What is Hemiplegic Migraine?
Hemiplegic migraine is a rare type of migraine that includes a ‘migraine aura.’ This ‘aura’ manifests as a temporary motor weakness during a migraine attack. Usually, the ‘aura’ in migraines is represented by visual problems. However, sometimes, the person may experience difficulty with sensation or speech. In a hemiplegic migraine, the ‘aura’ is motor weakness.
This type of migraine may be genetic, often passed down in families, called Familial Hemiplegic Migraine (FHM), or it could randomly develop in a person, referred to as Sporadic Hemiplegic Migraine (SHM).
FHM is a type of hemiplegic migraine that is inherited, meaning it runs in the family. To classify someone under FHM, they need to have at least one close relative who has experienced hemiplegic migraines. There are four different types of FHM (FHM1-4) that are categorized based on their specific genetic mutations:
- FHM1 is caused by a mutation in a specific gene and represents about 50% of FHM cases. It’s often related to cerebellar degeneration, a gradual deterioration of nerve cells in the brain.
- FHM2, accounting for less than 25% of FHM cases, is caused by a mutation in a different gene.
- FHM 3 is linked to a mutation in yet another particular gene.
- FHM4 is a designation when no known genetic mutation linked to FHM can be identified.
Individuals diagnosed with SHM do not have any family history of hemiplegic migraines. They may or may not have a family history of migraines with auras.
The unique feature of a hemiplegic migraine is the one-sided weakness that happens during some of the attacks. However, the ‘aura’ isn’t limited only to this weakness. Other symptoms like vision problems, tingling, numbness, uncoordinated movements, fever, or tiredness can also occur. Usually, the motor symptoms start in the hand and gradually spread to the arm and face. The weakness may switch sides during or between attacks. In rare instances, people may experience weakness on both sides.
The symptoms usually develop over 20 to 30 minutes, and in some cases, they may occur suddenly, mimicking a stroke. These symptoms can last a few hours to days and, in rare cases, even up to 4 weeks. In most cases, the symptoms completely go away. Headaches, which are a common feature of migraines, usually happen during or after the ‘aura.’ Severe hemiplegic migraines can result in brain dysfunction or a coma. Symptoms like hemiplegia (paralysis of one side of the body) and impaired consciousness can last for days to months before completely resolving. In some rare cases, these severe attacks may cause permanent brain damage, brain shrinkage, stroke, cognitive decline, and even death.
Seizures, separate from the hemiplegic migraines, have been noted in some patients with FHM, most commonly in those diagnosed with FHM2.
Migraine attacks typically begin in early life, usually during the first two decades. The frequency of these attacks tends to decrease with age.
What Causes Hemiplegic Migraine?
Hemiplegic migraines, a type of severe headache that can cause temporary paralysis on one side of the body, can be brought on by different things. This can include high-stress situations, not getting enough sleep, sleeping too much, emotional upset, physical exertion, and head injuries. Some studies have even suggested that a medical procedure known as conventional angiography, which is used to look at blood vessels, could trigger a hemiplegic migraine.
Risk Factors and Frequency for Hemiplegic Migraine
Migraines are common, affecting 15 to 20% of the population. However, hemiplegic migraine, a specific type of migraine, is quite rare; only about 0.01% of people have it. A study from Denmark showed that sporadic hemiplegic migraine affects 0.002% of people, while familial hemiplegic migraine affects 0.003%.
- The typical age for the first occurrence of a migraine is between 12 and 17 years old.
- Women are more likely to suffer from migraines than men, with the ratio ranging from 2.5 women for every man to 4.3 women for every man.
Signs and Symptoms of Hemiplegic Migraine
Hemiplegic migraines are characterized by repeated episodes of one-sided bodily weakness accompanying other migraines symptoms. Diagnosing the condition can be tricky and involves ruling out other potential causes of headaches and neurological issues. A thorough medical history that includes symptoms, potential triggers, family history, and other associated symptoms is critical.
Patients can experience around three attacks per year, but in some instances, these can increase to up to 250. Migraines could occur naturally or be triggered by factors like stress, exertion, emotional extremes, changes in sleep, exposure to bright light, and minor head injury.
During a migraine episode, a neurological exam could indicate unilateral hyperreflexia and positive Babinski sign. Motor and sensory symptoms generally impact the upper body more than the lower body. Between attacks, examination results typically return to normal. Some patients might exhibit signs of cerebellar issues, such as unsteady movements, speech difficulties, and abnormal eye movements.
