Vertigo, which is an illusion of movement in relation to the environment, is commonly experienced as part of a migraine headache.
Migraine is a disease characterized by periodic headaches, but patients often experience other symptoms, including dizziness. In some patients, dizziness can be the only symptom. The dizziness associated with migraines is called vertigo.
Vertigo is basically a sensation of a room spinning around you, while at rest. Nausea and sometimes vomiting is always associated with vertigo.
Motion sickness is a common migraine accompaniment as well. Most studies report about 50% of patients with migraines have motion sickness. Patients with migraine-associated vertigo often provide a long history of motion intolerance during car, boat, or air travel or all three. People with migraines are, in general, more sensitive to motion of the environment and to busy environments.
The symptoms of migraine-associated vertigo are variable and may feel like a room spinning at rest (true vertigo), a constant feeling of imbalance, and/or dizziness associated primarily when moving and not at rest. Symptoms directly associated with a migraine headache can occur prior to the onset of headache or during a headache.
Vertigo Without Headaches
It is also quite common to experience vertigo during a headache-free interval. As such, many patients who experience migraine-associated vertigo will experience dizziness as the main symptom even in the absence of a headache! In fact, most patients with migraine-associated vertigo have dizziness that occurs independently of the headache.
This last condition of someone experiencing vertigo without any headache confuses doctors and patients alike. It is far more common than thought and most of the time is a missed diagnosis and thereby a missed opportunity for treatment.
Prevalence of Migraine-Associated Vertigo
Reports indicate that 27-42% of all migraine patients report episodic vertigo. What is interesting is that about a third (about 36%) of these patients experienced vertigo during headache-free periods. The remainder experienced vertigo either just before or during the headache. The incidence of vertigo during the headache period was higher in patients with aura as opposed to those without aura.
Duration:
The vertigo symptoms may last for a few minutes or may be continuous for several weeks or even for months! In women, there is a strong association of dizziness occurring within the menstrual cycle.
The duration of the vertigo can also be quite variable. The frequencies of different durations of vertigo spells in migraine-associated vertigo are as follows:
o 7% experience vertigo for a duration of seconds.
o 31% experience vertigo for minutes to up to 2 hours.
o 5% have vertigo for 2-6 hours.
o 8% have vertigo for 6-24 hours.
o 49% experience vertigo for longer than 24 hours.
What Causes the Vertigo Associated with Migraines?
The most commonly accepted theory regarding the pathophysiology of migraine-associated vertigo is the Cortical Spreading Depression theory (CSD). Multiple authors propose that episodes of dizziness are similar to that of a migraine aura or are actually part of the aura.
But since only about 20% of migraine sufferers actually experience an aura, researches attribute the vertigo as part of a fluctuation of nerve cell ion channels. Recent understandings in a particular type of migraine – Familial Hemiplegic Migraine (FHM) have shown two genes responsible for controlling ion flow across nerve cell membranes.
These two genes affect changes in calcium, sodium and potassium channels. This alters the electrical conduction potentials of nerve cells. The result is a transient wave front that suppresses central neuronal activity. This depression spreads in all directions from its site of origin. These changes result in a reduction in cerebral blood flow in the areas of spreading depression.
Two authors have suggested that when dizziness is unrelated to headache, the dizziness occurs from the release of neuropeptides, including substance P, neurokinin A, calcitonin and gene–related peptide [CGRP]. No single hypothesis explains the headache or dizziness process in migraine at this time. Thus, the causes of the symptoms of migraine remain controversial.
Meniere’s Disease
There is another relatively common form of vertigo called Meniere’s Disease. Meniere’s Disease is not related to migraines at all. It has a classic triad of vertigo, hearing loss and tinnitus (ringing of the ears). The vertigo of Meniere’s Disease is frequently confused with migraine-associated vertigo.  Fortunately, the vertigo associated with the more common forms of migraines rarely have any hearing loss and also does not have much in the way of tinnitus.
Basilar Migraines
The is one ominous variant of migraine headaches called Basilar Migraines (or also known as Bickerstaff ‘s syndrome) which is a cross between a migraine and occasionally ends up in a stroke. Some features of Basilar Migraines include vertigo, hearing loss and tinnitus. Up to 80% of patients with Basilar Migraine have been reported to have sensorineural hearing loss.
So in the case of the Basilar Migraines, the vertigo might be indistinguishable from Meniere’s Disease during the headache-free intervals. Otherwise the presence of the headache would lend it toward the migraine component and should be treated as a migraine.
Clearly, Basilar Migraines are a more pernicious variety of migraine headache. Even though Basilar Migraines are classified as a sub-group of migraines, some believe that the stroke-like damage that is frequently associated with this group of headaches places it in a different category and should be treated very differently from the typical migraine.
Treatment
Unfortunately, the vertigo component of migraines is extremely resistant to standard treatment. The triptan class of drugs is relatively ineffective. Also, the standard anti-vertigo drugs like meclizine and phenergan also do not work well.