Voice-over: Welcome to Spotlight on Migraine, a podcast series hosted by the Association of Migraine Disorders. Through personal stories and interviews with experts, we expose the true scope of migraine by exploring symptoms, treatments, research topics, and more. This episode is brought to you in part by our generous sponsors Amgen, Novartis, Alder BioPharmaceuticals, and Teva Pharmaceuticals.
In today’s episode, we will hear from Dr. Michael Teixido, a neurotologist who specializes in conditions that affect hearing and balance. Dr. Teixido provides an in-depth explanation of the different types of migraine as well as the various symptoms associated with each disorder.
Dr. Michael Teixido: My name is Michael Teixido. I’m a neurotologist in Wilmington, Delaware. A neurotologist is a specialist in ear and hearing problems within the specialty of otolaryngology. As a neurotologist, I have a primary responsibility in my community for the care of patients with dizziness and balance disorders. I have, over many years, discovered that over half of the patients I see who are suffering from persistent complaints of dizziness have dizziness complaints which can be attributed to migraine.
When we learn about migraine in medical school, we are given lists of criteria which make a migraine official, as it were. These lists have their place. These criteria, which were established by the International Headache Society, are very important. They’re necessary for the conduct of epidemiologic studies and in drug efficacy studies.
But those criteria don’t encompass all of the patients who are likely to benefit from migraine treatment. They can be characterized as criteria which identify the most obvious cases. It would be a mistake for a physician to use those criteria as exclusion criteria for treatment by telling patients that “Well, you almost have migraine. If only you had one more from column B, then I would be able to treat you with this very effective migraine-specific medication.”
Unfortunately, this happens more often than we would like to think, and sometimes insurance companies don’t want to pay for medications when criteria aren’t specifically met. Therefore, we need to be very careful about how we identify migraine syndromes.
Migraine syndromes behave like migraine. They don’t necessarily have to look like migraine in the conventional way that we have seen it. The conventional way of seeing migraine is a headache that’s only on one side, that’s pounding, that may be preceded by some visual aura, and which causes a patient to get sick and need to lie down. Most migraines are not so severe and not so characteristic but will still benefit from migraine-specific treatment.
Migraine is an inherited disorder of defective ion channels in the brain. It is a syndrome of headaches with accompanying symptoms. We know that it is inherited because there are forms of migraine which have very particular clinical features which run in families, and it’s very easy to trace these forms of migraine. One example is familial hemiplegic migraine, a type of migraine in which the aura of the attack is a hemiparesis. So hemiplegia is a paralysis of one half of the body, so the arm and leg on one side of the body become temporarily useless.
That’s such a characteristic type of aura that it is easy to trace, and we can trace families. And when we have done that tracing, we discover that about half of the families have a defect in a particular calcium channel in the central nervous system, and therefore, they respond to calcium channel blockers. It is a rare syndrome, so that a person who treats a lot of migraine might meet someone with hemiplegic migraine two or three times a year.
The more typical aura symptom happens in the vision and is seen as a pattern of zigzag lines, which are bright and dark, and they start on the sides of the visual fields and spread upward and outwards, enlarging in size as they spread. The auras may last a few minutes. They can last as long as 20 or 30 minutes. And then they disappear. And after they disappear, there’s a brief period of, perhaps, minutes and then the onset of the more classic migraine headache. We call that kind of a migraine preceded by the visual aura a “classic migraine headache with aura.”
For every patient who has a migraine headache with aura, there are many more who have aura but never have headache at all. These so-called ocular migraines don’t happen in the eye at all. They happen in the occipital cortex. This is the cortex of the brain in the back, where visual information is processed. So you can imagine that there are waves of abnormal electrical activity that are proceeding very slowly, at 4 to 6 millimeters per minute, across the surface of the visual cortex in the back of the head, and those waves correspond to the bright and dark zigzag lines we see in our vision.
The auras may also take the form of sparkler-like dots or sometimes the form of a central blind spot in the vision. And those occur because of the same kind of electrical activity, which we call a “spreading depression,” on other parts of the surface of the brain. So the visual cortex isn’t the only portion of the brain that is susceptible to auras. It just happens to be the most commonly affected area.
Then probably the next most commonly affected area is an aura that traverses the speech area of the brain. And in this case, a patient, before a migraine attack, will have an inability to express themselves. They will not be able to communicate to their spouse that they are about to have a migraine. They can think the words, but they cannot form them.
These symptoms can mimic stroke, and this is the reason that patients who are having atypical aura symptoms and atypical syndromes of migraine plague emergency rooms and run up huge medical bills with scanning to eliminate the possibility that a stroke is, in fact, evolving. It is, of course, of supreme importance to identify a stroke early to be able to intervene and prevent a permanent injury. But fortunately, in the majority of cases, a patient who is known to have abnormal migraine activity can recognize that their symptoms are related to their migraine.
