Symptoms of Early Onset Seizures and Related Medical Conditions Described in Review Study

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by Alice Melao |

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Early identification and diagnosis of seizures can have major implications for their treatment and accurate prognosis. But in most cases it can be a challenge to differentiate between epileptic seizures and abnormal non-epileptic movements early in life, a review study suggests.

In the study, “Benign and severe early-life seizures: a round in the first year of life,” published in the Italian Journal of Pediatrics, Italian researchers analyzed the clinical manifestations and medical conditions linked to seizures during early infancy.

Brain development is significantly dependent on prenatal and early life events. Any alteration of the natural course of these early developmental periods might result in severe cerebral impairment, marked by developmental delay and intellectual disability, often associated with epileptic seizures and various secondary disorders.

Several events can cause seizures during childhood including fever, infections, head injury, and metabolic dysregulation, among others. Genetic alterations can also cause childhood seizures in rare cases.

Even though seizures are not uncommon during childhood, they represent a major concern for parents and caregivers. In most cases, epileptic movement is often subtle and not easily recognized, and seizures occurring in the first year of life can have a favorable course.

However, in some cases, the onset of seizures at birth or in the first months of life have a dramatic evolution with severe cerebral impairment.

Seizures can be classified based on their site of onset: focal, generalized, or unknown. These classifications can be further distinguished based on other manifestations, including the involvement of motor or non-motor symptoms, or alteration of the child’s awareness.

Dravet syndrome is a severe form of epilepsy that manifests during infancy. It was first described in 1978, and has been associated with multiple seizure types, long-lasting epileptic seizures with frequent episodes of status epilepticus — consecutive seizures without recovering consciousness between each episode.

Patients usually develop normally until they start experiencing seizures by 6 to 8 months of age, commonly triggered by fever.

However, if patients have genetic mutations in the sodium channel SCN1A gene, which accounts for 70 to 80 percent of all Dravet cases, they may have a slightly different disease presentation, with a different age of onset, type of seizure, and no effect on intellectual capacity.

Other genes have also been linked to Dravet syndrome-like manifestations, including SCN2A, SCN8A, SCN9A, SCN1B, PCDH19, GABRA1, GABRAG2, STXBP1, HCN1, CHD2, and KCNA2.

This disease is associated with a severe prognosis, for both epileptic seizures and cognitive impairment, and mortality rates among these patients is high.

Treatment is based on the use of anti-epileptic therapies. Sodium channel blocking medications are not advised for Dravet syndrome due to the genetic defects affecting the sodium channels (such as SCN1A mutations).

Attempts to treat the disease with pharmacological therapies have been made using several compounds, including topiramate, levetiracetam, stiripentol, or clobazam. In general, stiripentol treatment in this patient population is effective and well-tolerated and markedly reduces the frequency of prolonged seizures.

However, in most cases, many pharmacological strategies are of little benefit to patients. Alternative approaches are currently being explored, including gene therapies for patients with SCN1A mutations.

“The diagnosis of early-life seizures is complex, and includes conditions that can have a favorable course or dramatic effects. The onset of the first episode is cause of great concern for the parents and caregivers, and there is pressure for the pediatrician to express an immediate diagnosis. Correct diagnosis can help to produce appropriate treatment and accurate prognosis,” the researchers concluded.