Urinary organic metabolite screening of children with influenza-associated encephalopathy for inborn errors of metabolism using GC/MS.
BACKGROUND
Influenza-associated encephalopathy (IAE) occurs in childhood often with a serious clinical course and fatal outcomes. We screened children with IAE using GC/MS to determine whether they have metabolic disorders such as organic acidemias.


METHODS
Urine samples from 70 Japanese children with IAE were analyzed between 2001 and 2005 using GC/MS with solvent extraction and direct drying methods.


RESULTS
Apparent metabolic disorders in 6 of 70 tested children included vitamin B12-responsive methylmalonic acidemia (MMA; n=1), fructose-1,6-diphosphatase (FDPase) deficiency (n=1) and non-ketotic dicarboxylic aciduria (n=4) suggesting disorders of fatty acid oxidation. One child had an FDPase deficiency, for which glycerol infusion was contraindicated. Valproic acid metabolites were detected in 10 children and urinary glycerol excretion was increased in 22 of them after glycerol treatment.


CONCLUSIONS
Our results showed that inborn errors of metabolism (IEM), such as organic acidemias, are detectable among children with IAE. Patients with metabolic disorders such as an FDPase deficiency and MMA often have hypoglycemia, hyperammonemia and acute lactic acidemia. Importantly, a detection of FDPase deficiency in which glycerol infusion is contraindicated suggests careful selection of a treatment strategy for "acute encephalopathy". We detected valproic acid and its metabolites at a rate of 14%, which was considerably higher than that in a control population. Thus, convulsive disorders might be a risk factor associated with IAE.
Purevsuren
Jamiyan
J
Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 Enya, Izumo, Shimane 693-8501, Japan. jamiyan@med.shimane-u.ac.jp
Hasegawa
Yuki
Y
Kobayashi
Hironori
H
Endo
Mitsuru
M
Yamaguchi
Seiji
S
D000592:Amino Acid Metabolism, Inborn Errors / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D018792:Encephalitis, Viral / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D005990:Glycerol / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007223:Infant; D007251:Influenza, Human / Q000150:complications / Q000378:metabolism; D007564:Japan; D008297:Male; D053858:Metabolic Networks and Pathways / Q000502:physiology*; D012189:Retrospective Studies; D014556:Urine / Q000737:chemistry*
D005990:Glycerol