adverse effects, such as gastrointestinal ulceration, frequent central nervous system disorders and renal toxicity. These obstacles significantly limit the practical applications of IND and make that 10-20% of patients discontinue its use. Therefore, during the last three decades many attempts have been made to design novel formulations of IND aimed to increase its therapeutic benefits minimizing its adverse effects. In this review we summarize pharmacological information about IND and analyze its new lipid formulations and lipid bioconjugates as well as discuss their efficacy and potential application.

Hints on Diagnosing and Treating Headache

BACKGROUND

Headache, like dizziness, is one of the more common presenting complaints in outpatient care and in the emergency room. More than 200 varieties of headache have been described, and the false impression may arise that the diagnosis and treatment of these syndromes is a highly challenging task.

METHODS

This review is based on pertinent articles retrieved by a selective search in PubMed.

RESULTS

In primary headache, the headache is not a symptom but a disease in its own right. There are four types of primary headache: migraine, tension headache, trigeminal autonomic cephalalgia, and other primary headache disorders. By definition, the physical examination is normal, including the neurological examination. Secondary headache, in contrast, is a symptom of another disease (e.g., a tumor or cerebral hemorrhage). Triptans and nonsteroidal anti-inflammatory drugs (NSAID) are the drugs usually given for the acute treatment and prophylaxis of migraine. In tension headache, NSAID are given acutely, and tricyclic drugs for prophylaxis. There are various options for the treatment of trigeminal autonomic cephalalgia syndromes such as cluster headache and paroxysmal hemicrania. For group 4 headaches (other primary headache disorders), the treatment must be chosen on an individual basis; indomethacin is often effective.

CONCLUSION

If the patient is clearly suffering from none of the four types of primary headache, the problem must be a headache of a secondary nature, potentially reflecting a dangerous underlying disease. The treatment of headache is usually successful and thus highly rewarding for physicians of all medical specialties.

Case report of hypnic headache: a rare headache disorder with nocturnal symptoms

Background

Headache is one of the commonest complaints reported to physicians worldwide. Yet, arriving at the proper diagnosis can be a challenge in many patients. Although most headaches belong to common categories of migraine and tension-type headache, which are diagnosed and managed relatively easily, several uncommon headache disorders can lead to delays in diagnosis. Certain medications are more efficacious than others in managing these headache disorders, hence establishing the correct diagnosis is of paramount importance.

Case presentation

An 86-year-old female presented with chronic daily headache of 1 year duration. Her headaches were exclusively nocturnal and woke her up daily around midnight. Clinical examination was unremarkable. All basic investigations were normal. Subsequent gadolinium enhanced Magnetic Resonance Imaging (MRI) brain did not show any significant pathology. There was no satisfactory response to paracetamol, diclofenac sodium, mefenamic acid, tramadol, flunarizine and sodium valproate. Indomethacin was started with the provisional diagnosis of hypnic headache. There was absolute response by day 3 of indomethacin. She remains headache free on low dose indomethacin maintenance at 1 year after the diagnosis.

Conclusion

Better understanding of uncommon headache syndromes can help in early diagnosis and appropriate treatment. Hypnic headache should be considered in the differential diagnosis of chronic daily headaches, especially when nocturnal and occurs during sleep.

Primary Stabbing Headache in A Headache Clinic

Primary stabbing headache (PSH) is a short-lasting but troublesome headache disorder which has been known for several decades. We surveyed and registered consecutive patients with PSH in a headache clinic in Taiwan. A total of 80 patients (24 M/56 F, 53.2 ± 16.2 years) were enrolled in our study. Migraine was reported in 20 (25%) patients and was less common in those with PSH onset at >50 years than those with onset at <50 years (14% vs. 38%, P = 0.02). The headache was unilateral in 59% of the patients and always in a fixed area in 36%. The head pain frequently involved extratrigeminal regions (70%) and in 30 patients (38%) was accompanied by jolts, i.e. head or body movements. Indomethacin was effective (74%) in patients who received it. Our study showed primary stabbing headache was a common and easily treated headache disorder in headache clinic. However, 70% of our patients could not fulfil criterion A ‘exclusively or predominantly in the distribution of the first division of the trigeminal nerve’ and 15% could not fulfil criterion C ‘no accompanying symptoms’ of the International Classification of Headache Disorders-II criteria proposed for PSH.

