There are no diagnostic tests to confirm a diagnosis of migraine, so how is it diagnosed? Migraine is considered what's called, "a diagnosis of exclusion." That means that a diagnosis of migraine is achieved by ruling out, or excluding, other causes for the symptoms.
A doctor diagnoses migraine by:
- reviewing our medical history and our family's medical history;
- discussing our symptoms with us; and
- performing an examination, including any diagnostic tests they feel appropriate to exclude other causes for our symptoms.
Before going to the doctor, we should find out what we can about our family medical history. Is there a history of migraine in our family? Is there a history of "sick headaches" or sinus headaches? Especially a few generations back, people had what they called "sick headaches," which were probably migraines. Over 90 percent of what people think are sinus headaches are really migraines. If there's a history of migraine on one side of the family, there's a 50 percent chance of inheriting it. That increases to 75 percent when there's a history of migraine on both sides of the family.
Doctors will also need to discuss our symptoms with us. Since it's often difficult to remember everything once we get to the doctor, it's important to make a list of our symptoms to take with us.
Since no diagnostic tests can confirm migraine, it's not always necessary to run any tests to diagnose migraine. When the symptoms match the diagnostic criteria for migraine, the diagnosis is often made without tests. This is especially true if there's a family history of migraine. When tests are ordered, imaging studies are the most common. The American Headache Society has made two recommendations about imaging studies:
- Don’t perform neuroimaging studies in patients with stable headaches that meet criteria for Migraine.
Numerous evidence-based guidelines agree that the risk of intracranial disease is not elevated in migraine. However, not all severe headaches are migraine. To avoid missing patients with more serious headaches, a migraine diagnosis should be made after a careful clinical history and an examination that documents the absence of any neurologic findings, such as papilledema. Diagnostic criteria for migraine are contained in the International Classification of Headache Disorders
- Don’t perform computed tomography (CT) imaging for headache when magnetic resonance imaging (MRI) is available, except in emergency settings.
When neuroimaging for headache is indicated, MRI is preferred over CT, except in emergency settings when hemorrhage, acute stroke or head trauma are suspected. MRI is more sensitive than CT for the detection of neoplasm, vascular disease, posterior fossa and cervicomedullary lesions and high and low intracranial pressure disorders. CT of the head is associated with substantial radiation exposure which may elevate the risk of later cancers, while there are no known biologic risks from MRI.
It's important to realize that a diagnosis of "migraine" isn't a complete diagnosis. There are several forms of migraine, and it's important to know which one(s) we're dealing with. Migraine without aura is the most common, followed by migraine with aura. Other forms include migraine with brainstem aura, hemiplegic migraine, and others. You can find a list of the types of migraine and information on each of them below.
The American Headache Society's Choosing Wisely® Task Force. "Five Things Physicians and Patients Should Question." The American Headache Society. November, 2013.