Abstracts

RATIONALE: Proposed revisions to the [ssquote]Classification of Epileptic Disorders[ssquote] would replace the term [ssquote]cryptogenic[ssquote] with the term [ssquote]probably symptomatic.[ssquote] However, many pediatric patients with focal epilepsy have no clear etiology, no clear genetic predisposition and normal MRI scans, so the term [ssquote]cryptogenic[ssquote] may still have value. Participants should be able to decide whether the term [ssquote]cryptogenic[ssquote] remains valuable in classifying children with focal epilepsy.
METHODS: The epilepsy classification of 207 consecutive outpatients seen by a pediatric epileptologist during 2001-2002 was reviewed. The newly proposed ILAE classification system was used. For patients who could not be classified as having a specific epilepsy syndrome, 4 categories were used - idiopathic, cryptogenic, probably symptomatic, or symptomatic. [ssquote]Idiopathic[ssquote] patients had a known or strongly suspected genetic predispostion, [ssquote]cryptogenic[ssquote] patients had no obvious etiology, no other neuro-developmental problems and normal MRI scans, [ssquote]probably symptomatic[ssquote] patients had learning, behavioral or developmental disorders suggesting underlying brain dysfunction, and [ssquote]symptomatic[ssquote] patients had an obvious cause for their epilepsy.
RESULTS: The new classification system worked well for all pediatric patients except those with focal epilepsy. Easily classified were 52 children with generalized epilepsy (12 childhood absence, 12 other idiopathic generalized, 1 juvenile myoclonic, 11 infantile spasms, 3 Lennox-Gastaut, and 13 other symptomatic generalized); 9 patients with both focal and generalized epilepsy (all symptomatic); and 37 patients with epileptic seizures but not a diagnosis of epilepsy (13 with acute reactive seizures, 11 with suspected seizures, 8 with neonatal seizures, and 5 with a single seizure).
In contrast, only 8 of 109 children with focal epilepsy had a clear epilepsy syndome (5 benign rolandic, 2 benign occipital, and 1 Rasmussen[ssquote]s syndrome). The remaining 101 children with focal epilepsy were classified as follows: 0 idiopathic, 34 cryptogenic, 16 probably symptomatic, and 51 symptomatic. Response to treatment was favorable in the children with cryptogenic focal epilepsy, with 26/34 (79%) seizure-free after the 1st AED trial. In contrast, only 5/16 (31%) children with probably symptomatic focal epilepsy were seizure-free after the 1st AED trial, and only 10/51 (20%) children with symptomatic focal epilepsy were seizure-free after the 1st AED trial.
CONCLUSIONS: Pediatric patients with [ssquote]cryptogenic[ssquote] focal epilepsy are very different in response to treatment than pediatric patients with [ssquote]probably symptomatic[ssquote] and [ssquote]symptomatic[ssquote] focal epilepsy. Proposed revisions to the [ssquote]Classification of Epileptic Disorders[ssquote] should retain the term [ssquote]cryptogenic[ssquote] since it describes a distinct subset of pediatric patients with focal epilepsy.