New Headache Classification System

The International Classification of Headache Disorders, Third Edition (ICHD-III beta version) is now complete and ready for field testing.

“It’s out, it’s published, you should start using it immediately because it’s much better than the second edition,” Jes Olesen, MD, PhD, professor of neurology, University of Copenhagen, Glostrup Hospital, Denmark, told delegates to the 2013 International Headache Congress (IHC).

Dr. Olesen, who chaired the working group on migraine, encouraged delegates to start citing this new classification system and to participate in field testing, which will take place during the next few years, before publication of the final version.

If physicians note any mistakes or have comments, they should contact the chairperson of the relevant chapter, said Dr. Olesen, who anticipates that only minor modifications will be necessary.

The ICHD-III beta version is available at the International Headache Society Web site.

Chronic Migraine

One of the biggest changes in the current edition, which has been in the works for 3 years, is the addition of chronic migraines that occur on at least 15 days of the month for more than 3 months.

In the past, patients with these headaches were all diagnosed with migraine, whether they had 1 attack a year, 1 a month, 1 a week, or 1 a day, but there has been growing interest in considering the most severe end of the migraine spectrum as a separate entity, said Dr. Olesen.

Separating out chronic migraine is “parallel” to how tension type headache is treated in the classification system, he said. “Even in the first and second editions we had chronic tension type headache, which are tension type headaches on 15 days a month or more.”

In fact, many patients have tension headaches on a daily basis and are debilitated by it, he said. “So it’s important to single out that severe end of the spectrum; and for some reason we didn’t do it for migraine, but we’re doing it now.”

In addition to the frequency of attacks, there are a number of other criteria that have to be met before a diagnosis of chronic migraine should be given.

Other migraine classifications include the following: migraine with aura, migraine without aura, complications of migraine, probable migraine, and episodic syndromes that may be associated with migraine.

Migraine with aura is subdivided into migraine with typical aura; typical aura with headache; typical aura without headache; migraine with brainstem aura; hemiplegic migraine; several types of familial hemiplegic migraine; sporadic hemiplegic migraine, and retinal migraine.

For a diagnosis of migraine with aura, the following criteria must be met:

• One or more visual; sensory; speech; motor; brainstem; or retinal symptoms;
• At least 2 of these 4 criteria: (1) at least 1 aura symptom spreading gradually over 5 or more minutes and/or 2 or more symptoms occurring in succession; (2) each aura symptom lasts 5 to 60 minutes; (3) at least 1 aura symptom is unilateral; (4) the aura is accompanied or followed shortly by headache.

Although in the main body of the text, it is specified that a patient needs 2 of 4 criteria for migraine with aura, in the Appendix, they need to have 3 of 6 criteria; field testing will reveal which approach is better, said Dr. Olesen.

As in earlier editions, the new classification system distinguishes primary headaches, which are diseases in their own right, from secondary headaches, which are caused by something else.

Other Primary Headaches

For primary headaches other than migraine, some diagnostic entities have been rearranged and renamed. There are 4 subgroups: (1) physical exertion (primary cough headache; primary exercise headache; primary headache associated with sexual activity; primary thunderclap headache; (2) headaches associated with direct physical stimuli (cold-stimulus headache; external pressure headache); (3) epicranial headaches (primary stabbing headache; nummular headache; epicrania fugax (in the Appendix); and (4) other (hypnic headache; new daily persistent headache).

Some changes in the primary headache section include the following:

• Under headaches associated with sexual activity, the subtypes of preorgasmic and orgasmic headache have been eliminated.
• For thunderclap headaches, the headache must last at least 5 minutes, but the criterion of not recurring regularly during subsequent weeks or months has been discarded.
• Hypnic headaches no longer have to first occur after age 50 years.
• A number of pain characteristics under the new daily persistent headaches section have been eliminated.

New daily persistent headache is the only headache category in which onset should be “distinct and clearly remembered,” noted Shuu Jiun Wang, MD, professor and chairman, Faculty of Medicine, National Yang-Ming University School of Medicine, and deputy head, the Neurological Institute, Taipei Veterans General Hospital, Taiwan, who chaired the working group on other primary headaches.

As for Epicrania fugax, now included in the Appendix, this could be a possible new headache entity, said Dr. Wang. It consists of brief stabbing head pain that stems from a particular area of the head and rapidly radiates forward or backward in a wide linear or zigzag movement.

Secondary Headaches

The criteria in the secondary headache section have been presented in a new format. One change here is that it is not required that the causative agent be removed before a diagnosis. There are also no longer “probable secondary” headaches.

The main categories of secondary headache include the following: posttraumatic headache; headaches due to vascular disorders; headaches due to nonvascular disorders (such as tumors); headaches due to medications, toxins and other substances; medication overuse headaches; headaches due to infections; headaches due to metabolic (homeostatic) disturbances; headaches due to cranial, cervical, EENT, and dental disorders; and headaches due to psychiatric disease.

The Appendix lists headaches associated with various psychiatric disorders, including depressive disorder, separation anxiety, panic disorder, and social anxiety disorder. Also in the Appendix is the novel headache attributed to travel in space as well as headache due to airplane travel during landing.

Another addition in the Appendix is vestibular migraine. Among the criteria for this diagnosis are having vestibular symptoms of moderate or severe intensity lasting between 5 minutes and 72 hours, photophobia, and visual aura.

Dr. Olesen said he was “sceptical” about including vestibular migraine in the new classification system, but he supports having it in the Appendix. “The way it’s defined, it sort of overlaps with other entities, in particular, migraine with brainstem aura, but we will see how it works out. At least it can get more rigorous studies.”

The diagnostic criteria in the expanded Appendix can be field tested and used for research, but they are not meant for clinical use, added Dr. Olesen.

Classification Rule

An important “rule” with the new classification system is still “to put a diagnosis on every single distinct kind of headache the patient has,” said Dr. Olesen. “So some people need 2 headache diagnoses, and even 3 headache diagnoses.”

For example, a patient can have a diagnosis of both cluster headache and tension type headache. A patient with chronic migraine and medication overuse headache will also have 2 diagnoses.

Asked by a delegate why menstruation-related migraine is still in the Appendix and not in the main body, Dr. Olesen said that this type of migraine “is very important but not suitable” for the main classification body, partly because it does not apply to men and partly because subdividing migraine could create “a mess.”

“People have suggested dividing migraine into whether it’s refractory or nonrefractory; people have suggested subdividing it on whether its associated with sensitization and not associated with sensitization; people have suggested various other ways of subdividing migraine, but it becomes too confusing.

The first edition of the International Classification of Headache Disorders was published in 1988, and the second in 2004.

Information on field testing is available on the International Headache Society Web site or the World Health Organization (WHO) Web site. WHO is field testing the International Classification of Diseases, 11th Edition (ICD-11), and for its headache section, it will also test the ICHD-III. The 2 are identical except for the degree of detail, said Dr. Olesen.

Field testing should continue for 3 years, with the final version of the updated edition ready by 2016, said Dr. Olesen.

2013 International Headache Congress (IHC). Special HIS Session. Presented June 27, 2013.