Blood pressure changes in patients with migraine: Evidences, controversial views and potential mechanisms of comorbidity

Migraine and hypertension are common complaints and both have high prevalence worldwide. The comorbidity of migraine with hypertension is a common issue since 1913. Recent epidemiologic and population-based studies put some doubt regarding the association between migraine and hypertension, no association or even negative association was found by some authors. Authors who supported the positive association suggested that rennin-angiotensin system as a biological link between hypertension and CNS activities that are relevant for migraine pathogenesis. Authors who denied the association suggested a coincidental existence since any association between two prevalent health conditions is likely to be detected in large series. Authors who supported the negative association suggested a central regulatory and homeostatic process resulting in reduction of sensitivity to pain (a phenomenon called hypertension-associated hypalgesia). Baroreflex stimulation, endogenous opioids, catecholamines and calcitonin peptide may influence blood pressure and pain sensitivity in patients with migraine and lowers the number of migraine attacks in hypertensives. Despite the uncertainty still present in this field, a unifying view among most recent studies suggests that migraine is positively correlated with diastolic blood pressure but negatively correlated with systolic blood pressure and pulse pressure. Similar vascular risk profile and the abnormal properties of systemic as well as cranial arterial vessels exist in subjects with migraine and hypertension. On the other hand poor control of blood pressure may exacerbate the frequency and severity of migraine and other headaches. These evidences may suggest that both conditions may coexist as part of a systemic disease. Thus establishing the blood pressure should be a routine task in the assessment of all headache patients and the control of hypertension in migraine patients is an important factor for the success of migraine treatment and to lower cardioand cerebro-vascular risks.