Abstracts

Rationale: Infantile Epileptic Spasm Syndrome (IESS) is the most common infantile epilepsy with detrimental effects on long term neurodevelopmental prognosis. Delayed diagnosis and long lag time to treatment results in poor treatment response and epilepsy outcomes.


Methods: A total of 68 consecutive patients seen at our institution in the IESS clinic were included. Data was collected through retrospective chart review regarding demographics, clinical characteristics, MRI data and response to first line therapies. Data was compared using Chi-square and student T-test between the groups of “incidental IS” vs “reported IS.”


Results: Twenty patients (29%) were found in whom the diagnosis of infantile spasms was incidental through screening electroencephalogram (EEG) done for other reasons based on clinician suspicion but not due to parental reports of spasms. The remaining patients (n = 48, 71%) had their spasms reported by family. Of the twenty incidentally diagnosed patients 60% had an acquired etiology while 54% of the reported spasms were due to congenital etiology (p=0.02). Etiology of acquired incidental spasms included: hypoxic ischemic encephalopathy (n = 4), periventricular leukomalacia in the setting of prematurity (n = 3), cystic encephalomalacia resulting from grade IV hemorrhage or post anoxic injury (n = 3), and perinatal MCA stroke (n = 2). Of the patients with incidentally diagnosed spasms, 7 had congenital etiologies (lissencephaly, Aicardi, monogenic mutations in RNASEH2A, DYRK1A, EPG5, RHOBTB2, and SCN1A each). Abnormality in basal ganglia or brainstem structures was seen in 45% (9) of the incidentally discovered spasms vs 15% (7) of the spasms diagnosed after parental report (p=0.007). History of neonatal ICU admission (75% vs 42%, p=0.01) and neonatal seizures (45% vs 12.5%, p=0.003) were significantly more common among incidentally discovered group. All patients in the incidental IS group had preceding developmental delay while that was the case in only half of the patients in the reported IS group. Date of spasm onset could not be determined in the incidental IS group. Age at spasm diagnosis was higher in the incidental IS group (median 7.5 months) vs the reported IS group (median 6 months, p=0.2), though the difference was not statistically significant. Race was comparable among the two groups. Refractoriness to first line standard IS treatment was significantly higher among incidental IS group (70%) vs reported IS group (44%, p=0.048).


Conclusions: In our cohort of consecutively diagnosed patients, incidental diagnosis of IESS was seen in 29% of patients. Prior history of NICU admission, neonatal seizures, acquired etiology for spasms, basal ganglia and brainstem abnormalities on MRI and pre-existing developmental delay were risk factors for being in incidentally discovered IS group where parents and caregivers had not recognized ongoing spasms. The incidental IS patients were also diagnosed late and were significantly more refractory to standard IS treatment, thus highlighting the need for a high index of suspicion for screening and counseling for IS in at-risk patients.

Funding: There was no funding received in support of this abstract.