Hypothalamic activation in spontaneous migraine attacks

BACKGROUND: Migraine sufferers experience premonitory symptoms which suggest that primary hypothalamic dysfunction is a likely trigger of the attacks. Neuroendocrine and laboratory data also support this hypothesis. To date, positron emission tomography (PET) scans of migraine sufferers have demonstrated activation of brainstem nuclei, but not of the hypothalamus. OBJECTIVE: To record cerebral activations withH2 15OPET during spontaneous migraine without aura attacks. METHODS: We scanned 7 patients with migraine without aura (6 females and 1 male) in each of 3 situations: within 4 hours of headache onset, after headache relief by sumatriptan injection (between the fourth and the sixth hour after headache onset), and during an attack-free period. RESULTS: During the headache we found not only significant activations in the midbrain and pons, but also in the hypothalamus, all persisting after headache relief by sumatriptan. CONCLUSION: Hypothalamic activity, long suspected by clinical and experimental arguments as a possible trigger for migraine, is demonstrated for the first time during spontaneous attacks.     

Regional cerebral blood flow and oxygen metabolism during migraine with and without aura

Eleven cases of migraine with and without aura were investigated with positron emission tomography (PET). Regional cerebral blood flow (rCBF), oxygen metabolism (rCMRO₂) and oxygen extraction (rOER) were measured during baseline ( n =11), aura ( n = 6), headache ( n = 10) and after treatment with sumatriptan ( n = 4). Data were analysed using and ROI-based approach from 26 different anatomically defined regions, and also an exploratory approach whereby all subjects were normalized to a stereotactic brain atlas; t -maps were constructed by depicting significant changes between states. The exploratory approach revealed a region corresponding to the primary visual cortex with significant reductions in rCBF (23.1%) and rCMRO₂ (22.5%), but no change in rOER during the headache phase compared to baseline. These data suggest that cerebral ischemia was not the primary cause of the attacks in these cases.     

5HT2 receptors in cerebral cortex of migraineurs studied using PET and 18F-fluorosetoperone

Since the brain 5HT₂ receptors might be implicated in migraine pathogenesis, we have used positron emission tomography and ¹⁸F-fluorosetoperone, a 5HT₂ specific radioligand, to investigate in vivo the cortical 5HT₂ receptors in migraine subjects. Nine migraineurs who had either migraine with and without aura ( n = 5) or only migraine without aura ( n = 4) were studied between attacks. Twelve unmedicated healthy subjects of similar mean age were used as controls. Brain radioactivity was measured after ¹⁸F-setoperone IV injection for 90 min. A decrease of the regional specific distribution volumes (SDV) of the ligand was observed both in migraineurs and in controls. The age adjusted group means of SDV did not differ between patients and controls for the whole and for the right or left frontal, temporal, parietal and occipital cortex. These results suggest that cortical 5HT₂ receptors may be unaltered between attacks in migraine sufferers.     

Increased cerebrovascular pCO2 reactivity in migraine with aura- a transcranial Doppler study during hyperventilation

Cerebrovascular reactivity during hypocapnia was tested in 20 migraineurs (8 with aura, 12 without aura) and 30 sex- and age-matched healthy subjects, and during nitroglycerin-induced headache in 12 healthy subjects. Before and during hyperventilation, mean blood-flow velocity (V_mean) in the middle cerebral artery was measured with transcranial Doppler. In each subject a pCO₂ reactivity index (RI) was calculated as DV_mean/baseline V_mean)/ DpCO₂. Interictally, patients with migraine with aura showed higher RI ( p < 0.05 ANOVA and multiple range test) than controls, whereas migraineurs without aura did not differ from healthy subjects. Ictal and interictal RIs were similar in 9 patients suffering from migraine without aura. No side-to-side differences were detected in RI. During nitroglycerin-induced headache, the RIs were no different from those recorded during migraine attacks and in non-nitroglycerin-provoked healthy controls (p > 0.05, ANOVA and multiple range test). The exaggerated response in migraine with aura might predispose for the characteristic changes in rCBF seen during attacks.     

