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Background Migraine is associated with an increased risk of ischemic stroke. The associations are stronger in migraine with aura than in migraine without aura, in women than in men, and in younger subjects. However, the mechanisms by which migraine might increase the risk of ischemic stroke are debated. Methods We analysed the associations between migraine without aura and migraine with aura and the causes of ischemic stroke in patients aged 18–54 years treated consecutively in a university hospital stroke center. Results A total of 339 patients (mean/SD age 43.8/8.8 years, 62.83% male) were included. Migraine with aura was diagnosed in 58 patients, and migraine without aura in 54 patients. Patients with migraine with aura were younger and had fewer traditional cardiovascular risk factors than patients with no migraine. Migraine with aura was strongly associated with atrial fibrillation (odds ratio, 5.08; 95% confidence interval, 1.24–21.92; p = 0.011) and negatively associated with atherosclerosis (odds ratio, 0.29; 95% confidence interval, 0.05–0.97; p = 0.033) and small vessel disease (odds ratio, 0.13; 95% confidence interval, 0.00–0.87; p = 0.022). No other cause of stroke was significantly associated with migraine. The most common cause of stroke was atherosclerosis in no-migraine patients, dissection in migraine without aura patients and patent foramen ovale in migraine with aura patients. Atrial fibrillation was, together with dissection, the second leading cause of stroke in migraine with aura patients, accounting for 10.34% of cases in this subgroup. Conclusion We showed that atrial fibrillation was a common cause of ischemic stroke in young adults with migraine with aura.

Migraine is a complex brain disorder explained by the interaction of genetic and environmental factors. In monogenic migraines, including familial hemiplegic migraine and migraine with aura associated with hereditary small-vessel disorders, the identified genes code for proteins expressed in neurons, glial cells, or vessels, all of which increase susceptibility to cortical spreading depression. The study of monogenic migraines has shown that the neurovascular unit plays a prominent role in migraine. Genome-wide association studies have identified numerous susceptibility variants that each result in only a small increase in overall migraine risk. The more than 180 known variants belong to several complex networks of “pro-migraine” molecular abnormalities, which are mainly neuronal or vascular. Genetics has also highlighted the importance of shared genetic factors between migraine and its major co-morbidities, including depression and high blood pressure. Further studies are still needed to map all of the susceptibility loci for migraine and then to understand how these genomic variants lead to migraine cell phenotypes.

Purpose of reviewThe underlying mechanisms of migraine are complex and heterogenous. Advances in neuroimaging techniques during the past few decades have contributed to our understanding of migraine pathophysiology. Brain function in migraine patients has been widely explored using functional MRI (fMRI). This review will highlight the major fMRI findings that characterize the different phases of migraine. Recent findingsThe migraine attack starts with hypothalamic hyperexcitability and early reorganization of the common ascending pain and central trigeminovascular pathways. Moreover, the visual cortex becomes hyperexcitable during the aura phase. During the headache phase, further disruptions of the pontine, thalamic, sensorimotor and visual networks occur, although the hypothalamic activity and connectivity normalizes. The visual cortex remains hyperexcitable during the postdromal phase. Asymptomatic migraine patients can also experience functional alternations of pain and visual processing brain areas. At present, the heterogeneity of the asymptomatic phase and fMRI findings make it difficult to find common denominator.Summary fMRI studies have captured functional brain changes associated with migraine phases, leading to an improvement of our understanding of migraine pathophysiology. Further MRI studies are needed to disclose whether the migraine attack is triggered by intrinsic brain dysfunction or external factors. Keywords chronic migraine, functional connectivity, headache, migraine with aura, migraine without aura FUNCTIONAL MRI SEQUENCES USED TO STUDY MIGRAINETwo main fMRI sequences have been applied in migraine studies to investigate brain function: task-based fMRI, and resting-state (i.e. functional