Year : 2018 | Volume
: 6 | Issue : 1 | Page : 1--2
The international classification of headache disorders: Anything new in 3rd edition?
Department of Neurology, Smt. B.K. Shah Medical Institute and Research Centre, Vadodara, Gujarat, India
Dr. Sanjay Prakash
Department of Neurology, Smt. B.K. Shah Medical Institute and Research Centre, Piparia, Vadodara, Gujarat
|How to cite this article:|
Prakash S. The international classification of headache disorders: Anything new in 3rd edition?.J Integr Health Sci 2018;6:1-2
|How to cite this URL:|
Prakash S. The international classification of headache disorders: Anything new in 3rd edition?. J Integr Health Sci [serial online] 2018 [cited 2019 Apr 21 ];6:1-2
Available from: http://www.jihs.in/text.asp?2018/6/1/1/245023
Headache is one of the most common complaints seen in the clinical practice. The differential diagnosis of this highly prevalent symptom is vast, with over 300 different headache types and etiologies. Understanding the headache classification is a requisite for diagnostic testing and treatment.
The first modern attempt at classifying different headache disorders was done by an ad hoc committee formed by the National Institutes of Health in 1962. This classification system had brief glossary-type definitions of some headache disorders. The classification system tried to differentiate migraine headache with tension headaches. The International Headache Society (IHS) was formed in 1982, and they later formed a classification committee for headache disorders. The IHS published the first edition of ICHD in 1988. It included about 165 different types of headaches. A larger part of the classification system was mainly based on the opinion of experts rather than on published evidence. However, it was accepted immediately by the medical fraternity. It provided the uniform terminology and diagnostic features for the various headache disorders. The classification system was intended equally for the research and for clinical practice. It served the purpose and facilitated epidemiologic studies and clinical trials.
The IHS formulated and published the second edition of the International Classification of Headache Disorders (ICHD-2) in 2004, and it included about 259 different types of headaches. In 2013, the IHS published the beta version of the third edition (ICHD-3β). It was actually the “raw version” of the third edition, ahead of the final version. The IHS had a plan to get field testing of the different diagnostic criteria of different headache disorders. A larger number of studies have been conducted across the world. And now, the IHS published the third edition of ICHD in 2018 (ICHD-3). So, whereas the first edition was based mainly on the expert opinion, the third edition is largely evidence based.
The basic framework of classifications is almost same in all the classification systems and no changes have been made in the classification format in the third edition. It consists of four parts: (i) the primary headaches; (ii) the secondary headaches; (iii) painful cranial neuropathies, other facial pain and other headaches; and (iv) appendix.
Part 1 deals with the primary headache disorders. Primary headaches broadly classified into four chapters: (i) migraine, (ii) tension-type headache, (iii) trigeminal autonomic cephalalgias (TACs), and (iv) other primary headaches. There are five different types of TACs: cluster headache (CH), paroxysmal hemicrania (PH), short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) or cranial autonomic features (SUNA), and hemicrania continua (HC). HC was placed in the “other headaches” category in ICHD-2. However, it was included under the TACs in Group 3 in beta edition of classification system due to marked overlap with CH and PH in both clinical and therapeutic aspects. HC retained its position in Group 3 in the final version of the third edition classification. In “other primary headache,” there are ten different rare primary headaches.
Part 2 describes different secondary headaches. There are eight different groups (Chapter 5 to Chapter 12) for secondary headaches. Part 3 consists of mainly facial pain or neuralgia as well as chapter 14, for unclassifiable headache types. The appendix section is mainly for the research purpose. It largely includes (1) alternative diagnostic criteria for certain existing headache disorders, (2) suggested criteria for possible new headache entities, and (3) previously accepted headache disorders which have not been supported by good evidence. The appendix is thus a list of fertile research topics, and IHS encourages field testing for the headaches included in the appendix section.
There are very few changes in the recent ICHD-3 criteria. Some changes have been made in the criteria of migraine. In the field testing, it was noted that the appendix criteria for migraine with aura are superior to the criteria for migraine with aura of the main body of ICHD-3β, especially in distinguishing the aura from transient ischemic attacks (TIA). Therefore, appendix section criteria of migraine with aura have been moved to main section of the criteria. There are six different types of auras in migraine (visual, sensory, speech-language, motor, brain stem, and retinal). Six characteristics symptoms have been described for each aura: (i) at least one aura symptom spreads gradually over ≥5 min, (ii) two or more aura symptoms occur in succession, (iii) each individual aura symptom lasts 5–60 min, (iv) at least one aura symptom is unilateral, (v) at least one aura symptom is positive, and (vi) the aura is accompanied, or followed within 60 minutes, by headache. Only three (out of six) is required. This new criteria for migraine with aura will be more helpful in differentiating TIA with migrainous auras.
A few changes have been made in TACs. CH, PH, and SUNCT/SUNA have two subtypes: episodic and chronic. The distinction between episodic and chronic form is the duration of remission period in 1 year. In chronic variant, there will no remission or remission will be of <3 months. In earlier classification system, this period was only 1 month. There were a total of 10 cranial autonomic features in all five types of TACs in ICHD-3β edition. However, in the field testing, it was noted that facial flushing and aural fullness do not add to diagnostic discrimination. Therefore, it has been removed from the list of cranial autonomic features in all five TACs. Now, these cranial autonomic symptoms are included only in the appendix section of ICHD-3.
Hence, there are just a few changes in the new edition of the classification system. Overall, ICHD-3 criteria acknowledge the ICHD-3β.
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