Surgical indications for patients with hyperammonemia

The authors surgically treated seven of eight patients with congenital portosystemic shunt and hyperammonemia. This entity is uncommon in children.

The patients included five boys and three girls with a mean age of 8 years (range, 7 months to 24 years). Preoperative symptoms included hyperammonemia. Hepatic encephalopathy was evident in five patients. Diagnosis and assessment were made by ultrasound scan, magnetic resonance imaging (MRI), angiography, and 123 I-iodoamphetamine per-rectal portal scintigraphy. Surgical banding was done for five patients and transvenous coil embolization for two. One patient was not a surgical candidate because there were no intrahepatic portal veins.

In four of the five patients treated using surgical banding, and in both patients who underwent coil embolizations, hyperammonemia and clinical symptoms improved soon after surgery. However, in the remaining patient, hyperammonemia worsened after surgery, and reoperation was needed because of a severe portal hypertension, possibly caused by malconformation of hepatic veins.

For patients with congenital portosystemic shunt, early diagnosis and surgery are needed to prevent damage to central nerves caused by persistent hyperammonemia. Maldevelopment of the intrahepatic portal veins is a surgical option, if the patient has a normal liver architecture, but malconformation of hepatic veins or severe anomalies such as cardiac defects would rule out surgical intervention.