ABSTRACT
Migraine is the most common form of primary headache to present in clinical practice at all levels as it is disabling, while tension-type headache is generally not disabling, much less likely to cause patients to seek care. Headache coming on over several weeks that is worse in the morning and on coughing suggests raised intracranial pressure, in which case a contrast-enhanced computed tomography scan or magnetic resonance imaging scan, perhaps followed by angiography, would be appropriate. Subcortical structures, such as hypothalamus and brainstem nuclei, dorsal raphe nuclei, and locus ceruleus, form a network that initially is dysfunctional and facilitates increased afferent input through the trigeminovascular system and cortical overactivity due to dishabituation. Stimulation of the trigeminal ganglion leads to the release of powerful vasodilator neuropeptides such as calcitonin gene-related peptide from trigeminal neurons that innervate the cranial circulation. The role of imaging in patients with suspected migraine is to exclude structural causes for the headache such as arteriovenous malformations or tumors.
