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Brain Abnormalities Common in Children With First Seizure
SAN DIEGO—Children with a first recognized seizure have a higher rate of brain abnormalities than has been previously reported, according to Andrew J. Kalnin, MD, and colleagues. Among 281 children who underwent MRI within six months of their first seizure, 97 (35%) had at least one abnormality, and 38 (14%) had two or more abnormalities. Thirty-nine children (14%) had abnormalities that were judged to be significant, said Dr. Kalnin, Associate Professor of Radiology at the Indiana University School of Medicine in Indianapolis. Dr. Kalnin presented his group’s findings at the 60th Annual Meeting of the American Epilepsy Society.
“A significant abnormality was defined as an MRI finding reasonably likely to be related to seizure disorder,” Dr. Kalnin explained. “These were defined as at least one of the following: leukomalacia/gliosis, any gray matter lesion, mass lesion, vascular lesion, hippocampal abnormality, ventricular enlargement greater than 1.5 cm, or prominence of extra-axial fluid spaces greater than 1 cm. Structural abnormalities were examined on a case-by-case basis.”
The study included children ages 6 to 14 who had had a first recognized unprovoked seizure within the previous three months, regardless of whether they had had previous unrecognized or undiagnosed seizures. Children were excluded if their seizure had an acute etiology, including a toxin, infection, or trauma, or if they had a chronic illness. The majority of children (91%) had one seizure type, and a variety of seizure types and syndromes were represented, noted Dr. Kalnin. “Children with partial seizures slightly outnumbered those with generalized seizures, which is characteristic of this population,” he said.
The most frequent abnormalities observed were leukomalacia/gliosis (26%), other white matter lesions (30%), and volume loss (14%). Children with generalized and partial symptomatic/cryptogenic seizures were most likely to have an MRI abnormality (50% and 41%, respectively). About 33% of children with generalized idiopathic absence seizures had an abnormality, 28% of those with generalized tonic-clonic seizures had an abnormality, and 25% of children with idiopathic partial seizures had an abnormality.
Dr. Kalnin and colleagues offered reasons as to why their findings differed from those of two previous studies on brain abnormalities and seizures in children, which had reported rates of 21% and 13%: “First, imaging was limited to MRI, the current anatomic gold standard,” said Dr. Kalnin. “Second, imaging was performed nearer to the time of seizure onset, the first recognized seizure. Third, we applied a standardized classification system to the MRI findings and presented a more comprehensive description of imaging findings than these previous investigations. Finally, MRI findings were associated with various seizure syndromes, to provide a basis for more informed clinical decision-making.”
NR
—Colby Stong
Suggested Reading
Berg AT, Testa FM, Levy SR, Shinnar S. Neuroimaging in children with newly diagnosed epilepsy: a community-based study. Pediatrics. 2000;106:527-532.
Shinnar S, O’Dell C, Mitnick R, et al. Neuroimaging abnormalities in children with an apparent first unprovoked seizure. Epilepsy Res. 2001;43:261-269.
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