Oral sumatriptan for the acute treatment of probable migraine: first randomized, controlled study

OBJECTIVE: To evaluate the efficacy and tolerability of sumatriptan tablets in adults who meet International Headache Society (IHS) criteria for probable migraine but who do not meet IHS criteria for migraine with or without aura. BACKGROUND: Headaches with some but not all of the features of migraine meet criteria for probable migraine, a form of migraine recognized by the IHS. Probable migraine attacks are also prevalent and frequently underdiagnosed. METHODS: This was a randomized, multicenter, double-blind, placebo-controlled, parallel-group study. Adults (18 to 65 years) with a 1-year history of headaches that met 2004 IHS criteria for probable migraine without aura (same operational definition as 1988 IHS migrainous disorder) were eligible for enrollment. All patients were triptan- and ergot-na?ve and had never been diagnosed with migraine. Patients were randomized in a 1:1:1:1 fashion to receive sumatriptan 25, 50, or 100 mg conventional tablets or matching placebo and were instructed to treat a single moderate or severe probable migraine attack. A post hoc analysis was conducted to evaluate the population of patients who achieved headache relief sustained throughout the immediate posttreatment period. Patients who reported relief within 2 hours and subsequently lost headache relief within 4 hours were considered nonresponders. RESULTS: At 2 hours, more patients treated with sumatriptan achieved headache relief, the primary efficacy measure, compared with placebo, but differences only approached statistical significance for 100 mg (P= .053). The 2-hour headache relief rate in the sumatriptan 25 or 50 mg groups was not significantly different than placebo. The time to use of rescue was significantly shorter in the placebo group compared with the sumatriptan 100 mg group (P= .002). The time to use of rescue in the sumatriptan 25 or 50 mg groups was not significantly different than placebo. More patients treated with placebo (22%) lost headache relief within 4 hours compared with patients treated with sumatriptan 25 mg (17%), 50 mg (14%), or 100 mg (7%). A post hoc analysis demonstrated that at 2 hours, headache relief sustained through 4 hours (S 0-4 hours) was achieved in 44%, 49%, and 57% of patients treated with sumatriptan 25, 50, and 100 mg, respectively, compared with 34% of patients treated with placebo (P < .05 for sumatriptan 50 and 100 mg vs. placebo). All doses of sumatriptan were well tolerated and no serious adverse events were reported. CONCLUSION: These results suggest that oral sumatriptan may be effective and is well tolerated for the acute treatment of probable migraine without aura, however, the difference between sumatriptan and placebo was not statistically significant for the a priori defined primary endpoint.     

Role of vertebral artery hypoplasia in migraine

The role of cerebral hypoperfusion in the posterior circulation has not been clearly established in migraine. The purpose of this study was to determine the role of vertebral artery (VA) hypoplasia in the pathogenesis of migraine. We studied the extracranial part of VA in 59 migraine patients (17 with and 42 without aura) using color Doppler. In migraine with aura, 29% of patients had hypoplastic VA, and in migraine without aura 7%. In migraine with aura, mean diameter of the right VA was 2.7±0.7 mm, and of the left 3.3±0.7 mm; in migraine without aura mean diameter was 3.1±0.5 mm on the right, and 3.3±0.6 on the left. In migraine with aura, mean systolic blood flow velocity was 55±16 cm/s on the right, 60±17 cm/s on the left, in migraine without aura 57±18 cm/s on the right, 57±18 cm/s on the left. We observed higher frequency of hypoplastic VA in migraine with aura, suggesting that hypoplasia of VA may be an additional factor which can lead to hypoperfusion in the posterior circulation during the aura phase.     

Abnormal Photoreactivity in Ictal Migraine: Reversal by Sumatriptan

SYNOPSIS
The reactivity of posterior cerebral artery (PCA) to light stimulation was studied with transcranial Doppler in 9 migraine patients (5 with aura, 4 without aura) within six hours of the onset of headache (mean 115 ± 78 minutes). The PCA mean flow velocity was recorded while the patient was in the dark and with the eyes closed and, subsequently, while the light was on and with the eyes open. Both symptomatic and asymptomatic sides were recorded. The same test was repeated thirty minutes after injection of sumatriptan 6 mg sub-cutaneously and again on the third day after cessation of the attack. Photoreactivity was calculated, for each side and for each situation, as percent relative increase of the corresponding averaged mean flow velocity recorded in darkness. The results showed that, although absolute flow velocities were not statistically different between sides and situations, photoreactivity was significantly increased on the symptomatic side during attacks (+28% vs 15% respectively). After sumatriptan, photoreactivity became symmetrical and (nonsignificantly) inferior to the values recorded in the interictal period. These findings suggest that, during headache, peripheral resistance branches of PCA on the symptomatic side are hypersensitive to vasodilatory stimuli. This could represent the counterpart of the clinical scotomata and photophobia commonly experienced by migraine patients during attacks.     