Field testing primary stabbing headache criteria according to the 3rd beta edition of International Classification of Headache Disorders: a clinic-based study

BACKGROUND

The diagnostic criteria for primary stabbing headache (PSH) in the 3rd beta edition of International Classification of Headache Disorders (ICDH-3 beta) were recently revised. In the ICDH-3 beta, PSH is defined as short-lasting head pain spontaneous occurring as a single stab or series of stabs without autonomic symptoms and involving all head areas (i.e., not limited to the ophthalmic branch region of the trigeminal nerve). The aim of this study was to investigate the validity of the ICHD-3 beta criteria for PSH in a clinic-based setting.

METHODS

We prospectively collected data from patients with complaint of headache with stabbing pain without apparent cause at an initial visit to a secondary-care hospital from March 2009 to March 2014. Patients were followed up for 2 weeks to assess changes in clinical characteristics and secondary causes of pain.

RESULTS

Data from 280 patients with headache with stabbing pain without apparent cause were collected, and 245 patients were followed up for 2 weeks. Secondary causes for stabbing headache were observed in 9 patients (herpes zoster in 7 patients and Bell's palsy in 2 patients) after 2 weeks. The remaining 236 patients fulfilled the diagnostic criteria for PSH according to ICHD-3 beta. Only 22 patients met the diagnostic criteria for PSH according to ICHD-2.

CONCLUSIONS

All patients with headache with stabbing pain without cranial autonomic symptoms fulfilled the diagnostic criteria for PSH according to ICHD-3 beta at the initial visit. Secondary causes for headache with stabbing pain were revealed in a small proportion (3.7 %) of patients after 2 weeks of follow-up.

Indomethacin Responsive Headaches: Exhaustive Systematic Review with Pooled Analysis and Critical Appraisal of 81 Published Clinical Studies

OBJECTIVES

The relationship between indomethacin (IMC) and headache treatment has long intrigued clinicians and clinical researchers in Headache Medicine. Why is it efficacious in many types of headache disorders when other medications are not, and what is the mechanism behind its efficacy? IMC and headache related topics that have been explored in detail in the literature include IMC-responsive headache disorders ("traditional"), pharmacology of IMC, symptomatic headaches responsive to IMC, "novel" headache conditions that respond, cluster headache and IMC, IMC provoking headache, the issue about" absolute" and "non-absolute" effect of IMC on headache disorders, and the morphing trigeminal autonomic cephalalgias (TACs).

DATA SOURCE

A PubMed/MEDLINE search was used for Clinical Studies Categories and Systematic Reviews on the PubMed Clinical Queries. The search details were "indomethacin" AND "headache" spanning all previous years until February 1, 2015. Methods were in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

REVIEW METHODS

Articles were excluded if IMC had not been used to treat headache disorders in adults, if the article concerned IMC-responsive headaches but made no reference to the use of IMC, and articles not addressing the above mentioned topics.

RESULTS AND CONCLUSIONS

The "velocity" of publications on IMC and headache seems to be decreasing, particularly on the use of IMC for the treatment of TACs. The science behind the understanding of the putative mechanisms of IMC's action on headache has moved forward, but the answer to why it works better than other nonsteroidal anti-inflammatory drugs has been elusive. There are case reports of other rare headache disorders that may be responsive to IMC. The dosages of IMC used as a tool for detecting IMC responsive disorders vary according to different centers of investigation. In many circumstances, headache disorders similar to "primary" IMC-responsive disorders are actually symptomatic disorders. Cluster headache as an IMC-resistant headache disorder may not be as absolute as once thought. Sometimes, IMC has been found to provoke headache; differentiating IMC-provoked headache from IMC-resistant headache can make headache diagnosis and management difficult. As for the "absolute" responsiveness of IMC, it is possible that using higher dosages leads to higher sensitivity, probably at the expense of decreased specificity. There are many reports about the occurrence of two or more IMC-responsive disorders (latu sensu) in the same patient, which may be coincidental.

