Periaqueductal gray matter dysfunction in migraine: cause or the burden of illness?

Management of menstrual migraine

BACKGROUND

Migraine is more prevalent in women than men. Hormonal changes can influence the occurrence of migraine, particularly related to the menstrual cycle. Menstrual migraine may require both acute and preventive treatment.

REVIEW SUMMARY

Gender differences in migraine may be a result of variations in the central nervous system of men and women as well as the effects of estrogen. Migraine attacks occurring in the perimenstrual period respond well to acute treatment with triptans. Hormonal manipulation may reduce migraine occurrence, especially when related to hormonal fluctuations in the perimenstrual period.

CONCLUSIONS

Effective migraine management requires an understanding of the unique epidemiologic and pathophysiological factors affecting women. An understanding of associated hormonal influences facilitates development of individualized treatment plans.

Imaging chronic daily headache

New imaging technology allows us to study neurologic disorders that have had no previous structural basis. There have been recent reports on the involvement of nociceptive pathways in daily headache. A systematic review was performed using key words "chronic daily headache" and "imaging." This paper reviews the literature on imaging studies performed on daily headache with emphasis on the new imaging technology.

Pathophysiology, epidemiology, and impact of migraine

Despite a decade of progress, migraine headache remains prevalent, disabling, underdiagnosed, and undertreated in the United States. Migraine affects approximately 12% of the population, and the economic burden in terms of annual cost of labor lost to migraine disability is between $5.6 and $17.2 billion. The threshold for migraine may be genetically determined, although recent genetic and neurophysiologic studies point to migraine as possibly a channelopathy. Cerebral cortical and brain stem changes occur in migraine. Head pain and associated symptoms of migraine can be explained by activation of the trigeminal vascular system. Evidence has also been accumulated that suggests the release of nitric oxide is an important trigger mechanism. Introduction of the triptans has dramatically advanced acute migraine pharmacotherapy, and preventive therapy has greatly improved; however, public health initiatives may be needed to further advance diagnosis and treatment of this common and disabling disorder.

Medications and substances as a cause of headache: a systematic review of the literature

Medication- or substance-induced headache is probably an underrecognized entity with numerous etiologies, including prescribed medication, over-the-counter medication, illicit drugs, anesthetic agents, foods, food additives, beverages, vitamins, inhaled substances, and substances used in diagnostic procedures. The author performs a systemic review of the literature to provide an exhaustive description of the relationship between medications and substances and headaches of various types, along with pathophysiologic mechanisms whenever possible. Suggestions for improved identification of this phenomenon and its avoidance are provided. More scientific evaluation of substances and their possible association with headache is required with almost all substances indicated herein.

New developments in migraine prophylaxis

Migraine is a common neurological disorder that afflicts > or = 12% of the adult US population. Severe, frequent and disabling attacks require effective prophylaxis. Traditional preventive drugs such as beta-blockers, antidepressants and calcium antagonists, despite their documented efficacy, fail to offer relief for a significant proportion of migraine sufferers. Multiple threads of research over the last 15 years have led to the concept that migraine is generated from a hyperexcitable brain. This opens new perspectives in terms of preventive options, especially regarding the anticonvulsants agents. Additionally, different groups of substances, some of which nominated as non-orthodox agents, have been recently subjected to clinical trials and found to be effective. The aim of this review is to present and discuss the new options for migraine prevention.

Pathophysiology of headache

Clinical features of different headache syndromes have been described in great detail; however, its pathophysiology remains poorly understood. We review the latest findings in both human imaging studies and experimental animals to explain the possible mechanisms involved in the genesis of headache syndromes.

Opioid resistance in chronic daily headache: a synthesis of ideas from the bench and bedside

Chronic daily headache is a complex pain disorder that encompasses many diagnostic and therapeutic challenges. Our understanding of the pathophysiologic processes of intermittent migraine has improved over the past decade, but the biologic basis of chronic daily headache remains obscure. Some of the more common issues confounding management of patients who experience chronic daily headache are medication overuse, psychiatric comorbidity, refractoriness to pharmacologic treatments, and disability. Long-acting opioid analgesics would appear to provide a viable treatment option for those patients who remain refractory to other treatment interventions; however, clinical experience often does not support this belief. Current concepts of the pathophysiologic basis of chronic pain and associated neural plasticity may elucidate a biologic basis for the general inefficacy of opioids in the management of chronic daily headache. This article explores the models of pathophysiology for migraine and chronic daily headache, the concept of chronic daily headache as a neuropathic pain syndrome, neural plasticity in the context of neuropathic pain states, the physiologic basis for opioid tolerance and opioid-induced hyperalgesia, and how each of these conditions interact to provoke the general lack of opioid efficacy often observed in the management of chronic daily headache.