Sumatriptan in the Acute Treatment of Migraine Without Aura: Efficacy of 50-mg Dose

We conducted an open study on the efficacy of 50 mg of sumatriptan as an acute treatment for migraine without aura. We recruited 200 consecutive patients, with an established history of migraine without aura, presenting at a headache center. The patients were instructed to take half a 100-mg sumatriptan tablet for their next migraine attack, and to record details of their headache in a diary. The primary outcome of the study was headache relief from one migraine attack. Attacks were moderately intense (46%), moderate to severe (7%), or severe (47%). Total or partial benefit at 2 hours from the 50-mg dose was reported by 140 of 200 patients (70%). Thirty-six patients received no benefit from half a tablet, and 24 did not take sumatriptan, preferring their habitual medication. Side effects were few, mild, and short lasting. We conclude that the 50-mg oral dose is generally effective for migraine without aura attacks of both moderate and severe intensity and recommend this dose for all such patients. If, however, sumatriptan is ineffective at that dose it can be increased to a maximum of 100 mg.     

Positron Emission Tomography Studies in Headache

Positron emission tomography (PET) allows the quantitative measurement of regional cerebral flow (rCBF) in humans in quantitative terms. Gross changes in rCBF are due to variation in vessel diameter. Changes of rCBF also reflect synaptic activity (inhibition and excitation). Therefore, PET was used to monitor changes in blood flow during the aura and headache phase of a migraine attack and to investigate focal areas of increased or decreased blood flow, eg, in the brain stem and midbrain. Hemispheric rCBF was unchanged in spontaneous migraine attacks without aura. This was true for the headache side as well as for the nonheadache side. Sumatriptan had no effects on cerebral blood flow. Regional cerebral blood flow was increased in midline brain stem structures during the headache phase, but also when the headache had been treated with sumatriptan. This persisting increased activity might reflect activity of a presumed migraine center in the brain stem. These changes are specific for migraine attacks and are not seen during attacks of cluster headache. Positron emission tomography measurements in the early phase of a migraine attack in a single subject showed flow reductions in the occipital cortex spreading forwards; an observation which would be compatible with the existence of spreading depression in humans. Our attempts to study the aura phase with PET have, to date, been unsuccessful.     

Acetazolamide Testing of Cerebral Vasodilator Capacity Provokes "Vascular" But Not Tension Headaches

Cerebrovascular capacitance was tested by measuring local cerebral blood flow (LCBF) by xenon-contrasted CT scanning before and after the oral administration of 14.3 mg/kg of acetazolamide among 45 subjects including 15 age-matched controls without history of headache, 20 migraineurs with and without aura, 3 patients with cluster headache, and 7 patients with tension-type headache. Percentage increases of LCBF were measured in 10 regions located throughout both hemispheres. Laterality indices for asymmetric LCBF increases were calculated. Local cerebral blood flow in cortical gray matter increased 5.9% in controls, 9.9% in patients with tension headaches, but 18.6% in both migraine and cluster headache patients; significantly greater LCBF increases than among controls or among patients with tension headaches (P<0.05). Increases in LCBF were significantly asymmetric among migraine and cluster patients and provoked typical unilateral vascular headaches which responded to sumatriptan. Maximal asymmetric LCBF increases also corresponded to the reported side of the induced headaches confirming their vascular pathogenesis. Patients with tension headaches and controls without history of headache did not develop head pain after acetazolamide.     

Posterior Ischemic Optic Neuropathy Associated With Migraine

Anterior ischemic optic neuropathy is a well-recognized clinical syndrome that has been described in patients after an episode of migraine with visual aura (classic migraine) and, less commonly, after an episode of visual aura without headache (acephalgic migraine). Little emphasis, however, has been placed on migraine associated retrobulbar or posterior ischemic optic neuropathy. We report two cases of visual loss presumed to be due to posterior ischemic optic neuropathy that occurred In the setting of otherwise typical migraine episodes. We review the English language literature on Ischemic optic neuropathy associated with migraine. Although most cases of ischemic optic neuropathy associated with migraine are of the anterior variety, posterior ischemic optic neuropathy should be considered in the differential diagnosis of any patient with acute loss of vision and evidence for a retrobulbar optic neuropathy, during or after an attack of migraine headache or following an otherwise typical episode of visual aure without headache (acephalgic migraine).     

Prolonged migraine aura without headache arrested by sumatriptan. A case report with further considerations

The case of a 42-year-old woman with prolonged migraine visual aura without headache, whose long-lasting episodes of visual aura were successfully controlled by oral sumatriptan, is reported. Effectiveness of sumatriptan was unequivocal, since, after taking sumatriptan, duration of aura would drop from 1.5 h to approximately 20 min. This case suggests that sumatriptan may cross the blood-brain barrier and block spreading depression.     