Alzheimer's Disease: Exploring the Role of Inflammation and Implications for Treatment

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by both structural abnormalities and inflammation in the brain. While recent research has chiefly focused on the structural changes involved in AD, understanding the pathophysiology and associated inflammation of the AD brain helps to elucidate potential therapeutic and preventative options. By exploring the data supporting an inflammatory etiology of AD, we present a case for the use of existing evidence-based treatments addressing inflammation as promising options for treating and preventing AD. We present data demonstrating tumor necrosis factor alpha association with the inflammation of AD. We also discuss data supporting TNF alpha associated inflammation in traumatic brain injury, stroke, and spinal disc associated radiculopathy. We augment this previously unarticulated concept of a unifying pathophysiology of central nervous system disease, with reports of benefits of TNF alpha inhibition in many hundreds of patients with those diseases, including AD. We also assess the pathophysiologic and clinical trial evidence supporting the role of other inflammation resolving treatments in AD. In aggregate, the data from the several potentially effective therapeutic and preventative options contained within this report presents a clearer picture of next steps needed in research of treatment alternatives.

Perspectives on next steps in classification of oro-facial pain - part 1: role of ontology

The purpose of this study was to review existing principles of oro-facial pain classifications and to specify design recommendations for a new system that would reflect recent insights in biomedical classification systems, terminologies and ontologies. The study was initiated by a symposium organised by the International RDC/TMD Consortium Network in March 2013, to which the present authors contributed. The following areas are addressed: problems with current classification approaches, status of the ontological basis of pain disorders, insufficient diagnostic aids and biomarkers for pain disorders, exploratory nature of current pain terminology and classification systems, and problems with prevailing classification methods from an ontological perspective. Four recommendations for addressing these problems are as follows: (i) develop a hypothesis-driven classification structure built on principles that ensure to our best understanding an accurate description of the relations among all entities involved in oro-facial pain disorders; (ii) take into account the physiology and phenomenology of oro-facial pain disorders to adequately represent both domains including psychosocial entities in a classification system; (iii) plan at the beginning for field-testing at strategic development stages; and (iv) consider how the classification system will be implemented. Implications in relation to the specific domains of psychosocial factors and biomarkers for inclusion into an oro-facial pain classification system are described in two separate papers.

Indomethacin-responsive headaches

Indomethacin-responsive headaches are a heterogeneous group of primary headache disorders distinguished by their swift and often absolute response to indomethacin. The epidemiology of these conditions is incompletely defined. Traditionally, indomethacin-responsive headaches include a subset of trigeminal autonomic cephalalgias (paroxysmal hemicrania and hemicrania continua), Valsalva-induced headaches (cough headache, exercise headache, and sex headache), primary stabbing headache, and hypnic headache. These headache syndromes differ in extent of response to indomethacin, clinical features, and differential diagnoses. Neuroimaging is recommended to investigate for various organic causes that may mimic these headaches. Case reports of other primary headache disorders that also respond to indomethacin, such as cluster headache, nummular headache, and ophthalmoplegic migraine, have been described. These "novel" indomethacin-responsive headaches beg the question of what headache characteristics are required to qualify a headache as an indomethacin-responsive headache. Furthermore, they challenge the concept of using a therapeutic intervention as a diagnostic criterion.

Primary stabbing headache in adults and pediatrics: a review

Primary stabbing headache (PSH) is an under-recognized primary headache disorder, which often goes undiagnosed. It is mainly characterized by its ultrashort stabbing quality and can be easily overlooked both by patients and providers as it is often not severe enough to interfere significantly with daily life. However, PSH may be severe and require therapy, and it is important for providers to recognize this headache type, both in adult and pediatric populations, as well as to be able to distinguish it from secondary headache disorders. PSH also may be more common than previously thought.

[Therapy of trigeminal autonomic headaches]

Trigeminal autonomic cephalgias (TAC) are characterized by severe and strictly unilateral headaches with a frontotemporal and periorbital preponderance in combination with ipsilateral cranial autonomic symptoms, such as lacrimation, conjunctival injection, rhinorrhea, nasal congestion, and restlessness or agitation. One main differentiating factor is the duration of painful attacks. While attacks typically last 5 s to 10 min in SUNCT syndrome (short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing), paroxysmal hemicrania lasts 2-30 min and cluster headaches 15-180 min. Hemicrania continua represents a continuous TAC variant. From a therapeutic view, TACs differ substantially. Lamotrigine is used as first-choice prevention in SUNCT syndrome and indometacin in paroxysmal hemicrania. For cluster headaches, acute therapy with inhaled pure oxygen and fast-acting triptans (sumatriptan s.c. and intranasal zolmitriptan) is equally important to short-term preventive therapy with methysergide and cortisone and long-term prophylactic treatment comprising verapamil as drug of first choice and lithium carbonate and topiramate as drugs of second choice. In refractory cases of chronic cluster headache, neuromodulatory approaches such as occipital nerve stimulation and sphenopalatine ganglion stimulation are increasingly applied.

