Hemiplegic migraine (HM)
The severity of the weakness can differ greatly, for instance only one hand or the whole side of the body can be affected. Many patients also have other transient neurological complaints, called auras that gradually develop over time preceding headache such as:
- temporary visual changes: blind spots, flashing lights and zig-zagging lines
- temporary numbness or tingling in an arm, leg or the face
- difficulty with speech; slurred speech, trouble remembering words
- decreased consciousness
Causes of HM
In some of the HM patients, the condition is caused by a change in the hereditary material. Chromosomes are the carriers of hereditary properties and are made up of DNA (the genetic material). Genes are pieces of DNA that code for a certain hereditary trait. Each person has two copies of each gene. Parents always pass on one copy of the gene to their children. The child therefore has one copy of each gene from the father and one from the mother. A change in one of these genes (mutation) causes the functioning of the gene to be disrupted. For HM, mutations in three different genes can cause the disease: the CACNA1A gene, the ATP1A2 gene or the SCN1A gene.
Many patients with HM do not appear to have a mutation in any of these three genes. It is not fully known what causes the condition in these patients. There are indications that hereditary factors also play an important role in this. In these patients, the condition is probably caused by a combination of hereditary and environmental factors.
Symptoms of HM
Hemiplegic migraine patients mainly suffer from the intense aura symptoms that can last for a long time. Patients with FHM often have their first attack in childhood and usually have 2 to 3 attacks per year. Some patients have several attacks per month. The attack frequency usually decreases as a person gets older. Epilepsy is more common than average in families with FHM.
Sometimes the aura symptoms of HM are confused with a stroke. The aura phenomena can be distinguished from a stroke because they do not arise suddenly, but spread and follow each other within a few minutes.
The aura symptoms expand within a few minutes and often follow each other (for example, first problems with vision followed by loss of strength). It usually starts with vision problems and then the other symptoms appear. The duration of the aura symptoms differs per person and can vary from a few minutes to a few days. During or after these symptoms, the migraine headache occurs: usually a severe, throbbing and one-sided headache. The headache often gets worse with movement, so most patients feel the need to lie down in bed. Nausea and/or vomiting may also occur with the headache. Many patients have difficulty tolerating light, sound or odors during an attack.
Currently, there is no treatment to cure hemiplegic migraine. However, medications can be prescribed that may reduce the headache and accompanying symptoms. Usually this involves medication taken during an attack. As with normal aura symptoms (without hemiplegia), the aura symptoms cannot be reduced with acute treatment. Only the headache can be reduced with acute treatment.
Patients who have many or very severe attacks may benefit from daily preventive medication. With treatment we try to lower the attack frequency and reduce the severity of the attacks. The treatment is similar to that of regular migraine with aura.