Effects of the anti-migraine drug sumatriptan on muscle energy metabolism: relationship to side-effects

Sumatriptan succinate (Imitrex) is a 5-HT (5-hydroxytryptamine) agonist used for relief of migraine symptoms. Some individuals experience short-lived side-effects, including heaviness of the limbs, chest heaviness and muscle aches and pains. The effects of this drug on skeletal muscle energy metabolism were studied during short submaximal isometric exercises. We studied ATP flux from anaerobic glycolysis (An Gly), the creatine kinase reaction (CK) and oxidative phosphorylation (Ox Phos) using 31P nuclear magnetic resonance spectroscopy (31P MRS) kinetic data collected during exercise. It was found that side-effects induced acutely by injection of 6 mg sumatriptan succinate s.c. were associated with reduced oxygen storage in peripheral skeletal muscle 5-20 min after injection as demonstrated by a transient reduction in mitochondrial function at end-exercise. These results suggest that mild vasoconstriction in peripheral skeletal muscle is associated with the action of sumatriptan and is likely to be the source of the side-effects experienced by some users. Migraine with aura patients were more susceptible to this effect than migraine without aura patients.     

The Event-Related Potential P300 During Headache-Free Period and Spontaneous Attack in Adult Headache Sufferers

The event-related potential P300 has been studied in 15 migraine without aura sufferers, and in 15 episodic tension-type headache sufferers, during pain-free periods and during spontaneous headache attacks. There were no variations of potential, either of P₃ latency or N₂ -P₃ amplitude, in either group during the interictal period. Similarly, there were no variations of the P300 parameters in the group of tension-type headache subjects during headache attacks; by contrast, a significant elongation of latency ( P <0.01) and an increment of N₂-P₃ wave amplitude ( P <0.002) was observed in the group of migraineurs. The authors discuss the data in accordance with the etiopathogenic theories of migraine and the hypothesis that acetylcholine and norepinephrine are the neurotransmitters able to affect the event-related potential P300, which reflects cerebral activity during sensory information processing and analysis.     

Sumatriptan in Acute Migraine Using a Novel Cartridge System Self-Injector

SYNOPSIS
This double-blind. randomized, placebo-controlled, parallel-group, multicenter study assessed the efficacy, acceptability, safety, and tolerability of subcutaneous sumatriptan 6 mg administered using a novel cartridge system self-injector for the acute treatment of migraine.
Eighty-six patients treated one migraine attack at home with sumatriptan or placebo. A second identical injection was available after 1 hour for inadequate relief or if the headache recurred. Rescue medication was available I hour later. The primary end point was headache relief (improvement in headache from moderate or severe to mild or no pain) within 60 minutes of the first injection. Secondary end points included the acceptability of the self-injector, requirement for and efficacy of a second dose, relief of nonheadache symptoms, use of rescue medication, and adverse events.
Significantly more patients taking sumatriptan than placebo reported headache relief I hour after the first injection (88% vs 11%, P <0.001). The device was well accepted by patients; about 90% found it easy to use and wanted to take further medication using it. Significantly fewer patients taking sumatriptan than placebo required a second injection (33% vs 92%, P <0.001) or rescue medication after the second injection (35% vs 67% P <0.05). Significantly more patients taking sumatriptan than placebo reported headache relief after the second injection (83% vs 32%, P <0.01), and resolution of non-headache migraine symptoms (54% vs 23%, P <0.01). Sumatriptan was generally well tolerated.
Subcutaneous sumatriptan 6 mg self-administered using the novel self-injector is an effective, well accepted, and well tolerated acute treatment of migraine.     

Pharmacokinetics of rizatriptan tablets during and between migraine attacks

Gastric stasis during migraine attacks results in delayed absorption of several orally administered antimigraine agents. This study, as part of a larger trial, was conducted to examine the pharmacokinetics of rizatriptan tablets during and between migraine attacks. Participating patients met IHS criteria for migraine with or without aura, and suffered between one and eight migraines per month for the previous 6 months. In part 1 of the study, 21 patients were randomized to receive a single 5-mg tablet of rizatriptan or placebo in the migraine-free state. In part 2, the same patients were treated during migraine with rizatriptan 5-mg tablets (n=18) or placebo (n=3). Blood samples were obtained before dosing and 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 8, and 12 hours after dosing. The plasma concentration profile (ie, AUC_(0-∞), C_max, T_max) of rizatriptan 5-mg tablets administered during and between migraine attacks were comparable. The median T_max for rizatriptan between and during attacks was 1 hour, indicating rapid absorption even during a migraine attack. Rizatriptan 5 mg was well tolerated and 67% of the patients experienced headache relief 2 hours postdose.     