OnabotulinumtoxinA for hemicrania continua: open label experience in 9 patients

Background

Hemicrania continua is a strictly unilateral, continuous headache, typically mild to moderate in severity, with severe exacerbations commonly accompanied by cranial autonomic features and migrainous symptoms. It is exquisitely responsive to Indomethacin. However, some patients cannot tolerate treatment, often due to gastrointestinal side effects. Therapeutic alternatives are limited and controlled evidence lacking.

Methods

We present our experience of nine patients treated with OnabotulinumtoxinA for hemicrania continua. All patients were injected using the PREEMPT (Phase 3 REsearch Evaluating Migraine Prophylaxis Therapy) protocol for migraine.

Results

Five of nine patients demonstrated a 50% or more reduction in moderate to severe headache days with OnabotulinumtoxinA with a median reduction in moderate to severe headache days of 80%. Patient estimate of response was 80% or more in five subjects. The median and mean duration of response in the five responders was 11 and 12 weeks (range 6–20 weeks). Improvements were also seen in headache-associated disability

Conclusions

OnabotulinumtoxinA adds a potential option to the limited therapeutic alternatives available in hemicrania continua.

Diagnose and adios: practical tips for the ongoing evaluation and care of TAC patients taking indomethacin

Paroxysmal hemicrania and hemicrania continua are primary headache disorders characterized by unilateral attacks of severe pain around the orbit with associated autonomic features. They are unique in their absolute response to indomethacin. Diagnosis is made when patients with suspected paroxysmal hemicrania or hemicrania continua have the resolution of headache with therapeutic doses of indomethacin. Once diagnosis is made, limited data exists on the ongoing management of these patients. For patients who do not tolerate indomethacin, or wish to come off medication, there remain few options. This article will discuss the diagnosis of paroxysmal hemicrania and hemicrania continua and the ongoing management of patients on indomethacin, as well as options for patients who do not tolerate or need to come off indomethacin.

Mechanism of action of indomethacin in indomethacin-responsive headaches

Indomethacin, as a member of the non-steroidal anti-inflammatory drug class, plays a special role in the treatment of headaches. By definition, it is completely efficacious in the treatment of the primary headache disorders paroxysmal hemicrania and hemicrania continua. Therefore, indomethacin is also used as a tool for differential diagnosis in headache clinics. Indomethacin has a clear action as a cyclooxygenase inhibitor. Additional mechanisms and interactions with cell signaling pathways and inflammatory pathways are considered in this article. However, it is not known what mechanism or interaction with pathophysiological mechanisms is the key to indomethacin's specific pharmacology in headache therapy. Focusing on headache therapy, we summarize the current knowledge of pharmacology, treatment options, and recommendations for the use of indomethacin in primary headaches. New findings from the field of headache research, as well as from Alzheimer's disease and cancer research on the pharmacological actions of indomethacin and their potential implications on the pathophysiology of indomethacin sensitive headaches, are discussed.

Short lasting activity-related headaches with sudden onset in children: a case-based reasoning on classification and diagnosis

BACKGROUND

Short lasting headaches related to activity or cough are rare, particularly in childhood, and can be difficult to diagnose, especially in young children who are not able to describe their symptoms. In the literature there are few data on this topic in adults and the paediatric cases reported are even more rare.

FINDINGS

We present the clinical history of a 7-year-old child and a 3-year-old child both diagnosed as having activity-related headaches, characterized by sudden onset of short lasting (few seconds) attacks, that were triggered by cough or exercise. There were no accompanying symptoms and the neurological examination was normal in both cases. Brain magnetic resonance imaging showed, in the first case, a cerebellar pilocytic astrocytoma and, in the second case, a Chiari 1 malformation. Both cases received an early diagnosis, were surgically treated and had a good prognosis at follow-up.