When a symptom is new and unfamiliar to a patient, then they should have it evaluated to make sure that there is no urgency or that the symptom is not a herald of a more serious problem. But if a pattern of dysfunction happens — if the symptoms persist, and we know that it is not a stroke because of imaging and because of repeated neurologic exams — then we need to be much more aware that there are other processes that can cause those symptoms.
Migraine auras — in addition to aphasia and visual auras, which are considered classic migraine auras — can occur in other places. If they occur in the frontal lobes, then patients can have severe mood disturbances before their migraine attack. If they occur over the sensory or motor strip, then there can be a wave of numbness going over the entire body or of paralysis moving up or down the body. There may be a spreading depression over the vestibular area, causing dizziness. And I have patients who have vestibular migraine whose primary symptoms are associated with an aura coming from the cortex that disappears, and every episode is followed by a headache, and those are the only symptoms that they ever have.
There is compelling evidence to show that you can always predict the side of a migraine attack simply by looking at an MRI scan that is able to see the increased metabolic activity within the brain. If the nucleus of the trigeminal nerve — the nerve that innervates all of the blood vessels of the brain and in the head — is lit up on the right side or the left side, then that is the side that is having the migraine attack.
We know that that increased metabolic activity and the signal associated with it is not unique, however, to just the trigeminal nerve. There are, in fact, variable patterns of hyperactivity that can occur throughout the brain stem. But if the hyperactive activity involves the nucleus of the vestibular nerve, then my inner ear may be functioning normally, but the information that comes in from that normal inner ear gets distorted when it hits the vestibular nucleus, and I can have symptoms of dizziness that can be highly variable.
These symptoms might mimic anything that happens in the inner ear, but there can be some symptoms that occur that are unique and cannot be caused by something that is generated in the inner ear itself. The two most distinctive symptoms of vestibular migraine that are pathognomonic are a rocking sensation, in which the patient feels they are rocking back and forth or swaying, as if they’re sitting in a boat or standing on a dock that is floating; and a sense of disorientation in space, a sense that they are, in a sense, standing maybe behind themselves looking out into the room as an observer. These two symptoms, when they are described by a patient with dizziness, are strong pointers to a central mechanism of symptoms, and vestibular migraine should be thought of.
If a pattern of hyperactivity involves the cochlear nucleus where sound is processed, then we may have sound intolerance. We may have tinnitus or sound distortion. In fact, hyperacusis or phonophobia are cardinal symptoms of migraine, which we look for.
The effect of the change in brainstem function in migraineurs may have a relation to the sensitivity of some migraineurs to motion. When we ask migraineurs if they ever have a memory of being sick in the back seat of the car, an overwhelming number of them say that “Yes, I remember as a child getting sick in the back seat of the car, and in fact, I still can’t drive on back roads as a passenger. I have to be the one driving, or I become ill.”
We know that the inner ear of migraineurs is exceptionally sensitive, and many of them still avoid carnival rides. The ability of the inner ear to sense tilt is heightened in migraineurs compared to normal subjects, and in patients who have vestibular migraine, it is extraordinarily heightened. We know, then, that that phenomenon may not exist as a change in the function in the inner ear; it may be a change in the function of the interpretation of the information in the brainstem.
A patient who has vestibular migraine doesn’t always have symptoms that come from the brainstem. They can have symptoms that come from the cortex, because the vestibular nerve has a cortical representation, but they can also have an inner ear disturbance. Migraine does seem to be able to present in the inner ear. It is important to recognize that a lot of migraine phenomena in the head comes from the fact that the blood vessels in the head area innervated by the trigeminal nerve. Those blood vessels have nerves. These are unmyelinated nerves, and they’re called C-fibers.
These are the fibers that have the toxic inflammatory peptides CGRP, substance P, and neuropeptide Y, which can get secreted around blood vessels during a migraine attack. It turns out that the blood vessels in the inner ear itself are innervated by trigeminal nerve fibers, which are branches of the first division of the trigeminal nerve, and that the inner ear may be an innocent bystander and become injured during a migraine attack because it is so delicate.
There were compelling studies showing that electrical stimulation of V1 in laboratory animals could cause such severe changes in the blood vessels in the inner ear that proteins were able to penetrate through the walls of blood vessels into the surrounding tissues, and that when the inner ear itself was stimulated chemically, that there were similar changes with protein extravasation through the blood vessel walls in the brainstem. So this is another example of a feedback loop in migraine that we see all of the time.
When we talk about the inner ear and migraine, it is hard to avoid mentioning a common problem of dizziness called “benign paroxysmal positional vertigo.” Benign paroxysmal positional vertigo is a kind of dizziness which happens when patients lie down and roll over in bed. A lot of people get dizzy when they sit up first thing in the morning or stand up from a chair, but not very many people have dizziness when they lie down or roll over in bed unless they have loose crystals in the inner ear. And those patients have benign paroxysmal positional vertigo.
