Congenital cortical dysplasia

What is congenital cortical dysplasia?

Cortical dysplasia occurs when a child’s brain isn’t structured quite like a typical brain. Cortical dysplasia occurs before your child is born, when the brain is forming and developing. As a child’s brain forms, clusters of abnormal (dysplastic) and disorganized neurons (nerve cells) called a cortical dysplasia, appear within one or sometimes multiple regions of the brain.

Sometimes nerve cells are in the wrong place, and sometimes they have problems with their shape or structure. Because the cells aren’t like typical neurons, they can disrupt brain function, resulting in a much higher risk of seizures.

• Focal cortical dysplasia (FCD) is the most common cause of medically refractory epilepsy (epilepsy that does not respond to medication) among children and teens.

What are the different types of congenital cortical dysplasia?

The most common type of cortical dysplasia is focal cortical dysplasia (FCD). The term “focal” describes that these neurons are clustered in one part of the brain.

Focal cortical dysplasia has three types, and they all cause seizures. The main difference among the types is the age when seizures start. The type a person has depends on the type of cell or the abnormal neuron that's present and how cells are organized in the brain.

1. FCD Type I - This type often involves disorganized cells in the temporal lobe, the area at the side of the brain. It may not appear until adulthood. Type I often doesn’t show up on imaging scans. Your child’s doctor may recommend surgery to find what’s causing seizures.

2. FCD Type II - Type II has disorganized cells, but the cells are also large or misshapen. It can affect the temporal and frontal lobes. This type often has more severe symptoms. Children with FCD type II may have seizures beginning in early childhood.

3. FCD Type III - FCD type III is either a type I or type II along with another associated lesion such as a tumor, atrophy (shrinking) and hardening of the hippocampus (a part of the brain that affects memory and spatial abilities), early childhood injury, or abnormal development of blood vessels.

What are the signs and symptoms of congenital cortical dysplasia?

• Brief focal seizures where a child seems “frozen” or can’t answer questions

• Changes in some sensations, such as noticing a strange taste or smell

• A blank stare (like staring into space) for 10 to 20 seconds

• Eyelids fluttering and eyes looking upward or to one side

• Sudden stops and starts when talking

• Repetitive movements like chewing lips or moving a hand

• Twitching or shaking (called convulsions)

• Rigid body, sometimes with a clenched jaw or tongue-biting

Depending on the part of the brain that’s affected, some children have other related neurodevelopmental delays or problems with thinking or motor skills.

How is congenital cortical dysplasia diagnosed?

Children’s Health is a Level 4 Pediatric Epilepsy Center, the highest accreditation available. That means we have all available tools to get your child the correct diagnosis and treatment. The sooner we reach the right diagnosis, the sooner we can reduce your child’s seizures or even cure their epilepsy.

Noninvasive diagnostic tests

Your child has a detailed physical exam and we ask about past medical history and family history. We also try to learn how a seizure started, so we can pinpoint the seizure source and offer the most appropriate treatment.

Your doctor might order blood work to rule out other causes of seizures, like an infection or genetic cause.

We may perform a variety of brain-related tests, such as:

• Electroencephalogram (EEG) - This test uses electrodes on the outside of your child’s head to monitor electrical activity in the brain.

• MRI - An MRI scan uses magnetic fields (not radiation) to create pictures of the brain.

• Positron emission tomography (PET) scan - A PET scan uses a tiny amount of safe radioactive tracer injected into a blood vessel that allows your doctors to view activity in your child’s brain. It shows the brains use of glucose (sugar) and can help identify where a seizure may be starting.

• Subtraction ictal and inter-ictal SPECT (single-photon emission computed tomography) co-registered to MRI (SISCOM) - SISCOM scans are a specialized type of scan that measures and compares blood flow during and in between seizures. This can help pinpoint where a seizure may be starting. A short-lived and safe radioactive tracer is injected into a blood vessel both during and in between seizures and the scan is performed shortly afterwards.

• Magnetoencephalography (MEG) - A MEG test is a noninvasive test (similar to an EEG) that studies your child’s brain activity in real-time. Your child wears a special helmet that lets a computer record brain activity.

Diagnostic surgery

Some children may need an intracranial EEG, a type of EEG that requires surgery, to determine where their seizures are coming from.

This may be necessary if:

• Imaging and seizure history cannot identify where seizures are coming from

• Doctors are concerned that seizures may involve the eloquent cortex (a part of the brain that houses very important functions such as language or movement).

What causes congenital cortical dysplasia?

Cortical dysplasia is a brain defect that a child is born with. The condition is one of the most common causes of epilepsy and seizures. Doctors aren’t certain what causes cortical dysplasia. Researchers do know that certain genes are associated with the condition.

Families often worry that the lesion might grow or change as their child grows (as a tumor might). Although cortical dysplasia and seizures can be frightening, they do not grow or change as your child grows up.

How is congenital cortical dysplasia treated?

Treatment for cortical dysplasia focuses on controlling seizures. If your child is diagnosed with epilepsy, it is important to begin the right treatment as quickly as possible. Untreated epilepsy can increase your child’s risk of injury from seizures. Seizures can also make children feel sad or isolated and affect their school performance.

Your child’s treatment may include:

• Medication - We usually try medication first, which helps some – but not all – children.

• Ketogenic diet - Our team can advise on care such as a ketogenic diet, which includes a regimen of high-fat, low-carbohydrate foods.

• Surgery - Often, when we find the lesion and determine that that's where the seizures are coming from, we can offer epilepsy brain surgery. Surgery removes the dysplasia (the abnormal cells). Neurosurgeons (brain surgeons) remove this brain tissue and send it to the lab for analysis. If all of the abnormal brain cells are removed, your child could live seizure-free and possibly be able to stop medication in the future.