Primary headache disorders, particularly migraine and tension-type headache (TTH) are common worldwide and commonly result in widespread and substantial disability. Chronic migraine (CM) is defined as "headache occurring on 15 or more days per month for more than 3 months which has the features of migraine headache on at least 8 days per month".
The prevalence of CM in the general population is about 2%. It negatively affects emotional and family relationships, education, economic status, and general health. Migraine headaches might become quite severe and incapacitating for patients and management can be challenging even in experienced clinics.
Prophylactic interventions may include pharmacotherapy, behavioral therapy, physical therapy and other strategies. Management often requires the simultaneous use of these different therapeutic modalities. Once the headaches become refractory to conventional pharmacologic management minimally invasive techniques such as peripheral nerve blocks are feasible for pain relief and help to decrease the frequency of the attacks.
Preventive medications for chronic migraine treatment are less well studied than they are for episodic migraine. In addition, some trials evaluating treatment of chronic migraine are limited by one or more methodologic problems, such as small size, concomitant use of other prophylactic medications and/or lack of a specific headache diagnosis.
