Familial Hemiplegic Migraine

Migraine is one of the leading causes of disability in the world. The condition may affect your ability to function normally for long periods due to repeated or prolonged pain attacks or headaches. About 12% of Americans suffer from migraines over their lifetime, translating to about 30 million people.

Migraines primarily affect people 35–45,¹ though children may also experience the symptoms. There are several types of migraines, including familial hemiplegic migraine. 

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What is hemiplegic migraine?

A hemiplegic migraine is a rare form of migraine with a reported prevalence of 0.01%.² It causes stroke-like symptoms, including weakness or numbness on one side, confusion, blurred vision, loss of coordination, slurred speech, and a severe headache.

The symptoms may be mistaken for those of a stroke or epilepsy. It's not uncommon for people with these headaches to visit several doctors before receiving a correct diagnosis.

Types of hemiplegic migraine

Familial hemiplegic migraine (FHM)

Familial hemiplegic migraine (FHM) is a type of migraine that runs in families. It's also known as familial episodic ataxia with aura, hemiplegic headache, or spasmodic torticollis. The condition has a prevalence of 0.003%  and can affect people of any age and sex, but it usually occurs between 20 and 50 years old. 

If misdiagnosed or left untreated, it could lead to severe complications, including permanent disability or even death due to stroke symptoms such as paralysis or speech difficulties. Notably, episodes could lead to brain damage caused by a lack of oxygen supply during attacks. 

There are three main types of familial hemiplegic migraine:

  • Familial hemiplegic migraine type 1

  • Familial hemiplegic migraine type 2a (with aura)

  • Familial hemiplegic migraine type 2b (without aura)

Each of the FHMs has its own set of symptoms and triggers. The consensus among experts is that this is an inherited disorder that causes temporary paralysis on one side of the body, weakness or numbness in the face, speech difficulties, and often a severe headache.

Sporadic hemiplegic migraine (SHM)

Sporadic hemiplegic migraine (SHM) is a rare subtype of migraine with aura. SHM affects about 0.002% of the world's population, and it's much more common in children than adults. Most cases of SHM occur in children 8–12.

The exact cause of sporadic hemiplegic migraine isn't known, but researchers³ have established people with this condition have a genetic mutation on chromosome 19 known as SCN1A.

Stages of migraine attacks

Stage 1: Prodrome

This is the first stage of the attack, which starts one or two days before the migraine. During this stage, you may notice subtle changes that warn of upcoming migraine, including: 

  • Food cravings

  • Feeling tired or sleepy

  • Nausea

  • Difficulty concentrating

  • Neck stiffness

  • Increased thirst

  • Mood changes, such as irritability.

Stage 2: Aura

The second phase involves aura symptoms that often occur just before a headache develops and may last up to an hour. Symptoms include: 

  • Visual disturbances such as blind spots or flashing lights

  • Tingling in an arm or leg that moves upward into your face

  • Numbness on one side of your face

  • Speech problems

  • Difficulty reading or doing math problems

  • Trouble understanding what others are saying due to hearing loss

Stage 3: Attack

The third stage of migraine lasts from four to 72 hours if untreated. The symptoms may strike several times a month or occur rarely. During this stage, patients may experience pain on one side of the head or both sides, sensitivity to light, smell, or touch, nausea, and vomiting.

Stage 4: Post-drome

Post-drome stage occurs after a migraine attack. During this stage, you might feel confused, drained, and exhausted for up to 24 hours. Some people may also feel elated.

Symptoms of familial hemiplegic migraine (FHM)

Migraine headache pain

The most prevalent symptom of familial migraine is pain and throbbing, affecting both sides of your head. The headache may worsen if you have sensitivity to light and sound. Severe or extreme pain may last for hours or days before subsiding, and headaches can be mild or severe.

They often occur with an aura, including visual disturbance such as flashing lights or zigzag lines (called scintillating scotoma).

