The molecular basis of migraine is still not completely understood. An impairment of mitochondrial oxidative metabolism might play a role in the pathophysiology of this disease, by influencing neuronal information processing. Biochemical assays of platelets and muscle biopsies performed in migraine sufferers have shown a decreased activity of the respiratory chain enzymes. Studies with phosphorus magnetic resonance spectroscopy ((31)P-MRS) have demonstrated an impairment of the brain oxidative energy metabolism both during and between migraine attacks. However, molecular genetic studies have not detected specific mitochondrial DNA (mtDNA) mutations in patients with migraine, although other studies suggest that particular genetic markers (i.e. neutral polymorphisms or secondary mtDNA mutations) might be present in some migraine sufferers. Further studies are still needed to clarify if migraine is associated with unidentified mutations on the mtDNA or on nuclear genes that code mitochondrial proteins. In this paper, we review morphological, biochemical, imaging and genetic studies which bear on the hypothesis that migraine may be related to mitochondrial dysfunction at least in some individuals.
A variety of treatment attributes are important in determining the reasons involved in switching a triptan. To assess this attributes can provide additional information to supplement the traditional tests of efficacy provided by randomized clinical trials.
Headache is the most frequent symptom and sometimes the sole presentation of CVT.
A population-based longitudinal study suggests that obesity is a strong risk factor for the development of headaches on 15 or more days per month. Little is know about the influence of weight on the response to headache preventive treatment. Herein we prospectively assessed the influence of the baseline body mass index (BMI) on the response to headache preventive treatment. We included adults with episodic or chronic migraine (ICHD-2), or transformed migraine (Silberstein and Lipton criteria) that sought care in a headache clinic. BMI was assessed in the first visit. Baseline information included headache frequency, number of days with severe headache (prospectively obtained over 1 month), and headache-related disability (HIT-6). The same information was obtained after 3 months of preventive treatment. Subjects were categorized based on BMI in: normal weight (=24.9), overweight (25-29.9), or obese (>/=30). We contrasted the headache end-points using anova with post-test and Kruskal-Wallis with post-test. We used logistic regression to model BMI and headache parameters adjusting for covariates. Our sample consisted of 176 subjects (79.5% women, mean of 44.4 years). At baseline 40.9% had normal weight, 29.5% were overweight and 27.3% were obese. No significant differences were observed in the number of headache days at baseline. After treatment, frequency declined in the entire population, but no significant differences were found by BMI group. Regarding the number of days with severe pain per month, there were also no significant differences at baseline (normal = 6.1, overweight = 6.5, obese = 6.7), and improvement overall (P = 0.01). However, changes were greater in the obese (reduction in 2.7 days with treatment) and overweight (3.9) vs. normal (1.5, P < 0.01). Finally, HIT scores at baseline did not differ by BMI group (normal weight = 63.8, overweight = 64.1, obese = 63.6). However, compared with the normal weighted group, change in HIT scores (follow-up baseline) were greater in the obese (6.4 vs. 3.5, P < 0.05) and overweight groups (6.8 vs. 3.5, P < 0.05). In the logistic regression model, BMI did not account for changes in disability, headache frequency, or in the number of days with severe headache per month, after adjusting for covariates. Contrary to what we hypothesized, obesity at baseline does not seem to be related to follow-up refractoriness to preventive treatment.
A multicenter 3-year follow-up study was carried out on young patients with headache referred to tertiary headache centers or pediatric clinics. Three years after the first examination in 1993, 442 (of an original sample of 719) young outpatients with headache (226 females and 216 males) were re-examined. The diagnostic criteria of the International Headache Society (IHS) and those modified for migraine without aura by Winner et al were applied at both the baseline evaluation and the 3-year re-examination. At the follow-up, 290 children still had headache, 101 were in clinical remission, and 51 had dropped out. Using the current diagnostic criteria, only 46.2% of patients having migraine without aura, 50% of those having migraine with aura, and 35.3% of those suffering from migraine disorders which do not fulfill IHS criteria for migraine received the same diagnosis at the time of follow-up. The percentage of patients receiving a diagnosis of migraine without aura rose significantly when new modified criteria were used (60.5%), whereas a drop in the frequency of migraine disorders not fulfilling IHS criteria was observed at follow-up, both in patients with the diagnosis of migraine without aura at the first examination (4.6%) and in patients with migraine not always fulfilling IHS criteria at the first examination (6.2%). Among all patients who received this latter diagnosis at the first examination, it was possible to make a diagnosis of migraine with aura at the follow-up in 8.8% of cases and that of migraine without aura in 26.5%. No significant variations in the frequency of either episodic tension-type headache or chronic tension-type headache were found, with the exception of a slight decrease in the percentage of tension-type headache which did not fulfill IHS criteria, but the difference between the first examination and the follow-up values does not reach the level of statistical significance (5% versus 12%). As far as the evolution of migraine is concerned, 17.4% of patients with migraine were headache-free at the 3-year follow-up. In tension-type headache, the percentage of patients who were headache-free was particularly high in those with the episodic form (32.9%) and in those suffering from tension-type headache not fulfilling IHS criteria (29.1%). The majority of patients who had been diagnosed as having unclassifiable headache at the first examination received a correct diagnosis at the follow-up with the exception of one patient. As observed in adult patients, variations in the headache characteristics were also observed in children and adolescents (that is, migraine with aura can change to migraine without aura, or the latter can transform into episodic tension-type headache or chronic tension-type headache can change into the episodic form). This follow-up study was aimed at reaching a better understanding of headache disturbances in children and adolescents, examining, in particular, variations of headache with time in this stage of life.
Summary Objective Although many studies have attempted to describe treatment outcomes in patients with drug‐resistant epilepsy, results are often limited by the adoption of nonhomogeneous criteria and different definitions of seizure freedom. We sought to evaluate treatment outcomes with a newly administered antiepileptic drug (AED) in a large population of adults with drug‐resistant focal epilepsy according to the International League Against Epilepsy (ILAE) outcome criteria. Methods This is a multicenter, observational, prospective study of 1053 patients with focal epilepsy diagnosed as drug‐resistant by the investigators. Patients were assessed at baseline and 6, 12, and 18 months, for up to a maximum of 34 months after introducing another AED into their treatment regimen. Drug resistance status and treatment outcomes were rated according to ILAE criteria by the investigators and by at least two independent members of an external expert panel (EP). Results A seizure‐free outcome after a newly administered AED according to ILAE criteria ranged from 11.8% after two failed drugs to 2.6% for more than six failures. Significantly fewer patients were rated by the EP as having a “treatment failure” as compared to the judgment of the investigator (46.7% vs 62.9%, P < 0.001), because many more patients were rated as “undetermined outcome” (45.6% vs 27.7%, P < 0.001); 19.3% of the recruited patients were not considered drug‐resistant by the EP. Significance This study validates the use of ILAE treatment outcome criteria in a real‐life setting, providing validated estimates of seizure freedom in patients with drug‐resistant focal epilepsy in relation to the number of previously failed AEDs. Fewer than one in 10 patients achieved seizure freedom on a newly introduced AED over the study period. Pseudo drug resistance could be identified in one of five cases.
(1) When assessing adverse events, the method of data collection may dramatically influence the results. (2) From those subjects who did not self-report adverse events after using a triptan, most of them will report positively if presented with a list of side effects.
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