Interictal and postictal contingent negative variation in migraine without aura

Cortical hyperexcitability is thought to explain the more enhanced contingent negative variation (CNV) amplitudes and impaired CNV habituation that have been found during the interictal period in migraine without aura. These CNV characteristics have been shown to normalize to the level of healthy controls during an attack. This study aimed to replicate the interictal findings, and additionally examine whether migraineurs show reduced CNV amplitudes during the postattack period. Of 12 patients with migraine without aura and their sex- and age-matched healthy controls, CNV characteristics were recorded once in an interictal period, once during the postattack period within 30 hours after an attack that was treated with sumatriptan, and once after an attack that was treated with habitual nonvasoactive medication (counterbalanced). The present results did not confirm the enhanced CNV early and late wave amplitudes or impaired habituation, and cortical hyperexcitability that have previously been reported in the interictal period in patients with migraine without aura. During the postattack period, a decrease in CNV early and late amplitudes was found but only after sumatriptan use. This reduction in CNV amplitudes was most prominent over the frontal cortex and could reflect cortical hypoexcitability, possibly related to a suppression of central catecholaminergic activity by sumatriptan.     

Cerebrovascular reactivity in migraine during headache-free intervals

Alterations of intracranial vessel tone have been implicated in the pathophysiology of migraine. The cerebrovascular reactivity was measured by means of transcranial Doppler in 60 migraine patients with ( n =30) or without aura ( n =30) during the headache-free interval and in 30 healthy controls. The vasomotor response was evaluated during hypercapnia induced by inhalation of a mixture of CO_z 5% and O₂ 95% and during hypocapnia obtained after voluntary hyperventilation. To improve the power of the study in detecting possible abnormalities of cerebrovascular reactivity, two different measures were performed at 1 week intervals in migraine patients and controls. Reactivity index values during CO₂ inhalation were significantly different ( p =0.01) among the three groups during the first and second measurements; in particular, lower values were found in patients suffering from migraine without aura with respect to controls ( p <0.05, Scheffe's test). Values of reactivity index obtained following induction of hypocapnia did not differ between migraine patients and controls (all p values >0.05). Our data suggest a reduced vasodilatory response to hypercapnia of cerebral arterioles in patients suffering from migraine without aura with respect to controls that might be related to baseline arteriolar vasodilation.     

A randomized open-label study of sodium valproate vs sumatriptan and metoclopramide for prolonged migraine headache

ObjectiveThe objective of this study is to compare the efficacy and tolerability of intravenous valproic acid (iVPA) with intramuscular metoclopramide + subcutaneous (SQ) sumatriptan for prolonged acute migraine.BackgroundIntravenous valproic acid has been explored as a possible treatment of acute migraine. Sumatriptan and newer generation triptans are also effective for migraine. However, iVPA has not yet been compared with triptans in head-to-head studies.MethodsPatients presenting with moderate to severe intensity migraine without aura were randomized to receive either 400 mg of iVPA or 10 mg intramuscular metoclopramide + 6 mg SQ sumatriptan (30 patients in each study arm). The severity of headache and other associated symptoms such as photophobia and phonophobia were assessed at baseline and after 20 minutes and 1, 2, 4, and 24 hours. The primary end point was to compare the efficacy of the 2 study treatments in relieving headache from moderate-severe to none-mild and of other associated symptoms within a period of 24 hours.ResultsPain relief from severe or moderate to mild or none was obtained in 53.3% of subjects in the iVPA arm and 23.3% in the metoclopramide + sumatriptan arm at 1 hour following treatment (P = .033), whereas 60% and 30% reported pain relief at 2 hour (P = .037). There was no other significant difference in alleviation of associated migraine symptoms between the 2 arms. No serious adverse effects were noted.ConclusionTreatment with iVPA was more effective than metoclopramide + SQ sumatriptan during the first 2 hours in patients with a prolonged migraine.     

Hemiplegic migraine aura begins with cerebral hypoperfusion: imaging in the acute phase

Imaging studies of spontaneous migraine aura have proved challenging because of the episodic and unpredictable nature of migraine attacks. Two patients with signs of acute ischemic stroke were evaluated for thrombolysis and turned out to suffer from familial hemiplegic migraine. It was possible to record the early phase of the hemiplegic aura with computed tomography with perfusion sequences and magnetic resonance imaging. We found cerebral hypoperfusion in the relevant cortical areas within the first hour after onset of aura symptoms. This report supports the concept that migraine aura across the migraine spectrum is caused by similar mechanisms. In a setting with efficient cooperation between headache and stroke neurologists, thrombolysis centers provide the set-up and opportunity to record aura symptoms at an early phase. Furthermore, in the time of ready access to acute systemic thrombolysis treatment, these cases underscore the importance of an accurate headache history, especially in younger patients.