Oral sodium phenylbutyrate for hyperammonemia associated with congenital portosystemic shunt: a case report.

ABSTRACT

OBJECTIVES: The efficacy of sodium phenylbutyrate (SPB) for hyperammonemia associated with congenital portosystemic shunt (CPSS) remains unknown. We show the effectiveness of oral SPB. CASE PRESENTATION Our patient had CPSS with severe hypoplasia of extrahepatic portal veins. At 9 months of age, to assess the efficacy of oral SPB, we evaluated the 24 h fluctuations of venous ammonia levels. In the first two days without SPB, ammonia levels were above 80 µmol/L for half a day. On the third and fourth days, administration of oral SPB three times a day decreased ammonia to acceptable levels, except at midnight. On the fifth day, another oral SPB administration at 8 pm decreased ammonia at midnight. Low levels of branched-chain amino acids, as well as coagulation disturbances, were observed without apparent symptoms. At 12 months of age, he showed normal psychomotor development. CONCLUSIONS: Oral SPB may be effective for hyperammonemia associated with CPSS.