Ergotamine and dihydroergotamine: a review

The ergot alkaloids were the first specific antimigraine therapy available. However, with the advent of the triptans, their use in the treatment of migraine has declined and their role has become less clear. This review discusses the pharmacology, efficacy, and safety of the ergots. In randomized clinical trials, oral ergotamine was found to be superior to placebo, but inferior to 100 mg of oral sumatriptan. In contrast, rectal ergotamine was found to have higher efficacy (73% headache relief) than rectal sumatriptan (63% headache relief). Intranasal dihydroergotamine was found to be superior to placebo, but less effective than subcutaneous and intranasal sumatriptan. Ergotamine is still widely used in some countries for the treatment of severe migraine attacks. It is generally regarded as a safe and useful drug if prescribed for infrequent use, in the correct dose, and in the absence of contraindications; however, safer and more effective options do exist in the triptans. In patients with status migrainous and patients with frequent headache recurrence, ergotamine is still probably useful.

New migraine preventive options: an update with pathophysiological considerations

BACKGROUND

The pharmacological treatment of migraine may be acute or preventive. Frequent, severe and long-lasting migraine attacks require prophylaxis. Multiple threads of research over the last 15 years have led to the concept that migraine is generated from a hyperexcitable brain. A variety of causes for hyperexcitability of the brain in migraine have been suggested. These causes include low cerebral magnesium levels, mitochondrial abnormalities, dysfunctions related to increased nitric oxide or the existence of a P/Q type calcium channelopathy. The better knowledge about migraine pathophisiology led us to discuss new treatment options.

OBJECTIVES

The aim of the present study is to present an evidence-based review of some new drugs or some agents that even though available for a long time, are not frequently used.

METHODS/RESULTS

We present a review of anticonvulsants with various mechanisms of action such as lamotrigine, gabapentin, topiramate, tiagabine, levetiracetam and zonisamide. We also review natural products, like riboflavin and magnesium, botulinum toxin A, a specific CGRP antagonist and the anti-asthma medication montelukast, with pathophysiological discussion.

CONCLUSIONS

We aimed to present an update of newer or less frequently used preventive migraine therapies, drugs that might reduce the burden and the costs of a disease that should be considered as a public health problem all around the world.

The role of temporomandibular disorders and cervical dysfunction in tension-type headache

It has been estimated that 30% to 80% of the population has at least one tension-type headache each year. Tension-type headaches can be located in any region of the head, which can confuse a differential diagnosis with temporomandibular joint disorders and cervical dysfunction. The roles of temporomandibular joint disorders and cervical dysfunction in tension-type headache are evaluated. Definitions, pathophysiology, and treatment considerations for each are discussed.

Sumatriptan scavenges superoxide, hydroxyl, and nitric oxide radicals: in vitro electron spin resonance study

BACKGROUND

The molecular mechanisms of migraine have not yet been clarified. Oxygen free radicals have been implicated in the genesis of many pathological processes, including migraine. Sumatriptan succinate is known to be a very effective drug for acute relief of migraine attack.

OBJECTIVE

To investigate the direct scavenging activities of sumatriptan for superoxide, hydroxyl, and nitric oxide (NO) radicals using electron spin resonance (ESR) spectroscopy.

METHODS

Measurement of superoxide and hydroxyl radical scavenging activities was performed by ESR using 5,5-dimethyl-1-pyrroline-N-oxide as a spin trap. NO was generated from 1-hydroxy-2-oxo-3-(N-3-methyl-3-aminopropyl)-3-methyl-1-triazene and analyzed by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl produced from the reaction between 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and NO.

RESULTS

The ESR study demonstrated that sumatriptan scavenged superoxide, hydroxyl, and NO in a dose-dependent manner.

CONCLUSIONS

Sumatriptan has direct scavenging activity on free radicals and NO. Acute migraine drugs with antioxidant properties may provide heretofore unheralded benefits via this mechanism.

