Migraine Diagnostic Criteria: Important Updates
As we've often discussed, the ICHD (International Classification of Headache Disorders) is the gold standard for diagnosis and classification of Migraine and Headache Disorders. The ICHD is now on its third version, ICHD-III (beta). With this comes many updates, including some important Migraine-related changes.
ICHD-III (beta) was officially unveiled at the International Headache Congress in June 2013, following exhaustive efforts by a committee charged with updating the guidelines. The ICHD is a project of the International Headache Society with the goal of providing worldwide consistency in diagnosis and classification of Headache Disorders. At the American Headache Society's Scottsdale Headache Symposium I had the opportunity to attend a presentation offering an overview of the most significant changes offered in ICHD-III (beta).
MIGRAINE-RELATED CHANGES IN ICHD-III (BETA):
- While Chronic Migraine was classified as a subcategory of Complications of Migraine under ICHD-II, it's now it's own category of Migraine under ICHD-III (beta).
- ICHD-III (beta) does not require Headache Specialists to choose between diagnosing Chronic Migraine and Medication Overuse Headache; if a patient meets the criteria for both, both can and should be formally diagnosed.
- For whatever reason, patients experiencing Migraine with Aura were not considered candidates for this diagnosis under the previous version of the ICHD. This has been changed under ICHD-III (beta).
- The ICHD-III (beta) provides more diagnostic specificity and clarity.
Medication Overuse Headache
- While Medication Overuse Headache (MOH) is not classified under Migraine under the ICHD, it's not only a common diagnosis among Migraine patients, but for some patients can also negatively impact our response to preventive treatments.
- Under ICHD-II, patients diagnosed with a primary headache disorder were also to be diagnosed with Medication Overuse Headache if they met the criteria for both.
- Unfortunately, Chronic Migraine was excluded from this guideline under ICHD-II. As mentioned above, ICHD-III (beta) instructs Headache Specialists to diagnose patients meeting the criteria for both Chronic Migraine and Medication Overuse Headache with both diagnoses.
- Under the ICHD-III (beta) reclassification, Migraine variations associated with aura or aura-like symptoms have been collected under the Migraine with Aura heading.
- Migraine with Typical Aura: This category of classification essentially replaces what we've been referring to as Migraine with Aura under ICHD-II.
- Migraine with Prolonged Aura: This designation has been removed from ICHD-III (beta). The committee in charge of updating the ICHD explains the majority of Migraine patients with attacks falling under this designation meet the criteria for one of the Migraine with Aura definitions, making the category redundant. The committee suggests physicians should diagnose Migraine attacks meeting the appropriate criteria accordingly.
- Migraine with Brainstem Aura: This type of Migraine was known under ICHD-II as Basilar Artery Migraine. The distinguishing characteristic is Migraine with symptoms originating from the brainstem, but with no motor weakness.
Familial Hemiplegic Migraine
- Under ICHD-III (beta), Familial Hemiplegic Migraine (FHM) has been subdivided into four categories.
- Breaking FHM down into these subtypes recognizes research that has been able to identify specific genes within families related to FHM.
- The first three are for classification of specific genes. The fourth type is for classification of any patient who does not have any of the three (as yet) identified genes, but otherwise meets the diagnostic criteria.
- Diagnosis of any type of FHM requires the patient meet the ICHD-III (beta) criteria for Hemiplegic Migraine.
- Under the ICHD system generally, the appendix is used to make tentative additions to the classification system for further exploration and discussion.
- In recognition of fascinating research about infant colic as a possible first indication of Migraine, the ICHD reclassification committee added Infantile Colic to the appendix in this update.
- No doubt it should be fascinating to see how both new research and this possible new category of Migraine is handled in future updates to the ICHD.
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