Diagnostic issues in migraine.

Headache poses diagnostic challenges to the clinician for many reasons. It is an extremely common complaint, and may be associated with acute illness or serious pathology such as brain tumor or cerebral aneurysm. However, the majority of patients experiencing recurrent headache in the population suffer either from a variant of tension-type headache or migraine. Because migraine is more likely to be disabling, it becomes the most likely diagnosis for any patient presenting with recurrent headache interfering with function. Although the diagnostic criteria developed by the International Headache Society in 1998 are useful as a guide, migraine may be more readily recognized in a clinical setting by its consideration at the top of the differential for patients presenting with recurrent headache. This article reviews the standard diagnostic criteria for migraine, while also addressing the primary and secondary headache syndromes that may be considered in a differential diagnosis. The indications and roles for specific investigative procedures such as neuroimaging are reviewed. Specific emphasis is placed on the clinical recognition of migraine in the context of an assortment of headache conditions.