A hemiplegic migraine is a rare form of migraine often confused with a stroke. In this type of migraine, a person may develop neurological symptoms, including weakness on one side of the body.

Hemiplegic migraines come in two categories: familial hemiplegic migraine (FHM) and sporadic hemiplegic migraine (SHM).

This article explores the symptoms, causes, and treatments for both types of hemiplegic migraine (HM).

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Both types of HM can have genetic links, but someone with SHM may be the first person to be diagnosed in their family.

The two distinct types of hemiplegic migraine have slightly different causes, symptoms, and risk factors.

Familial hemiplegic migraine

This form of HM occurs in families in which there may be a genetic abnormality or mutation that affect certain genes in the brain.

These genes affect the communication between parts of the brain called neurons and chemical neurotransmitters.

When a person is affected by FHM due to a genetic abnormality, there is a 50 percent chance that their children will also be affected.

Typically, FHM symptoms are noticed first during childhood and adolescence and decrease with age.

Sporadic hemiplegic migraine

Often, those affected by SHM do not have a family history of hemiplegic migraines. However, they may still be affected by a genetic abnormality. This is also true for those with FHM.

Someone with SHM may be the first person in a family to be diagnosed. However, this does not rule out the possibility that they have a parent with the abnormal gene who has never experienced SHM symptoms.

Although the symptoms of HM vary from person to person, they may include:

  • migraine
  • unilateral body weakness in the face, arms, or legs
  • visual disturbances such as blind spots, light flashes, zigzag, or double vision
  • numbness or tingling of the face or in an extremity, such as an arm or a leg
  • speech difficulty
  • headache
  • symptoms similar to meningitis or inflammation associated with it
  • motor weakness
  • clumsiness or lack of coordination
  • confusion
  • drowsiness
  • change in consciousness
  • memory loss
  • nausea and vomiting
  • sensitivity to light or sound
  • psychosis

Some people are affected more severely. If this is the case, symptoms can include:

In extremely severe, but rare cases, HM can be fatal. However, it is normally very treatable.

Short term vs. long term symptoms

Most of those suffering from HM will experience neurological symptoms, ranging from 1 hour to several days. However, there are some people who have symptoms of memory loss and attention difficulties that persist for weeks or months.

The symptoms associated with HM are normally temporary, but in rare cases there may be permanent effects, including:

  • coordination difficulties
  • sensory changes
  • language changes
  • involuntary eye movements

Both types of HM can be caused by genetic abnormalities. For FHM, certain foods, stress, or a minor head trauma may also be a trigger.

As many as 12-60 percent of those who have migraines report certain food are a trigger. Foods that often cause a problem include:

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Some people find that wine, cheese, or chocolate trigger a hemiplegic migraine.
  • alcohol
  • cheese
  • chocolate

Alcohol is thought to contribute to migraines for the following reasons:

  • increased risk of dehydration
  • more blood going to the head
  • potential for preservative sulfites

Alcohol triggers vary, but migraines are commonly reported after consuming:

  • red wine
  • beer
  • champagne
  • whiskey

Due to the high levels of the chemical tyramine, certain cheeses and other foods have been reported to trigger migraine. Foods with high levels of tyramine include:

  • aged cheeses, such as gouda or parmesan
  • processed meats
  • olives
  • pickles
  • chocolate
  • nuts

The caffeine content in chocolate may also contribute to headaches. Similarly, stress and hormonal changes inducing chocolate cravings may be factors.

The presence of abnormal chemical and electrical brain signals are additional possibilities. These affect how the brain processes chemicals known as neurotransmitters.

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A person will have had at least two HM attacks before they are diagnosed with the condition.

In order to diagnose the presence of HM, a doctor will look at symptoms in addition to examining someone. They will also look at family history.

The Genetic and Rare Diseases Information Center explains the criteria for diagnosis as having at least two HM attacks.

An HM attack has a two-part definition. Firstly, to be considered an HM attack, a person must be experiencing a migraine. This will be accompanied by temporary symptoms affecting motor weakness, vision, senses, and speech.

In addition, a person will have at least two of these four characteristics:

  • at least one neurological symptom that spreads gradually over 5 minutes or more
  • two or more symptoms that occur in succession
  • each individual non-motor symptom lasts 5 to 60 minutes, and motor symptoms lasts up to 72 hours
  • at least one symptom on one side only
  • the visual, sensory or motor symptom accompanied or followed by a headache within 1 hour

For a correct HM diagnosis, all other potential reasons for the symptoms must be ruled out. Other potential causes include something called a transient ischemic attack or TIA, and a stroke.

The goal of treatment of HM is prevention and symptom management. It will include the use of medications, such as:

Due to the risk of stroke, certain medications are not recommended for people with HM. These include drugs that constrict blood vessels, such as triptans and ergotamines.

To help doctors, it is recommended that people who are affected by HM wear a medical ID bracelet, due to the risk of impaired speech and consciousness during an attack.