Epilepsy of Infancy with Migrating Focal Seizures is one of the more recently discovered epilepsy syndromes having first been described in 1995. The reason for it’s late discovery is that it’s extremely rare and affects somewhere between 1 in 200,000 to 1 in 400,000 people.
The syndrome is believed to be due to abnormal genes, which have been found in some of the latest research and studies. These mutations affect the flow of ions through nerve cells, particularly potassium, which is what is today believed to cause this particular epilepsy syndrome. Common mutations found include KCNT1, SCN2A, GABRA1 and GABRB1, which are found in around 70% of cases of Epilepsy of Infancy with Migrating Focal Seizures.
This seizures have been known by other names in the past, including:
Most children with this syndrome will start to experience seizures within the first few months of being born. The seizures are typically focal in nature, but they may present differently from case to case. Some things to look out for include a stiffness of the body, particularly in the arms and legs, chewing movements or movement of the arms and legs that appear as though pedalling an imaginary bicycle. Some more unusual features of these symptoms may include excessive saliva, tears or a flushing of the face, which are known as autonomic features.
In the first instance, seizures will likely only happen every few days, however, they can rapidly increase in frequency until seizures are occurring multiple times in the same day. In some cases, seizures can occur as many as 100 times a day.
The seizures usually last between 30 seconds to 1 minute, but the duration may extend in older children.
Unfortunately, most babies with this syndrome will make very little development progress and can even lose the development they made before the epilepsy began.
Diagnosis is commonly made through a detailed history of seizure activity, alongside an electroencephalogram (EEG) test, which will usually confirm the diagnosis. The EEG test will likely show the different focal seizures beginning in different parts of the brain, hence the ‘migrating’ part of this syndrome’s name.
In some cases, the child may need to be admitted to a specialist for an extended EEG over the course of 2 – 4 days to make sure the seizures are captured.
Unfortunately, it’s unlikely that epilepsy medications will be 100% effective at controlling seizures. For this reason, children with Epilepsy of Infancy with Migrating Focal Seizures are always referred to a specialist neurologist. Medications typically have an effect for a short time frame before wearing off, which means they need to be reviewed regularly to maintain any level of control over seizures.
Other treatments may be considered with this syndrome, including the ketogenic diet, steroids or vagus nerve stimulation. A medication called quinidine may also be helpful in cases where the mutation is to the KCTN1 gene.
With this syndrome, seizures are rarely under control for more than a few days at a time, which makes the outlook less hopeful. Many children with Epilepsy of Infancy with Migrating Focal Seizures will sadly pass away during childhood, the majority due to complications of syndrome, which includes repeated chest infections.
Sudden unexpected death in epilepsy (SUDEP) is a high risk with this particular syndrome. Many children will need to be fed through a percutaneous endoscopic gastrostomy (PEG) to ensure they are well hydrated and receiving the nutrition they require. Children who do survive with this syndrome will likely have severe developmental problems and require lifelong care.