Clues for minimal hepatic encephalopathy in children with noncirrhotic portal hypertension.

OBJECTIVE: In children with noncirrhotic extrahepatic portal vein obstruction (EHPVO), minimal hepatic encephalopathy (MHE) was reported in a few series, but neither is it routinely investigated nor does consensus about its diagnosis exist. In this prospective observational study we aimed at detecting the prevalence of MHE in children with EHPVO and providing a practical diagnostic protocol. METHODS: A consecutive sample of 13 noncirrhotic children (age range 4-18 years) with EHPVO underwent a screening for MHE based on level of fasting ammonia, quantified electroencephalogram (EEG) evaluation, and a wide battery of 26 psychometric tests exploring learning ability, abstract reasoning, phonemic and semantic fluency, selective attention, executive functions, short-term verbal and visual memory, long-term verbal memory, and visuopractic ability. RESULTS: Five children had at least 2 altered psychometric tests. Selective attention, executive function, and short-term visual memory were the domains more frequently altered, and 4 tests were enough to detect 80% of these children. Fasting ammonia plasma level was increased in 6 children. EEG mean dominant frequency adjusted for age was associated with serum ammonia concentration (ß = -0.44 ± 0.19, P < 0.05). As a whole, children with EHPVO showed trends for lower α (median 41% vs 49%) and higher θ power than controls (median 41% vs 49% and 29% vs 20%, respectively). CONCLUSIONS: MHE affects approximately 50% of children with EHPVO and, therefore, is worthwhile to be investigated. Three simple tools, serum ammonia, quantified EEG, and neuropsychological examination, focused on selective attention, executive function, and short-term visual memory can be used effectively in the evaluation of MHE in this setting.