In most cases, two or more auras appear and evolve over 20 to 30 minutes before resolving over several hours. These usually manifest in the following order:
- Visual symptoms
- Sensory symptoms
- Motor symptoms
- Language disruptions
- Brainstem symptoms
Motor symptoms often start in the hand before spreading to the arms and face. The one-sided symptoms may switch between right and left during or between attacks, while some patients might experience bilateral symptoms. Motor weakness can range from mild to severe and in rare cases, reversible paralysis can last up to four weeks.
Headache intensity varies and can occur on one or both sides of the head independently of the aura symptoms’ side. They might occur before or during the visual symptoms.
More severe migraine episodes may feature certain specific symptoms, which can include:
- Delusions
- Sleepiness
- Brain swelling
- Seizures
- Fever
- Meningismus (neck stiffness and headache)
- Increased white cells in cerebrospinal fluid
- Confusion
- Agitation
- Brain injury due to lack of blood supply
Testing for Hemiplegic Migraine
If you have sudden, intense headaches, your doctor might need to do some tests to make sure there isn’t a different cause for the problem, especially if this is a new headache pattern for you, the symptoms last a long time, and you don’t have a family history of similar headaches. These might include scans of your brain, a study of the fluid that surrounds your brain and spinal cord, and a test that measures the electrical activity in your brain.
Brain scans, like a CT or MRI, are generally normal during a headache attack. However, in a very small number of cases, they might show swelling or increased blood flow in certain parts of the brain. If done during the headache attack, a specialized type of MRI might show certain veins in the brain becoming more prominent.
In one type of severe headache known as familial hemiplegic migraine (FHM1), brain scans can sometimes show shrinkage in certain parts of the brain. More broadly, brain scans can sometimes show brain shrinkage and evidence of dead brain tissue in severe cases of migraines that cause weakness on one side of the body.
An electroencephalogram (EEG), which measures the electrical activity in your brain, might be done if your doctor suspects you’re having seizures rather than headaches. Lastly, your doctor might want to study the fluid that surrounds your brain and spinal cord, which can sometimes show an increased number of cells in a few cases.
Genetic testing isn’t recommended for everyone. It might be useful if your severe headaches started at a young age, you have unusual neurological symptoms along with the headaches, and your headaches are different in severity and symptoms from other relatives who also have severe headaches.
According to the International Classification of Headache Disorders, a diagnosis of hemiplegic migraine (a type of severe headache that comes with reversible muscle weakness on one side of the body) requires at least two attacks that follow a specific pattern, listed as follows:
The attacks must involve:
- Fully recoverable muscle weakness
- Fully recoverable changes in vision, sensation, and/or speech/language
In addition, at least three of the below must also occur:
- At least one headache symptom that slowly increases over more than 5 minutes
- Two or more symptoms in a row
- At least one symptom on one side of the body
- At least one sensation felt in the body
- Each headache symptom lasts between 5 and 60 minutes
- A headache that starts within 60 minutes of when the other symptoms start
The diagnosis also requires that there isn’t a better explanation for the symptoms according to the International Classification of Headache Disorders.
Treatment Options for Hemiplegic Migraine
The symptoms of a hemiplegic migraine can be distressing and frightening. It’s crucial to diagnose it accurately and begin the appropriate treatment to control and prevent future episodes. Treatment usually involves medication to stop an attack once it has started, referred to as ‘abortive’ medication, and preventative medication to reduce the frequency and severity of future attacks. In severe cases, hospitalization and additional support may be needed.
Having a hemiplegic migraine means you might take the same abortive and preventive medications that are used for a regular migraine with aura, but you should avoid certain medications that could potentially worsen blood flow issues in the brain. To treat the acute episodes, over-the-counter painkillers (NSAIDs) and anti-nausea medications (antiemetics) are usually used. Some studies have shown that a drug called intranasal ketamine, administered at the start of an attack, can be beneficial for those with a genetic form of hemiplegic migraine.
Although the use of another group of migraine medication – triptans – is debated, some patients still find them effective. For those looking for preventative measures, medications such as verapamil, flunarizine, lamotrigine, naloxone, and acetazolamide are recommended. It’s advised to start with verapamil, flunarizine, or acetazolamide, and if these do not produce satisfactory results, then lamotrigine could be tried. This is particularly true for patients who experience more aura symptoms than a headache.
There are also other prevention medications, like amitriptyline, topiramate, and valproic acid, which can be used. There is some caution against using migraine treatments like triptans or ergotamines and beta-blockers due to their potential risk of causing constriction of the blood vessels in the brain. In one case, a child with severe symptoms of hemiplegic migraine found relief from taking methylprednisone.
