The terminology of Migraine can be confusing, especially as it evolves. This is usually simplified by following the International Headache Society’s International Classification of Headache Disorders, 2nd Edition (ICHD-II), which is considered the “gold standard” for diagnosing and classifying Migraine and other headache disorders. As research progresses, however, the ICHD-II evolves, and the terminology evolves with it.
This is the case with the term “transformed Migraine.” The first edition of the ICHD, which was published in 1988, did not have a diagnostic category for chronic Migraine (CM). There was a division within the “headache” medicine community with European doctors being of the opinion that Migraine was an episodic disorder and Americans disagreeing.
Doctors found it difficult to classify and diagnose more and more patients who were presenting with “headaches” that were occurring nearly daily; were sometimes Migraine, were sometimes tension-type headaches; and were sometimes difficult to distinguish between the two. Some doctors, including Dr. Ninan Matthew, Dr. Stephen Silberstein, and Dr. Richard Lipton, began using the term “transformed Migraine,” which was described as Migraine which began manifesting in episodic Migraine attacks, increasing in frequency and changing characteristics, and resulting in almost daily less severe headaches punctuated by severe and debilitating Migraine attacks.
In 1996, Silberstein and Lipton set forth these criteria for the classification of transformed Migraine:4
Daily or almost daily (more than 15 days/month) head pain for more than 1 month
Average headache duration of more than 4 hours/day (if untreated)
At least 1 of the following:
History of episodic migraine meeting any International Headache Society (IHS) criteria
History of increasing headache frequency with decreasing severity of migrainous features over at least 3 months
Headache at some time meets IHS criteria for migraine other than duration
Does not meet criteria for new daily persistent headache or hemicrania continua
Not attributable to another disorder
In 2006, the International Headache Society added a new appendix to ICHD-II to address diagnosis and classification of chronic Migraine. Since then, the term “chronic Migraine” has taken the place of the term “transformed Migraine.”
I hope this helps clear up any confusion you might have about the term “transformed Migraine.” I know how hard it can be to keep is all straight. It seemed that I had just gotten to the point of really understanding “transformed Migraine” when the IHS criteria was updated and we stopped using it in favor of chronic Migraine. Ah, well; that’s progress!
For the IHS diagnostic and classification criteria and other information about chronic Migraine, see our Chronic Migraine Overview.
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1. Headache Classification Committee of the International Headache Society. “The International Classification of Headache Disorders, 2nd Edition.” Cephalalgia 24 (s1). doi: 10.1111/j. 1468-2982.2003.00824.x 2. Headache Classification Committee of the International Headache Society. “Brief Report: New appendix criteria open for a broader concept of chronic migraine” Cephalalgia, 2006, 26, 742–746. 3. Headache Classification Committee of the International Headache Society. “Classification and diagnostic criteria for headache disorders, cranial neuralgias and facial pain.” Cephalalgia. 1988;8(Suppl. 7):1-96. 4. Silberstein, Stephen D., MD. “Managing Chronic Migraine in 2011: Background” Medscape Neurology. April 18, 2011.