In Part II of this series, we explored the very important question of How and why do migraine headaches start? Why, especially, do refractory headaches occur? Refractory headaches, which are generally understood to be headaches that do not respond well to treatment and which can pose significant disability for the afflicted, are often felt to be rather mysterious in origin, and I have seen many patients who are tormented by the lack of knowledge as to the cause of their disabling headaches. They may have been told that the problem is a psychiatric
one. While it is true the emotional factors certainly can play an important role in headache, as I will discuss in the next post, it is uncommon for emotional factors alone to be the cause of refractory headache. Or, perhaps a patient’s refractory headaches are attributed to an entity called “medication overusage headache (MOH).” This is a somewhat controversial topic. It describes a type of headache that is attributed to the use of medications to treat headache on a frequent basis, usually meaning more than three or four days a week. There are many problems with this diagnosis, though. There are concerns about how studies on MOH are performed, and the data is not particularly strong to support the entity as being as common as some researchers and doctors think it is. I will write about this topic in an upcoming post. While I believe that MOH does exist, in my opinion and experience, MOH is over-diagnosed. The biggest problem with attributing headaches to MOH is that it causes the doctor to stop thinking about other causes for the chronic headache and to just focus on stopping the medication,
which, for some patients, is the only thing allowing them to go to work and take care of a family. I think it is critically important to continue searching for a cause for the headache, even in – especially in! – a patient who is taking pain medications on a frequent basis.
This point leads us back to the studies we were discussing in Part II. Nerves on the inside of the head that are relevant to migraine can travel through the skull and reside on the outside of the head, as has been shown in both mice and humans. Therefore, theoretically, disease states affecting the outside of the head, such as pressure on the nerves on the back of the head (the occipital nerves, as discussed in Part !) or the front of the head (the trigeminal nerve branches, as discussed in Part II) can lead to pain that can be experienced by the sufferer just like a migraine headache. It is important to note that this phenomenon has not been proven to occur, because it has not been studied. There has not been an interest in the research conducted in headache medicine to understand the role of nerves on the outside of the head.
It is important to know that the largest source, by far, of funding for research in the study of headaches is from the pharmaceutical industry. The pharmaceutical industry certainly conducts research that is critically important to our many aspects of our understanding of headache disorders, and that industry has not (yet) had an interest in the role of nerves on the outside of the head. For this reason, there is no specific research on the manner in which pain caused by pressure on nerves on the outside of the head causes headache. The knowledge that we headache doctors have is driven solely by our clinical experience.
My clinical experience – meaning the experience that I have gained from seeing patients with headache disorders for over 25 years, and working specifically with patients who have pressure on the nerves of the skull for about 20 years – is that the condition of nerve compression as a cause of headache is very common. It is certainly not the only cause of refractory headache – there are other causes, some physical, some emotional – however nerve compression is a common cause. The condition will cause pain that usually has typical characteristics in terms of
pain location, frequency, character, aggravating and alleviating factors, and intensity. In my experience and the experience of most doctors who are knowledgeable in this area, occipital nerve compression is more common than compression of the trigeminal nerve branches. The condition can be diagnosed and often treated successfully with medical interventions. Some patients do well with an expanded version of the surgery we discussed in Part I, which removes
pressure from the nerves. That pressure is from muscles around the nerve and through which the nerve travels, as well as inflammatory tissue caused by the pressure on the nerve. A research study was published in 2016 that proved the existence of inflammation in the back of the skull in patients who had nerve compression; in these patients, who were undergoing occipital nerve decompression surgery, a small piece of the covering of the skull bone was
removed and examined for the presence of genes that indicate the presence of inflammation.
Those results were then compared to similar pieces of tissue removed the skull in patients who were undergoing brain surgery for other reasons. Dr. Rami Burstein, as discussed in Part II of this blog, is an eminent researcher in headache pathophysiology, and his lab at Harvard is one of only a few in the world that can conduct this type of research. Dr. Burstein found significantly increased genetic markers for inflammation in the samples from the headache patients compared to the non-headache controls. Feel free to take a look at the paper See Link
that was published from this highly sophisticated research, and the important conclusions drawn from it: as stated in the abstract, this works demonstrates “the first set of evidence for localized extracranial pathophysiology in chronic migraine.”
In my experience, there is a broad range of ways in which patients with occipital nerve compression can experience pain. In some people, the situation is straightforward. They have constant, daily pain at the occiput (the low back of the head, just above the neck) with tenderness at that area. Those patients are usually diagnosed pretty quickly as having an occipital nerve problem, often by a doctor or treating provider, and sometimes by the patient or a family member who goes in search of an answer to the critical question of ‘what is back there to hurt so much?’ I am always impressed and delighted when a patient or a loved one figures out the diagnosis through curiosity and independent research. In other people, the situation is not straightforward. The pain may not be predominantly occipital – it may be more prominent elsewhere in the head, including in the more typical ‘brain-driven migraine’ locations of the forehead. They may not have a lot of tenderness on the nerves. They may have other prominent symptoms that can be problematic, and they may have pain that is more in the neck than in the head – a symptom which, incidentally, has been reported to be very common in
chronic headache disorders. Those patients may look just like regular migraine sufferers, except for their very frequent pain and their less robust response to migraine medications. This is probably the type of patient that I see the most – the patient who kind of looks like regular migraine, but kind of doesn’t. The patient who may respond, at least somewhat, to some medications, yet who continues to have frequent pain. The patient who knows, or senses, that
something more is going on than simply a migraine triggered by stress or hormonal changes.
The patient is correct. There often is more going on, and it is a condition that can be diagnosed and treated effectively.
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