Etiological classication of seizures in pediatric age group (6-12years) – MRI study

Background: A seizure is an occurrence of signs or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. The present study aims to study the etiological factors and clinical profile for new-onset seizures in children aged 6-12 years and to determine the frequency of Magnetic resonance imaging (MRI) abnormalities in the pediatrics age group with new-onset unprovoked seizure and those with inadequately investigated longstanding epilepsy and classify the etiology based on the MRI findings. Methods: A prospective study involving a total of 50 patients was recruited aged between 6 to 12 years. All of them underwent neuro-imaging with MRI. Uncooperative patients were imaged following sedation and monitoring by the anesthetist. All children aged 6-12 years who presented with new-onset seizures were included. All MR images were obtained at a 3-mm section thickness except magnetization-prepared rapid gradient-echo images, which are obtained at a 1.8-mm section thickness. Results: Of the 50 patients 28 presented with generalized tonic-clonic seizures, 12 with simple partial seizures, 10 with complex partial seizures. Generalized seizures were a more common presentation than partial seizures in children 6-12 years of age. Conclusion: With the positivity of the MRI in the new-onset seizure in children between 6-12 years in our study gives an important aspect of the essential factor of imaging in pediatric new-onset seizures. spin-echo-planar


Introduction
A seizure is an occurrence of signs or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.When the above is associated with motor components then they are known as convulsions.Epilepsy is a condition characterized by recurrent (two or more) unprovoked seizures occurring 24 hours apart.However, it is not always that the information derived from these investigations changes the line of management and there is always a concern regarding cost and radiation exposure.[6,7].
Hence it is essential to evolve a method to identify children with symptomatic epilepsy by clinical criteria so that seizures are better managed and expensive investigations can be judiciously used.

Material and Methods
A prospective study involving pediatric patients presenting with new-onset, recurrent and refractory seizures to the pediatric department was done.A total of 50 patients were recruited aged between 6 to 12 years.Following evaluation by a pediatrician and a neurologist, all these patients underwent appropriate investigations.All of them underwent neuro-imaging with MRI.Uncooperative patients were imaged following sedation and monitoring by the anesthetist.
Inclusion criteria: All children aged 6-12 years who presented with new-onset seizures were included.
Exclusion criteria: Children with a previous history of seizures, developmental retardation, and prior neurological abnormality, seizure mimics, and trauma were excluded.After getting informed written consent from the parents, the data were collected and entered in a Pro forma.
Magnetic Resonance Imaging was performed on a Siemens 1.5 Tesla Magnetom scanner.The protocol at our institution includes the following sequences, All MR images were obtained at a 3-mm section thickness except magnetization-prepared rapid Gradient-echo images, which are obtained at a 1.8mm section thickness.

Results
Of the 50 patients, 28 presented with generalized tonic-clonic seizures, 12 with simple partial seizures, 10 with complex partial seizures (Refer Table.1).
Table 2 shows the correlation of Generalized tonicclonic seizures (GTCS) with the positive finding was the most common (15 patients), followed by simple partial seizures (CPS) in 10 patients, complex partial seizures (SPS) in 8 patients.In this study, the most prevalent cause of epilepsy was Cryptogenic (26%), followed by Hypoxic Ischemic Encephalopathy (20%) (Refer Table .3).Of the 50 patients who underwent MRI study, 46% had normal imaging and 54% had abnormal imaging as shown in Table 4.Our study population consisted of 56% of patients who had presented with a history of generalized tonic-clonic seizures.Thus a majority of the patients presenting with generalized seizure is in tune with other studies conducted in developing countries.In the present study, generalized tonic-clonic seizures (GTCS) were the most common type seen in 56% followed by complex partial seizures (CPS) in 20%, simple partial seizures (SPS) in 24%.Another study by Saha SP et al concluded that simple partial seizures constituted 10.5% of total seizures, complex partial constituted 21.1% of total seizures. [8] In a study made by Singhi S et al, seizures were partial complex in 65% and simple partial in 35%.
[9] Present results are comparable with these studies.We found positive MRI findings in 56% of the patients presenting with seizures.Our study had a relatively higher percentage of positive findings because of inclusion criteria of patients presenting with a minimum of 2 episodes of seizure.The patients visiting our hospital are from the rural background, who visits the hospital only when they are seriously ill.In our study population, 60% of the patients had a previous history of multiple episodes of seizures.
The other reason could also be due to the high resolution 1.5 tesla MRI scanner used.In our study structural abnormality could not be detected in 45.6% of patients.Among these 55% had presented with generalized tonic-clonic seizures.
Hence cases with generalized tonic-clonic seizures constituted maximum to the cryptogenic cause.The most common cause of seizure based on MRI findings in our study was found to be cryptogenic.
[1].Seizures are common in the pediatric age group and occur in 10% of children.Less than 1/3rd of seizures in children are caused by epilepsy.[2].The etiological spectrum of acute symptomatic seizures in developing countries is different from developed countries.In developing countries like India, intracranial infections still constitute the single largest cause of childhood seizures.[3-5].The tremendous advances in neuroradiological investigations and electroencephalogram (EEG) have resulted in a series of noninvasive diagnostic procedures.
The present study aims to study the etiological factors and clinical profile for new-onset seizures in children aged 6-12 years and to determine the frequency of MRI abnormalities in the pediatrics age group with new-onset unprovoked seizure and those with inadequately investigated longstanding epilepsy and classify the etiology based on the MRI findings.

Figure 1 :
Figure 1: T2W sagittal image showing prominent perivascular spaces in the corpus callosum.

Figure
Figure 2: T2 FLAIR Axial image showing bilateral subcortical white matter hyperintensities and porencephalic cysts consistent with hypoxic-ischemic injury.

et al: Etiological classification of seizures in pediatric International Journal of Medical Research and Review 2021;9(4)
ConclusionGeneralized seizures were common presentation than partial seizures in children 6-12 years of age.Positivity of the MRI in the new-onset seizure in children between 6-12 years in our study emphasizes the importance of imaging in pediatric new-onset seizures.