Introduction

Postdrome. After a migraine attack, there is usually a postdrome phase, in which patients may feel exhausted and mentally foggy for a while.

Chronic Migraines

In some cases, patients eventually experience on-going and chronic headaches. In fact, in an analysis using two different diagnostic methods, between 87 - 90% of daily chronic headaches were actually migraines. Some experts believe that, unless otherwise demonstrated, any chronic headache consisting of episodes of disabling pain that recur regularly over years should be considered as a migraine.

Chronic migraines may occur from overuse of migraine medications (called a rebound headache) or may develop over time (called transformed migraine).

Rebound Headache. The most common cause of chronic migraine is the rebound effect, which is a cycle caused by overuse of migraine medications. The process involves the following:

• Patients typically have taken pain medication for more than 3 days a week on an ongoing basis.
• When the patients stop taking medication, they experience a rebound headache.
• They start taking the drugs again.
• Eventually the headache simply persists, and medications are no longer effective.

Medications implicated in rebound migraines include nonprescription painkillers (acetaminophen, aspirin, ibuprofen), barbiturates, sedatives, narcotics, and migraine medications, particularly those that also contain caffeine. (Heavy caffeine use can also cause this condition.)

Transformed Migraines. In some cases, migraines themselves evolve into chronic, daily headaches called transformed migraines. Such headaches resemble tension headaches but are more likely to be accompanied by gastrointestinal distress and mental or visual disturbances and, in women, to be affected by menstrual cycles. In one study, the risk for transformed migraines were associated with other factors, including allergies, asthma, hypothyroidism, hypertension, and a daily intake of caffeine.

Definitions of Classic and Common Migraine Attacks

Migraines are defined by the number and length of attacks and whether an aura is present.

Definition of Migraines without Auras (Common Migraine). To be defined as a migraine without aura, a patient should have at least five attacks that have the following characteristics: