Chronic headache: Stop the pain before it starts

CASE Eric K, age 25, is in your office, seeking help for chronic headache—which he’s had nearly every day for the past 9 months. He says that the headaches vary in quality and intensity. Sometimes the pain is in the right temporal area; has a throbbing, pulsating quality; and is accompanied by nausea and photophobia. These headaches are incapacitating, with an intensity of 10 on a scale of one to 10. When they occur, the patient reports, all he can do is take migraine medication and lie down in a darkened room for several hours, until the pain goes away. He cannot identify any triggers.

He also gets headaches that are not incapacitating, but occur almost daily, the patient says, describing a dull bilateral pressure that usually begins in the afternoon and worsens until he takes headache medication. He denies any fever, chills, weight loss, visual changes, or tinnitus. His medical history is significant only for obesity, but a system review is positive for depression and insomnia. Physical examination reveals normal vital signs; normal head, eyes, ears, nose, and throat (HEENT); and normal fundoscopic and neurological exams.

Patients like Mr. K can be challenging for primary care physicians, but referral to a neurologist is indicated only in the most intractable cases. For the vast majority of patients with frequent headaches, family physicians can perform the diagnostic work-up and oversee treatment. This review will help with both.

What kind of headache?

While most headaches are sporadic in nature, the prevalence of “chronic daily headache” ranges from 3% to 5% worldwide.^1-3

Chronic daily headache is not a diagnosis, however, nor is it an indication that a patient has a headache every day. According to the International Classification of Headache Disorders (ICHD-II), chronic daily headache encompasses several distinct primary headache disorders that have a frequency of ≥15 times per month for at least 3 months. These disorders are also classified by duration, as long (>4 hours) or short.⁴

The text and tables that follow focus on the diagnosis and treatment of the 4 primary headache disorders of long duration—chronic migraine (CM), chronic tension-type headache (CTTH), hemicrania continua (HC), and new daily persistent headache (NDPH) (TABLE 1).^4,5 Although medication overuse headache (MOH) is not a primary headache, it is included in this review because it often contributes to and complicates treatment of primary headache disorders. What’s more, most chronic daily headache syndromes are inextricably linked to medication overuse.^6,7

Which individuals are at risk?
Risk factors for chronic headache include female sex, older age, obesity, heavy caffeine consumption, tobacco use, low educational level, overuse of abortive headache medications, and a history of head and neck trauma.⁸ Episodic migraine (EM)—that is, migraines that occur ≤14 times a month—is also a risk factor for chronic headache.

ICHD-II classifies EM as a progressive disease that transforms to CM at a rate of 3% per year.⁹ Transformation of EM to CM has been found to occur after as few as 5 days of barbiturates or 8 days of opiates per month.¹⁰

Patients with EM should be warned about the potential for migraines to become chronic and have their acute headache medications replaced with a prophylactic drug if the frequency approaches 2 per week.

TABLE 1
Diagnosing and treating chronic headache^4,5