Intravenous magnesium sulphate in the acute treatment of migraine without aura and migraine with aura. A randomized, double-blind, placebo-controlled study

Magnesium sulphate has been used in the acute treatment of migraines; some studies found it to be a highly effective medication in the acute control of migraine pain and associated symptoms. This randomized, double-blind, placebo-controlled study assesses the effect of magnesium sulphate on the pain and associated symptoms in patients with migraine without aura and migraine with aura. Sixty patients in each group were assigned at random to receive magnesium sulphate, 1000 mg intravenously, or 0.9% physiological saline, 10 ml. We used seven parameters of analgesic evaluation and an analogue scale to assess nausea, photophobia and phonophobia. In the migraine without aura group there was no statistically significant difference in the patients who received magnesium sulphate vs. placebo in pain relief. The analgesic therapeutic gain was 17% and number needed to treat was 5.98 at 1 h. There was also no statistical difference in relief of nausea. We did observe a significant lower intensity of photophobia and phonophobia in patients who received magnesium sulphate. In the migraine with aura group patients receiving magnesium sulphate presented a statistically significant improvement of pain and of all associated symptoms compared with controls. The analgesic therapeutic gain was 36.7% at 1 h. A smaller number of patients continued to have aura in the magnesium sulphate group compared with placebo 1 h after the administration of medication. Our data support the idea that magnesium sulphate can be used for the treatment of all symptoms in migraine with aura, or as an adjuvant therapy for associated symptoms in patients with migraine without aura.

Chronic daily headache: nosology and pathophysiology

Systematic scientific classification of primary headaches is inexact, relying on clinical features because the disorders lack diagnostic markers, although the International Headache Society classification has been successful in providing relatively homogenous clinical groups for pathophysiological and therapeutic studies. One area in which there have been particular difficulties and uncertainty is in classifying patients with frequent headache, particularly chronic daily headache. Clinical research on the topic is limited, and imprecise because of uncertainties of definition. Rigorous basic or applied clinical research is a rarity, attested to by a paucity of new publications in the past year. Accordingly, the scientific basis of chronic daily headaches remains to be determined. There is agreement on one issue: for headache specialists and neurologists this is an important clinical problem. We take the position that chronic daily headache is what it says--frequent headache. As hematologists make a diagnosis of anemia, which invites further investigation and sub-classification, neurologists might diagnose chronic daily headache not to imply that all its causes are the same but simply to begin the clinical process.

Chronic daily headache prophylaxis with tizanidine: a double-blind, placebo-controlled, multicenter outcome study

OBJECTIVE

To assess the efficacy of tizanidine hydrochloride versus placebo as adjunctive prophylactic therapy for chronic daily headache (chronic migraine, migrainous headache, or tension-type headache).

BACKGROUND

Tizanidine is an alpha2-adrenergic agonist that inhibits the release of norepinephrine at both the spinal cord and brain, with antinociceptive effects that are independent of the endogenous opioid system. Previous open-label studies have suggested the drug may be effective for treatment of chronic daily headache.

METHODS

Two hundred patients completed a 4-week, single-blind, placebo baseline period, with 134 fulfilling selection criteria and then randomized to tizanidine or placebo. Ninety-two patients completed at least 8 weeks of treatment (tizanidine, n = 45; placebo, n = 47), and 85 patients completed 12 weeks of treatment (tizanidine, n = 44; placebo, n = 41). Most patients (77%) met the diagnostic criteria for migraine of the International Headache Society; 23% had either chronic migrainous headache or chronic tension-type headache. Tizanidine was slowly titrated over 4 weeks to 24 mg or the maximum dose tolerated (mean, 18 mg; SD, 6.4; median, 20.0; range, 2 to 24), divided equally over three dose intervals per day. Overall headache index ([headache days x average intensity x duration in hours]/28 days) was the primary end point.