Lastly, each person may have their own set of triggers – actions, food, environment, stress, etc. – that can initiate a hemiplegic migraine headache, so it’s beneficial if they are identified and avoided if possible.
What else can Hemiplegic Migraine be?
Hemiplegic migraines can often seem similar to various other brain conditions that result in headaches and motor difficulties. Here are some of these conditions:
- TIA (Transient Ischemic Attack): While both these conditions can be temporarily reversed, a TIA develops more suddenly, and it’s less likely to involve aura symptoms like queasiness, throwing up, and sensitivity to light.
- Infections like meningitis, encephalitis, and brain abscess might also cause a headache and motor symptoms, but these can be differentiated through other symptoms like a rash, fever, brain scan and examination of spinal fluid.
- Brain tumors can often cause gradually worsening neurological symptoms with visible findings on a brain scan.
- Seizures that come with post-seizure paralysis can be set apart by symptoms like limb shaking at the start and confusion after the seizure.
Some inherited disorders can also cause a headache and signs of brain deficits. Disorders like MELAS (mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes), hereditary hemorrhagic telangiectasia, and CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) can be distinguished by their clinical features, neuroimaging, and genetics.
Rare metabolic disturbances like homocystinuria and ornithine transcarbamylase deficiency can occasionally present with headache and symptoms similar to a stroke. Conditions like the syndrome of stroke-like migraine attacks after radiation therapy (SMART) is set apart by a history of brain radiation treatment and specific imaging findings.
A disorder named alternating hemiplegia of childhood, caused by changes in the ATP1A3 gene, can also be distinguished from a migraine by additional signs like cognitive impairment, rigid, jerky movement, nystagmus, epilepsy, and a loss of coordination and balance.
Another possible condition that might present with headaches and stroke-like events with temporary half-paralysis is the Sturge-Weber syndrome.
What to expect with Hemiplegic Migraine
In most people with hemiplegic migraine, symptoms typically go away, though they can last for a while. In rare cases, hemiplegic migraines can lead to permanent brain damage, mental decline, or even death. Worse outcomes are often linked to getting this type of migraine at a young age, having very severe attacks, recurrent comas, or seizures.
As people get older, the frequency of attacks usually decreases after the age of 50. The attacks then evolve into more typical migraines without any physical symptoms. It’s important to note that having migraines with aura, a type of migraine that comes with warning signs like flashing lights, can increase a person’s risk of having a stroke. This risk also applies to people with hemiplegic migraines.
Also, people with this type of migraine can experience acute ischemic strokes, which occur when blood flow to the brain is blocked due to factors like plaque build-up in the arteries. Therefore, it’s important for such individuals to consider immediate interventions to treat strokes and strategies to reduce the risk of vascular diseases.
Possible Complications When Diagnosed with Hemiplegic Migraine
‘Status Migrainosus’ is a severe kind of migraine attack that lasts for more than 72 hours. It causes extreme pain that might require the patient to be hospitalized.
Then there are ‘Migrainous Infarctions’ or strokes. People with migraines and visible warning signs (also known as auras) are more likely to have a stroke. This type of stroke occurs when the warning signs last for more than an hour and the brain imaging shows signs of a stroke.
‘Persistent Aura without Infarction’ is a condition where the warning signs continue for more than a week after the migraine headache has ended. It has similar symptoms to a stroke caused by a migraine, but brain imaging does not show any signs of a stroke.
‘Migraine-aura Triggered Seizure’ is a seizure that occurs due to a migraine attack with warning signs. The seizure typically happens within an hour after the migraine attack.
Furthermore, certain mental health issues, such as major depressive disorder, bipolar disorder, or posttraumatic stress disorder, are more common in people with migraine headaches.
Rare but serious complications can include:
- Permanent neurological damage
- Decrease in mental abilities
- Death
Preventing Hemiplegic Migraine
It’s important to quickly identify and manage migraine headaches because they can sometimes be extremely painful and interfere with how you live your life. People with migraines should understand that these headaches generally go through several stages and learn about the advantages of different treatments to stop the headaches when they start (abortive therapy) and prevent them from happening (prevention therapy).
Changes in your day-to-day life can also reduce how often these headaches occur and how bad they are when they do occur. If your symptoms get worse or you start to experience new symptoms related to your nerves or brain, you should see a doctor promptly, as you might need a type of scan (neuroimaging) to find out what’s causing these changes.
