Clinical profile and treatment outcome of epilepsy syndromes in children: A hospital-based study in Eastern Nepal

Objective

It is often difficult to diagnose epilepsy syndromes in resource-limited settings. This study was aimed to investigate the prospect of ascertaining the diagnosis, clinical profile, and treatment outcomes of epilepsy syndromes (ESs) among children in a resource-limited setting.

Methods

This was a descriptive study done from 01/07/2009 to 15/06/2017 among children (1-17 years of age) with unprovoked seizures presenting to the pediatric neurology clinic of a university hospital in eastern Nepal. Diagnosis, classification, and treatment of seizures were based upon International League Against Epilepsy guidelines.

Results

Of 768 children with unprovoked seizures, 120 (15.6%) were diagnosed as ES. The age of onset of seizure was unique for each ES. Developmental delay and cerebral palsy were present in 47.5% and 28.3% children, respectively. Common ESs were West syndrome (WS)-26.7%, generalized tonic-clonic seizures alone (GTCSA)-21.7%, self-limited childhood epilepsy with centrotemporal spikes (SLCECTS)-12.5%, childhood absence epilepsy (CAE)-10.0%, Lennox-Gastaut syndrome (LGS)-10.0%, other developmental and epileptic encephalopathies (DEE)-5.8%, self-limited familial infantile epilepsy (SLFIE)-4.2%, and juvenile myoclonic epilepsy (JME)-3.3%. Among children with known outcomes (87/120), overall response to pharmacotherapy and to monotherapy was observed in 72.4% (63/87) and 57.5% (50/87) children, respectively. All children with GTCSA, SLFIE, genetic epilepsy with febrile seizure plus (GEFS+), CAE, SLCECTS, and JME responded to pharmacotherapy and they had normal computerized tomography scans of the brain. Seizures were largely pharmaco-resistant in progressive myoclonus epilepsy (PME)-100.0%, LGS-73.0%, WS-52.0%, and other DEEs-40%.

Significance

A reasonable proportion (15.6%) of unprovoked seizures could be classified into specific ES despite limited diagnostic resources. WS was the most common ES. GTCSA, SLCECTS, CAE, and LGS were other common ESs. GTCSA, SLFIE, CAE, SLCECTS, GEFS+, and JME were largely pharmaco-responsive. PME, WS, and LGS were relatively pharmaco-resistant. Electro-clinical diagnosis of certain ES avoids the necessity of neuroimaging.

Epilepsy Overview and Revised Classification of Seizures and Epilepsies

PURPOSE OF REVIEW

The classification of seizures, epilepsies, and epilepsy syndromes creates a framework for clinicians, researchers, and patients and their families. This classification has evolved over the years, and in 2017 the International League Against Epilepsy (ILAE) published an operational classification of seizures and epilepsies. Understanding this classification is important in the diagnosis, treatment, and understanding of seizures and epilepsies, including epilepsy incidence.

RECENT FINDINGS

The 2017 ILAE classification system builds on newly formulated definitions of seizures and epilepsy. Seizure classification begins by determining whether the initial manifestations of the seizure are focal or generalized. If the onset of the seizure is missed or unclear, the seizure is of unknown onset. Focal seizures are classified according to the individual's level of awareness, the most prominent motor or nonmotor features of the seizure, and whether the focal seizure evolves to a bilateral tonic-clonic seizure. Similarly, generalized seizures are classified according to motor or nonmotor manifestations. Motor seizures are either tonic-clonic or other motor seizures. Nonmotor generalized seizures primarily refer to absence seizures. Similar to seizure classification, the epilepsies can be classified as focal or generalized. In addition, the new classification system recognizes two new categories: combined generalized and focal epilepsy and unknown epilepsy. The concept of an epilepsy syndrome has been introduced under the new classification system and refers to a cluster of features incorporating seizure types, EEG, imaging, and other features including genetics. The new classification system emphasizes the etiology of seizures and epilepsies.

SUMMARY

The recent ILAE seizure and epilepsy classification system aims to create a framework to better classify seizures and the epilepsies. Universal adoption and implementation of this system will enable patients, their families, clinicians, and researchers to better define and treat the epilepsies. Incidence studies have not generally classified seizures and the epilepsies, and use of this classification system, which emphasizes etiology, will lead to a better understanding of epilepsy incidence.

Quantitative analysis of phenotypic elements augments traditional electroclinical classification of common familial epilepsies

OBJECTIVE

Classification of epilepsy into types and subtypes is important for both clinical care and research into underlying disease mechanisms. A quantitative, data-driven approach may augment traditional electroclinical classification and shed new light on existing classification frameworks.

METHODS

We used latent class analysis, a statistical method that assigns subjects into groups called latent classes based on phenotypic elements, to classify individuals with common familial epilepsies from the Epi4K Multiplex Families study. Phenotypic elements included seizure types, seizure symptoms, and other elements of the medical history. We compared class assignments to traditional electroclinical classifications and assessed familial aggregation of latent classes.

RESULTS

A total of 1120 subjects with epilepsy were assigned to five latent classes. Classes 1 and 2 contained subjects with generalized epilepsy, largely reflecting the distinction between absence epilepsies and younger onset (class 1) versus myoclonic epilepsies and older onset (class 2). Classes 3 and 4 contained subjects with focal epilepsies, and in contrast to classes 1 and 2, these did not adhere as closely to clinically defined focal epilepsy subtypes. Class 5 contained nearly all subjects with febrile seizures plus or unknown epilepsy type, as well as a few subjects with generalized epilepsy and a few with focal epilepsy. Family concordance of latent classes was similar to or greater than concordance of clinically defined epilepsy types.

SIGNIFICANCE

Quantitative classification of epilepsy has the potential to augment traditional electroclinical classification by (1) combining some syndromes into a single class, (2) splitting some syndromes into different classes, (3) helping to classify subjects who could not be classified clinically, and (4) defining the boundaries of clinically defined classifications. This approach can guide future research, including molecular genetic studies, by identifying homogeneous sets of individuals that may share underlying disease mechanisms.

[Epileptic spasms in infants. Beyond hypsarrhythmia]

Epileptic spasms are the most frequent type of epileptic seizures in infants. They can also occur beyond the period of infancy, within the context of other epileptic encephalopathies or as an expression of a focal or generalised epilepsy. The clinical semiology of epileptic spasms varies greatly. They sometimes consist of very subtle clinical manifestations, which occur in series, without the typical axorhizomelic contraction, or in association with focal seizures. The critical EEG correlate is also very variable and basically consists of the combination of a hypervoltage slow wave, a bout of rapid low-amplitude activity or a diffuse attenuation of the trace. The electromyographic recording of both deltoids during the EEG-video study helps to detect clinically subtle spasms and to define certain features of them that are clinically hard to determine. The classic interictal EEG pattern of hypsarrhythmia, or one of its variants, is not always present. Epileptic spasms can sometimes be mistaken for another type of paroxysmal episodes that can be epileptic or non-epileptic, and the EEG-video study may play a key role for the differential diagnosis. Taken together, the findings from the EEG-video study allow an adequate diagnosis and classification of the different epileptic seizures and syndromes, which can optimise both the therapeutic management and aetiological investigation.