A Brief Guide to Diagnosis and Management of New-Onset, Unprovoked Seizures in Children
Making the Right Diagnosis:
Is it a truly a seizure?
Seizures are one of the most common neurological problems seen in the pediatric age range. However, there are also many other disorders which can mimic seizures, and need to be excluded. Studies have shown that approximately one quarter to one third of children referred for what is thought to be “new-onset seizures” turn out to have one of these other mimics. A careful history of the actual spell is the most important information to achieve an accurate diagnosis, and it is very helpful to get information from the child him/herself, regarding what they recall, as well as any witness to the actual spell. While a number of tests are often done in such cases, none of these is as helpful at making the diagnosis as a careful history.
If it is a seizure, is it unprovoked?
In many children, seizures occur only if “provoked”, meaning that they are solely brought on in the presence of specific factors such as high fever, glucose or electrolyte disturbances, brain infection, trauma, etc. In a child presenting with new-onset seizures, your doctor will perform a careful assessment to rule out these conditions. The most common provoking factor in young children is fever, and such “febrile seizures” or “febrile convulsions” are seen in 3-5% of all children five years and younger. Seizures that occur only with provoking factors are not considered epilepsy. If no clear provoking factor is identified, the seizure is termed “unprovoked”, and indicates a greater risk of epilepsy.
If it is an unprovoked seizure, is it the first one?
Epilepsy is traditionally defined as two or more unprovoked seizures. Approximately one quarter of children who present with a “first” unprovoked seizure will turn out to have had a previous seizure that was much more subtle, and therefore not previously recognized. Such subtle seizures can include absence seizures (brief staring spells), myoclonus (brief muscle jerks), focal dyscognitive seizures (staring with unresponsiveness and abnormal movements such as rubbing, chewing, etc) or nocturnal seizures (which are suggested by intermittent bed wetting, excessive drool on the pillow, unexplained bites of the tongue/cheek, etc). Recognition of prior seizures is important as it confirms a diagnosis of epilepsy and often results in recommendations for initiation of antiepileptic drug treatment.
If this is a first unprovoked seizure, what is the chance it will happen again?
The chance of a second seizure occurring in a child with a first unprovoked seizure is between 40-50%. Most seizures recur in the first 6 months, and recurrences are much less common after two years. The most important predictor of recurrence is underlying cause – children who have a change on their MRI felt to be causal for the seizure are at higher risk of recurrence. Other factors which predict higher recurrence include abnormal EEG (particularly in children without a known cause), abnormalities on neurological examination, and intellectual disability.
What tests are needed?
An outpatient EEG is usually done in a child presenting with a first seizure for the following reasons:
The EEG is typically done as an outpatient, rather than immediately after the event, because EEG performed several days after the event provides better information about baseline brain function. It is best to record both sleep and wakefulness during the EEG, as some types of change are seen in one state alone.
An MRI is not needed in every child with new-onset seizures, but is usually obtained in those with a focal onset (seizure that starts on one side of the body/brain), those with focal EEG discharges (with the possible exception of children felt to have a specific epilepsy type called Benign Epilepsy of Childhood with Centrotemporal Spikes) or children with either focal abnormalities on neurological examination or underlying intellectual disability. At times, other features in the history or physical examination may alert your doctor to obtain an MRI. The MRI looks for structural changes in the brain that could be causal for the seizures, which may include developmental changes, blood vessel malformations or other lesions such as tumors, scarring, etc.
There are no clear guidelines regarding bloodwork. However many doctors check electrolytes, calcium, magnesium, blood sugar and kidney function in children presenting with new-onset generalized tonic-clonic seizures or before starting a seizure medication.
A spinal tap is rarely needed in children with new-onset seizures other than to rule out brain infection.
An EKG should be considered to rule out an abnormal heart rhythm, in children with new-onset generalized tonic clonic seizures, unless there is another cause found.
Does my child need to start daily medication?
Most children are not started on daily medication after their first seizure, given the fact that less than half will go on to have further seizures. At times however, medication is recommended in children with particularly severe seizures (such as prolonged events) or if the risk is felt to be high due to abnormal findings on EEG or MRI. Starting antiepileptic medication after the first seizure has been shown to reduce the recurrence risk of further seizures in the subsequent two years, but does not alter the long-term outcome of epilepsy. In comparison to children who are treated immediately after the first seizure, those who begin treatment after two or more seizures do not have lower rates of ultimate seizure control or lower rates of outgrowing their epilepsy. There is also no evidence to suggest that those waiting to start medicine until after a second seizure occurs have higher rates of medical complications from seizures.
Following a first seizure, many doctors will discuss rescue medication with families. Such medication is only used if a subsequent seizure is prolonged (usually more than 5 minutes) or recurrent (usually more than 3 seizures per hour). Most physicians consider beginning treatment after a second seizure, particularly if it occurs in close proximity to the first, as the risk for subsequent seizures is now greater than 70%.
What precautions should I take for my child?
Seeing your child have a seizure can be very frightening for many parents. However, in reality, the risk of harm to a child from a seizure is very low, provided the child is in a safe environment. Because most seizures occur without warning, some precautions are needed. However, excessive restrictions should be avoided to maximize the child’s social development. The biggest danger to children with seizures is water. As such, school-aged children and teens who are too old to be directly supervised by their parents while in the bath should shower rather than bathe. Children are encouraged to be active, however would need to have supervision by someone other than the lifeguard while swimming, and should wear a lifejacket if boating or engaging activities close to lakes, streams, etc. Other common suggested restrictions are that children should not climb higher than they are tall, and should avoid potentially dangerous activities such as skydiving and scuba diving.
Conversely, children and teens with new-onset seizures can usually fully participate in all other sports, including contact sports, can participate in play dates and sleep overs with friends. Teens with new-onset seizures can go out with friends without parental supervision and hold part-time jobs.
It is recommended that adults who are directly responsible for supervising the child/teen, such as teachers, coaches, daycare providers, etc be told that the child has had a single seizure and what to do in the event of a subsequent event.
Given that the risk of seizure recurrence becomes lower with the greater amount of time passed after a first seizure, restrictions can usually be eased if the child goes two years without recurrence.
by Elaine Wirrell, MD
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