Abstracts

Rationale: To establish a standardized protocol of metabolic testing in children with epilepsy and developmental delay. Methods: Records of all children visited to Seoul National University Children's Hospital between Feb 2004 and Mar 2009 were reviewed. Studies classified as “metabolic” for this review include: (1) plasma amino acids, ammonia levels, and lactate/pyruvate; (2) cerebrospinal fluid (CSF) amino acids, glucose, and lactate/pyruvate; (3) urine organic acids; and (4) mitochondrial respiratory chain (MRC) assay. Results: Eighty-seven patients (56 males, 31 females) were included. Mean age at seizure onset was 1.1 years and mean age at testing was 5.7 years. Seventeen of 85 patients (19%) exhibited elevation in blood lactate and one patients showed increased lactate/pyruvate ratio. Hyperammonemia was identified in 20%. Plasma amino acid analysis was performed in 73 of 87 patients (84%). Eleven of these 73 patients (15%) manifested elevation in alanine or proline. Urine organic acid analysis was performed in 67 of 87 patients (77%) and 8 patients (12%) showed lactic aciduria and/or ketonuria. In CSF studies, there were 8 patients with elevation in lactate level (8/10, 80%) and 1 patient (17%) with increased alanine. MRC assay was performed in patients who had multiple systemic symptoms or signs which was not correlated with other metabolic metabolic testing. Sixteen patients (16/87, 18%) were included and 14 of these patients (88%) presented isolated or combined MRC defect. Conclusions: In children with epilepsy and developmental delay, the yield of metabolic testing without MRC assay was low (5.7%) but significantly increased after adding MRC assay (17%). Because of low yield of routine metabolic testing, new strategy to metabolic evaluation is needed. If patients present 2 or more additional systemic symptoms or signs without definite abnormal findings in routine metabolic testing, MRC assay should be considered.