Epileptic spasms without hypsarrhythmia in infancy and childhood: tonic spasms as a seizure type

Abstract

Epileptic spasms were defined by the International League Against Epilepsy Task Force on Classification and Terminology in 2001 as a specific seizure type. Epileptic spasms without hypsarrhythmia have been described in some series of patients, occurring either in infancy or childhood. More prolonged epileptic spasms without hypsarrhythmia were previously defined as a different seizure type, and referred to as "tonic spasm seizures". Here, we present a 5-year-old boy who started having epileptic spasms without hypsarrhythmia at 8 months of age, effectively treated with oxcarbazepine. With the withdrawal of medication, epileptic spasms returned. Video-EEG monitoring revealed high-voltage slow waves superimposed by low-voltage fast activity, followed by an electrodecremental phase and a burst of asymmetric fast activity, time-locked to clinical tonic spasm seizures. Brain MRI showed left temporal atrophy with temporal pole grey/white matter junction blurring and ictal PET-CT showed left basal frontal hypermetabolism. Seizures were refractory to several AEDs and vigabatrin was introduced with seizure cessation. Despite efforts to classify epileptic spasms, these are still considered as part of the group of unknown seizure types. In some cases, a focal origin has been suggested, leading to the term "periodic spasms" and "focal spasms". In this case, epileptic spasms without hypsarrhythmia, associated with tonic spasms, may be a variant of focal spasms and might be considered as an epileptic syndrome. [Published with video sequence]A cluster of three tonic spasms, characterized by sudden flexion of the head and proximal muscles, lasting 5, 4.3 and 1 second, respectively. The spasms were accompanied simultaneously by upward deviation of the eyes and oral automatisms at the end.Key words for the video research on www.epilepticdisorders.com

The impact of hypsarrhythmia on infantile spasms treatment response: Observational cohort study from the National Infantile Spasms Consortium

“…The youngest patients (<3 months) were less likely to have hypsarrhythmia at presentation, but patients without hypsarrhythmia were seen at all ages (2 months to 2 years). A similar overrepresentation of patients <3 months was reported previously in a cohort of patients with infantile spasms without hypsarrhythmia, where 3 of 16 (19%) were <3 months of age at onset . In our data, there were no other factors that correlated with absence of hypsarrhythmia.…”

“…A similar overrepresentation of patients <3 months was reported previously in a cohort of patients with infantile spasms without hypsarrhythmia, where 3 of 16 (19%) were <3 months of age at onset. 22 In our data, there were no other factors that correlated with absence of hypsarrhythmia. Specifically, there was no difference in the time from onset of infantile spasms to diagnosis of infantile spasms based on hypsarrhythmia.…”

“…Separating hypsarrhythmia from the associated epileptic spasms and the underlying pathology has been challenging. Cohort studies of patients with infantile spasms without hypsarrhythmia suggest that they have varied outcomes and respond to treatments similar to those with hypsarrhythmia . However, patients with and without hypsarrhythmia have never been compared systematically within the same data set.…”

Single-Epileptic Spasms with or without Hypsarrhythmia: A Study of 16 Patients

“…ES associated with other epileptic encephalopathies, such as Lennox-Gastaut syndrome (LGS), epilepsy with myoclonic and atonic seizures, Dravet syndrome, and epilepsy with focal migrating seizures of infancy have also been described. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] In this study, we evaluated the electroclinical features, etiology, treatment, and outcome of 16 patients with single-ESs with hypsarrhythmia or WoH.…”

Identification of Hypsarrhythmia in Children with Microcephaly Infected by Zika Virus

“…The Congenital Zika Virus Infection can cause severe brain abnormalities and diverse electroencephalographic abnormalities [ 1 ]. Among these is hypsarrhythmia, an unusual activity of the electroencephalogram (EEG), found in a few types of epilepsy and known for interictal and spike-and-wave discharges in an irregular and disorganized background [ 2 , 3 , 4 , 5 , 6 ].…”