Comprehensive review and update on chronic migraine

ABSTRACT

Chronic migraine (CM) is a common and disabling neurologic disorder. CM is defined as more than 15 days a month over a 3-month period, including at least 8 days per month on which their headaches and associated symptoms meet diagnostic criteria for migraine. Quality of life is highly compromised in patients with this condition, and comorbidities are more frequent than with episodic migraine. The diagnosis requires a carefully-conducted patient interview and neurologic examination, sometimes combined with additional diagnostic tests, to differentiate CM from secondary headache disorders and other primary chronic headaches. CM typically develops from episodic migraine over months to years. Several factors are associated with an increased risk of episodic migraine developing into CM, including the frequent use of abortive migraine drugs. Through identification of risk factors for progression to CM, clinicians can educate patients about modifiable risk factors and can begin appropriate individualized preventive therapy. There is a high frequency of medication overuse in CM. The first step in the management of CM complicated by medication overuse is withdrawal of the overused drugs and detoxification treatment. This article provides an overview of CM, including its epidemiology, risk factors for its development, and information on its pathophysiology, diagnosis, and management.