Migraine Myth of the Month: Migraine Diagnosis Requires a Brain Imaging Study
Many patients presenting to a medical provider for evaluation of migraine become uneasy - even angry - when that provider fails to order a brain CT or MRI scan. Understandably convinced that "there must be something wrong with my brain to cause this terrible pain", they worry that a brain tumor, aneurysm or some similarly serious structural abnormality will be missed unless a scan is performed.
As indicated elsewhere in this issue, the diagnosis of migraine is made largely on the basis of the history provided by the patient; even with its remarkable resolution, brain MRI will not demonstrate the presence or absence of a structural abnormality responsible for a patient's migraine. Migraine is believed to be a genetic disorder whose clinical manifestations reflect a biologically hypersensitive brain (link to vol 2, pg 6), and we currently lack any test or biologic marker that is sufficiently specific or sensitive to confirm the clinical diagnosis. The physical examination that the provider performs and whatever tests he or she may order are done to exclude other conditions that may mimic migraine…not to “make the diagnosis”.
Far too many scans are performed on patients with migraine whose diagnosis could be made with confidence on the basis of the history and physical exam alone. The tendency to uniformly request a brain imaging study in every patient who presents with migrainous headache is not an indicator of expert medical care. Conversely, diagnosis and management of migraine on the basis of a history and physical exam alone is hardly an indicator of shoddy medical care.