Knowing your subtype: does it matter?

There are many different subtypes of migraine. Do you know yours? Do you need to know your subtype?

Migraine is a very complex genetic disorder with lots of different symptoms. It's caused by different gene mutations that affect similar genes. That results in different presentations but basically the same disorder. Doctors differentiate between these slightly different presentations through a classification system that lists certain symptoms as belonging to a certain subtype of migraine. 

Sometimes you can figure out for yourself which subtype - or subtypes, you can have more than one - you have, but the differences are subtle so it's best to have your diagnosis confirmed by a neurologist that specialises in migraine. 

The classifications doctors use is called the International Classification of Headache Disorders. This is usually shortened to ICHD, and we're on the third edition so it's usually referred to as the ICHD3. This classification has all of the headache disorders, but the largest section by far is part 1 - migraine.  

To put it simply, all migraine is split firstly into migraine without aura, and migraine with aura. Then there is a number of subtypes under migraine with aura: typical aura with and without headache, brainstem aura, hemiplegic migraine and retinal migraine. 

The ICHD3 also lists a classification for chronic migraine - which is 15 days a month of headache, 8 of which are migraine days, which can be any of the migraine with or without aura subtypes. Under complications of migraine, the classification lists status migrainous - the never-ending migraine attack, persistent aura, migrainous infarction - a stroke caused by a migraine attack, and migraine triggered seizure. 

There's a number of other types of migraine that we refer to in the community which haven't quite made it into the classifications yet. This is because the medical community are fairly cautious, and we need a lot more research to be completely sure they are variants of migraine. 

The first of these are classified as 'episodic syndromes that may be related to migraine' and include presentations that mainly affect children. They are Abdominal Migraine and related Cyclical Vomiting Syndrome, Benign Proximal Torticollis and Benign Proximal Vertigo. 

You may be thinking right now that there are a few things missing from the list! Where's vestibular migraine!? 

Don't worry, it's there, in the appendix. The appendix includes more recent science of migraine recommended for inclusion in the next iteration of the classifications. There's quite a significant difference in the proposals, including two types of menstrual migraine - pure menstrual migraine and menstrually related migraine, splitting chronic migraine into two - one with pain-free days and the other with continuous pain, and adding vestibular migraine, visual snow, and infantile colic to the list. The understanding of migraine is developing so fast there is likely to be many more changes proposed for the ICHD4.

Does it matter? Well sometimes, yes. There are different treatments that work for different types, and some treatments are not allowed for certain subtypes. For example, triptans are not recommended for brainstem or hemiplegic migraine types. There are also different risks, like for example the higher stroke risk with migraine with aura subtypes. 

Research is still continuing on migraine genetics, figuring out which gene mutations link to which forms of migraine. Some we know, like the main hemiplegic migraine genes. Part of this work is also developing treatments to specifically target the issue created by that gene mutation. When the genetic puzzle is fully understood we're likely to have lots and lots of migraine subtypes, a bit like there's lots and lots of types of Ehlers Danlos Syndrome

In the meantime, we still have to just try the different treatments to find what works for us. However, you may be able to speed up the process by getting your subtype diagnosed, and then connecting with others with your subtype in the Migraine Australia Chat Group to find out what has worked for them.  

Read more about the types of migraine. 

 

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  • Raphaella Kathryn Crosby
    published this page in News 2021-04-01 19:54:52 +1000