By Jonathan Gladstone, M.D.
FRCPC, Gladstone Headache Clinic
Since she was 13, Terri has been experiencing migraine without aura approximately 1-2 times per month. Terri, who is now 21, also gets migraine with visual aura a few times per year and, on several occasions, has experienced migraine with a sensory aura (numbness/tingling up one arm and into her face). However, over the last 18 months, she has had five more dramatic episodes in which she experienced pronounced weakness/paralysis on one side of her body (leg, arm, and face) together with sensory symptoms (numbness/tingling on the same side of the body) and/or visual symptoms (blurriness/loss of vision on one side).
The weakness can last up to 12 hours and has led to Emergency Department visits on each occasion, with co-workers, family members, and Terri herself concerned that she could be suffering a stroke. CT scans and MRIs of her brain have been normal, ruling out a stroke. She was sent for tests of her heart and the blood vessels in her neck as well tests to determine if her blood was prone to form clots. All came back normal.
Terri was eventually referred to a headache specialist. Review of her family history found that her mother and maternal grandmother had similar symptoms, particularly as teenagers and young adults. Their attacks eventually became less frequent and disappeared by menopause. The neurologist was intrigued by this family history and the significant and prolonged attacks of weakness. She wondered about a diagnosis called familial hemiplegic migraine and ordered the newly available genetic tests for this disorder. Interestingly, genetic testing confirmed that Terri did indeed have familial hemiplegic migraine. Terri’s unusual events were finally explained and she was placed on a preventive medication in an attempt to decrease the frequency and/or severity of her attacks.
About 20% of migraineurs have migraine with aura. Individuals with migraine with aura occasionally or frequently experience neurologic symptoms prior to onset and/or during their headaches. These unusual symptoms may include (1) visual disturbances (bright flickering lights, colored zigzag lines, blurriness, or loss of vision), (2) sensory disturbances (numbness and/or tingling on one side of the body which often creeps slowly from the fingertips to the face), or (3) speech difficulties (difficulty finding words, mixing up words, not making sense). Individuals may experience only one aura symptom, two symptoms may occur concurrently, or multiple aura symptoms may progress sequentially. The auras are fully reversible (i.e., symptoms disappear and aren’t permanent) and typically last anywhere from 5 to 60 minutes. Occasionally, people can experience aura symptoms without having a subsequent headache, this is known as typical migraine aura without headache.
WHAT IS HEMIPLEGIC MIGRAINE?
A rare and more dramatic subtype of migraine with aura is hemiplegic migraine. This is an unusual migraine disorder that affects only a very small segment of the population. With hemiplegic migraine, the aura consists of weakness or paralysis of one side of the body (often an arm and leg) occurring in association with any of the visual, sensory, or speech disturbances described above. The aura in hemiplegic migraine is more prolonged and can last anywhere from 5 minutes to 24 hours (see Table 1).
The symptoms of hemiplegic migraine can be dramatic and frightening, and individuals with hemiplegic migraine often see many healthcare providers in their quest to understand their condition. They may visit their primary care physicians, emergency medicine doctors, and/or neurologists. Many patients are diagnosed as having suffered a stroke or a mini-stroke (also known as a TIA or transient ischemic attack) and are placed on stroke prevention medications. Others are thought to have transient neurologic symptoms due to epilepsy or multiple sclerosis. Often patients undergo multiple tests to investigate the cause of their symptoms: CT scan or MRI of the brain, EEG (brain wave test), echocardiogram (ultrasound of the heart), and/or a holter monitor (24hr monitor of heart rhythms).
Interestingly, in the last decade, migraine researchers have discovered that many individuals with symptoms of hemiplegic migraine have other family members who are similarly affected. When hemiplegic migraine runs in families, it’s called familial hemiplegic migraine. Individuals who do not have family members with similar symptoms are diagnosed as having sporadic hemiplegic migraine.
Attacks of hemiplegic migraine can begin during childhood, adolescence, or during early adulthood. Attacks are quite uncommon in individuals older than 50. Individuals with hemiplegic migraine may have attacks frequently (once a week) or very infrequently (once a year). The attacks can occur spontaneously, may be provoked by emotional stressors or sleep deprivation, or can occur following mild head trauma.
Individuals with hemiplegic migraine do not have weakness/paralysis with every headache. On some occasions, they may simply have a regular migraine headache, while at other times the migraine may be preceded (or accompanied) by any combination of weakness, visual changes, numbness, and/or language dysfunction.
Individuals with hemiplegic migraine may develop many other unusual aura symptoms during or preceding their headache, including dizziness, loss of balance/incoordination, double vision, and slurred speech. Occasionally, more dramatic symptoms such as confusion, a decreased level of consciousness, and even coma can occur.
Notably, some patients with hemiplegic migraine have unsteadiness or imbalance that isn’t just limited to their attacks of migraine. In these individuals, incoordination/imbalance progresses slowly over time and can be a permanent symptom.
HOW IS HEMIPLEGIC MIGRAINE DIAGNOSED AND TREATED?
Many patients in the United States have been told by their healthcare providers that they might have hemiplegic migraine. Unfortunately, until now, there was no way to definitively make a diagnosis of hemiplegic migraine. However, in the past decade, genetic research into familial hemiplegic migraine has discovered three different genetic defects that can cause familial hemiplegic migraine. Starting early in 2006, genetic testing for the most common genetic changes in familial hemiplegic migraine became available in the United States. If you think you may be suffering from hemiplegic migraine, talk with your healthcare provider about whether or not genetic testing for familial hemiplegic migraine is appropriate for you.
Individuals with hemiplegic migraine are advised against using triptan medications (Amerge, Axert, Frovat, Imitrex, Maxalt, Relpax, or Zomig) since they theoretically could worsen attacks or lead to permanent deficits. This should be discussed with a healthcare provider. A medication called verapamil (a calcium-channel blocker) may be helpful in decreasing the frequency and severity of hemiplegic migraine attacks.
FAMILIAL HEMIPLEGIC MIGRAINE AND THE FUTURE
Amazingly, scientists in research laboratories in Europe have developed mice that have been genetically engineered to have hemiplegic migraine. These hemiplegic migraine mice will allow researchers to better understand how and why these unusual attacks occur. Hopefully, in the not-too-distant future, medical researchers will utilize the information learned from these mice to create more effective medications to help prevent disabling attacks in individuals with hemiplegic migraine.
Diagnostic Criteria for Familial Hemiplegic Migraine (FHM)
A. At least two attacks fulfilling criteria B and C
B. The aura consists of fully reversible motor weakness and at least one of the following:
C. At least two of the following: