Abstract
We describe a 6-year-old boy admitted with lethargy and somnolence. Laboratory tests showed hyperammonaemia (arterial level 186 μmol/l) and slightly elevated prothrombin time. The patient was treated with sodium benzoate, lactulose and a protein-restricted diet. This resulted in an insufficient decrease in blood ammonia levels. Metabolic investigations were unrevealing apart from a slightly elevated urinary glutamine concentration. Liver tissue showed steatosis and mildly decreased activity of N-acetylglutamate synthase suggesting partial deficiency. Treatment with N-carbamyl glutamate did not affect serum ammonia levels. Colour Doppler sonography and MR angiography demonstrated a patent ductus venosus. After surgical ligation of the ductus venosus, serum ammonia levels returned to normal and mental and motor performance improved markedly.
Conclusion In late onset hyperammonaemia, partial N-acetylglutamate synthase deficiency and portocaval shunt should be ruled out.
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Received: 3 January 2000 / Accepted: 23 May 2000
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Broere, D., van Gemert, W., Kneepkens, C. et al. A 6-year-old boy with hyperammonaemia: partial N-acetylglutamate synthase deficiency or portosystemic encephalopathy?. Eur J Pediatr 159, 905–907 (2000). https://doi.org/10.1007/PL00008367
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DOI: https://doi.org/10.1007/PL00008367