Focal seizures
Start in one area of the brain. May include rhythmic movements in one limb, staring episodes, unusual sensations, or brief altered awareness. Can spread to become generalised.
What is a seizure?
Understanding seizures.
A seizure is caused by a sudden surge of abnormal electrical activity in the brain. In SCN2A-related conditions and other DEEs, this abnormal activity arises because the underlying gene change affects how brain cells communicate and regulate their electrical signals.
Seizures can look very different depending on which part of the brain is affected, what is happening in that region, and the age and development of the child. A single child may experience more than one type of seizure, and the pattern may change over time.
Common seizure types
What you may see, what they're called.
Tonic seizures
Sudden stiffening of the muscles, body, arms, or legs become rigid. Can cause falls if standing. Usually last only a few seconds; may happen in clusters.
Clonic seizures
Rhythmic, jerking movements, typically of the arms, legs, or face. May occur alone or as part of a tonic-clonic seizure.
Tonic-clonic (previously "grand mal")
Both stiffening (tonic) and rhythmic jerking (clonic) phases. Typically last one to three minutes, followed by tiredness, confusion, or sleep (the postictal phase).
Myoclonic seizures
Brief, sudden muscle jerks, often in the arms or upper body. Can be subtle and easily missed, particularly in young children.
Absence seizures
Brief episodes of staring or "switching off", the child appears unresponsive for a few seconds before resuming normal activity. No physical movements.
Epileptic spasms
Short, sudden flexing or extending of the body or limbs (formerly called infantile spasms when in infancy). Often in clusters, typically on waking. Require prompt treatment.
Febrile seizures
Some children with SCN2A-related conditions have increased sensitivity to fever, with seizures triggered or worsened by elevated body temperature.
Not every child with an SCN2A variant will have all, or any, of these seizure types. Your child's specific presentation will depend on their variant, their age, and many other factors. Your neurologist is the best source of guidance.
Seizure first aid
What to do, and what not to do.
General guidance. Your neurologist will provide specific instructions tailored to your child's condition and seizure type.
During
- Stay calm, stay with your child
- Note the time, how long the seizure lasts matters
- Move them away from anything hard or sharp
- Place them on their side if unconscious
- Do not put anything in their mouth
- Do not restrain them
- Speak calmly if they're conscious
After
- Stay with your child as they recover
- Postictal tiredness, confusion or sleep is normal
- Note: type of movements, duration, which side
- Follow rescue-medication instructions if prescribed
Call an ambulance if
- Seizure lasts > 5 minutes (or your neurologist's threshold)
- A second seizure occurs before full recovery
- Difficulty breathing during or after
- Seizure in water
- Injury during the seizure
- You are unsure, or this is the first observed seizure
Medication safety
Anti-seizure medications and SCN2A, what you need to know.
Anti-seizure medications (ASMs) are the primary treatment for seizures in SCN2A and DEE. Choosing the right medication, and avoiding the wrong one, requires knowing your child's specific SCN2A variant type.
Why variant type matters
SCN2A variants can be broadly classified as gain of function (GoF) or loss of function (LoF):
- GoF variants cause the sodium channel to be overactive. Sodium channel blockers, phenytoin, carbamazepine, oxcarbazepine, lamotrigine, are often effective.
- LoF variants cause the sodium channel to be underactive. Sodium channel-blocking medications may worsen the condition and should generally be avoided or used with significant caution.
This is not a theoretical distinction. There are documented cases of children with LoF variants whose seizures worsened after being prescribed sodium channel-blocking medications that are standard treatment for other epilepsy types.
Make this part of every clinical handover
Make sure every clinician who treats your child, including emergency-department staff, locums, and any specialist who is new to your child, knows your child's SCN2A variant type and the medications that should be used carefully or avoided. The SCN2A Emergency Information Card is designed to communicate this clearly in time-sensitive situations.
What if medication is not working?
It is not uncommon for seizures in SCN2A and DEE to be difficult to control with a single medication, or to require adjustment over time. If your child's seizures are not responding, discuss with your treating team:
- Review of the variant type and whether current medications align with it
- Second opinion from a neurologist experienced in SCN2A or genetic epilepsy
- Referral to a specialist epilepsy centre
- Consideration of participation in a clinical trial
- Assessment of factors (sleep, stress, illness, medication interactions) that may be affecting seizure frequency
Rescue medications
Rescue medications.
Some children with SCN2A or DEE have rescue medications, medications given during or after a prolonged seizure to stop it before it becomes a medical emergency. These are typically fast-acting medications administered by carers (not only by medical staff), given at home or in the community.
Common rescue medications include midazolam (given into the cheek or nose) and diazepam (rectal). Your neurologist will prescribe a rescue medication if it is appropriate, and provide training in when and how to administer it.
If your child has a rescue medication, make sure everyone responsible for their care, school staff, extended family, regular carers, knows what it is, where it is kept, and when and how to use it.
Records
Seizure monitoring and record-keeping.
Keeping a clear record of your child's seizures is one of the most practical things you can do to support their care. A seizure diary helps your treating team identify patterns, assess medication effectiveness, and make informed adjustments.
A seizure record should note:
- Date and time
- Type of seizure (or your best description of what you observed)
- Duration
- Possible triggers (illness, fever, missed medication, disrupted sleep)
- Recovery time and any postictal features
- Any rescue medication used
Many families use smartphone apps designed for seizure tracking. Your neurologist or epilepsy nurse may recommend one, or SCN2A Australia can suggest options used by our community.
The bigger picture
Seizures and quality of life.
Managing seizures is important, but so is maintaining quality of life. The goal of treatment is not zero seizures at any cost; it is to find the best balance between seizure control and the side effects of medication, and to support your child's development and wellbeing.
Families often find that it takes time and adjustment to reach a medication regimen that works. That process can be exhausting and sometimes disheartening. Connecting with other families who have navigated similar challenges, and who know what this feels like, is one of the most valuable things SCN2A Australia can offer.