Infantile spasms in trisomy 21

Christopher W. Beatty, Joanna E. Wrede and Heidi K. Blume.  Diagnosis, Treatment, and Outcomes of Infantile Spasms in the Trisomy 21 Population . Seizure. In press.

Highlights

• Time from onset to diagnosis is similar in T21 and idiopathic infantile spasms (IS).

• Time from treatment to resolution is similar in T21 and idiopathic IS.

• T21 related IS are less likely to develop epilepsy than idiopathic IS.

Abstract

Purpose

To determine if there are differences in the timing of diagnosis and response to treatment between infants with infantile spasms (IS) and Trisomy 21 (T21) and those with idiopathic IS.

Methods

This was a retrospective study evaluating the time from onset of IS to diagnosis, treatment of IS, time from treatment to resolution of IS, and development of epilepsy in children with T21 and IS compared to children with idiopathic IS.

Results

Thirteen children with T21 and IS were identified over a 10 year period and compared to 32 children in the control group. There was no significant difference in age of onset, time between onset and diagnosis, or acute response to treatment. However, the children with idiopathic IS were more likely to go on to develop epilepsy than those with T21 and IS (41% vs. 0, p = 0.006).

Conclusion

The children with T21 and IS were diagnosed and treated similarly to those patients with idiopathic IS. There were no significant differences in the age of onset, time between the onset and diagnosis of IS, or acute treatment response of IS between the T21 and control groups. However those with T21 and IS had a lower risk of subsequent epilepsy following IS than those with idiopathic IS. IS in the T21 population appears to be inherently different from IS of unknown etiology.

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From the article:

One limitation of the study was the variability of the work-up between the two cohorts.

Not all children with T21 and IS underwent neuroimaging given that many providers did

not feel this was necessary. This may have allowed the inclusion of some children with

structural abnormalities. Additionally, the children identified as idiopathic underwent

varied evaluations, most notably with regard to genetic testing. It is possible that some

children with an underlying genetic etiology were included in the study and altered the

outcome data. However, the rate of relapse and rate of developing epilepsy found in this

study is similar to what has been reported in the literature for this cohort with relapse

rates from 13-20% and subsequent epilepsy in 5-47 %.

This study was not able to assess the neurodevelopmental outcome of the children. Given

the altered developmental trajectory of those children with T21, it would be necessary to

have structured neurodevelopmental assessment to address this issue and given the

retrospective nature of this study it was not possible…

 Overall, this study demonstrates that the time from onset to diagnosis and time from

treatment to clinical and EEG response was not significantly different between the T21

cohort and children with idiopathic IS. Despite these similarities, those with T21 as the

primary etiology for IS appeared to be less likely to have recurrence of spasms following

treatment and were less likely to develop epilepsy after resolution of IS. This suggests

that IS in the T21 population is a distinct entity and their responsiveness to ACTH in our

cohort suggests this may be a treatment of choice for these children.