Weakness or numbness (paresthesia) 

If you experience weakness or numbness in your arm, leg, face, or another body part, it could signify familial hemiplegic migraine (FHM). The symptoms may vary from person to person. Some people with FHM feel their arms and legs cramping up, while others have difficulty controlling their muscles.

Paresthesia—a tingling sensation or pins and needles—may also occur on one or both sides of the body. You should see your doctor if you notice any of these symptoms:

  • Feelings of tingling or pins and needles in your arms or legs

  • Loss of sensation in parts of your body (numbness)

  • Weakness that begins gradually

Inability to feel and control limbs properly (ataxia)

Ataxia is the inability to feel and control limbs properly. It's usually accompanied by a loss of balance, making it difficult to walk or stand up without assistance. This symptom lasts for hours in many and can cause them to fall over if they try to move around on their own. Symptoms of ataxia include:

  • Loss of balance

  • Inability to walk properly

Weakness on one side of your body (hemiplegia)

Hemiplegia is typically on one side of the body but can also be on both sides. The weakness may only last for a few hours or a few days. It can affect the face, arms, and legs, so you may notice that your face droops to one side or you cannot raise one arm above your head. You may also have problems speaking because of weakness in parts of your face, such as around your mouth or tongue.

The symptoms occur after an attack begins and usually last until the migraine headache has stopped.

Loss of consciousness or partial loss of consciousness (stupor)

A stupor is a state of near-unconsciousness or lack of awareness caused by injury, illness, substance use, or other factors. Stupor is also a symptom of several diseases, including:

  • Brain injury

  • Stroke

  • Brain tumor

Changes in alertness

One of the first signs of FHM is trouble following instructions or understanding what others are saying. If a person with FHM has a migraine attack and is confused, sleepy, or inattentive, it may be challenging to communicate with others. Changes in alertness may show through:

  • General confusion

  • Difficulty paying attention

  • Difficult communicating with others

Causes of familial hemiplegic migraine

Familial hemiplegic migraine is a genetic neurological condition. It's passed down in families, and you can inherit it from your parents or grandparents. However, not all forms of migraine are genetic: Only FHM is.

Familial hemiplegic migraine is rare, with fewer than 1% of migraine patients having a genetic predisposition for this condition. 

The good news? You don't have to worry about passing it on to your children unless they also inherit the gene that makes them susceptible to FHM, but this would be unusual.

Parents can pass it on even if they don't have signs themselves. This is because they may have a genetic mutation that predisposes them to FHM but with no symptoms yet—meaning their children could be affected by it even though they don't show any signs.

Familial hemiplegic migraine tends to run in families; many people who have it can trace it back at least two generations in their family tree. Your risk depends on how many people in your family were diagnosed with this condition before you. Research shows the risk of migraines rises to 75% if both parents have it.

One parent must have an alteration (mutation)

One parent must have an alteration (mutation) in one of three genes that may be related to familial hemiplegic migraine: CACNA1A, SCN1A, or ATP1A2. The mutation must be on a dominant allele for a child to inherit familial hemiplegic migraine from their parents. 

Triggers of familial hemiplegic migraine


Stress is a trigger for many people who suffer from familial hemiplegic migraines. Stress could be anything from physical stress (exercise, sleep deprivation) to emotional stress (relationship issues, financial problems). Accepting and dealing with stress appropriately is crucial for symptom management. 

Sleep loss

Sleep deprivation is another common trigger for migraines. Research⁴ has shown that people who suffer from migraine headaches have less deep sleep than those without migraines, and some experts have suggested that this lack of deep sleep may be what causes migraine attacks. You must get at least seven hours of sleep per day.  

Hormonal fluctuations (menstrual cycle, pregnancy)

Hormonal fluctuations⁵ is one of the most common triggers of familial hemiplegic migraines. Moreover, they can cause other triggers, such as stress and lack of sleep.