CONCLUSIONS

When headache has a recent onset, it presents suddenly, and it is triggered by strain, even with normal neurological examination, neuroimaging is mandatory in order to exclude secondary headaches, especially in children.

Treatment of miscellaneous idiopathic headache disorders (Group 4 of the IHS classification)--report of an EFNS task force

BACKGROUND AND PURPOSE

Certain miscellaneous idiopathic headache disorders, which are regarded as entities, are grouped in Chapter 4 of the International Classification of Headache Disorders. Recent epidemiological research suggests that these headache disorders are underdiagnosed.

OBJECTIVES

To give expert recommendations for the different drug and non-drug treatment procedures of these different headache disorders based on a literature search and on consensus of an expert panel.

METHODS

All available medical reference systems were screened for all kinds of clinical studies on these headache disorders. The findings in these studies were evaluated according to the recommendations of the EFNS resulting in level A, B or C recommendations and good practice points.

RECOMMENDATIONS

For all headache disorders, acute and prophylactic drug treatment is recommended based on case series and on expert consensus. Furthermore, recommendations for the differential diagnoses are given because these headache disorders can also present with a symptomatic form. The most effective drug for the majority of these headache disorders is indomethacin, mostly applied as long-term or short-term prophylaxis.

Incidence and influence on referral of primary stabbing headache in an outpatient headache clinic

Primary stabbing headache (PSH) is a pain, as brief, sharp, jabbing stabs, predominantly felt in the first division of trigeminal nerve. Population studies have shown that PSH is a common headache. However, most people suffer attacks of low frequency or intensity and seldom seek for medical assistance. There are few clinic-based studies of PSH, and its real influence as a primary cause for referral to neurology outpatient offices is to be determined. We aim to investigate the burden of PSH as main complaint in an outpatient headache clinic. We reviewed all patients with PSH (ICHD-II criteria), attended in an outpatient headache clinic in a tertiary hospital during a 2.5-year period (January 2008–June 2010). We considered demographic and nosological characteristics and if PSH was main cause of submission. 36 patients (26 females, 10 males) out of 725 (5%) were diagnosed of PSH. Mean age at onset 34.1 ± 2.9 years (range 10–72). Mean time from onset to diagnosis 68.8 ± 18.3 months. Twenty-four patients fulfilled ICHD-II criteria for other headaches (14 migraine, 6 tension-type headache, 2 hemicrania continua, 1 primary cough headache and 1 primary exertional headache). 77.7% of patients were submitted from primary care. In 14 patients (39%), PSH was main reason for submission, its intensity or frequency in 5 (35.7%) and fear of malignancy in 9 (74.3%). Only two patients of those who associated other headaches were submitted due to PSH. In conclusion, PSH is not an uncommon diagnosis in an outpatient headache office. However, and according to our data, it is not usually the main cause of submission to a headache clinic.

Focus on therapy of the Chapter IV headaches provoked by exertional factors: primary cough headache, primary exertional headache and primary headache associated with sexual activity

Primary cough headache, primary exertional headache and primary headache associated with sexual activity are distinct entities, even though they share several features: acute onset, the absence of structural brain disease and exertional factors as precipitating events. In this short review, we illustrate the possible treatment strategies on the basis of information collected from a systematic analysis of the international literature.

Functional and molecular characterization of prostaglandin E2 dilatory receptors in the rat craniovascular system in relevance to migraine

Introduction: Migraine pain is thought to involve an increase in trigeminal nerve terminal activity around large cerebral and meningeal arteries, leading to vasodilatation. Because prostaglandin E2 (PGE2) is elevated in cephalic venous blood during migraine attacks, and is also capable of inducing headache in healthy volunteers, we hypothesize that PGE2 dilatory receptors, EP2 and EP4, mediate the response.

Materials and methods: By the use of specific agonists and antagonists, the dilatory effect of PGE2 was characterized in rat cranial arteries by use of in vivo and in vitro methods. Furthermore, EP2 and EP4 quantitative messenger RNA (mRNA) receptor expression was studied in the rat craniovascular system.

Results: Our results suggest that EP4, and to a lesser degree EP2, receptors mediate the dilatory effect of PGE2 in the craniovascular system in rats. Thus, antagonism of these receptors might be of therapeutic relevance in migraine.