Abstract
Not long ago I published an editorial in this journal about the future of headache classification (1). However, thing are moving fast in our field. The Third International Headache Classification Committee had its first meeting in September 2009 in Philadelphia, planning for a quick and rather minor revision of ICHD-2, primarily including new criteria for the secondary headaches. It was planned to be named ICHD-2R. However, when many good brains are put to work on a theme like classification, new ideas sprout. It became apparent that, for the primary headaches as well, a number of changes were already needed. International Headache Society (IHS) president, Hans-Christoph Diener, suggested that yet another modification of ICHD-2 might be confusing and that it would be better instead to develop a more thorough revision, even if the process would take more time and involve greater expense. Another important reason for a change in plan was that the World Health Organization (WHO) had just started work on the next version of the International Classification of Diseases, ICD-11. This presents a golden opportunity for greater recognition of headache disorders, our aim being to achieve complete congruence between the IHS and the WHO classifications of headache. The WHO classifications change only every 20 years or so. We agreed, therefore, that it is important to develop a version of the IHS classification that can be incorporated into the ICD-11 and can be used for a considerable length of time. We realized that harmonizing the classification documents could yield considerable positive effects on the recognition of headache disorders and the reimbursement of their treatment in many countries. After debate in the classification committee the new proposal was accepted, and later the board of the IHS decided to follow this recommended path.
The roadmap for the ICHD-3 is now the following. The committee will meet for the second time in Nice, in association with the congress of the European Headache Federation and the Migraine Trust International, and again in association with the American Headache Society meeting in 2011, and will hold a last meeting in the winter of 2012. After desk editing, we expect the ICHD-3 to be printed toward the end of 2012, designated January 2013. At that time it will also be available on the website of the IHS. It will be necessary to translate the document for use throughout the world, as with the two first editions. A condensed pocket version and an extensive set of slides will also be developed.
In which ways will ICHD-3 differ from ICHD-2? In the migraine chapter the diagnostic criteria will probably not change. Chronic migraine will move from the appendix into the main body of the classification (2), and some simplification of the classification of migraine with aura may be relevant. We may introduce so-called “specifiers” in the migraine chapter and perhaps in other chapters as well. They can be used to subdivide existing migraine types for a special purpose, such as scientific study. Treatment-responsive and treatment-refractory migraine is a possible example. Specifiers are not intended to be used by the practicing physician. Only small changes are expected regarding tension-type headache and trigeminal autonomic cephalalgias, while more substantial changes are necessary in Chapter 4: Other Primary Headaches, in response to important nosographic studies of some of these disorders.
In accordance with our initial plans, relatively extensive changes will be made regarding the secondary headaches. This is first and foremost in order to implement the new general criteria for secondary headaches already published (3). They allow, contrary to the existing criteria, the diagnosis of a secondary headache before it is treated. In accordance with the new general criteria, we shall move the already-published criteria for medication overuse headache (2) into the main body of the classification. Thus, a patient with medication overuse shall receive the diagnosis irrespective of the result of withdrawal. A number of other changes also seem justified and will be discussed by the working groups. As previously, there is a working group of some five to 10 experts for each of the chapters in the classification, so that broad input is assured.
The classification committee is very interested in input not only from members of working groups but also from the headache community at large. If you have comments already now, please go to the IHS website of the classification committee and send your comments to the chairperson of the relevant working group; do not send them to me. We plan to post a beta version of the entire ICHD-3 at the earliest possible time and would also be happy to receive feedback on that in due course. Again, comments should be directed to the chair of the relevant working group.
I look forward to an exciting work process with a good deal of interaction. We hope that this process and the ICHD-3 itself will allow IHS members to be better equipped for future research and care.