If you're trying to control your familial hemiplegic migraines, you should take steps to minimize the impact hormonal changes have on your migraines.

Weather changes

It's not the actual change in temperature, barometric pressure, and humidity that cause the migraine, but rather your body's reaction to this change in environment. Weather changes can be due to seasonal changes, or they can happen on a random day during any time of year. 

Temperature changes are most likely to cause a hemiplegic migraine, although humidity and barometric pressure also play a role in triggering them as well.

Alcohol or skipping meals

Some foods can increase the likelihood of a familial hemiplegic migraine. These include those with high nitrates, such as cured and deli meats or hot dogs. Other foods that may trigger a familial hemiplegic migraine are caffeine-containing items like chocolate, caffeinated beverages, and coffee. 

Alcohol is also a trigger for some people, and you should avoid it when you have a headache.


Familial hemiplegic migraine is diagnosed by ruling out other causes. The doctor will ask about your family history and symptoms, including when they occur and if any triggers could be causing the attacks. They may also ask about your medications and how long you've been taking them.

If FHM seems likely, your doctor will conduct tests to confirm it, such as an electroencephalogram (EEG) or magnetic resonance imaging (MRI). If these tests do not reveal anything conclusive, your doctor may refer you to a neurologist for further testing.

Importance of proper diagnosis

Proper diagnosis of familial hemiplegic migraine is crucial to rule out other issues. Most symptoms of FHM can be confused with symptoms of stroke because of paralysis. The difference is that familial hemiplegic migraine is temporary and usually affects one side of the body. In contrast, stroke occurs when blood flow to part of the brain is blocked by a clot or ruptured artery, causing permanent damage. Familial hemiplegic migraine symptoms similar to those of a stroke include:

  • Slurred speech

  • Weakness on one side of your face and body

  • Loss or double vision


There is no cure for FHM. The only way to manage the condition is to treat any symptoms and triggers and keep a migraine diary. 


There is preventive and abortive medication: You take preventative medications daily to reduce the frequency and severity of migraine attacks. In contrast, you take abortive medicines at the start of a migraine attack to stop it from progressing.

Abortive medication for acute attacks

Abortive medications include triptans like Imitrex (sumatriptan), which can be effective in up to 76% of people⁶ with hemiplegic migraines, and ergots such as Zomig (zolmitriptan). 

Ergots work best if you take them as soon as your first symptoms appear. If you take them later, they may not be effective because they don't reach their peak level in your bloodstream until one hour after ingestion. They can still ease some associated nausea or vomiting by reducing inflammation around blood vessels in your brainstem.     

Medication, such as beta-blockers,⁷ may also be preferred to reduce the frequency and severity of attacks. However, some people using the drugs experience side effects such as fatigue or dizziness. Talk with your doctor about possible drug interactions before taking any medication.

Other forms of medication and treatment 

Other forms of treatment include:

  • Botox injections for reducing spasms on one side of the face during an episode

  • Certain antidepressants called tricyclics

  • Anticonvulsants like Topamax (topiramate)

  • Anti-nausea drugs such as Zofran (ondansetron)

  • Magnesium supplements and oxygen therapy during an attack may work

  • Acupuncture (although there is no scientific evidence for its effectiveness)

  • Physiotherapy exercises, such as massaging your neck muscles

  • You can also use cognitive behavior therapy⁸ sessions where you learn how to change negative thoughts and behaviors associated with having hemiplegic migraines. 

Preventive measures

Preventative measures include:

  • Managing stressors like insomnia or hormonal changes.

  • Don’t smoke cigarettes or drink alcohol or caffeine excessively.

  • You should also ensure you get plenty of sleep each night (at least seven hours) so your body has time to recover. 

  • It's also advisable not to eat anything too rich in fat before bedtime. This helps prevent gassiness when sleeping. Gas can make migraines worse.