RESULTS

Tizanidine was shown to be superior to placebo in reducing the overall headache index (P =.0025), as well as mean headache days per week (P =.0193), severe headache days per week (P =.0211), average headache intensity (P =.0108), peak headache intensity (P =.0020), and mean headache duration (P =.0127). The mean percentage improvement during the last 4 weeks of treatment with tizanidine versus placebo was 54% versus 19% for the headache index (P =.0144), 55% versus 21% for severe headache days (P =.0331), 35% versus 19% for headache duration (P =.0142), 35% versus 20% for peak headache intensity (P =.0106), 33% versus 20% for average headache intensity (P =.0281), and 30% versus 22% for total headache days (P =.0593). Patients receiving tizanidine also scored higher ratings of overall headache improvement on a visual analog scale (P =.0069). There was no statistically significant difference in outcome for patients with chronic migraine versus those with only migrainous or tension-type headache. Adverse effects reported by more than 10% of the patients included somnolence (47%), dizziness (24%), dry mouth (23%), and asthenia (19%). Dropouts due to adverse events did not differ significantly between tizanidine and placebo.

CONCLUSIONS

The results support tizanidine as an effective prophylactic adjunct for chronic daily headache, including migraine, migrainous headache, and tension-type headache. These results also suggest the possible importance of an alpha2-adrenergic mechanism underlying the pathophysiology of this spectrum of headache disorders.

High headache prevalence among women with hemochromatosis: the Nord-Trøndelag health study

In this large cross-sectional population-based study, 51,272 persons responded to a headache questionnaire and were screened for hemochromatosis. Phenotypic hemochromatosis and the C282Y/C282Y genotype were both associated with an 80% increase in headache prevalence evident only among women. The reason for this association is unclear, but one may speculate that iron overload alters the threshold for triggering a headache by disturbing neuronal function.

Hereditary haemochromatosis in two cousins with cluster headache

A 60-year-old woman with secondary chronic cluster headache had increased serum ferritin and serum transferrin saturation and was homozygous for the C282Y mutation in the HFE gene, which is indicative of hereditary haemochromatosis. Treatment with venesection that normalized her iron stores led to a radical improvement of her headache complaints that had been daily for several years. Later, the headache returned to some degree in spite of normal serum ferritin levels. Her cousin, a 33-year-old man who had had episodic cluster headache for several years, also had increased transferrin saturation and was compound heterozygous for two mutations, a genotype known to be associated with a slightly increased frequency of haemochromatosis. This is the first report of a headache disorder in a patient with hereditary haemochromatosis. The coexistence of the two disorders may be a mere coincidence, but the temporary improvement of headache from depletion of iron stores may indicate a causal relation, possibly mediated by iron deposits in pain-modulating centres in the brainstem.

Cortical spreading depression and gene regulation: relevance to migraine

Cortical spreading depression (CSD) may be the underlying mechanism of migraine aura. The role of CSD in initiating a migraine headache remains to be determined, but it might involve specific changes in gene expression in the brain. To examine these changes, four episodes of CSD at 5-minute intervals were induced in the mouse brain by application of 300mM KCl, and gene expression was examined 2 hours later using cDNA array and reverse transcriptase-polymerase chain reaction. Controls consisted of groups that received anesthesia only, attachment of recording electrodes only, and application of 0.9% NaCl. Of the over 1,180 genes examined in our experiments, those consistently regulated by CSD included vasoactive peptides; the vasodilator atrial natriuretic peptide was induced by CSD, while the vasoconstrictor neuropeptide Y was downregulated. Other genes specifically regulated by CSD were involved in oxidative stress responses (major prion protein, glutathione-S-transferase-5, and apolipoprotein E). L-type calcium channel mRNA was upregulated. In summary, CSD regulates genes that are intrinsic to its propagation, that identify accompanying vascular responses as a potential source of pain, and that protect against its potential pathological consequences. We believe these observations have strong relevance to the mechanisms of migraine and its outcomes.

Neurovascular headache and a midbrain vascular malformation: evidence for a role of the brainstem in chronic migraine

Migraine is a common, disabling form of primary headache that has been linked by functional imaging studies to activation in the rostral brainstem. In specialty clinics migraine is most commonly seen in association with frequent less feature full headache that has been called transformed migraine or more recently termed chronic migraine. A patient is described with frequent migraine, 3 days per week, and less feature full headaches on other days. The patient has a cavernoma in the midbrain that has bled. She was previously headache free and now has contralateral daily headache. The patient supports the functional imaging observations from positron emission tomography (PET) that the rostral brainstem is pivotal in migraine pathophysiology, particularly the contralateral midbrain periaqueductal grey matter. Moreover, the patient's lesion provides biologically plausible support that a single entity causes her clinical presentation: chronic migraine, not two-disorders, migraine and tension-type headache.