We have found that the chance of having BPPV is much higher if you have migraine than if you don’t have migraine. This suggests that having migraine and changes in the vasculature of the inner ear may be severe enough to injure the inner ear, to the point that the tiny organ which has the crystals is injured, and these crystals can fall off and cause this other very recognizable problem. In fact, we have patients who have BPPV, and we fix it, and they do well until they have another very severe migraine attack, and their BPPV recurs in conjunction with that migraine attack. And after many repetitions of that cycle, we treat them with a preventive medication, which eliminates the migraine attacks, and their recurrences of BPPV stop.
Meniere’s disease and migraine are undoubtedly related. If we know that there are about 13% of the general population with migraine, about 56% of patients who have Meniere’s disease have migraine. That’s not likely to be a coincidence. If we have patients who have bilateral Meniere’s disease, 85% of them have migraine. What could be the connection?
We think that in some individuals, the inner ear is injured as an innocent bystander in a migraine attack so that the secretion of inflammatory peptides or other vascular changes in the inner ear may not just come and go in the inner ear but actually harm the inner ear in a way that leads to a very generalized injury, which then continues to behave as Meniere’s disease.
It is unusual that Meniere’s disease patients also complain of exacerbation of their symptoms with stress and with changes in weather, that their symptoms are exacerbated when they consume too much caffeine. And it is interesting that in laboratory studies over time, the responsiveness of the inner ear and its blood flow to certain stimulants goes down. This is what we see in inner ears which have depleted numbers of C-fibers. So in a sense, the inner ear of a patient with Meniere’s disease can burn out over time, just the way the head pain in a migraineur tends to burn out over time.
There are more and more physicians who are now aware, in their Meniere’s patients, that they should be treating migraine headache if it is present. And since it is present so much of the time, migraine treatment comes first, and a large majority of their patients improve to the point that they don’t need to move on to other treatments for their Meniere’s disease. And specifically, patients are able to avoid destructive treatments, which treat and solve the problem of recurrent vertigo episodes in Meniere’s disease by destroying the function of the inner ear with surgery or with particular chemicals.
Another example of a problem that happens during a migraine episode is a change in the autonomic nervous system that is characteristic of a migraine attack. Now, the autonomic nervous system is one which regulates the tone of our blood vessels and regulates the action of muscles in our bowel and regulates the rate of our heart.
If the balance of the constriction and dilation of the blood vessels or the tone of these smooth muscles are changed during a migraine episode, we can have lots of different symptoms. We may get dizzy when we stand up because blood will pool in the extremities. We may not digest our food well. We may have what’s called “abdominal migraine,” and there are many patients who have a primary problem with an attack of abdominal pain, diarrhea, perhaps bloating that is not associated with headache but which actually is a migraine playing out in the nervous system of the abdomen and in the bowel — and which can go treated as irritable bowel for years, but with little effect.
Every year, I have at least one of my patients ask me if they can go off of their irritable bowel medications because since we treated their vestibular migraine, their bowels are perfectly fine. And in fact, they probably had abdominal migraine all along.
Another unusual manifestation of migraine that is away from the head and neck and that relates to dysfunction in the autonomic nervous system is precordial migraine. Some patients will have a distinct dysrhythmia in the heart from overactivity or [hyperactivity?] of the vagus nerve, which innervates the heart, as a syndrome before their migraine headache occurs. These are unusual manifestations and often go unrecognized, but disappear when we take medications which are effective in preventing the migraine headaches.
We can say that migraine is very highly variable. Within a family, each person may have migraine in their own way, and in the course of a patient with migraine’s life, there is a generalized change in the presentation of symptoms so that a migraineur who is an adolescent may have classic migraine with aura, but later on in life, the headache becomes less prominent and atypical symptoms such as dizziness or abdominal symptoms may take center stage.
When you ask these patients whether they still have any headache, you often discover that they do, indeed, have mild headaches, but they are so mild compared to the severe, incapacitating head pain they had as an adolescent that they don’t believe it is migraine at all. They don’t consider it a headache at all. Others don’t have any headache at all, but they just have these secondary symptoms.
Voice-over: Teva is committed to the goal of transforming the lives of those suffering from migraine by creating solutions to reinvent the migraine paradigm by placing people at the center of everything they do. You can visit www.moretomigraine.com for tools and resources for living with migraine.
Voice-over: Thank you for tuning in to Spotlight on Migraine. For more information on migraine disease, please visit MigraineDisorders.org.
This podcast is sponsored in part by Amgen/Novartis, Teva Pharmaceuticals and Alder BioPharmaceuticals.
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