Hemiplegic migraine is a rare type of migraine headache. Like other migraines, hemiplegic migraine causes intense and throbbing pain, nausea, and sensitivity to light and sound. It also causes temporary weakness, numbness and tingling, and paralysis on one side of the body. These symptoms start before the headache. “Hemiplegia” means paralysis.

Hemiplegic migraine affects a small number of people who get migraine with aura. Aura includes visual symptoms, like flashes of light and zigzag patterns that happen before or during a migraine. Aura also includes other sensory problems and trouble speaking. In people with hemiplegic migraine, the weakness or paralysis happens as part of the aura.

There are two types of hemiplegic migraine. Which type you have is based on your family history of migraines:

  • Familial hemiplegic migraine (FHM) affects at least two close relatives in the same family. If you have FHM, each of your children will have a 50 percent chance of inheriting the condition.
  • Sporadic hemiplegic migraine (SHM) affects people who don’t have any family history of the condition.

A hemiplegic migraine causes symptoms like confusion and trouble speaking, which are similar to those of a stroke. Seeing a neurologist or headache specialist for tests can help you get the right diagnosis and treatment.

Many of the same drugs used to treat regular migraines also work for hemiplegic migraines. A few medications may prevent these headaches before they start:

  • High blood pressure medications may reduce the number of migraines you get and make these headaches less severe.
  • Anti-seizure drugs might also help with this type of headache.

Drugs called triptans are one of the main treatments for regular migraines. However, they’re not recommended for people with hemiplegic migraines. They could make hemiplegic migraine symptoms worse, or cause permanent damage. Triptans include sumatriptan (Imitrex), zolmitriptan (Zomig), and rizatriptan (Maxalt).

Hemiplegic migraine is caused by changes (mutations) to genes. A few genes have been linked to hemiplegic migraine, including:

  • ATP1A2
  • PRRT2
  • SCN1A

Genes carry the instructions for making proteins that help nerve cells communicate. Mutations in these genes affect the release of brain chemicals called neurotransmitters. When the genes are mutated, communication between certain nerve cells is interrupted. This can lead to severe headaches and vision disturbances.

In FHM, the gene changes run in families. In SHM, the gene changes happen spontaneously.

Triggers of hemiplegic migraine

Common triggers of hemiplegic migraines include:

  • stress
  • bright lights
  • intense emotions
  • too little or too much sleep

Other migraine triggers include:

  • foods like processed foods, aged cheeses, salty foods, and the additive MSG
  • alcohol and caffeine
  • skipping meals
  • weather changes

Symptoms of hemiplegic migraine can include:

  • weakness on one side of your body — including your face, arm, and leg
  • numbness or tingling in the affected side of your face or limb
  • flashes of light, double vision, or other vision disturbances (aura)
  • trouble speaking or slurred speech
  • drowsiness
  • dizziness
  • loss of coordination

Rarely, people with hemiplegic migraines have more serious symptoms, such as the following:

  • confusion
  • loss of control over movement
  • decreased consciousness
  • memory loss
  • coma

The symptoms can last from a few hours to a few days. Memory loss can sometimes continue for months.

Doctors diagnose hemiplegic migraine based on its symptoms. You’ll be diagnosed with this type of headache if you’ve had at least two attacks of migraine with aura, weakness, and vision, speech, or language symptoms. These symptoms should go away after your headache improves.

Hemiplegic migraine can be hard to tell apart from other conditions, like stroke or mini-stroke (also called transient ischemic attack). Its symptoms can also be similar to diseases like multiple sclerosis or epilepsy.

To rule out conditions with similar symptoms, your doctor will do tests like these:

  • A CT scanuses X-rays to make pictures inside your body.
  • An MRI uses strong magnets and radio waves to make pictures inside your body.
  • An electroencephalogrammeasures the electrical activity in your brain.
  • An echocardiogramuses sound waves to create pictures of your heart.

If you have one or more family members with this type of migraine, you might want to have genetic testing. However, most people with FHA will not test positive. Researchers have not yet found all the genes linked to this condition.

Attacks of hemiplegic migraines often start in childhood or young adulthood. You’re more likely to have this type of headache if it runs in your family. If one of your parents has hemiplegic migraine, you have a 50 percent chance of also getting these headaches.

You may not be able to prevent hemiplegic headaches if they run in your family. However, you can take medicine to cut down on the number of headaches you get.

Another way to prevent these migraines is to avoid any factors that trigger your headaches.

Some people stop getting migraines as they get older. In other people, the condition doesn’t go away.

Having migraines with aura can double your risk for some types of stroke — especially in women. The risk increases even more if you smoke (men and women) or take birth control pills (women). However, the risk of stroke in general is still pretty low.