Diet for people affected with FHM

Diet can be a powerful tool for managing your migraine symptoms. While it won't work for everyone, it may provide some relief for those who experience migraines triggered by certain foods or beverages. 

Diet is a preventative measure. Eating healthy food low in fat and sugar will help you maintain a healthy weight, which can also assist in preventing migraines.

Foods to eat

For the digestive system to function properly, you must eat low-fat, high-fiber foods, and rich in magnesium and calcium.

Include fresh fruits, vegetables, whole grains, legumes, lean protein such as chicken or fish, and low-fat dairy products in your diet if you have FHM. In moderation, include healthy fats such as olive oil or nuts while avoiding saturated fats like butter or lard.

Foods to avoid

You will want to avoid foods with MSG (monosodium glutamate), nitrates, and nitrites. Many people with FHM are sensitive to aspartame and artificial sweeteners, so it's essential to read labels carefully if you consume these products. Avoid processed foods, caffeine, and alcohol, as they can be triggers.

Risk factors for FHM

Family history

Mutations in a single gene called ATP1A2 cause FHM. This mutation prevents sodium channels from working properly at nerve endings (called axons) inside the body's cells. Some people with FHM have inherited one copy of their mutated gene from each parent; these people have autosomal dominant inheritance or ADHA. 

If you inherit this gene mutation directly from your parents, you'll likely develop FHM.


You are more likely to develop familial hemiplegic migraine if you are female than male. Women are two to three times more likely than men to have this condition. It's also not clear why there is a higher risk for women.

Silence of genes

Your body can turn genes on and off in a process called transcription, resulting in the formation of proteins. Your body silences some genes to prevent protein overproduction and reduce the risk of cancer. The silencing of genes can be done by a variety of mechanisms:

  • Covalent modification (e.g., methylation)

  • Formation of repressive complexes (e.g., heterochromatin)

  • Methylation or histone acetylation

A single genetic mutation in the ATP1A2 gene

A single genetic mutation in the ATP1A2 gene causes a form of familial hemiplegic migraine, which accounts for some cases of FHM.

The ATP1A2 gene produces an enzyme called P/Q-type calcium channel subunit α2 that generates electrical signals within neurons (brain cells). Mutations in this gene disrupt normal calcium signaling and create an imbalance between excitatory and inhibitory neurotransmission. This imbalance leads to spontaneous neuronal firing, which may be responsible for some symptoms associated with FHM 2.

Several potential mutations can occur within this gene, as with other forms of familial hemiplegic migraine. However, research has only found one type that specifically causes FHM 2. 

When should I see a doctor?

When your migraine begins, you must see a doctor because it may be something other than FHM, such as a stroke or transient ischemic attack (TIA). You should see a doctor immediately if you notice any of the above-mentioned symptoms. 

The doctor will rule out any other illness that presents the same symptoms and can focus on managing the familial hemiplegic migraine. 

The lowdown

There's a lot to figure out when dealing with familial hemiplegic migraines. With the correct diagnosis and medications, you can manage it. It also rules out other conditions that may present similar symptoms.

There isn't any real evidence showing that the condition can be fatal, but it's better to have the symptoms well controlled. It isn't all about medication, though. You also need to ensure you eat right and avoid some of the major triggers of the condition. 

Understanding the symptoms of FHM and working with a doctor will ensure you manage the condition.

FAQs: Familial hemiplegic migraine

How can I stop FHM?

Since a genetic mutation causes familial hemiplegic migraines, they can't be stopped or prevented. However, treatment is available to help you manage the symptoms.

How long does It take to recover from FHM?

If you have familial hemiplegic migraine, your symptoms may worsen if you move around during an attack. You should rest quietly and wait for the episode to end. You can return to normal activities once the attack is over, usually taking 1 to 72 hours without treatment.

Can this migraine lead to a stroke?

As much as familial hemiplegic migraine can present symptoms similar to a stroke, it doesn't lead to stroke.

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